Solar panels

Abstract

A luminescent solar concentrator (LSC) includes first, second, and third waveguides and a photovoltaic cell. The first waveguide includes a first substrate and a first luminophore on the first substrate and / or embedded in the first substrate. The second waveguide includes a second substrate and a second luminophore on the second substrate and / or embedded in the second substrate. The third waveguide includes a third substrate and a third luminophore on the third substrate and / or embedded in the third substrate. The photovoltaic cell is coupled to the first, second, and third waveguides. The second waveguide is between the first and third waveguides. The LSC is configured to receive light in a direction defined from the first waveguide to the third waveguide.

Description

Attorney Docket No. 6550-000525-WO-POASOLAR PANELSCROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application claims the benefit of U.S. Provisional Application No.63 / 740,565, filed on December 31 , 2024. The entire disclosure of the above application is incorporated herein by reference.FIELD

[0002] The present disclosure relates to solar panels including luminescent solar concentrators (LSCs) and photovoltaics (PVs).BACKGROUND

[0003] Luminescent Solar Concentrators (LSCs) have gained attention as an approach to deploying solar harvesting systems with the potential for very low cost. However, the power conversion efficiency (PCE) of these systems has remained low and thus there has been limited market penetration.SUMMARY

[0004] The present devices and methods relate to systematic deconstruction of the solar spectrum to improve LSCs with high PLQYs in each spectral region. This is facilitated by decoupling multi-luminophores into multi-lightguide architectures and synthesizing novel small-molecule donor-acceptor-donor (DAD) derivatives with suitable PLQY in each spectral regime. The present devices and methods achieve several PCE records including for (1) a single-component LSC of 5.7% based on DAD1 and for a ternary-LSC of 7.7% with demonstrated important self-consistency checks. The present devices and methods demonstrate the potential for LSCs to achieve higher performances, paving the way for more applications for this low-cost and highly compelling technology.

[0005] At least one example embodiment relates to a luminescent solar concentrator (LSC) device.

[0006] In at least one example embodiment, the LSC includes a first waveguide, a second waveguide, a third waveguide, and a photovoltaic cell. The first waveguide includes a first substrate and a first luminophore. The first luminophore is on the firstAttorney Docket No. 6550-000525-WO-POAsubstrate, embedded in the first substrate, or both on the first substrate and embedded in the first substrate. The second waveguide includes a second substrate and a second luminophore. The second luminophore is on the second substrate, embedded in the second substrate, or both on the second substrate and embedded in the second substrate. The third waveguide includes a third substrate and a third luminophore. The third luminophore is on the third substrate, embedded in the third substrate, or both on the third substrate and embedded in the third substrate. The photovoltaic cell is coupled to the first waveguide, the second waveguide, and the third waveguide. The second waveguide is between the first waveguide and the third waveguide. The LSC device is configured to receive light in a direction defined from the first waveguide to the third waveguide.

[0007] In at least one example embodiment, the LSC device has a power conversion efficiency (PCE) of greater than or equal to 5%.

[0008] In at least one example embodiment, the PCE is greater than or equal to 7.5%.

[0009] In at least one example embodiment, the LSC device has an external quantum efficiency (EQE) of greater than or equal to about 60%.

[0010] In at least one example embodiment, the LSC device has a fill factor of greater than or equal to 0.7. The LSC has an open circuit voltage of greater than or equal to 1 V.

[0011] In at least one example embodiment, the photovoltaic cell is coupled to a first edge surface of the first waveguide, a second edge surface of the second waveguide, and a third edge surface of the third waveguide.

[0012] In at least one example embodiment, the first luminophore has a first photoluminescent quantum yield (PLQY). The second luminophore has a second PLQY less than the first PLQY. The third luminophore has a third PLQY less than the second PLQY.

[0013] In at least one example embodiment, the first PLQY ranges from 80% to 98%. The second PLQY ranges from 30% to 80%. The third PLQY ranges from 20% to 70%.

[0014] In at least one example embodiment, the first waveguide and the second waveguide define a first airgap therebetween. The second waveguide and the third waveguide define a second airgap therebetween.Attorney Docket No. 6550-000525-WO-POA

[0015] In at least one example embodiment, a first distance between the first waveguide and the second waveguide is less than or equal to 150 micrometers (pm). A second distance between the second waveguide and the third waveguide is less than or equal to 150 pm.

[0016] In at least one example embodiment, the first waveguide and the second waveguide define a first layer therebetween. The first layer has an index of refraction ranging from 1 to 1.35. The second waveguide and the third waveguide define a second layer therebetween. The second layer has an index of refraction ranging from 1 to 1.35.

[0017] In at least one example embodiment, a first thickness of the first layer ranges from 1 micrometer (pm) to 150 pm. A second thickness of the second layer ranges from 1 pm to 150 pm.

[0018] In at least one example embodiment, the first waveguide is in direct contact with the second waveguide. The second waveguide is in direct contact with the third waveguide.

[0019] In at least one example embodiment, the first luminophore has a first peak absorbance between 300 nanometers (nm) and 500 nm. The second luminophore has a second peak absorbance between 500 nm and 700 nm. The third luminophore has a third peak absorbance between 700 nm and 800 nm.

[0020] In at least one example embodiment, one of the first luminophore, the second luminophore, or the third luminophore includes a benzothiadiazole donor-acceptor-donor having the structure:, , , an alkyl.

[0021] In at least one example embodiment, one of the first luminophore, the second luminophore, and the third luminophore is a benzothiadiazole donor-acceptor-donor having the structure:Attorney Docket No. 6550-000525-WO-POA

[0022] In at least one example embodiment, one of the first luminophore, the second luminophore, and the third luminophore is a benzothiadiazole donor-acceptor-donor having the structure:10023] In at least one example embodiment, the first luminophore includes a benzothiadiazole donor-acceptor-donor having the structure:The third luminophore includes a BODIPY derivative having the structure:

[0024] In at least one example embodiment, the second luminophore includes a benzothiadiazole donor-acceptor-donor having the structure:Attorney Docket No. 6550-000525-WO-POA

[0025] In at least one example embodiment, the second luminophore includes CIS / ZnS quantum dots.

[0026] In at least one example embodiment, the LSC is visually opaque.

[0027] At least one example embodiment relates to a luminescent solar concentrator (LSC) device. The LSC includes a waveguide and a photovoltaic cell. The waveguide includes a first luminophore, a second luminophore, and a third luminophore. The photovoltaic cell is coupled to the waveguide. The LSC device is visually opaque. The LSC device has a power conversion efficiency (PCE) of greater than or equal to 7%.

[0028] In at least one example embodiment, the LSC device has a peak external quantum efficiency of greater than 60%.

[0029] In at least one example embodiment, the LSC device has a fill factor of greater than or equal to 0.7 and an open circuit voltage of greater than or equal to 1 V.

[0030] In at least one example embodiment, the LSC device has an optical quantum efficiency of greater than 50%.

[0031] In at least one example embodiment, the waveguide includes a first waveguide, a second waveguide, and a third waveguide. The first waveguide includes a first substrate and the first luminophore. The second waveguide includes a second substrate and the second luminophore. The third waveguide includes a third substrate and the third luminophore.

[0032] In at least one example embodiment, the waveguide includes a substrate, the first luminophore, the second luminophore, and the third luminophore. The first luminophore is embedded in the substrate, on a surface of the substrate, or both embedded in the substrate and on a surface of the substrate. The second luminophore is embedded in the substrate, on a surface of the substrate, or both embedded in the substrate and on a surface of the substrate. The third luminophore is embedded in the substrate, on a surface of the substrate, or both embedded in the substrate and on a surface of the substrate.

[0033] In at least one example embodiment, the waveguide further includes a fourth luminophore.

[0034] At least one example embodiment relates to a solar panel.

[0035] In at least one example embodiment, the solar panel comprises a benzothiadiazole donor-acceptor-donor having the structure:Attorney Docket No. 6550-000525-WO-POA, , , , an alkyl.

[0036] In at least one example embodiment, the benzothiadiazole donor-acceptor-donor includes:

[0037] In at least one example embodiment, the solar panel has a peak external quantum efficiency (EQE) of greater than 60%.

[0038] In at least one example embodiment, the solar panel has a fill factor of greater than or equal to 0.7 and an open circuit voltage of greater than or equal to 1 V.

[0039] At least one example embodiment relates to a solar panel.

[0040] In at least one example embodiment, the solar panel comprises a benzothiadiazole donor-acceptor-donor having the structure:

[0041] At least one example embodiment relates to a solar panel.

[0042] In at least one example embodiment, the solar panel comprising a benzothiadiazole donor-acceptor-donor having the structure:Attorney Docket No. 6550-000525-WO-POADRAWINGS

[0043] The drawings described herein are for illustrative purposes only of selected embodiments and not all possible implementations and are not intended to limit the scope of the present disclosure.

[0044] FIGS. 1A-1 B illustrate a luminescent solar concentrator (LSC) device according to at least one example embodiment. FIG. 1A is a perspective view. FIG. 1 B is a schematic sectional view.

[0045] FIG. 2 is a schematic perspective view of another LSC device according to at least one example embodiment.

[0046] FIG. 3 is a schematic perspective view of another LSC device according to at least one example embodiment.

[0047] FIG. 4 is a schematic perspective view of another LSC device according to at least one example embodiment.

[0048] FIGS. 5A-5B illustrate LSC devices having top-mounted PV cells. FIG. 5A is a schematic perspective view of an LSC according to at least one example embodiment. FIG. 5B is a schematic perspective view of another LSC according to at least one example embodiment.

[0049] FIG. 6 is a schematic perspective view of a photovoltaic (PV) device according to at least one example embodiment.

[0050] FIG. 7A is a schematic of a novel ternary multi-lightguide LSC architecture with full-spectrum (UV, VIS, and NIR) light harvesting according to at least one example embodiment. Each lightguide is separated by an air gap enabling total internal reflection and isolation of the emission from each luminophore.

[0051] FIG. 7B is a graph illustrating idealized absorption and emission characteristics for selectively harvesting the UV, VIS, and NIR regions.

[0052] FIGS. 7C-7E illustrate molecular structure and normalized absorption and emission profiles of three luminophores used in the multi-luminophore-multi-lightguide LSC of FIG. 7A. FIG. 7C relate to the benzothiadiazole donor-acceptor-donor DAD1 (UV-VIS1). FIG. 7D relates to bisbenzothiadiazole DAD2 (VIS2). FIG. 7E relates to BODIPYAttorney Docket No. 6550-000525-WO-POA(NIR). Absorption spectra are shown in solid lines and emission spectra are shown in dotted lines.

[0053] FIGS. 8A-8L relate to characterization of single components as a function of concentration. FIG. 8A illustrates the transmission spectrum for DAD1. FIG. 8B illustrates a J-V curve for DAD1. FIG. 8C illustrates EQE for DAD1. FIG. 8D illustrates POE for DAD1. FIG. 8E illustrates the transmission spectrum for DAD2. FIG. 8F illustrates a J-V curve for DAD2. FIG. 8G illustrates EQE for DAD2. FIG. 8H illustrates POE for DAD2. FIG. 8I illustrates the transmission spectrum for BODIPY. FIG. 8J illustrates a J-V curve for BODIPY. FIG. 8K illustrates EQE for BODIPY. FIG. 8L illustrates POE for BODIPY.

[0054] FIGS. 9A-9D related to champion ternary devices with black and reflective silver backgrounds according to at least one example embodiment. FIG. 9A is an absolute absorbance spectrum. FIG. 9B illustrates EQE spectra. FIG. 90 illustrates J-V curves with black and specular reflective silver backgrounds. FIG. 9D illustrates photon balance check for the ternary-LSC.

[0055] FIGS. 10A-10I relate to the synthetic scheme for synthesis of DAD1 according to at least one example embodiment. FIG. 10A illustrates acceptor synthesis (Compounds 1 and 2). FIG. 10B illustrates donor synthesis (Compounds 23, 4, and 5). FIG. 10C illustrates donor-acceptor Suzuki coupling. FIG. 10D illustrates synthesis of Compound 1 , 4,7-dibromobenzo[c][1 ,2,5]thiadiazole, according to at least one example embodiment. FIG. 10E illustrates synthesis of Compound 2, 4,7-bis(4,4,5,5-tetramethyl-1 ,3,2-dioxaborolan-2-yl)benzo[c][1 ,2,5]thiadiazole, according to at least one example embodiment. FIG. 10F illustrates synthesis of Compound 3, 2-bromo-9,9-dimethyl-7-nitro-9H-fluorene, according to at least one example embodiment. FIG. 10G illustrates synthesis of Compound 4: 7-bromo-9,9-dimethyl-9H-fluoren-2-amine according to at least one example embodiment. FIG. 10H illustrates synthesis of Compound 5, 7-bromo-N,N-diethyl-9,9-dimethyl-9H-fluoren-2-amine, according to at least one example embodiment. FIG. 101 illustrates synthesis of DAD1 according to at least one example embodiment.

[0056] FIGS. 11A-11 I relate to the synthetic scheme for synthesis of DAD2 according to at least one example embodiment. FIG. 11 A illustrates acceptor synthesis (Compounds 6, 7, and 8). FIG. 11 B illustrates donor synthesis (Compounds 9 and 10). FIG. 11C illustrates donor-acceptor Suzuki coupling. FIG. 11 D illustrates synthesis of Compound 6, 4,7-dibromo-5,6-dinitrobenzo[c][1 ,2,5]thiadiazole, according to at least oneAttorney Docket No. 6550-000525-WO-POAexample embodiment. FIG. 11 E illustrates synthesis of Compound 7, 4,7-dibromobenzo[c][1 ,2,5]thiadiazole-5,6-diamine, according to at least one example embodiment. FIG. 11 F illustrates synthesis of Compound 8, 4,8-dibromo-1 H,5H-benzo[1 ,2-c:4,5-c']bis([1 ,2,5]thiadiazole), according to at least one example embodiment. FIG. 11 G illustrates synthesis of Compound 9, 2-bromo-9-hexyl-9H-carbazole, according to at least one example embodiment. FIG. 11 H illustrates synthesis of Compound 10, 9-hexyl-2-(4,4,5,5-tetramethyl-1 ,3,2-dioxaborolan-2-yl)-9H-carbazole, according to at least one example embodiment. FIG. 111 illustrates synthesis of DAD2 according to at least one example embodiment.

[0057] FIG. 12 illustrates DAD1 absorption and emission spectra in different solvents. Absorption spectra are shown in solid lines and emission spectra are shown in dotted lines.

[0058] FIG. 13 illustrates DAD1 absorption and emission spectra in different polymer matrices. Absorption spectra are shown in solid lines and emission spectra are shown in dotted lines.

[0059] FIG. 14 illustrates DAD2 absorption and emission spectra in different solvents. Absorption spectra are shown in solid lines and emission spectra are shown in dotted lines.

[0060] FIGS. 15A-15C related to optical simulation for the single component-LSCs scalability: Peak EQE of different luminophore concentration as a function of the LSC plate. FIG. 15A is for DAD1. FIG. 15B is for DAD2. FIG. 15C is for BODIPY.

[0061] FIGS. 16A-16D illustrate absorption and emission of the single luminophore-LSC in the optimal conditions with the calculated overlap integral (Ol). FIG.16A is for DAD1. FIG. 16B is for DAD2. FIG. 16C is for BODIPY. FIG. 16D is for LR305 as a reference luminophore. Absorption spectra are shown in solid lines and emission spectra are shown in dotted lines.

[0062] FIG. 17 is a graph illustrating luminophore emissions in host material of DAD1 , DAD2, and BODIPY. The EQE of the edge-mounted GaAs is presented as the dotted line.

[0063] FIG. 18 illustrates J-V curves of a blank borosilicate glass void of any emitter with a black and a reflective silver background with a GaAs edge mounted PV on one side.

[0064] FIGS. 19A-19C relate to importance of the optical isolation as realized when no airgap is introduced between the three lightguides. FIG. 19A is a SchematicAttorney Docket No. 6550-000525-WO-POArepresentation of the no-airgap architecture of the ternary LSC. FIG. 19B illustrates a J-V curve of the no-airgap architecture of the ternary LSC. FIG. 19C illustrates EQE of the no-airgap architecture of the ternary LSC.

[0065] FIGS. 20A-20C relate to simulated EQE for the ternary-LSC. FIG. 20A is BODIPY having a PLQY of 80%. FIG. 20B is DAD2 having a PLQY of 80%. FIG. 20C is DAD2 and BODIPY having 80% PLQY.

[0066] FIG. 21 relates to a photostability example of single-luminophore LSCs. Normalized peak values of absorption spectra A(A) for DAD1 , B) DAD2, and BODIPY LSCs as a function of time under constant illumination.

[0067] FIGS. 22A is a schematic of the QD-ternary multi-lightguide LSC architecture with full-spectra (UV, VIS, and NIR) light harvesting in accordance with at least the embodiment of Example 2. FIG. 22B shows absorption (solid line) and emission (dotted line) spectra of CIS / ZnS QDs according to at least the embodiment of Example 2.

[0068] FIG. 23A-23C relate to CIS / ZnS QDs characterization as function of concentration. FIG. 23A illustrates transmission spectra. FIG. 23B illustrates EQE. FIG.23C illustrates J-V with black background.

[0069] FIGS. 24A-24D relate to a champion QD-ternary device with black and reflective silver backgrounds. FIG. 24A illustrates an absolute absorbance spectrum. FIG. 24B illustrates EQE spectra. FIG. 24C illustrates J-V curves with black and reflective backgrounds. FIG. 24D illustrates photon balance check for the ternary-LSC.

[0070] FIGS. 25A-25D illustrate a donor-acceptor-donor component chart. FIG.25A shows a DAD molecule. FIG. 25B illustrates donors: Benzo-selenadiazolo-thiadiazole (BSDTD), Benzo-bis-thiadiazole (BBTD), Benzo-selenadiazole (BSD), Benzo-thiadiazole (BTD), Benzo-thiadiazolo-quinoxaline (BTDQ). BTD has a few functional groups — hydrogen, fluoride (F), and nitro (N) — which are added to the end of BTD in the name (when not hydrogen), and BTDQ can be functionalized with methyl (m), fluoride (F), trifluoromethyl (TFM), a set of fused phenyl rings (f), and 4-fluorophenyl (FPh) groups that are similarly added to the name. FIG. 25C illustrates acceptors: bromide (Br), triphenyl-amine (TPA), carbazole (Cbz), fluorene (Fl). There are some DADs where fluorene is modified such that the dimethyl is replaced by dioctyl (Flo). FIG.25D illustrates different functional groups including hydrogen (H), dimethyl amine (dma), diethyl amine (dea), azetidine (az), pyrrolidine (pyr), and piperidine (pip) that may functionalize Cbz, Fl, and Flo.Attorney Docket No. 6550-000525-WO-POA

[0071] FIG 26A is a donor-acceptor-donor (DAD) structure in which a BTD acceptor is bonded to two Fl-dea donors. FIG. 26B is a graph illustrating absorption (solid lines) and emission (dotted lines) spectra of the DAD dye in different solvents. FIG. 26C is a graph illustrating absorption (solid lines) and emission (dotted lines) spectra of the DAD dye in different polymer hosts. As shown in the FIGS., while exhibiting minor changes in absorption, some more dramatic shifts in PL peak position are observed.

[0072] FIGS. 27A-27C relate performance of LSC devices including BTD-FI-dea cast into PLMA. FIG. 27A is a graph illustrating transmittance spectra of the DAD as a function of weight percentage. FIG. 27B is a graph illustrating characteristic J-V for different weight percentages. FIG. 27E is a graph illustrating EQE curves different weight percentages.

[0073] FIGS. 28A-28B relate to scalability and lifetime of DAD LSC according to at least one example embodiment. FIG. 28A is a graph illustrating EQE. Using the overlap integral of each concentration, the peak device EQE was calculated as a function of LSC size. FIG. 28B is a graph illustrating absorbance measured over time under constant 1-sun illumination for the DAD LSC. A greater than 40% reduction in blueshift in peak absorption is observed after 264 hours.

[0074] FIG. 29 relates to the effect of acceptor conjugation on DAD absorption and emission. The absorption (solid line) and normalized emission (dotted line) of the standard BTD-based DAD redshifts -200-300 nm when expanded to BTDQFPh or BBTD. The emission of BBTD-FI-pyr is noisier, which is consistent with the lower measured PLQY compared with the BTD or BTDQFPh acceptors.

[0075] FIG. 30 is a graph illustrating absorption and emission Spectra of D-t-A-t-D vs D-A-D. The absorption (solid line) and emission (dotted line) spectra of thiophenebridged DAD and standard DAD molecules showcase a significant shift in absorption with notably smaller shifts in emission.

[0076] FIGS. 31A-31 F relate to NIR DAD LSC performance. FIG. 31 A is a graph illustrating transmittance of an LSC including an edge-mounted GaAs solar cell. FIG. 31 B is a graph illustrating EQE of the LSC including the edge-mounted GaAs solar cell. FIG.31 C is a graph illustrating J-V characteristic of the LSC including the edge-mounted GaAs solar cell. FIG. 31 D is a graph illustrating transmittance of an LSC including an edgemounted Si solar cell. FIG. 31 E is a graph illustrating EQE of the LSC including the edgemounted Si solar cell. FIG. 31 F is a graph illustrating J-V characteristic of the LSC including the edge-mounted Si solar cell. The LSCs are distinguished by either GaAsAttorney Docket No. 6550-000525-WO-POA(FIGS. 31 A-31 C) or Si- (FIGS. 31 D-31 F) edge-mounted PVs dependent on the emission of DAD molecule. The low PLQY of these NIR DAD are on display creating large disparities in the absorption to EQE transition, with a sharper reduction when compared to the BTD-FI-dea LSCs presented earlier.DETAILED DESCRIPTION

[0077] Example embodiments are provided so that this disclosure will be thorough, and will fully convey the scope to those who are skilled in the art. Numerous specific details are set forth such as examples of specific compositions, components, devices, and methods, to provide a thorough understanding of embodiments of the present disclosure. It will be apparent to those skilled in the art that specific details need not be employed, that example embodiments may be embodied in many different forms and that neither should be construed to limit the scope of the disclosure. In some example embodiments, well-known processes, well-known device structures, and well-known technologies are not described in detail.

[0078] The terminology used herein is for the purpose of describing particular example embodiments only and is not intended to be limiting. As used herein, the singular forms “a,” “an,” and “the” may be intended to include the plural forms as well, unless the context clearly indicates otherwise. The terms “comprises,” “comprising,” “including,” and “having,” are inclusive and therefore specify the presence of stated features, elements, compositions, steps, integers, operations, and / or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and / or groups thereof. Although the open-ended term “comprising,” is to be understood as a non-restrictive term used to describe and claim various embodiments set forth herein, in certain aspects, the term may alternatively be understood to instead be a more limiting and restrictive term, such as “consisting of” or “consisting essentially of.” Thus, for any given embodiment reciting compositions, materials, components, elements, features, integers, operations, and / or process steps, the present disclosure also specifically includes embodiments consisting of, or consisting essentially of, such recited compositions, materials, components, elements, features, integers, operations, and / or process steps. In the case of “consisting of,” the alternative embodiment excludes any additional compositions, materials, components, elements, features, integers, operations, and / or process steps, while in the case of “consisting essentially of,” any additional compositions, materials, components, elements, features, integers, operations, and / or process steps that materially affect the basic and novel characteristicsAttorney Docket No. 6550-000525-WO-POAare excluded from such an embodiment, but any compositions, materials, components, elements, features, integers, operations, and / or process steps that do not materially affect the basic and novel characteristics can be included in the embodiment.

[0079] Any method steps, processes, and operations described herein are not to be construed as necessarily requiring their performance in the particular order discussed or illustrated, unless specifically identified as an order of performance. It is also to be understood that additional or alternative steps may be employed, unless otherwise indicated.

[0080] When a component, element, or layer is referred to as being “on,” “engaged to,” “connected to,” or “coupled to” another element or layer, it may be directly on, engaged, connected or coupled to the other component, element, or layer, or intervening elements or layers may be present. In contrast, when an element is referred to as being “directly on,” “directly engaged to,” “directly connected to,” or “directly coupled to” another element or layer, there may be no intervening elements or layers present. Other words used to describe the relationship between elements should be interpreted in a like fashion (e.g., “between” versus “directly between,” “adjacent” versus “directly adjacent,” etc.). As used herein, the term “and / or” includes any and all combinations of one or more of the associated listed items.

[0081] Although the terms first, second, third, etc. may be used herein to describe various steps, elements, components, regions, layers and / or sections, these steps, elements, components, regions, layers and / or sections should not be limited by these terms, unless otherwise indicated. These terms may be only used to distinguish one step, element, component, region, layer or section from another step, element, component, region, layer or section. Terms such as “first,” “second,” and other numerical terms when used herein do not imply a sequence or order unless clearly indicated by the context. Thus, a first step, element, component, region, layer or section discussed below could be termed a second step, element, component, region, layer or section without departing from the teachings of the example embodiments.

[0082] Spatially or temporally relative terms, such as “before,” “after,” “inner,” “outer,” “beneath,” “below,” “lower,” “above,” “upper,” and the like, may be used herein for ease of description to describe one element or feature's relationship to another element(s) or feature(s) as illustrated in the figures. Spatially or temporally relative terms may be intended to encompass different orientations of the device or system in use or operation in addition to the orientation depicted in the figures.Attorney Docket No. 6550-000525-WO-POA

[0083] Throughout this disclosure, the numerical values represent approximate measures or limits to ranges to encompass minor deviations from the given values and embodiments having about the value mentioned as well as those having exactly the value mentioned. Other than in the working examples provided at the end of the detailed description, all numerical values of parameters (e.g., of quantities or conditions) in this specification, including the appended claims, are to be understood as being modified in all instances by the term “about” whether or not “about” actually appears before the numerical value. “About” indicates that the stated numerical value allows some slight imprecision (with some approach to exactness in the value; approximately or reasonably close to the value; nearly). If the imprecision provided by “about” is not otherwise understood in the art with this ordinary meaning, then “about” as used herein indicates at least variations that may arise from ordinary methods of measuring and using such parameters. For example, “about” may comprise a variation of less than or equal to 5%, optionally less than or equal to 4%, optionally less than or equal to 3%, optionally less than or equal to 2%, optionally less than or equal to 1%, optionally less than or equal to 0.5%, and in certain aspects, optionally less than or equal to 0.1%.

[0084] In addition, disclosure of ranges includes disclosure of all values and further divided ranges within the entire range, including endpoints and sub-ranges given for the ranges.

[0085] Example embodiments will now be described more fully with reference to the accompanying drawings.

[0086] At least one example embodiment relates to a solar panel. The solar panel may be a luminescent solar concentrator (LSC) or a photovoltaic (PV). Unless otherwise specified, “solar panel” as used herein refers to an LSC and / or a PV. The solar panel may include one or more photoactive materials. In at least one example embodiment, the photoactive material includes one or more benzothiadiazole donor-acceptor-donor (DAD) molecules, as will be discussed in greater detail below.

[0087] The solar panel may include greater than or equal to 2 photoactive materials (e.g., greater than or equal to 3, greater than or equal to 4, greater than or equal to 4, greater than or equal to 5). One or more photoactive materials can be combined in a waveguide, or photoactive materials may be associated with different respective waveguides. The solar panel may include greater than or equal to 2 waveguides (e.g., greater than or equal to 3, greater than or equal to 4, greater than or equal to 4, greater than or equal to 5). In at least one example embodiment, the photoactive material is aAttorney Docket No. 6550-000525-WO-POAternary photoactive material including three different photoactive materials. In one example, the solar panel is an LSC having three waveguides, with each waveguide including different characteristics, such as a different photoactive material (e.g., luminophore).

[0088] Power conversion efficiency (PCE) is derived from current-density (J) -voltage (V) curves, and specifically the electrical power generated divided by the incident solar power. In at least one example embodiment, the solar panel has a PCE of greater than or equal to about 5% (e.g., greater than or equal to about 5.25%, greater than or equal to about 5.5%, greater than or equal to about 5.75%, greater than or equal to about 6%, greater than or equal to about 6.25%, greater than or equal to about 6.5%, greater than or equal to about 6.75%, greater than or equal to about 7%, greater than or equal to about 7.25%, greater than or equal to about 7.5%, greater than or equal to about 7.75%, greater than or equal to about 8%, greater than or equal to about 8.25%, greater than or equal to about 8.5%, greater than or equal to about 8.75%, greater than or equal to about 9%, greater than or equal to about 9.25%, greater than or equal to about 9.5%, or greater than or equal to about 9.75%). In at least one example embodiment, the PCE is less than or equal to about 10%.

[0089] As used herein, external quantum efficiency (EQE) is the efficiency of converting photons of a particular wavelength to electrons. In at least one example embodiment, the solar panel may have a peak EQE (also referred to as the “device peak EQE”) of greater than or equal to about 50% (e.g., greater than or equal to about 51%, greater than or equal to about 52%, greater than or equal to about 53%, greater than or equal to about 54%, greater than or equal to about 55%, greater than or equal to about 56%, greater than or equal to about 57%, greater than or equal to about 58%, greater than or equal to about 59%, greater than or equal to about 60%, greater than or equal to about 61%, greater than or equal to about 62%, greater than or equal to about 63%, greater than or equal to about 64%, or greater than or equal to about 65%).

[0090] As used herein, the optical quantum efficiency (also referred to as the “internal photon efficiency”) is the ratio of the number of emitted photons reaching the waveguide edge to the number of photons absorbed of a certain wavelength by the luminescent material. In at least one example embodiment, the solar panel has an optical quantum efficiency of greater than or equal to about 50% (e.g., greater than or equal to about 55%, greater than or equal to about 60%, greater than or equal to about 65%, greater than or equal to about 70%, or greater than or equal to about 75%). The opticalAttorney Docket No. 6550-000525-WO-POAquantum efficiency may be less than or equal to about 80% (e.g., less than or equal to about 75%, less than or equal to about 70%, less than or equal to about 65%, less than or equal to about 60%, or less than or equal to about 55%).

[0091] As used herein, the fill factor (FF) is the ratio of the maximum power point (MPP) voltage times the MPP short circuit current density divided by the open circuit voltage and the short circuit current density. In at least one example embodiment, the solar panel has a FF of greater than or equal to about 0.55 (e.g., greater than or equal to about 0.6, greater than or equal to about 0.65, greater than or equal to about 0.7, greater than or equal to about 0.75). The FF may be less than or equal to about 0.8 (e.g., less than or equal to about 0.75, less than or equal to about 0.7, less than or equal to about 0.65, less than or equal to about 0.6, or less than or equal to about 0.55).

[0092] In at least one example embodiment, the solar panel has an open circuit voltage (Voc) of greater than or equal to about 0.5 V (e.g., greater than or equal to about 0.55 V, greater than or equal to about 0.6 V, greater than or equal to about 0.65 V, greater than or equal to about 0.7 V, greater than or equal to about 0.75 V, greater than or equal to about 0.8 V, greater than or equal to about 0.85 V, greater than or equal to about 0.9 V, greater than or equal to about 0.95 V, or greater than or equal to about 1 V).

[0093] As used herein, “substantially absorbent” means that the light absorbing material (e.g., the solar panel) absorbs greater than or equal to about 50% of light of a particular wavelength (e.g., greater than or equal to about 55%, greater than or equal to about 60%, greater than or equal to about 65%, greater than or equal to about 70%, greater than or equal to about 75%, greater than or equal to about 80%, or greater than or equal to about 85%). In at least one example embodiment, the solar panel is substantially absorbent to all light at wavelengths ranging from about 300 nm to about 750 nm. In at least one example embodiment, the solar panel is visually opaque. In at least one example embodiment, the solar panel has an average visible transmittance (AVT) of less than 20%, less than 15%, less than 10%, less than 5%, less than 2%, less than 1 %.

[0094] The solar panel includes a photoactive material. In at least one example embodiment, the photoactive material includes one or more benzothiadiazole donor-acceptor-donors (DAD). In at least one example embodiment, the benzothiadiazole DAD includesAttorney Docket No. 6550-000525-WO-POAwhere R includes one or more ofY includes C(A2), N-A, or a combination thereof, and A is an alkyl. For example, the benzothiadiazole DAD may include LIV-VIS DAD1 having the structure:In at least one other example embodiment, the benzothiadiazole DAD may include VIS2 DAD2 having the structure:In at least one other example embodiment, the benzothiadiazole DAD may include a DAD having the following structure:Attorney Docket No. 6550-000525-WO-POAAdditionally or alternatively, the photoactive material may include one or more BODIPYs or BODIPY derivatives. For example, the photoactive material may include an NIR BODIPY derivative having the following structure:Additionally or alternatively, the photoactive material may include quantum dots. For example, the photoactive material may include copper indium disulfide (CIS) or copper indium diselenide capped with a ZnS shell (e.g., CIS / ZnS) quantum dots. The CIS / ZnS may have a peak emission at greater than or equal to about 600 nm (e.g., greater than or equal to about 630 nm, greater than or equal to about 650 nm, greater than or equal to about 675 nm, greater than or equal to about 700 nm, greater than or equal to about 725 nm, greater than or equal to about 750 nm, greater than or equal to about 775 nm, greater than or equal to about 800 nm, greater than or equal to about 825 nm, greater than or equal to about 850 nm, greater than or equal to about 875 nm, or greater than or equal to about 900 nm). The CIS / ZnS may have a peak emission at less than 100 nm.

[0095] The solar panel may include multiple photoactive materials. The photoactive material(s) may be luminophores. In at least one example embodiment, the solar panel includes a ternary photoactive material including a first photoactive material, a second photoactive material, and a third photoactive material. Each of the photoactive materials may have different characteristics, as will be described in greater detail below.Attorney Docket No. 6550-000525-WO-POA

[0096] In at least one example embodiment, the first, second, and third photoactive materials are first, second and third luminophores. Each of the luminophores may have a different photoluminescent quantum yield (PLQY). In at least one example embodiment, the first luminophore has a first PLQY of greater than or equal to about 80% (e.g., greater than or equal to about 82%, greater than or equal to about 84%, greater than or equal to about 85%, greater than or equal to about 86%, greater than or equal to about 88%, greater than or equal to about 90%, greater than or equal to about 92%, greater than or equal to about 94%, greater than or equal to about 95%, or greater than or equal to about 96%). The first PLQY may be less than or equal to about 98% (e.g., less than or equal to about 96%, less than or equal to about 95%, less than or equal to about 94%, less than or equal to about 92%, less than or equal to about 90%, less than or equal to about 88%, less than or equal to about 86%, less than or equal to about 85%, less than or equal to about 84%, or less than or equal to about 82%).

[0097] In at least one example embodiment, the second luminophore has a second PLQY of greater than or equal to about 30% (e.g., greater than or equal to about 35%, greater than or equal to about 40%, greater than or equal to about 45%, greater than or equal to about 50%, greater than or equal to about 55%, greater than or equal to about 60%, greater than or equal to about 65%, greater than or equal to about 70%, or greater than or equal to about 75%). The second PLQY may be less than or equal to about 80% (e.g., less than or equal to about 75%, less than or equal to about 70%, less than or equal to about 65%, less than or equal to about 60%, less than or equal to about 55%, less than or equal to about 50%, less than or equal to about 45%, less than or equal to about 40%, or less than or equal to about 35%). In at least one example embodiment, the second PLQY is less than the first PLQY.

[0098] In at least one example embodiment, the third luminophore has a third PLQY of greater than or equal to about 20% (e.g., greater than or equal to about 25%, greater than or equal to about 30%, greater than or equal to about 35%, greater than or equal to about 40%, greater than or equal to about 45%, greater than or equal to about 50%, greater than or equal to about 55%, greater than or equal to about 60%, or greater than or equal to about 65%). The third PLQY may be less than or equal to about 70% (e.g., less than or equal to about 65%, less than or equal to about 60%, less than or equal to about 55%, less than or equal to about 50%, less than or equal to about 45%, less than or equal to about 40%, less than or equal to about 35%, less than or equal to aboutAttorney Docket No. 6550-000525-WO-POA30%, or less than or equal to about 25%). In at least one example embodiment, the third PLQY is less than the first PLQY and / or the second PLQY.

[0099] The first, second, and third photoactive materials each have a different absorption spectrum. Accordingly, the absorption across a wide range of wavelengths may be larger than in a single-photoactive material system. The first, second, and third photoactive materials may have different primary absorption peaks (also referred to as “largest peak absorptions”). When the photoactive materials are used in an LSC, the absorption peaks of the first, second, and third photoactive materials may each be less than a bandgap of a PV cell (e.g., the PV cell 108 of FIGS. 1A-1 B, the PV cell 208 of FIG. 2, the PV cell 308 of FIG. 3, the PV cell 408 of FIG. 4, the PV cells 508 of FIG. 5A, and / or the PV cells 558 of FIG. 5B).

[0100] In at least one example embodiment, the first photoactive material has a first primary absorption peak at a wavelength of greater than or equal to about 300 nm (e.g., greater than or equal to about 325 nm, greater than or equal to about 350 nm, greater than or equal to about 375 nm, greater than or equal to about 400 nm, greater than or equal to about 425 nm, greater than or equal to about 450 nm, or greater than or equal to about 475 nm). The first primary absorption peak may be less than or equal to about 500 nm (e.g., less than or equal to about 475 nm, less than or equal to about 450 nm, less than or equal to about 425 nm, less than or equal to about 400 nm, less than or equal to about 375 nm, less than or equal to about 350 nm, or less than or equal to about 325 nm). The first photoactive material may have additional absorption peaks (e.g., a first secondary absorption peak) below 400 nm.

[0101] In at least one example embodiment, the second photoactive material has a second primary absorption peak at a wavelength of greater than or equal to about 500 nm (e.g., greater than or equal to about 525 nm, greater than or equal to about 550 nm, greater than or equal to about 575 nm, greater than or equal to about 600 nm, greater than or equal to about 625 nm, greater than or equal to about 650 nm, or greater than or equal to about 675 nm). The second primary absorption peak may be less than or equal to about 700 nm (e.g., less than or equal to about 675 nm, less than or equal to about 650 nm, less than or equal to about 625 nm, less than or equal to about 600 nm, less than or equal to about 575 nm, less than or equal to about 550 nm, or less than or equal to about 525 nm). In at least one example embodiment, the second primary absorption peak may be at a shorter wavelength than the first primary absorption peak. The secondAttorney Docket No. 6550-000525-WO-POAphotoactive material may have additional absorption peaks (e.g., a second secondary absorption peak) below 450 nm.

[0102] In at least one example embodiment, the third photoactive material has a third primary absorption peak at a wavelength of greater than or equal to about 650 nm (e.g., greater than or equal to about 675 nm, greater than or equal to about 700 nm, greater than or equal to about 725 nm, greater than or equal to about 750 nm, greater than or equal to about 775 nm, greater than or equal to about 800 nm, greater than or equal to about 825 nm, greater than or equal to about 850 nm, greater than or equal to about 872 nm, greater than or equal to about 900 nm, greater than or equal to about 925 nm, greater than or equal to about 950 nm, or greater than or equal to about 975 nm). The third primary absorption peak may be less than or equal to about 1000 nm (e.g., less than or equal to about 975 nm, less than or equal to about 950 nm, less than or equal to about 925 nm, less than or equal to about 900 nm, less than or equal to about 875 nm, less than or equal to about 850 nm, less than or equal to about 825 nm, less than or equal to about 800 nm, less than or equal to about 775 nm, less than or equal to about 750 nm, less than or equal to about 725 nm, less than or equal to about 700 nm, or less than or equal to about 675 nm). In at least one example embodiment, the third primary absorption peak may be at a shorter wavelength than the first primary absorption peak and / or the second primary absorption peak.

[0103] In at least one example embodiment, the solar panel having multiple luminophores (e.g., first, second, and third luminophores) has full spectrum absorption in the 300-750 nm range. In at least one example embodiment, the solar panel may have an absorption of greater than or equal to about 30% at all wavelengths in the 300-750 nm range (e.g., greater than or equal to about 35%, greater than or equal to about 40%, greater than or equal to about 45%, greater than or equal to about 50%, greater than or equal to about 55%, greater than or equal to about 60%, greater than or equal to about 65%, greater than or equal to about 70%, greater than or equal to about 75%, or greater than or equal to about 80%).

[0104] In at least one example embodiment, each of the first, second, and third photoactive materials has a different emission spectrum. In at least one example embodiment, the first photoactive material has a first primary emission peak of greater than or equal to about 500 nm (e.g., greater than or equal to about 525 nm, greater than or equal to about 550 nm, greater than or equal to about 575 nm, greater than or equal to about 600 nm, greater than or equal to about 625 nm, greater than or equal to aboutAttorney Docket No. 6550-000525-WO-POA650 nm, greater than or equal to about 675 nm, greater than or equal to about 700 nm, or greater than or equal to about 725 nm). The first primary emission peak may be less than or equal to about 750 nm (e.g., less than or equal to about 725 nm, less than or equal to about 700 nm, less than or equal to about 675 nm, less than or equal to about 650 nm, less than or equal to about 625 nm, less than or equal to about 600 nm, less than or equal to about 575 nm, less than or equal to about 550 nm, or less than or equal to about 525 nm).

[0105] In at least one example embodiment, the second photoactive material has a second primary emission peak of greater than or equal to about 600 nm (e.g., greater than or equal to about 625 nm, greater than or equal to about 650 nm, greater than or equal to about 675 nm, greater than or equal to about 700 nm, greater than or equal to about 725 nm, greater than or equal to about 750 nm, greater than or equal to about 775 nm, greater than or equal to about 800 nm, or greater than or equal to about 825 nm). The second primary emission peak may be less than or equal to about 850 nm (e.g., less than or equal to about 825 nm, less than or equal to about 800 nm, less than or equal to about 775 nm, less than or equal to about 750 nm, less than or equal to about 725 nm, less than or equal to about 700 nm, less than or equal to about 675 nm, less than or equal to about 650 nm, or less than or equal to about 625 nm). In at least one example embodiment, the second primary emission peak is at a longer wavelength than the first primary emission peak.

[0106] In at least one example embodiment, the third photoactive material has a third primary emission peak of greater than or equal to about 700 nm (e.g., greater than or equal to about 725 nm, greater than or equal to about 750 nm, greater than or equal to about 775 nm, greater than or equal to about 800 nm, greater than or equal to about 825 nm, greater than or equal to about 850 nm, or greater than or equal to about 875 nm). The third primary emission peak may be less than or equal to about 900 nm (e.g., less than or equal to about 875 nm, less than or equal to about 850 nm, less than or equal to about 825 nm, less than or equal to about 800 nm, less than or equal to about 775 nm, less than or equal to about 750 nm, or less than or equal to about 725 nm). In at least one example embodiment, the third primary emission peak is at a longer wavelength than the first primary emission peak and / or the second primary emission peak.

[0107] As used herein, “substantially transparent” means that the photoactive material transmits greater than or equal to about 50% of light of a particular wavelengthAttorney Docket No. 6550-000525-WO-POA(e.g., greater than or equal to about 60%, greater than or equal to about 70%, greater than or equal to about 80%, or greater than or equal to about 90% of the light having the particular wavelength). In at least one example embodiment, the first photoactive material is substantially transparent to light having a wavelength of greater than or equal to about 600 nm (e.g., greater than or equal to about 625 nm, greater than or equal to about 650 nm, greater than or equal to about 675 nm, greater than or equal to about 700 nm, greater than or equal to about 725 nm, greater than or equal to about 750 nm, or greater than or equal to about 775 nm). The first photoactive material may be less than or equal to about 800 nm (e.g., less than or equal to about 775 nm, less than or equal to about 750 nm, less than or equal to about 725 nm, less than or equal to about 700 nm, less than or equal to about 675 nm, less than or equal to about 650 nm, or less than or equal to about 625 nm).

[0108] In at least one example embodiment, the second photoactive material is substantially transparent to light having a wavelength of greater than or equal to about 700 nm (e.g., greater than or equal to about 725 nm, greater than or equal to about 750 nm, greater than or equal to about 775 nm, greater than or equal to about 800 nm, greater than or equal to about 825 nm, greater than or equal to about 850 nm, or greater than or equal to about 875 nm). The second photoactive material may be less than or equal to about 900 nm (e.g., less than or equal to about 875 nm, less than or equal to about 850 nm, less than or equal to about 825 nm, less than or equal to about 800 nm, less than or equal to about 775 nm, less than or equal to about 750 nm, or less than or equal to about 725 nm).

[0109] In at least one example embodiment, the third photoactive material is substantially transparent to light having a wavelength of greater than or equal to about 800 nm (e.g., greater than or equal to about 825 nm, greater than or equal to about 850 nm, greater than or equal to about 875 nm, greater than or equal to about 900 nm, greater than or equal to about 925 nm, greater than or equal to about 950 nm, or greater than or equal to about 975 nm, or greater than or equal to about 1000 nm). The third photoactive material may be less than or equal to about 1025 nm (e.g., less than or equal to about 1000 nm, less than or equal to about 975 nm, less than or equal to about 950 nm, less than or equal to about 925 nm, less than or equal to about 900 nm, less than or equal to about 875 nm, less than or equal to about 850 nm, or less than or equal to about 825 nm).Attorney Docket No. 6550-000525-WO-POA

[0110] The first photoactive material has first EQE that is a contribution of the first photoactive material to the EQE of the full solar panel. In at least one example embodiment, the first EQE has a first peak EQE that is greater than or equal to about 50% (e.g., greater than or equal to about 55%, greater than or equal to about 58%, greater than or equal to about 60%, or greater than or equal to about 62%). The first peak EQE is less than or equal to about 65% (e.g., less than or equal to about 62%, less than or equal to about 60%, less than or equal to about 58%, or less than or equal to about 55%).

[0111] The second photoactive material has second EQE that is a contribution of the second photoactive material to the EQE of the full solar panel. In at least one example embodiment, the second EQE has a second peak EQE that is greater than or equal to about 5% (e.g., greater than or equal to about 10%, greater than or equal to about 15%, greater than or equal to about 20%, greater than or equal to about 25%, greater than or equal to about 30%, or greater than or equal to about 35%). The second peak EQE is less than or equal to about 40% (e.g., less than or equal to about 35%, less than or equal to about 30%, less than or equal to about 25%, less than or equal to about 20%, less than or equal to about 15%, or less than or equal to about 10%).

[0112] The third photoactive material has third EQE that is a contribution of the third photoactive material to the EQE of the full solar panel. In at least one example embodiment, the third EQE has a third peak EQE that is greater than or equal to about 4% (e.g., greater than or equal to about 6%, greater than or equal to about 8%, greater than or equal to about 10%, greater than or equal to about 12%, or greater than or equal to about 15%). The third peak EQE is less than or equal to about 20% (e.g., less than or equal to about 15%, less than or equal to about 12%, less than or equal to about 10%, less than or equal to about 8%, or less than or equal to about 6%).

[0113] In at least one example embodiment, the first photoactive material has a first overlap integral (QI) of less than or equal to about 30 (e.g., less than or equal to about 25, less than or equal to about 20, less than or equal to about 15, less than or equal to about 10, or less than or equal to about 5). In at least one example embodiment, the second photoactive material has a second QI of less than or equal to about 20 (e.g., less than or equal to about 15, less than or equal to about 13, less than or equal to about 10, less than or equal to about 8, less than or equal to about 5, or less than or equal to about 3). In at least one example embodiment, the third photoactive material has a third QI of less than or equal to about 60 (e.g., less than or equal to about 55, less than orAttorney Docket No. 6550-000525-WO-POAequal to about 50, less than or equal to about 45, less than or equal to about 40, less than or equal to about 35, less than or equal to about 30, less than or equal to about 25, less than or equal to about 20, or less than or equal to about 15).

[0114] In at least one example embodiment, the first photoactive material has a first short-circuit current density (Jsc) of greater than or equal to about 5 mA / cm2(e.g., greater than or equal to about 5.5 mA / cm2, greater than or equal to about 6 mA / cm2, or greater than or equal to about 6.5 mA / cm2). In at least one example embodiment, the second photoactive material has a second short-circuit current density (Jsc) of greater than or equal to about 1 mA / cm2(e.g., greater than or equal to about 1.5 mA / cm2, greater than or equal to about 2 mA / cm2, or greater than or equal to about 2.5 mA / cm2). In at least one example embodiment, the third photoactive material has a third short-circuit current density (Jsc) of greater than or equal to about 0.75 mA / cm2(e.g., greater than or equal to about 1 mA / cm2, greater than or equal to about 1.25 mA / cm2, greater than or equal to about 1.5 mA / cm2, greater than or equal to about 1.75 mA / cm2, greater than or equal to about 2 mA / cm2, greater than or equal to about 2.5 mA / cm2, or greater than or equal to about 3 mA / cm2).

[0115] FIGS. 1A-1 B illustrate a luminescent solar concentrator (LSC) device according to at least one example embodiment. FIG. 1A is a perspective view. FIG. 1 B is a schematic sectional view.

[0116] With reference to FIG. 1A, an LSC device 100 according to at least one example embodiment is shown. The LSC device 100 includes a first waveguide 102, a second waveguide 104, and a third waveguide 106. In at least one other example embodiment, an LSC includes a single waveguide, two waveguides, four waveguides, five waveguides, or more than five waveguides. The LSC device 100 may have any of the characteristics described above, including, but not limited to PCE, EQE, optical quantum efficiency, FF, Voc, and / or absorption.

[0117] The LSC device 100 further includes a PV cell 108 coupled to the waveguides 102, 104, 106. The PV cell 108 may be coupled (e.g., indirectly or directly coupled) to first, second, and third side surfaces 110, 112, 114 of the first, second, and third waveguides 102, 104, 106, respectively. In at least one example embodiment, as shown, the LSC device 100 is a single-junction, multi-waveguide LSC in which multiple waveguides (i.e., the first, second, and third waveguides 102, 104, 106) are coupled to the same PV cell (i.e., the PV cell 108). Although a single PV cell 108 is shown, an LSCAttorney Docket No. 6550-000525-WO-POAmay include more than one PV cell (e.g., two or more PV cells, three or more PV cells, or four or more PV cells).

[0118] An LSC may include PV cells coupled at different or additional locations, such as other side surfaces (e.g., opposite of and / or perpendicular to the sides surfaces 110, 112, 114), top surfaces (see, e.g., FIGS. 5A-5B), and / or bottom surfaces. In at least one example embodiment, an LSC includes multiple waveguides coupled to one another and spaced apart by airgaps, with one or more PV cells on a top surface of a top waveguide (see, e.g., the top surface 120 of the first waveguide 102) and / or a bottom surface of a bottom waveguide (see, e.g., the bottom surface 142 of the third waveguide 142). In at least one example embodiment, an LSC further includes an index matching layer between (e.g., directly between) each PV cell and respective waveguide. The index matching layer may be in the form of a gel. An index matching layer may facilitate optical transfer of luminophore emission to the PV cells. As used herein, an “index matching” material or layer refers to a material or layer having an index of refraction that is within about 10% of an index of refraction of waveguide (or substrate of the waveguide) (e.g., within about 7%, within about 5%, within about 3%, within about 2%, or within about 1 %).

[0119] In at least one example embodiment, the PV cell 108 has a bandgap of greater than or equal to about 0.7 eV (e.g., greater than or equal to about 0.8 eV, greater than or equal to about 1.0 eV, greater than or equal to about 1.2 eV, greater than or equal to about 1.4 eV, greater than or equal to about 1.6 eV, greater than or equal to about 1.8 eV, greater than or equal to about 2.0 eV, greater than or equal to about 2.2 eV, greater than or equal to about 2.4 eV, greater than or equal to about 2.6 eV, or greater than or equal to about 2.8 eV). The PV cell 108 may have a bandgap of less than or equal to about 3.0 eV (e.g., less than or equal to about 2.8 eV, less than or equal to about 2.6 eV, less than or equal to about 2.4 eV, less than or equal to about 2.2 eV, less than or equal to about 2.0 eV, less than or equal to about 1.8 eV, less than or equal to about 1.6 eV, less than or equal to about 1.4 eV, less than or equal to about 1.2 eV, less than or equal to about 1.0 eV, or less than or equal to about 0.8 eV). In at least one example embodiment, the PV cell 108 includes germanium (Ge); amorphous germanium (a-Ge); gallium (Ga); gallium arsenide (GaAs); silicon (Si); amorphous silicon (a-Si); silicongermanium (SiGe); amorphous silicon-germanium (a-SiGe); gallium indium phosphide (GalnP); copper indium selenide (diselenide), copper indium sulfide (disulfide), or combinations thereof (CIS); copper indium gallium selenide, copper indium galliumAttorney Docket No. 6550-000525-WO-POAsulfide, or combinations thereof (CIGS); cadmium telluride (CdTe); perovskites (PV), such as CHsNHsPbh, CHsNHsPbCIsand CHsNHsPbBrs; or any combination thereof.

[0120] With reference to FIG. 1 B, the LSC device 100 is configured to receive light in a direction 118 from the first waveguide 102 to the second waveguide 106. The first waveguide 102 includes a first front surface 120 and a first back surface 122 opposite the first front surface 120. The first front surface 120 is configured to receive light 124 (e.g., directly), as will be discussed in greater detail below. The first waveguide 102 includes a first substrate 126 and plurality of first luminophores 128. The first substrate 126 may be formed from or include glass or plastic (e.g., polyethylene, polycarbonate, polymethyl methacrylate, polydimethylsiloxane, and / or polypropylene, polyvinyl chloride, or a combination thereof). The plurality of first luminophores 128 may be the same as the first photoactive material, described above. The plurality of first luminophores 128 may be embedded in the substrate 126, as shown. Additional or alternatively, the plurality of first luminophores 128 may be provided in a layer or film on the first front surface 120 and / or the first back surface 122.

[0121] Distribution of the first luminophores 128 throughout the first substrate 126 may be heterogeneous or homogeneous. In at least one example embodiment, the first luminophores 128 are uniformly distributed throughout the first substrate 126 and / or a film or layer on a surface of the first substrate 126. In at least one example embodiment, a region (e.g., film, or layer) containing the first luminophores 128, and optionally a first dopant, may be neat. The first substrate 126 and / or region containing the first luminophores 128 may extend continuously and uninterrupted between all sides of the first waveguide 102. The first waveguide 102 may be flat, unwrinkled, and / or level such that it is not choppy or highly textured. In at least one example embodiment, the first top and / or bottom surfaces 120, 122 of the first waveguide 102 are smooth. As used herein, “smooth” means surfaces having a root mean square (RMS) roughness of less than or equal to about 575 nm (e.g., less than or equal to about 550 nm, less than or equal to about 500 nm, less than or equal to 400 nm, less than or equal to 300 nm, less than or equal to 200 nm, less than or equal to 100 nm, less than or equal to 50 nm, less than or equal to 10 nm, less than or equal to 5 nm, or less than or equal to 2 nm). In at least one other example embodiment, the region or layer containing the first luminophores 128 is neat, continuous, uninterrupted, uniform, flat, and / or smooth until it reaches a boundary defined by an edge of a top and / or bottom mounted PV cell (see, e.g., FIGS. 5A-5B).Attorney Docket No. 6550-000525-WO-POA

[0122] The first, second, and third luminophores 128, 130, 132 may be provided in the LSC at different concentrations or the same concentration. Concentration may be defined as an initial solution concentration (i.e., luminophore in solution, prior to adding mounting media and drying), film concentration (i.e., luminophore concentration in a final film disposed on a substrate), or waveguide concentration (i.e., luminophore concentration in a waveguide). The initial solution is combined and / or mixed with a mounting media that can act as the waveguide or attach to a surface of a waveguide when solidified. The solution may include toluene, dichloromethane (DCM), chlorobenzene (CB), acetonitrile (ACN), dimethyl sulfoxide (DMSO), acetone, or any combination thereof.

[0123] In at least one example embodiment, the first luminophores 128 are provided at a first initial solution concentration. In at least one example embodiment, the first initial solution concentration is greater than or equal to about 0.01 mg / mL (e.g., greater than or equal to about 0.02 mg / mL, greater than or equal to about 0.05 mg / mL, greater than or equal to about 0.1 mg / mL, greater than or equal to about 0.2 mg / mL, greater than or equal to about 0.5 mg / mL, greater than or equal to about 1 mg / mL, greater than or equal to about 2 mg / mL, greater than or equal to about 5 mg / mL, greater than or equal to about 10 mg / mL, greater than or equal to about 15 mg / mL, greater than or equal to about 20 mg / mL, greater than or equal to about 25 mg / mL, greater than or equal to about 30 mg / mL, greater than or equal to about 40 mg / mL, greater than or equal to about 50 mg / m, greater than or equal to about 60 mg / mL, greater than or equal to about 70 mg / mL, greater than or equal to about 80 mg / mL, greater than or equal to about 90 mg / mL, greater than or equal to about 100 mg / mL, or greater than or equal to about 150 mg / mL). The first initial solution concentration may be less than or equal to about 200 mg / mL (e.g., less than or equal to about 150 mg / mL, less than or equal to about 100 mg / mL, less than or equal to about 90 mg / mL, less than or equal to about 80 mg / mL, less than or equal to about 70 mg / mL, less than or equal to about 60 mg / mL, less than or equal to about 50 mg / mL, less than or equal to about 40 mg / mL, less than or equal to about 30 mg / mL, less than or equal to about 25 mg / mL, less than or equal to about 20 mg / mL, less than or equal to about 15 mg / mL, less than or equal to about 10 mg / mL, less than or equal to about 5 mg / mL, less than or equal to about 2 mg / mL, less than or equal to about 1 mg / mL, less than or equal to about 0.5 mg / mL, less than or equal to about 0.2 mg / mL, less than or equal to about 0.1 mg / mL, less than or equal to about 0.05 mg / mL, or less than or equal to about 0.02 mg / mL).Attorney Docket No. 6550-000525-WO-POA

[0124] In at least one example embodiment, the first luminophores 128 are provided at a first film concentration. In at least one example embodiment, the first film concentration is greater than or equal to about 0.01 mg / mL (e.g., greater than or equal to about 0.02 mg / mL, greater than or equal to about 0.05 mg / mL, greater than or equal to about 0.1 mg / mL, greater than or equal to about 0.2 mg / mL, greater than or equal to about 0.5 mg / mL, greater than or equal to about 1 mg / mL, greater than or equal to about 2 mg / mL, greater than or equal to about 5 mg / mL, greater than or equal to about 10 mg / mL, greater than or equal to about 15 mg / mL, greater than or equal to about 20 mg / mL, greater than or equal to about 25 mg / mL, greater than or equal to about 30 mg / mL, greater than or equal to about 40 mg / mL, greater than or equal to about 50 mg / m, greater than or equal to about 60 mg / mL, greater than or equal to about 70 mg / mL, greater than or equal to about 80 mg / mL, greater than or equal to about 90 mg / mL, greater than or equal to about 100 mg / mL, or greater than or equal to about 150 mg / mL). The first film concentration may be less than or equal to about 200 mg / mL (e.g., less than or equal to about 150 mg / mL, less than or equal to about 100 mg / mL, less than or equal to about 90 mg / mL, less than or equal to about 80 mg / mL, less than or equal to about 70 mg / mL, less than or equal to about 60 mg / mL, less than or equal to about 50 mg / mL, less than or equal to about 40 mg / mL, less than or equal to about 30 mg / mL, less than or equal to about 25 mg / mL, less than or equal to about 20 mg / mL, less than or equal to about 15 mg / mL, less than or equal to about 10 mg / mL, less than or equal to about 5 mg / mL, less than or equal to about 2 mg / mL, less than or equal to about 1 mg / mL, less than or equal to about 0.5 mg / mL, less than or equal to about 0.2 mg / mL, less than or equal to about 0.1 mg / mL, less than or equal to about 0.05 mg / mL, or less than or equal to about 0.02 mg / mL).

[0125] In at least one example embodiment, the first luminophores 128 are provided at a first waveguide concentration. In at least one example embodiment, the first waveguide concentration is greater than or equal to about 0.01 mg / mL (e.g., greater than or equal to about 0.02 mg / mL, greater than or equal to about 0.05 mg / mL, greater than or equal to about 0.1 mg / mL, greater than or equal to about 0.2 mg / mL, greater than or equal to about 0.5 mg / mL, greater than or equal to about 1 mg / mL, greater than or equal to about 2 mg / mL, greater than or equal to about 5 mg / mL, greater than or equal to about 10 mg / mL, greater than or equal to about 15 mg / mL, greater than or equal to about 20 mg / mL, greater than or equal to about 25 mg / mL, greater than or equal to about 30 mg / mL, greater than or equal to about 40 mg / mL, greater than or equal to about 50Attorney Docket No. 6550-000525-WO-POAmg / m, greater than or equal to about 60 mg / mL, greater than or equal to about 70 mg / mL, greater than or equal to about 80 mg / mL, greater than or equal to about 90 mg / mL, greater than or equal to about 100 mg / mL, or greater than or equal to about 150 mg / mL). The first waveguide concentration may be less than or equal to about 200 mg / mL (e.g., less than or equal to about 150 mg / mL, less than or equal to about 100 mg / mL, less than or equal to about 90 mg / mL, less than or equal to about 80 mg / mL, less than or equal to about 70 mg / mL, less than or equal to about 60 mg / mL, less than or equal to about 50 mg / mL, less than or equal to about 40 mg / mL, less than or equal to about 30 mg / mL, less than or equal to about 25 mg / mL, less than or equal to about 20 mg / mL, less than or equal to about 15 mg / mL, less than or equal to about 10 mg / mL, less than or equal to about 5 mg / mL, less than or equal to about 2 mg / mL, less than or equal to about 1 mg / mL, less than or equal to about 0.5 mg / mL, less than or equal to about 0.2 mg / mL, less than or equal to about 0.1 mg / mL, less than or equal to about 0.05 mg / mL, or less than or equal to about 0.02 mg / mL).

[0126] The second waveguide 104 includes a second front surface 130 and a second back surface 132 opposite the second front surface 130. The second front surface 130 is configured to receive light 124 (e.g., indirectly, through the first waveguide 102). The second waveguide 104 includes a second substrate 136 and plurality of second luminophores 138. The second substrate 136 may include glass or plastic (e.g., polyethylene, polycarbonate, polymethyl methacrylate, polydimethylsiloxane, and / or polypropylene, polyvinyl chloride, or a combination thereof). The plurality of second luminophores 138 may be the same as the second photoactive material, described above. The plurality of second luminophores 138 may be embedded in the substrate 136, as shown. Additional or alternatively, the plurality of second luminophores 138 may be provided in a layer or film on the second front surface 130 and / or the second back surface 132.

[0127] Distribution of the second luminophores 138 throughout the second substrate 136 may be heterogeneous or homogeneous. In at least one example embodiment, the second luminophores 138 are uniformly distributed throughout the second substrate 136 and / or a film or layer on a surface of the second substrate 136. In at least one example embodiment, a region (e.g., film, or layer) containing the second luminophores 138, and optionally a second dopant, may be neat. The second substrate 136 and / or region containing the second luminophores 138 may extend continuously and uninterrupted between all sides of the second waveguide 104. The second waveguideAttorney Docket No. 6550-000525-WO-POA104 may be flat, unwrinkled, and / or level such that it is not choppy or highly textured. In at least one example embodiment, the second top and / or bottom surfaces 130, 132 of the second waveguide 104 are smooth. In at least one other example embodiment, the region or layer containing the second luminophores 138 is neat, continuous, uninterrupted, uniform, flat, and / or smooth until it reaches a boundary defined by an edge of a top and / or bottom mounted PV cell (see, e.g., FIGS. 5A-5B).

[0128] In at least one example embodiment, the second luminophores 138 are provided at a second initial solution concentration. In at least one example embodiment, the second initial solution concentration is greater than or equal to about 0.01 mg / mL (e.g., greater than or equal to about 0.02 mg / mL, greater than or equal to about 0.05 mg / mL, greater than or equal to about 0.1 mg / mL, greater than or equal to about 0.2 mg / mL, greater than or equal to about 0.5 mg / mL, greater than or equal to about 1 mg / mL, greater than or equal to about 2 mg / mL, greater than or equal to about 5 mg / mL, greater than or equal to about 10 mg / mL, greater than or equal to about 15 mg / mL, greater than or equal to about 20 mg / mL, greater than or equal to about 25 mg / mL, greater than or equal to about 30 mg / mL, greater than or equal to about 40 mg / mL, greater than or equal to about 50 mg / m, greater than or equal to about 60 mg / mL, greater than or equal to about 70 mg / mL, greater than or equal to about 80 mg / mL, greater than or equal to about 90 mg / mL, greater than or equal to about 100 mg / mL, or greater than or equal to about 150 mg / mL). The second initial solution concentration may be less than or equal to about 200 mg / mL (e.g., less than or equal to about 150 mg / mL, less than or equal to about 100 mg / mL, less than or equal to about 90 mg / mL, less than or equal to about 80 mg / mL, less than or equal to about 70 mg / mL, less than or equal to about 60 mg / mL, less than or equal to about 50 mg / mL, less than or equal to about 40 mg / mL, less than or equal to about 30 mg / mL, less than or equal to about 25 mg / mL, less than or equal to about 20 mg / mL, less than or equal to about 15 mg / mL, less than or equal to about 10 mg / mL, less than or equal to about 5 mg / mL, less than or equal to about 2 mg / mL, less than or equal to about 1 mg / mL, less than or equal to about 0.5 mg / mL, less than or equal to about 0.2 mg / mL, less than or equal to about 0.1 mg / mL, less than or equal to about 0.05 mg / mL, or less than or equal to about 0.02 mg / mL).

[0129] In at least one example embodiment, the second luminophores 138 are provided at a second film concentration. In at least one example embodiment, the second film concentration is greater than or equal to about 0.01 mg / mL (e.g., greater than or equal to about 0.02 mg / mL, greater than or equal to about 0.05 mg / mL, greater than orAttorney Docket No. 6550-000525-WO-POAequal to about 0.1 mg / mL, greater than or equal to about 0.2 mg / mL, greater than or equal to about 0.5 mg / mL, greater than or equal to about 1 mg / mL, greater than or equal to about 2 mg / mL, greater than or equal to about 5 mg / mL, greater than or equal to about 10 mg / mL, greater than or equal to about 15 mg / mL, greater than or equal to about 20 mg / mL, greater than or equal to about 25 mg / mL, greater than or equal to about 30 mg / mL, greater than or equal to about 40 mg / mL, greater than or equal to about 50 mg / m, greater than or equal to about 60 mg / mL, greater than or equal to about 70 mg / mL, greater than or equal to about 80 mg / mL, greater than or equal to about 90 mg / mL, greater than or equal to about 100 mg / mL, or greater than or equal to about 150 mg / mL). The second film concentration may be less than or equal to about 200 mg / mL (e.g., less than or equal to about 150 mg / mL, less than or equal to about 100 mg / mL, less than or equal to about 90 mg / mL, less than or equal to about 80 mg / mL, less than or equal to about 70 mg / mL, less than or equal to about 60 mg / mL, less than or equal to about 50 mg / mL, less than or equal to about 40 mg / mL, less than or equal to about 30 mg / mL, less than or equal to about 25 mg / mL, less than or equal to about 20 mg / mL, less than or equal to about 15 mg / mL, less than or equal to about 10 mg / mL, less than or equal to about 5 mg / mL, less than or equal to about 2 mg / mL, less than or equal to about 1 mg / mL, less than or equal to about 0.5 mg / mL, less than or equal to about 0.2 mg / mL, less than or equal to about 0.1 mg / mL, less than or equal to about 0.05 mg / mL, or less than or equal to about 0.02 mg / mL).

[0130] In at least one example embodiment, the second luminophores 138 are provided at a second waveguide concentration. In at least one example embodiment, the second waveguide concentration is greater than or equal to about 0.01 mg / mL (e.g., greater than or equal to about 0.02 mg / mL, greater than or equal to about 0.05 mg / mL, greater than or equal to about 0.1 mg / mL, greater than or equal to about 0.2 mg / mL, greater than or equal to about 0.5 mg / mL, greater than or equal to about 1 mg / mL, greater than or equal to about 2 mg / mL, greater than or equal to about 5 mg / mL, greater than or equal to about 10 mg / mL, greater than or equal to about 15 mg / mL, greater than or equal to about 20 mg / mL, greater than or equal to about 25 mg / mL, greater than or equal to about 30 mg / mL, greater than or equal to about 40 mg / mL, greater than or equal to about 50 mg / m, greater than or equal to about 60 mg / mL, greater than or equal to about 70 mg / mL, greater than or equal to about 80 mg / mL, greater than or equal to about 90 mg / mL, greater than or equal to about 100 mg / mL, or greater than or equal to about 150 mg / mL). The second waveguide concentration may be less than or equal to about 200Attorney Docket No. 6550-000525-WO-POAmg / mL (e.g., less than or equal to about 150 mg / mL, less than or equal to about 100 mg / mL, less than or equal to about 90 mg / mL, less than or equal to about 80 mg / mL, less than or equal to about 70 mg / mL, less than or equal to about 60 mg / mL, less than or equal to about 50 mg / mL, less than or equal to about 40 mg / mL, less than or equal to about 30 mg / mL, less than or equal to about 25 mg / mL, less than or equal to about 20 mg / mL, less than or equal to about 15 mg / mL, less than or equal to about 10 mg / mL, less than or equal to about 5 mg / mL, less than or equal to about 2 mg / mL, less than or equal to about 1 mg / mL, less than or equal to about 0.5 mg / mL, less than or equal to about 0.2 mg / mL, less than or equal to about 0.1 mg / mL, less than or equal to about 0.05 mg / mL, or less than or equal to about 0.02 mg / mL).

[0131] The third waveguide 106 includes a third front surface 140 and a third back surface 142 opposite the third front surface 140. The third front surface 140 is configured to receive light 124 (e.g., indirectly, through the first waveguide 102 and the second waveguide 104). The third waveguide 106 includes a third substrate 146 and plurality of third luminophores 148. The third substrate 146 may include glass or plastic (e.g., polyethylene, polycarbonate, polymethyl methacrylate, polydimethylsiloxane, and / or polypropylene, polyvinyl chloride, or a combination thereof). The plurality of third luminophores 148may be the same as the third photoactive material, described above. The plurality of third luminophores 148may be embedded in the third substrate 146, as shown. Additional or alternatively, the plurality of third luminophores 148 may be provided in a layer or film on the third front surface 140 and / or the third back surface 142.

[0132] Distribution of the third luminophores 148 throughout the third substrate 146 may be heterogeneous or homogeneous. In at least one example embodiment, the third luminophores 148 are uniformly distributed throughout the third substrate 146 and / or a film or layer on a surface of the third substrate 146. In at least one example embodiment, a region (e.g., film, or layer) containing the third luminophores 148, and optionally a third dopant, may be neat. The third substrate 146 and / or region containing the third luminophores 148 may extend continuously and uninterrupted between all sides of the third waveguide 106. The third waveguide 106 may be flat, unwrinkled, and / or level such that it is not choppy or highly textured. In at least one example embodiment, the third top and / or bottom surfaces 140, 142 of the third waveguide 106 are smooth. In at least one other example embodiment, the region or layer containing the third luminophores 148 is neat, continuous, uninterrupted, uniform, flat, and / or smooth until itAttorney Docket No. 6550-000525-WO-POAreaches a boundary defined by an edge of a top and / or bottom mounted PV cell (see, e.g., FIGS. 5A-5B).

[0133] In at least one example embodiment, the third luminophores 148 are provided at a third initial solution concentration. In at least one example embodiment, the third initial solution concentration is greater than or equal to about 0.01 mg / mL (e.g., greater than or equal to about 0.02 mg / mL, greater than or equal to about 0.05 mg / mL, greater than or equal to about 0.1 mg / mL, greater than or equal to about 0.2 mg / mL, greater than or equal to about 0.5 mg / mL, greater than or equal to about 1 mg / mL, greater than or equal to about 2 mg / mL, greater than or equal to about 5 mg / mL, greater than or equal to about 10 mg / mL, greater than or equal to about 15 mg / mL, greater than or equal to about 20 mg / mL, greater than or equal to about 25 mg / mL, greater than or equal to about 30 mg / mL, greater than or equal to about 40 mg / mL, greater than or equal to about 50 mg / m, greater than or equal to about 60 mg / mL, greater than or equal to about 70 mg / mL, greater than or equal to about 80 mg / mL, greater than or equal to about 90 mg / mL, greater than or equal to about 100 mg / mL, or greater than or equal to about 150 mg / mL). The third initial solution concentration may be less than or equal to about 200 mg / mL (e.g., less than or equal to about 150 mg / mL, less than or equal to about 100 mg / mL, less than or equal to about 90 mg / mL, less than or equal to about 80 mg / mL, less than or equal to about 70 mg / mL, less than or equal to about 60 mg / mL, less than or equal to about 50 mg / mL, less than or equal to about 40 mg / mL, less than or equal to about 30 mg / mL, less than or equal to about 25 mg / mL, less than or equal to about 20 mg / mL, less than or equal to about 15 mg / mL, less than or equal to about 10 mg / mL, less than or equal to about 5 mg / mL, less than or equal to about 2 mg / mL, less than or equal to about 1 mg / mL, less than or equal to about 0.5 mg / mL, less than or equal to about 0.2 mg / mL, less than or equal to about 0.1 mg / mL, less than or equal to about 0.05 mg / mL, or less than or equal to about 0.02 mg / mL).

[0134] In at least one example embodiment, the third luminophores 148 are provided at a third film concentration. In at least one example embodiment, the third film concentration is greater than or equal to about 0.01 mg / mL (e.g., greater than or equal to about 0.02 mg / mL, greater than or equal to about 0.05 mg / mL, greater than or equal to about 0.1 mg / mL, greater than or equal to about 0.2 mg / mL, greater than or equal to about 0.5 mg / mL, greater than or equal to about 1 mg / mL, greater than or equal to about 2 mg / mL, greater than or equal to about 5 mg / mL, greater than or equal to about 10 mg / mL, greater than or equal to about 15 mg / mL, greater than or equal to about 20Attorney Docket No. 6550-000525-WO-POAmg / mL, greater than or equal to about 25 mg / mL, greater than or equal to about 30 mg / mL, greater than or equal to about 40 mg / mL, greater than or equal to about 50 mg / m, greater than or equal to about 60 mg / mL, greater than or equal to about 70 mg / mL, greater than or equal to about 80 mg / mL, greater than or equal to about 90 mg / mL, greater than or equal to about 100 mg / mL, or greater than or equal to about 150 mg / mL). The third film concentration may be less than or equal to about 200 mg / mL (e.g., less than or equal to about 150 mg / mL, less than or equal to about 100 mg / mL, less than or equal to about 90 mg / mL, less than or equal to about 80 mg / mL, less than or equal to about 70 mg / mL, less than or equal to about 60 mg / mL, less than or equal to about 50 mg / mL, less than or equal to about 40 mg / mL, less than or equal to about 30 mg / mL, less than or equal to about 25 mg / mL, less than or equal to about 20 mg / mL, less than or equal to about 15 mg / mL, less than or equal to about 10 mg / mL, less than or equal to about 5 mg / mL, less than or equal to about 2 mg / mL, less than or equal to about 1 mg / mL, less than or equal to about 0.5 mg / mL, less than or equal to about 0.2 mg / mL, less than or equal to about 0.1 mg / mL, less than or equal to about 0.05 mg / mL, or less than or equal to about 0.02 mg / mL).

[0135] In at least one example embodiment, the third luminophores 148 are provided at a third waveguide concentration. In at least one example embodiment, the third waveguide concentration is greater than or equal to about 0.01 mg / mL (e.g., greater than or equal to about 0.02 mg / mL, greater than or equal to about 0.05 mg / mL, greater than or equal to about 0.1 mg / mL, greater than or equal to about 0.2 mg / mL, greater than or equal to about 0.5 mg / mL, greater than or equal to about 1 mg / mL, greater than or equal to about 2 mg / mL, greater than or equal to about 5 mg / mL, greater than or equal to about 10 mg / mL, greater than or equal to about 15 mg / mL, greater than or equal to about 20 mg / mL, greater than or equal to about 25 mg / mL, greater than or equal to about 30 mg / mL, greater than or equal to about 40 mg / mL, greater than or equal to about 50 mg / m, greater than or equal to about 60 mg / mL, greater than or equal to about 70 mg / mL, greater than or equal to about 80 mg / mL, greater than or equal to about 90 mg / mL, greater than or equal to about 100 mg / mL, or greater than or equal to about 150 mg / mL). The third waveguide concentration may be less than or equal to about 200 mg / mL (e.g., less than or equal to about 150 mg / mL, less than or equal to about 100 mg / mL, less than or equal to about 90 mg / mL, less than or equal to about 80 mg / mL, less than or equal to about 70 mg / mL, less than or equal to about 60 mg / mL, less than or equal to about 50 mg / mL, less than or equal to about 40 mg / mL, less than or equal to about 30 mg / mL, lessAttorney Docket No. 6550-000525-WO-POAthan or equal to about 25 mg / mL, less than or equal to about 20 mg / mL, less than or equal to about 15 mg / mL, less than or equal to about 10 mg / mL, less than or equal to about 5 mg / mL, less than or equal to about 2 mg / mL, less than or equal to about 1 mg / mL, less than or equal to about 0.5 mg / mL, less than or equal to about 0.2 mg / mL, less than or equal to about 0.1 mg / mL, less than or equal to about 0.05 mg / mL, or less than or equal to about 0.02 mg / mL).

[0136] In at least one example embodiment, the first and second waveguides 102, 104 are spaced apart by a first distance 150. The first distance 150 may be greater than or equal to about 0.5 micrometers (pm) (e.g., greater than or equal to about 1 pm, greater than or equal to about 2 pm, greater than or equal to about 5 pm, greater than or equal to about 10 pm, greater than or equal to about 15 pm, greater than or equal to about 20 pm, greater than or equal to about 30 pm, greater than or equal to about 40 pm, greater than or equal to about 50 pm, greater than or equal to about 60 pm, greater than or equal to about 70 pm, greater than or equal to about 80 pm, greater than or equal to about 90 pm, greater than or equal to about 100 pm, greater than or equal to about 110 pm, greater than or equal to about 120 pm, greater than or equal to about 130 pm, or greater than or equal to about 140 pm). The first distance 150 may be less than or equal to about 150 pm (e.g., less than or equal to about 140 pm, less than or equal to about 130 pm, less than or equal to about 120 pm, less than or equal to about 110 pm, less than or equal to about 100 pm, less than or equal to about 90 pm, less than or equal to about 80 pm, less than or equal to about 70 pm, less than or equal to about 60 pm, less than or equal to about 50 pm, less than or equal to about 40 pm, less than or equal to about 30 pm, less than or equal to about 20 pm, less than or equal to about 15 pm, less than or equal to about 10 pm, less than or equal to about 5 pm, less than or equal to about 2 pm, or less than or equal to about 1 pm). In at least one example embodiment, the LSC device 100 includes a first airgap 152 between the first and second waveguides 102, 104.

[0137] In at least one example embodiment, the second and third waveguides 104, 106 are spaced apart by a second distance 154. The second distance 154 may be greater than or equal to about 0.5 micrometers (pm) (e.g., greater than or equal to about 1 pm, greater than or equal to about 2 pm, greater than or equal to about 5 pm, greater than or equal to about 10 pm, greater than or equal to about 15 pm, greater than or equal to about 20 pm, greater than or equal to about 30 pm, greater than or equal to about 40 pm, greater than or equal to about 50 pm, greater than or equal to about 60 pm, greater than or equal to about 70 pm, greater than or equal to about 80 pm, greater than or equal toAttorney Docket No. 6550-000525-WO-POAabout 90 pm, greater than or equal to about 100 pm, greater than or equal to about 110 pm, greater than or equal to about 120 pm, greater than or equal to about 130 pm, or greater than or equal to about 140 pm). The second distance 154 may be less than or equal to about 150 pm, (e.g., less than or equal to about 140 pm, less than or equal to about 130 pm, less than or equal to about 120 pm, less than or equal to about 110 pm, less than or equal to about 100 pm, less than or equal to about 90 pm, less than or equal to about 80 pm, less than or equal to about 70 pm, less than or equal to about 60 pm, less than or equal to about 50 pm, less than or equal to about 40 pm, less than or equal to about 30 pm, less than or equal to about 20 pm, less than or equal to about 15 pm, less than or equal to about 10 pm, less than or equal to about 5 pm, less than or equal to about 2 pm, or less than or equal to about 1 pm). The second distance 154 may be the same as the first distance 150 or different from the first distance 150. In at least one example embodiment, the LSC device 100 includes a second airgap 156 between the second and third waveguides 104, 106.

[0138] The LSC device 100 is configured to receive the light 124. In at least one example embodiment, the LSC device 100 is configured to receive the light 124 from a front side 158. Accordingly, the light 124 (or portions of the light, as described in greater detail below) sequentially reaches the first waveguide 102, and then the second waveguide 104, and then the third waveguide 106.

[0139] A first portion 160 of the light 124 (i.e., light within a first wavelength range) is absorbed by the first luminophores 128 in the first waveguide 102. The absorbed first portion 160 of the light 124 excites the first luminophore 128, causing the first luminophore to emit light 162 of a different wavelength. The emitted light 162 is guided, by the first waveguide 102, toward edges of the first substrate 126 and the PV cell 108 to generate a current. The first luminophore 128 is substantially transparent to a second portion 164 of the light 124 (i.e., light within a second wavelength range) and a third portion 166 of the light 124 (i.e., light within a third wavelength range). Thus, the second and third portions 164, 166 of the light 124 pass through the first waveguide 102 and are received by the second waveguide 104.

[0140] The second portion 164 of the light 124 is absorbed by the second luminophores 138 in the second waveguide 104. The absorbed second portion 164 of the light 124 excites the second luminophores 138, causing the second luminophores to emit light 168 of a different wavelength. The emitted light 168 is guided, by the second waveguide 104, toward edges of the second substrate 136 and the PV cell 108 toAttorney Docket No. 6550-000525-WO-POAgenerate a current. The second luminophores 138 are substantially transparent to the third portion 166 of the light 124. Thus, the third portion 166 of the light 124 passes through the second waveguide 104 and is received by the third waveguide 106.

[0141] The third portion 166 of the light 124 is absorbed by the third luminophores 148 in the third waveguide 106. The absorbed third portion 166 of the light 124 excites the third luminophores 148, causing the third luminophores 148 to emit light 170 of a different wavelength. The emitted light 170 is guided, by the third waveguide 106, toward edges of the third substrate 146 and the PV cell 108 to generate a current.

[0142] FIG. 2 is a schematic perspective view of another LSC device according to at least one example embodiment.

[0143] In at least one example embodiment, as shown in FIG. 2, an LSC device 200 includes first, second, and third waveguides 202, 204, 206 and a PV cell 208. The LSC 200 may further include an index matching layer or material. The LSC device 200 is the same as the LSC device 100 (shown in FIGS. 1A-1 B) except that the LSC device 200 includes first and second low index layers 210, 212 instead of airgaps. The first low index layer 210 is between the first waveguide 202 and the second waveguide 204. The first low index layer 210 defines a first thickness 220. In at least one example embodiment, the first thickness 220 is greater than or equal to about 0.5 pm (e.g., greater than or equal to about 1 pm, greater than or equal to about 2 pm, greater than or equal to about 5 pm, greater than or equal to about 10 pm, greater than or equal to about 15 pm, greater than or equal to about 20 pm, greater than or equal to about 25 pm, greater than or equal to about 50 pm, greater than or equal to about 75 pm, greater than or equal to about 100 pm, or greater than or equal to about 125 pm). The first thickness 220 may be less than or equal to about 150 pm (e.g., less than or equal to about 125 pm, less than or equal to about 100 pm, less than or equal to about 75 pm, less than or equal to about 50 pm, less than or equal to about 25 pm, less than or equal to about 20 pm, less than or equal to about 15 pm, less than or equal to about 10 pm, less than or equal to about 5 pm, less than or equal to about 2 pm, or less than or equal to about 1 pm).

[0144] In at least one example embodiment, the first low index layer 210 is formed from or includes a material having a first index of refraction. The first index of refraction may be greater than 1 (e.g., greater than or equal to about 1.05, greater than or equal to about 1.1 , greater than or equal to about 1.15, greater than or equal to about 1.2, greater than or equal to about 1.25, greater than or equal to about 1.3, greater than or equal to about 1.35, greater than or equal to about 1.4, greater than or equal to about 1.45, greaterAttorney Docket No. 6550-000525-WO-POAthan or equal to about 1.5, greater than or equal to about 1.75, greater than or equal to about 2, greater than or equal to about 2.25, greater than or equal to about 2.5, greater than or equal to about 3, greater than or equal to about 3.5, greater than or equal to about 4, or greater than or equal to about 4.5). The first index of refraction may be less than or equal to about 5 (e.g., less than or equal to about 4.5, less than or equal to about 4, less than or equal to about 3.5, less than or equal to about 3, less than or equal to about 2.5, less than or equal to about 2.25, less than or equal to about 2, less than or equal to about 1.75, less than or equal to about 1.5, less than or equal to about 1.45, less than or equal to about 1.4, less than or equal to about 1.35, less than or equal to about .3, less than or equal to about 1.25, less than or equal to about 1.2, less than or equal to about 1.15, less than or equal to about 1.1 , or less than or equal to about 1.05). The first low index layer 210 may include a polymer, an oxide, a porous polymer, a porous oxide, an aerogel, or any combination thereof.

[0145] The second low index layer 212 is between the second waveguide 204 and the third waveguide 206. The second low index layer 212 defines a second thickness 222. In at least one example embodiment, the second thickness 222 is greater than or equal to about 0.5 pm (e.g., greater than or equal to about 1 pm, greater than or equal to about 2 pm, greater than or equal to about 5 pm, greater than or equal to about 10 pm, greater than or equal to about 15 pm, greater than or equal to about 20 pm, greater than or equal to about 25 pm, greater than or equal to about 50 pm, greater than or equal to about 75 pm, greater than or equal to about 100 pm, or greater than or equal to about 125 pm). The second thickness 222 may be less than or equal to about 150 pm (e.g., less than or equal to about 125 pm, less than or equal to about 100 pm, less than or equal to about 75 pm, less than or equal to about 50 pm, less than or equal to about 25 pm, less than or equal to about 20 pm, less than or equal to about 15 pm, less than or equal to about 10 pm, less than or equal to about 5 pm, less than or equal to about 2 pm, or less than or equal to about 1 pm). The first and second thicknesses 220, 222 may be the same or different.

[0146] In at least one example embodiment, the second low index layer 212 is formed from or includes a material having a second index of refraction. The second index of refraction may be greater than 1 (e.g., greater than or equal to about 1.05, greater than or equal to about 1.1 , greater than or equal to about 1.15, greater than or equal to about 1.2, greater than or equal to about 1.25, greater than or equal to about 1.3, greater than or equal to about 1.35, greater than or equal to about 1.4, greater than or equal to aboutAttorney Docket No. 6550-000525-WO-POA1.45, greater than or equal to about 1.5, greater than or equal to about 1.75, greater than or equal to about 2, greater than or equal to about 2.25, greater than or equal to about 2.5, greater than or equal to about 3, greater than or equal to about 3.5, greater than or equal to about 4, or greater than or equal to about 4.5). The second index of refraction may be less than or equal to about 5 (e.g., less than or equal to about 4.5, less than or equal to about 4, less than or equal to about 3.5, less than or equal to about 3, less than or equal to about 2.5, less than or equal to about 2.25, less than or equal to about 2, less than or equal to about 1.75, less than or equal to about 1.5, less than or equal to about 1.45, less than or equal to about 1.4, less than or equal to about 1.35, less than or equal to about .3, less than or equal to about 1.25, less than or equal to about 1.2, less than or equal to about 1.15, less than or equal to about 1.1 , or less than or equal to about 1.05). The second index of refraction may be the same as or different than the first index of refraction. The second low index layer 212 may include a low index polymer, an oxide, or a combination of a low index polymer and an oxide. The first and second low index layers 210, 212 may be formed from the same material or different materials.

[0147] An LSC may include PV cells coupled at different or additional locations, such as other side surfaces (e.g., opposite of and / or perpendicular to the sides surfaces 110, 112, 114), top surfaces (see, e.g., FIGS. 5A-5B), and / or bottom surfaces. In at least one example embodiment, an LSC includes multiple waveguides coupled to one another and spaced apart by low index layers, with one or more PV cells on a top surface of a top waveguide, and index matching region to facilitate emission optically transfer to the PV cells, as will be discussed in greater detail in the discussion accompanying FIG. 5B.

[0148] FIG. 3 is a schematic perspective view of another LSC device according to at least one example embodiment.

[0149] In at least one example embodiment, as shown in FIG. 3, an LSC device 300 includes first, second, and third waveguides 302, 304, 306 and a PV cell 308. The LSC device 300 is the same as the LSC device 100 (shown in FIGS. 1 A-1 B) except that the LSC device 300 does not include airgaps or low index materials between the waveguides 302, 304, 306. Instead, the first waveguide 302 is directly adjacent to the second waveguide 304. The first and second waveguides 302, 304 may be in direct contact with one another. The second waveguide 304 is directly adjacent to the third waveguide 306. The second and third waveguides 304, 306 may be in direct contact with one another.Attorney Docket No. 6550-000525-WO-POA

[0150] An LSC may include PV cells coupled at different or additional locations, such as other side surfaces, top surfaces (see, e.g., FIGS. 5A-5B), and / or bottom surfaces. In at least one example embodiment, an LSC includes multiple waveguides coupled to and in direct contact with one another, with one or more PV cells on a top surface of a top waveguide (see, e.g., the top surface of the first waveguide 302) and / or a bottom surface of a bottom waveguide (see, e.g., the bottom surface of the third waveguide 306). In at least one example embodiment, an LSC further includes an index matching layer between each PV cell and respective waveguide. The index matching layer may be in the form of a gel. In at least one example embodiment, the first, second, and third waveguides 302, 304, 306 are in direct contact with one another and the LSC device 300 is free of index matching layers between the waveguides 302, 304, 306.

[0151] FIG. 4 is a schematic perspective view of another LSC device according to at least one example embodiment.

[0152] In at least one example embodiment, as shown in FIG. 4, an LSC device 400 includes a waveguide 402 and a PV cell 408. The LSC device 400 may be the same as the LSC device 100 of FIGS. 1 A-1 B, except that the LSC device 400 includes a single waveguide (i.e., the waveguide 402) with a ternary luminophore system instead of three different waveguides. The LSC 400 may further include an index matching material or layer.

[0153] The LSC device 400 includes greater than or equal to 2 different luminophores (e.g., greater than or equal to about 3 different luminophores, greater than or equal to about 4 different luminophores, greater than or equal to about 5 different luminophores, or greater than or equal to about 5 different luminophores). In at least the example embodiment shown, the waveguide 402 includes a substrate 410, a first luminophore 412, a second luminophore 414, and a third luminophore 416. The first, second, and third luminophores 412, 414, 416 are the same as the first, second, and third luminophores 128, 138, 148 of the LSC device 100 of FIGS. 1 A-1 B. In at least one other example embodiment, an LSC device may include a subset of the first, second, and third luminophores 412, 414, 416, and / or additional different luminophores.

[0154] The luminophores 412, 414, 416 may be embedded in the substrate 410, as shown. Additional or alternatively, the luminophores 412, 414, 416 may be provided in one or more layers or films on a front surface 420 of the substrate 410 and / or a back surface 422 of the substrate 410. In at least one example embodiment, each of the luminophores 412, 414, 416 is distributed throughout substantially the same region of theAttorney Docket No. 6550-000525-WO-POAsubstrate 410 (and / or layer / film). In at least one other example embodiment, the luminophores are disposed in different regions.

[0155] Distribution of the luminophores 412, 414, 416 throughout the substrate 410 may be heterogeneous or homogeneous. In at least one example embodiment, the luminophores 412, 414, 416 are uniformly distributed throughout the substrate 410 and / or a film or layer on a surface of the substrate 410. In at least one example embodiment, a region (e.g., film, or layer) containing the luminophores 412, 414, 416, and optionally a dopant, may be neat. The substrate 410 and / or region containing the luminophores 412, 414, 416 may extend continuously and uninterrupted between all sides of the waveguide 402. The waveguide 402 may be flat, unwrinkled, and / or level such that it is not choppy or highly textured. In at least one example embodiment, the second top and / or bottom surfaces 420, 422 of the waveguide 402 are smooth.

[0156] FIG. 5A is a schematic perspective view of another LSC device according to at least one example embodiment.

[0157] In at least one example embodiment, as shown in FIG. 5A, an LSC device 500 includes a waveguide 502 and one or more PV cells 508. The LSC device 500 may further include an index matching material between the waveguide 502 and each of the PV cells 508. The LSC device 500 is the same as the LSC device 400 (shown in FIG. 4) except that the PV cells 508 are on a front surface 520 and / or a back surface 522 of the waveguide 502 instead of a side surface 524 of the waveguide 502. In at least one example embodiment, each of the PV cells 508 has an elongated shape. Each of the PV cells 508 includes an active face (i.e., a face that is configured to receive light) that faces the waveguide 502.

[0158] In at least one example embodiment, the PV cells 508 are adjacent to a periphery of 508 of the front surface 420. The PV cells 508 (i.e., an outermost edge of the PV cells 508) are disposed within a distance 530 from an edge 532 of the waveguide 502. In at least one example embodiment, the distance 530 is less than or equal to about 5 centimeters (cm) (e.g., less than or equal to about 4 cm, less than or equal to about 3 cm, less than or equal to about 2 cm, less than or equal to about 1 cm, less than or equal to about 90 nm, less than or equal to about 80 nm, less than or equal to about 70 nm, less than or equal to about 60 nm, less than or equal to about 50 nm, less than or equal to about 40 nm, less than or equal to about 30 nm, less than or equal to about 25 nm, less than or equal to about 20 nm, less than or equal to about 15 nm, less than or equalAttorney Docket No. 6550-000525-WO-POAto about 10 nm, less than or equal to about 5 nm, less than or equal to about 2 nm, or less than or equal to about 1 nm).

[0159] The front and back surfaces 520, 522 each define a first or main portion 550. The main portions 550 are free of PV cells. The front and / or back surface 520, 522 may further include a second or PV cell portion 552 having PV cell(s) 508 thereon. In at least one example embodiment, each of the PV cell portions 550 is less than or equal to about 20% of the respective front or back surface 520, 522 (e.g., less than or equal to about 18%, less than or equal to about 15%, less than or equal to about 12%, less than or equal to about 10%, less than or equal to about 8%, less than or equal to about 6%, less than or equal to about 5%, less than or equal to about 4%, less than or equal to about 3%, or less than or equal to about 2%). For example, in the embodiment shown, the PV cells 508 cover less than or equal to about 20% of the front 520 (e.g., less than or equal to about 18%, less than or equal to about 15%, less than or equal to about 12%, less than or equal to about 10%, less than or equal to about 8%, less than or equal to about 6%, less than or equal to about 5%, less than or equal to about 4%, less than or equal to about 3%, or less than or equal to about 2%).

[0160] FIG. 5B is a schematic sectional view of another LSC device according to at least one example embodiment.

[0161] In at least one example embodiment, as shown in FIG. 5B, an LSC device 550 includes a first waveguide 552, a second waveguide 554, a third waveguide 556, and one or more PV cells 558. The LSC device 550 further includes low index regions 560 and first index matching regions 562. The LSC device 550 is the same as the LSC device 200 of FIG. 2, except for a location of the PV cells 558 and first index matching regions 562. Each of the PV cells 558 is disposed on a front face 564 of the first waveguide 552. Each of the PV cells 558 includes an active face 566 disposed toward or facing the first waveguide 552, as in FIG. 5A. The LSC device 550 may additionally or alternatively include one or more PV cells on a back face 568 of the third waveguide 556.

[0162] The low index regions may be or include low index materials having indices of refraction as described in the discussion accompanying FIG. 2 and / or air, as described in the discussion accompanying FIGS. 1A-1 B. One of the low index regions 560 is disposed between the first and second waveguides 552, 554 and the other of the low index regions is disposed between the second and third waveguides 554, 556.

[0163] In at least one example embodiment, the LSC device 550 further includes the first index matching regions 562. The first index matching regions 562 are disposedAttorney Docket No. 6550-000525-WO-POAbetween adjacent waveguides and within and / or adjacent to the low index regions 560. The first index matching regions 562 may be aligned (e.g., vertically) with the PV cells 558 to facilitate optically transferring emission from luminophores in the waveguides 552, 554, 556 to the PV cells 558. In at least the example embodiment shown, each PV cell 558 LSC device 550 has an associated index matching region 562 in each of the low index regions 560.

[0164] The LSC device 550 may include a plurality of discrete first index matching regions 562, with each first index matching region 562 being associated with a respective one of the PV cells 558. Each of the index matching regions 562 may have the same width 570 and / or length (i.e., parallel to an edge of the first waveguide 552 and perpendicular to the width) as the associated PV cell 558. In other example embodiments, an LSC device may include one or more continuous or uninterrupted index matching regions associated with multiple PV cells.

[0165] The first index matching regions 562 may each have an index of refraction that is similar to or the same as that of the waveguides 552, 554, 556 to optically transfer luminophore emission to the PV cells 558, as discussed above. The index of refraction may also be similar to or the same as that of the PV cells. In at least one example embodiment, the first index matching regions 562 have an index of refraction of greater than or equal to 1.3 (e.g., greater than or equal to 1.35, greater than or equal to 1.4, greater than or equal to 1.45, greater than or equal to 1.5, greater than or equal to 1.55, greater than or equal to 1.6, greater than or equal to 1.65). The index of refraction of the first index matching regions 562 may be less than or equal to 1.65 (e.g., less than or equal to 1.6, less than or equal to 1.55, less than or equal to 1.5, less than or equal to 1.45, less than or equal to 1.4, or less than or equal to 1.35).

[0166] In at least one example embodiment, the LSC device 550 further includes second index matching regions 572. The second index matching regions 572 are disposed between each of the PV cells 558 and the first waveguide 552 to facilitate optically transferring luminophore emission to the PV cells 558. In at least one example embodiment, the second index matching regions 572 have an index of refraction of greater than or equal to 1.3 (e.g., greater than or equal to 1.35, greater than or equal to 1.4, greater than or equal to 1.45, greater than or equal to 1.5, greater than or equal to 1.55, greater than or equal to 1.6, greater than or equal to 1.65). The index of refraction of the second index matching regions 572 may be less than or equal to 1.65 (e.g., less than or equal to 1.6, less than or equal to 1.55, less than or equal to 1.5, less than orAttorney Docket No. 6550-000525-WO-POAequal to 1.45, less than or equal to 1.4, or less than or equal to 1.35). The first and second index matching layers 562, 572 may include polymers, oxides, gels, adhesives, or any combination thereof. In at least one example embodiment, the LSC device 550 may be free of second index matching regions 572.

[0167] FIG. 6 is a schematic perspective view of a photovoltaic (PV) device according to at least one example embodiment.

[0168] In at least one example embodiment, as shown in FIG. 6, a photovoltaic (PV) device 600 is provided. The PV device 600 (e.g., the entire PV device 600) may have any of the characteristics described above, including, but not limited to PCT, EQE, optical quantum efficiency, FF, Voc, and / or total absorption.

[0169] The PV device 600 generally includes a first electrode 602, a second electrode 604, and a photoactive layer 606 between the first and second electrodes 602, 604. In at least one example embodiment, one or both of the first and second electrodes 602, 604 may be disposed on a substrate 608. In at least one example embodiment, the first electrode 602 may be positioned on the substrate 608 and include materials that act as the electrode, such that the substrate and electrode are visibly indistinguishable (not shown).

[0170] The active layer 606 includes a wavelength-selective light-absorbing material, such as the first photoactive material, the second photoactive material, and / or the third photoactive material, described above. In at least one example embodiment, the PV device 600 optionally includes a complementary layer 610 including an electron acceptor. The complementary layer 610 can be a distinct layer, as shown, or may be included in the active layer 606. Therefore, the active layer 606 can comprise, consist essentially of, or consist of the photoactive material and the electron acceptor, or the active layer 606 can comprise, consist essentially of, or consist of the photoactive material. As used herein, the term “consists essentially of” means that a layer can only include trace amounts, i.e., less than or equal to about 10 wt. %, of additional unavoidable impurity materials that do not substantially affect the activity (i.e., by less than about 10%) generated by the pairing of the electron donor (photoactive material) and electron acceptor.

[0171] The active layer or donor layer 606 may define a first or donor thickness 620. In at least one example embodiment, the first thickness 620 is greater than or equal to about 3 nm (e.g., greater than or equal to about 5 nm, greater than or equal to about 10 nm, greater than or equal to about 15 nm, greater than or equal to about 20 nm,Attorney Docket No. 6550-000525-WO-POAgreater than or equal to about 25 nm, greater than or equal to about 30 nm, greater than or equal to about 40 nm, greater than or equal to about 50 nm, greater than or equal to about 60 nm, greater than or equal to about 70 nm, greater than or equal to about 80 nm, or greater than or equal to about 90 nm). The first thickness 620 may be less than or equal to about 100 nm (e.g., less than or equal to about 90 nm, less than or equal to about 80 nm, less than or equal to about 70 nm, less than or equal to about 60 nm, less than or equal to about 50 nm, less than or equal to about 40 nm, less than or equal to about 30 nm, less than or equal to about 25 nm, less than or equal to about 20 nm, less than or equal to about 15 nm, less than or equal to about 10 nm, or less than or equal to about 5 nm).

[0172] The complementary layer 610 may define a second or acceptor thickness 622. In at least one example embodiment, the second thickness 622 is greater than or equal to about 3 nm (e.g., greater than or equal to about 5 nm, greater than or equal to about 10 nm, greater than or equal to about 15 nm, greater than or equal to about 20 nm, greater than or equal to about 25 nm, greater than or equal to about 30 nm, greater than or equal to about 40 nm, greater than or equal to about 50 nm, greater than or equal to about 60 nm, greater than or equal to about 70 nm, greater than or equal to about 80 nm, or greater than or equal to about 90 nm). The second thickness 622 may be less than or equal to about 100 nm (e.g., less than or equal to about 90 nm, less than or equal to about 80 nm, less than or equal to about 70 nm, less than or equal to about 60 nm, less than or equal to about 50 nm, less than or equal to about 40 nm, less than or equal to about 30 nm, less than or equal to about 25 nm, less than or equal to about 20 nm, less than or equal to about 15 nm, less than or equal to about 10 nm, or less than or equal to about 5 nm).

[0173] The PV 600 may define a third or overall thickness 624. In at least one example embodiment, the overall thickness 624 is greater than or equal to about 10 nm (e.g., greater than or equal to about 20 nm, greater than or equal to about 30 nm, greater than or equal to about 40 nm, greater than or equal to about 50 nm, greater than or equal to about 75 nm, greater than or equal to about 125 nm, greater than or equal to about 150 nm, greater than or equal to about 175 nm, greater than or equal to about 200 nm, or greater than or equal to about 225 nm). The overall thickness 624 may be less than or equal to about 250 (e.g., less than or equal to about 225 nm, less than or equal to about 200 nm, less than or equal to about 175 nm, less than or equal to about 150 nm, less than or equal to about 125 nm, less than or equal to about 100 nm, less than or equal toAttorney Docket No. 6550-000525-WO-POAabout 75 nm, less than or equal to about 50 nm, less than or equal to about 40 nm, less than or equal to about 30 nm, or less than or equal to about 20 nm).

[0174] Although not shown, in at least one example embodiment, the PV device 600 further includes one or more buffer layers (not shown) positioned between any of the layers 606, 610 and electrodes 602, 604. The buffer layers may block excitons, modify a work function or collection barrier, induce ordering or templating, and / or serve as optical spacers.

[0175] In at least one example embodiment, the electrodes 602, 604 may include thin metal (e.g., Ag, Au, Al, and / or Cu), indium tin oxide (ITO), tin oxide, aluminum doped zinc oxide, metallic nanotubes, metal nanowires (e.g., Ag, Au, Al, and / or Cu), conductive low-e stack, low-e single-silver stack, low-e double-silver stack, low-e triple-silver stack, or any combination thereof.

[0176] In at least one example embodiment, the substrate 608 may include glass, plastic (e.g., polyethylene, polycarbonate, polymethyl methacrylate, and / or polydimethylsiloxane), or any combination thereof. Multiple PVs 600 may be stacked monolithically or otherwise to form multifunction PVs.Example 1A. Introduction.

[0177] As the desire for sustainable and renewable energy sources increases, so too does the demand for the development of highly efficient and cost-effective solar technologies. Among the various approaches, LSCs have emerged as a promising technology to supplement PV systems due to their low cost and their ability to capture both direct and diffuse sunlight effectively diversifying where PVs can be implemented and enabling new market applications. LSCs generally include a lightguide doped or coated with luminophores that absorb sunlight and re-emit photons at a longer wavelength. The majority of emitted photons are waveguided via total internal reflection towards the PV cells. LSCs can reduce the amount of required PV material, reducing the overall cost. For an ideal LSC the maximum theoretical PCE is the same as the Shockley-Queisser limit of a single-junction solar cell at 33.7% when there is 100% absorption, luminescence, and collection efficiency along with ultranarrow emission (delta function), zero emission-absorption overlap (Heaviside function) and reduced Stokes shift. However, based on practical considerations, this value is reduced to 23.5% for an ideal device with only optical losses (from the lightguide efficiency and reflections), and 18.0% for a general device due to non-ideal luminescence and re-absorption losses. Today, theAttorney Docket No. 6550-000525-WO-POAhighest reported PCE of an opaque LSC (5x5 cm2, paired with four GaAs cells attached in parallel to the sides) is 7.1% based on a set of two organic luminophores with total absorption ranging from 350 nm to 600 nm that only integrates to a PCE of about 3.6% based on the reported EQE. Additionally, the reported EQE measurements show current generation at wavelengths longer than 600 nm, which is believed to be attributed to light scattered at the diffuse backside mirror. A recent consensus statement on the reporting protocol of power-producing LSCs emphasizes that direct illumination of the edgemounted PV results in a significantly overestimated short-circuit current density (Jsc). This value is among a significant number of highest LSC efficiencies reported that have been disputed and discussed as a result of questionable methods. Thus the highest reported PCEs with closely matching integrated EQEs are 6.8% and 3.65% and a certified PCE of 4.4%.

[0178] Diverse classes of luminophores with various wavelength-selectivity have emerged for LSC applications, including organic dyes, nanoclusters, quantum dots and rare-earth ion complexes. Multi-luminophore LSCs allow for maximized, full-spectrum light-harvesting but also often lead to a reduction in the PCE because of the overlap between the absorption and emission of the different luminophores, resulting in potentially severe reabsorption losses and reduction in the overall PLQY of the combined system which is often limited to the lowest PLQY of all the combined luminophores. This suggests that the improvement of the architecture of the LSC is just as important as that of the luminophores. To demonstrate the potential of full-spectrum LSCs, this example presents a novel LSC design based on an improved multi-lightguide architecture with multiple novel luminophores. In contrast to existing designs, the proposed methodology involves effectively harvesting through the ultraviolet (UV), visible (VIS), and nearinfrared (NIR) regions of the solar spectrum with the highest possible photoluminescence quantum yield (PLQY) for each spectral region. FIG. 7A schematizes the new ternarylightguide architecture, highlighting the important airgap strategy to isolate the absorption / emission bands of each luminophore (idealized in FIG. 7B). The luminophores targeting each of these spectral regimes were then selected, synthesized, and optimized with the highest achievable PLQY in the host polymer matrix, as shown in FIGS. 7C-7E. Among these luminophores, the newly synthesized benzothiadiazole based organic Donor-Acceptor-Donor (DAD) small molecules, DAD1 , (FIG. 7C) are distinguished by near-unity PLQY, broad absorption profile and low overlap integral between the absorption and luminescence. In turn, this leads to the highest PCE reported for a singleAttorney Docket No. 6550-000525-WO-POAcomponent LSC based on DAD1. By optimizing each of the single components, the combined total architecture leads to a ternary-luminophore LSC (50.8x50.8 mm2) that achieves a record PCE of 7.7% with a specular-reflective (non-scattering) background, the highest PCE among opaque LSC devices that is also self-consistent and directly comparable to other PV technologies.B. Full Spectrum Harvesting.

[0179] To exploit the maximum photon flux in the UV and VIS solar spectrum, this example sought to broaden the utility of newly synthesized and highly tunable based DAD systems. Central to the design, is benzothiadiazole, a versatile synthon which facilitated the generation of unique donor-acceptor architectures outlined in this example. Through novel design approaches and optimizations, these DAD fluorophores benefit from their unique excitonic character, and ability to largely tune their optical bandgaps across the spectrum by modulating both donor and / or acceptor moieties. DAD1 and DAD2 molecular structures along with their optical properties are presented in FIG. 7C and FIG.7D, respectively. The absorption profile of DAD1 shows two primary transitions: higher energy maxima at 355 / 360 nm attributed to the IT to IT* and n to IT* of the aminofluorene moiety and a lower energy band ( max 476 nm) arising from intramolecular charge transfer from the peripheral aminofluorene donor to the central benzothiadiazole acceptor core. As such, DAD1 is referred to as the UV-VIS1 component in the multi-luminophore LSC. When these compounds were first synthesized and measured for the PLQY in a range of polar and non-aromatic solvents (e.g. DCM, chloroform, ethanol) the PLQY were unremarkable and < 10%, but with substantial Stokes shift (180-265 nm). Surprisingly, when the PLQY is measured in toluene (non-polar aromatic), DAD1 shows a near-unity value of 98%, displaying ca. 80 nm hypsochromic shift in the maximum emission (FIGS.12-13, Table 3). While the rationale for this dramatic variation remains unknown, DAD1 retains a high PLQY of 95% within the non-polar host polymer matrix as well. These unique properties of DAD1 make it an important component in achieving high PCE.

[0180] Molecular engineering of the benzothiadiazole acceptor from DAD1 was redshifted via annulation of a second benzothiadiazole unit to the existing core yields bisbenzothiadiazole. Initial screening of similar alkylamino donors (such as in DAD1) paired to the bisbenzothiadiazole acceptors resulted in extensive red-shifted absorption and emission wavelengths. These spectral shifts, however, were associated with a significantly decreased PLQY. This necessitated a more electronically balanced donor / acceptor pair for the target optical window while reducing the PLQY loss. Notably,Attorney Docket No. 6550-000525-WO-POApairing a more electron rich donor, N-hexylcarbazole, with the bisbenzothiadiazole acceptor provided DAD2 which maintained the characteristic DAD absorption fingerprint (FIG. 7D) accompanied by a large red-shifted absorption compared to DAD1 (-150 nm, with the visible absorption peak at -630 nm). DAD2 is thus referred to as the VIS2 component. Analogous to DAD1 , the highest PLQY was measured in toluene at 70%, while achieving 40% in the polymer matrix (FIG. 14, Table 4). The emission of DAD2 peaks at 765 nm (135 nm Stokes shift), with a tailing extending to 900 nm, making it a viable emitter for both Si and GaAs-paired LSCs. The detailed synthesis and molecular characterization of DAD1 and DAD2 are reported in the supplementary information.

[0181] Lastly, to make use of the higher photon flux in the NIR spectrum, the third luminophore employed in the design of this example is a BODIPY derivative synthesized and demonstrated with absorption and emission maxima at 728 nm and 740 nm, respectively (FIG. 7E). Despite the small Stokes shift (12 nm), this BODIPY derivative shows a narrow emission width that limits reabsorption loss combined with a PLQY in polymer matrix slightly above 30% (in DOM solution up to 40%). These values are believed to be among the highest values for this NIR absorption and emission range.C. Single Components Optimization

[0182] Single-component LSC device optimization was first performed en route to an optimal multi-luminophore LSC device. The exhaustive optimization considered different parameters including the luminophore concentration and its solubility limit in the host polymer, and possible host-emitter interactions. The optimum PCE with and without a reflective background, and scalability based on optical modeling were studied in detail.

[0183] To improve the PCE of the single- and ternary-component LSCs, it is important to select PV cells with a bandgap that aligns closely with the emission edge of the selected luminophores. Si is a common PV cell mounted in LSCs, but the lower voltage (-0.55-0.60 V) leads to performance reduction unless the voltage drop is balanced with greater absorption closer to 1000 nm (a spectral region that is notably difficult from a luminescent molecular design perspective to reach with any PLQY greater than a few percent). Because the emission spectra of all luminophores are positioned below 900 nm, GaAs is an ideal PV for the edge-mounted cell, offering the potential to maximize PCE of LSC-PV devices by offering a high quantum efficiency (95% peak), high fill factor (0.80-0.81) and high open circuit voltage (1.0 V). The EQE of GaAs PV cell and emission spectra of each luminophore in the ternary LSC are reported in FIG.17.Attorney Docket No. 6550-000525-WO-POA

[0184] To ensure the accuracy of the measurements in this example, standard protocols for measuring the performance of LSC-PVs have been followed (including reporting of J-V, EQE, transmittance, reflectance, and photon balance data collection, including the J-V characteristics of a blank LSC-PV system- FIG. 18D and Table 8). For the J-V measurements, this example corrects for spectral irradiance mismatch between the light source and the reference (AM1.5G). This error is usually expressed as the mismatch correction factor (M), which has been calculated for all the measurements (see Note S1) and applied to correct the illumination intensity. Notably, all the M values are within + / -3 % of 1.0.

[0185] After optimization of the UV-VIS1 single component device, this example achieves a POE of 4.77% with a black background (FIGS. 8A-8D, Table 5). The EQE peak at 480 nm reaches 68% as a result of the near-unity PLQY (FIG. 8B). The practical EQE limit for an LSC is -72% due to the front side reflection (1-R = 96%) and light trapping efficiency in a lightguide with a 1.5 refractive index (qiightguide = 75%). Luminescence reabsorption is often a significant loss mechanism in LSCs. It is quantified by the overlap integral (QI, equation in Note S2), which is concentration dependent and is calculated as 3.9 for DAD1 at optimal conditions (FIG. 16A). For reference, the QI for LR305 (PLQY -100%, peak absorption near 80%) is estimated at -13 (FIG. 16D) where smaller values are more preferable to reduce reabsorption losses. Due to the small QI for DAD1 , the peak EQE values obtained from optical simulations highlight the suitability of DADI-LSCs for scaling up to practical sizes exceeding 1 m, even when used at high concentrations (FIG. 15A). With the incorporation of a specular-reflective background, the DAD1-LSC achieves a POE of 5.70% (FIG. 8D), the highest value reported for a single-luminophore LSC (Table 10).

[0186] In contrast for the VIS2 component, DAD2 has a considerably larger overlap integral (QI = 12.3, FIG. 16B) despite its still substantial Stokes shift. This is commonly observed when dealing with red-shifted luminophores, as a result of the increased vibrational states, larger conformational flexibility, and more potential isomeric states which broaden the absorption tail. The higher QI value is revealed in the results of the optical simulations, where the EQE peak drops from 25% to 10% if scaled up to 1 meter (FIG. 13). Increasing the concentration from 0.2 mg / mL to 1.0 mg / mL yields a PCE of 1.94% with a black background, resulting in 2.38% PCE when a specular reflective mirror is used for a double-pass LSC. These results are presented in FIGS. 8E-8H and Table 6.Attorney Docket No. 6550-000525-WO-POA

[0187] For the NIR component, the BODIPY achieves an optimal PCE value of 1.75% at 0.2 mg / mL when measured with a reflective background, despite maintaining a similar performance at the different concentrations (FIGS. 8I-8L, Table 7). The higher the concentration of BODIPY, the larger the overlap between the absorption and emission spectra is, thus BODIPY possesses the largest reabsorption loss (Ol= 54.5, FIG. 16C) and a concentration maximum for maximum performance. The larger Ol elucidates the lower EQE values of the NIR peak while increasing the concentration from 0.1 mg / mL to 0.8 mg / mL, thus explains the optimal conditions.

[0188] Optimal single-component LSC-PV devices are summarized in Table 1 , below, and then used for multicomponent, multi-lightguide ternary device optimization incorporating DAD1 , DAD2, BODIPY (Table 1).

[0189] Table 1. Photovoltaic parameters of opaque single component-LSCs at the optimal concentration for DAD1 , DAD2 and BODIPY, measured with a specular reflective mirror as a background.D. Ternary LSC Device Structure and Optimization.

[0190] Based on the individual-LSC optimization, the configuration of the multi-luminophore LSC is as follows: the first lightguide is DAD1 (UV-VIS1 component), as it possesses the highest PLOY (95%), thus ensuring the maximum efficient photon harvesting. The second layer is DAD2, the VIS2 absorbing compound with the second highest PLOY (40%), and lastly is NIR BODIPY with the lowest PLOY (30%). This is referred to as the ternary-LSC. As illustrated in FIG. 7A, the three discrete lightguides are separated with an air gap to optically isolate the waveguided luminescence in each lightguide, thus reducing or preventing parasitic reabsorption. For example, when all the luminophores of the ternary-LSC are stacked without an airgap, the efficiency falls to about4% as they become nearly limited by the lowest PLOY (FIGS. 19A-19C).

[0191] The absolute absorbance of the ternary-LSC is shown in FIG. 9A, highlighting the full spectrum absorption in the 300-750 nm range. The optimal luminophore stacking was found to follow the ordering of highest PLQY first and theAttorney Docket No. 6550-000525-WO-POAlowest last. When measured with a matte black background, the EQE peaks at 66% at 490 nm due to the high PLQY (95%) of DAD1 , while achieving a maximum 20% from DAD2 at 650 nm, and 13% from BODIPY at 720 nm (FIG. 9B). These values are consistent with the measured PLQY and absorption of the individual LSCs, accounting for reflections from the stacked lightguides. The integrated photo-current densityfrom this EQE profile is 8.68 mA / cm2. This value is consistent with the measured current ((Jseas= 8-73 mA / cm2) from the J-V curve presented in FIG. 9C and results in the highest self-consistent LSC-PCE, with a value of 6.9%. FIG. 9B shows the same device measured with a specular reflective mirror for a double-pass opaque device (following the blank LSC optimization with different backgrounds, FIGS. 18A-18D). The EQE peaks increase due to reflection of the unabsorbed photons back to the device, where the maximum benefit is observed for the bottom layers, namely BODIPY and DAD2, with 20% and 10% increase in the EQE values, while the peak of DAD1 gets the minimum increase of only 5%, as most of the photons have been already absorbed. This enhancement results in9.87 mA / cm2(M= 1.03), and J™asof 9.92 mA / cm2, resulting in a record POE for a self-consistent opaque LSC, reaching 7.7%. A summary of the champion device photovoltaic parameters is presented in Table 2, below.

[0192] Table 2. Photovoltaic parameters of the champion ternary device with black and reflective silver backgrounds.

[0193] Another important consistency check to validate the performance of the ternary-LSC is the photon balance. FIG. 9D shows the three different independent measurements used for the photon balance check, including the transmittance T(A), the reflectance R(A), and the EQE(A) at every wavelength. The photon balance (EQE(A)+T(A)+R(A) < 1) is shown to be consistent, further helping give confidence in the values reported in this example. Furthermore, the inclusion of the EQE in the photon balance allows for the inclusion of optical losses where the luminophores absorb. This limits the photon balance to 72% where the near-unity PLQY DAD1 absorbs, as seen at around 490 nm, providing another consistency check of the presented data.Attorney Docket No. 6550-000525-WO-POA

[0194] This example looks ahead and considers strategies to further enhance the LSC performance to approach theoretical and practical limits. Approaching the PCE limit necessitates a near-unity PLQY for all materials used while achieving full-spectrum harvesting. The largest parameter to tackle is the PLQY in the NIR region, which is currently 30-35% for the BODIPY derivative. Chemical design of new NIR luminophores could provide a path to overcome these obstacles despite synthetic challenges, improving the PLQY value closer to 80%. To account for the possibility of higher PLQY, a simulated EQE is presented in FIGS. 20A-20C for three different scenarios, where PLQY is considered as 80% for (A) BODIPY, (B) DAD2, and (C) both BODIPY and DAD2. This simulation assumes moderately low reabsorption loss, as the PLQY is not the only parameter hindering the performance of the NIR component, but also the relatively large overlap between the absorption and emission spectra. Under these assumptions, the estimated overall efficiency can reach >12%, closer to the practical theoretical limit (Table 9).

[0195] Finally, LSC lifetime is an important metric. The photostability of each single-component LSCs were studied and are shown in FIG. 21. The absorbance A(A) spectrum is used to monitor the degradation of total light absorption for each luminophore as the PLQY and attached PV cell are essentially unchanging with time. While BODIPY-LSC shows almost no photodegradation upon continuous light irradiation under 1 sun past 1300 hours, the DAD1-LSC maintains 75% of its initial performance, while DAD2-LSC shows a significant degradation, revealed in the photobleaching of the absorption after 600 hours. Previous literature on molecular changes and molecular salt counterion changes have demonstrated effective methods to enhance the lifetime of organic molecules. Studying different acceptor moieties for the DAD1 molecule, this example has found that different acceptors on both extremities of DAD1 can maintain high PLQY while extending the lifetime significantly, maintaining about 100% of the performance for over 1000 hours. Moreover, converting these neutral molecules to molecular salts (e.g. via straightforward quaternization) counterion selection could further enhance photostability to extrapolated lifetimes of many years.E. Conclusion.

[0196] This example demonstrates an LSC device employing a multi-luminophore composition with a multi-lightguide design. This architecture incorporates distinct lightguides, each containing highly luminescent materials with complimentary absorption profiles spanning the ultraviolet, visible, and near-infrared from 300 nm to 750 nm,Attorney Docket No. 6550-000525-WO-POAincluding novel donor-acceptor-donor (DAD) molecules with quantum yield close to unity. Exploiting the high PLQY (95%) of DAD1 , along with the low overlap integral, and strong (and wide) absorption result in a world record single component LSC of 5.7% PCE. This example further sets a multi-luminophore efficiency record of 7.7% PCE with important self-consistency checks (as with other PV cells) by positioning the visible component DAD1 , the highest PLQY as the top layer, and layering the other components in a decreasing order of PLQY, with the VIS2 DAD2 as the second component and the NIR BODIPY as the bottom layer in discrete waveguides. These devices set a new benchmark for LSC-PV devices and help identify important pathways for future improvements and commercialization.F. Supplementary Information.

[0197] FIGS. 10A-1 OC illustrate a synthetic scheme for synthesis of DAD1.

[0198] The donor-acceptor-donor was synthesized in 6 linear steps starting from commercially available 2,1 ,3 benzothiadiazole. Bromination in the presence of bromine and acetic acid yielded the dibromo acceptor which was subsequently di-borylated yielding acceptor Compound 2. Next, 2-bromo-9,9-dimethyl fluorene was first nitrated, then reduced to the free amine using iron and ammonium chloride. Alkylation of the amino group took place in the presence of potassium carbonate and ethyl iodide, furnishing donor moiety Compound 5. Suzuki coupling between acceptor Compound 2 and Compound 5, yielded the donor-acceptor-donor Compound 6 in 56% yield.

[0199] FIG. 10D illustrates synthesis of Compound 1 : 4,7-dibromobenzo[c][1 ,2,5]thiadiazole according to at least one example embodiment.

[0200] To a 500 mL 3 neck round bottom flask, was added benzo[c][1 ,2,5]thiadiazole (10.0 g, 73.44 mmol, 1 equiv), and 150 mL HBr (48%), and the mixture was stirred at 60°C for a period of 15 min. After this time, bromine (11.3 mL, 220 mmol, equiv) dissolved in 130 mL HBr (48%) was added via addition funnel over the period of 1 hour (slowly) to the reaction mixture. After complete addition a reflux adapter was attached, and the reaction brought to reflux (125°C) for a period of 6 hours. The reaction turned a dark red color with visible orange solids forming during reflux. Once the reaction was complete, 500 mL saturated sodium bisulfite was added to quench excess bromine. The precipitate was then subsequently filtered via vacuum filtration, washed with 250 mL water, followed by 50 mL of ice-cold ether. The semi-dried washed crude was dried further under vacuum overnight, yielding a fluffy yellow solid. Compound 1Attorney Docket No. 6550-000525-WO-POA(19.5 g, 90%). 1 H-NMR (500 MHz, CDCI3) 5 (ppm) 7.73 (s, 2H). 13C-NMR (126 MHz CDCI3) 5 (ppm) 153.12, 132.52, 114.07.

[0201] Compound 1 was synthesized according to a previously reported procedure: H. Akpinar, A.; Balan, D.; Baran, E. K. Unver.; L. Toppare. Donor-acceptor-donor type conjugated polymers for electrochromic applications: benzimidazole as the acceptor unit. Polymer, 2010, 51 , 6123-6131 , which is incorporated herein by reference in its entirety.

[0202] FIG. 10E illustrates synthesis of Compound 2: 4,7-bis(4,4,5,5-tetramethyl-1 ,3,2-dioxaborolan-2-yl)benzo[c][1 ,2,5]thiadiazole.

[0203] To a degassed mixture of Compound 1 (200 mg mmol, equiv), potassium acetate (1.1 g, mmol, equiv), B2Pin2 (518 mg, mmol, equiv), all dissolved in anhydrous DME (16 mL was added PdCl2(dppf)*CH2Cl2 (25 mg mmol, equiv). The resultant mixture was stirred under an atmosphere of argon at 100 °C for 14 hours. After this time, the mixture was cooled to room temperature and filtered by vacuum, before concentrating the filtrate under reduced pressure. The resulting crude solid was then subject to flash column chromatography (25% DCM in hexanes) yielding a pale-yellow solid. Compound 2 (0.20 g, 39 %). 1 H-NMR (500 MHz, CDCIs) 5 (ppm) 8.13 (s, 2H), 1.44 (s, 24H). 13C-NMR (126 MHz, CDCI3) 5 (ppm) 138.84, 137.92, 137.21 , 84.72, 84.60, 77.41 , 77.36, 77.16, 76.91 , 25.17, 25.06, 1.17. HRMS (ESI+): calcd. for C18H26B2N2O4S [M+H]: 389.1872; found 389.1884.

[0204] Compound 2 was synthesized according to a previously reported procedure: Sun, N.; Wang, C.; Wang, H.; Yang, L.; Jin, P.; Zhang, W.; Jiang, J. Multifunctional Tubular Organic Cage-supported Ultrafine Palladium Nanoparticles for Sequential Catalysis. Angewandte Chemie 2019, 131 (50), 18179-18184, which is incorporated herein by reference in its entirety.

[0205] FIG. 10F illustrates synthesis of Compound 3: 2-bromo-9,9-dimethyl-7-nitro-9H-fluorene.

[0206] To a stirred solution of Compound 2 (2.0 g, 7.34 mmol, equiv) in glacial acetic acid (20 mL) and acetic anhydride (20 mL) was dropwise added 9.4 mL of nitric acid (65%) via syringe at 0°C. The resulting reaction mixture was then warmed to room temperature and stirred for about 8 h, until Compound 2 was fully consumed by TLC (1 % EtOAc in hexanes). After this time, the reaction mixture was poured into 200 mL of deionized water, and an orange-yellow precipitate formed in the solution. The solid was filtered, washed with water (3 x 8.0 mL), dried under vacuum at 50 °C, and subsequentlyAttorney Docket No. 6550-000525-WO-POArecrystallized from acetonitrile yielding as a pale-yellow solid. Compound 3 (1.61 g, 70 %). 1 H NMR (500 MHz, CDCI3) 58.30 - 8.24 (m, 2H), 7.81 (m, 1 H), 7.67 (d, J = 8.1 Hz, 1 H), 7.64 (d, J = 1.8 Hz, 1 H), 7.55 (dd, J = 8.1 , 1.8 Hz, 1 H), 1.55 (s, 6H).13C NMR (126 MHz, CDCI3) 5 156.94, 154.24, 147.42, 144.61 , 135.81 , 130.88, 126.61 , 123.69, 123.56, 122.75, 120.27, 118.38, 47.58, 26.65.

[0207] Compound 3 was synthesized according to a previously reported procedure: Chen, P.; Wang, H.-M.; Liu, G.-J.; Zhang, S. X.-A. Design, Synthesis and Properties of near-infrared Molecular Switches Containing a Fluorene Ring. Organic & Biomolecular Chemistry , 2016, 14, 4456-4463, which is incorporated herein by reference in its entirety.

[0208] FIG. 10G illustrates synthesis of Compound 4: 7-bromo-9,9-dimethyl-9H-fluoren-2-amine.

[0209] A mixture of Compound 3 (1.61 g, 5.08 mmol, equiv), iron powder (0.851 g, 15.25 mmol, 3.0 equiv.) and ammonium chloride (0.543 g, 10.17 mmol, 2.0 equiv) was dissolved in an aqueous solution of ethanol (40 mL EtOH / 11 mL H2O) and subsequently refluxed under an argon atmosphere for 4 hours. After complete consumption of Compound 3 by TLC, the reaction mixture was added 20 mL of aqueous saturated sodium bicarbonate and filtered by vacuum. After removing most of the ethanol from the resultant filtrate under reduced pressure, the mixture was filtered. The solid obtained was then washed with water (3 x 10 mL) and dried under vacuum at 50 °C, to give as an orange-brown solid, which was used in the next step without further purification. Compound 4 (1.18 g, 81 %). 1 H-NMR (500 MHz, CDCI3) 5 (ppm) 7.47 (dd, J = 4.9, 3.1 Hz, 2H), 7.44-7.37 (m, 2H), 6.73 (d, J = 2.2 Hz, 1 H), 6.66 (dd, J = 8.1 , 2.2 Hz, 1 H), 3.80 (s, 2H), 1.43 (s, 6H).13C-NMR (126 MHz, CDCI3) 5 (ppm) 155.22, 154.87, 146.50, 138.69, 129.87, 129.15, 125.83, 121.04, 120.03, 119.06, 114.14, 109.36, 46.85, 27.17.

[0210] Compound 4 was synthesized according to a previously reported procedure: Chen, P.; Wang, H.-M.; Liu, G.-J.; Zhang, S. X.-A. Design, Synthesis and Properties of near-infrared Molecular Switches Containing a Fluorene Ring. Organic & Biomolecular Chemistry 2016, 14 (19), 4456-4463, which is incorporated herein in by reference in its entirety.

[0211] FIG. 10H illustrates synthesis of Compound 5: 7-bromo-N,N-diethyl-9,9-dimethyl-9H-fluoren-2-amine.

[0212] To a solution of Compound 4 (1.53 g, 1.73 mmol) in anhydrous DMF (20 mL) was added potassium carbonate (720 mg, 5.21 mmol, 3.0 equiv) portion wise,Attorney Docket No. 6550-000525-WO-POAfollowed by iodoethane (0.49 mL, 6.08 mmol, 3.5 equiv).The resulting reaction mixture was stirred at 80 °C for 10 h, and then cooled to room temperature. After removing the solvent (DMF) under reduced pressure at 30 °C, the residue was diluted with dichloromethane (100 mL) and water (20 mL). The organic phase was separated, and the aqueous layer was extracted with dichloromethane (70 mL). The combined organic layers were sequentially washed with water (40 mL) and brine (40 mL), before being dried over anhydrous Na2SO4. The dried organic layers were subsequently concentrated under reduced pressure, yielding a crude residue, which was purified by flash column chromatography on silica gel, [hexanes, to hexanes / ethyl acetate 99:1] to afford a pale orange-yellow solid. Compound 5 (0.87 g, 47% yield). 1 H-NMR (500 MHz, CDCIs) 5 (ppm) 7.51 (d, J = 8.4 Hz, 1 H), 7.45 (d, J = 1.7 Hz, 1 H), 7.41 -7.35 (m, 2H), 6.69-6.63 (m, 2H), 3.42 (q, J = 7.1 Hz, 4H), 1.44 (s, 6H), 1.21 (t, J = 7.1 Hz, 6H). 13C-NMR (126 MHz, CDCI3) 5 155.16, 154.80, 148.04, 139.05, 129.76, 125.98, 125.67, 121.02, 119.62, 118.25, 110.76, 105.51 , 77.26, 77.21 , 77.01 , 76.75, 46.90, 44.69, 27.36, 12.60.

[0213] Compound 5 was synthesized according to a previously reported procedure: (see Chen et al. for Compound 4, above).

[0214] FIG. 10I illustrates synthesis of DAD1.

[0215] Compound 2 (330 mg, 0.96 mmol, 1.0 equiv), and Compound 5 (388 mg, 0.48 mmol, 2.2 equiv), followed by anhydrous K2CO3 (663 mg, 4.8 mmol, 10.0 equiv) were weighed in a two-necked round-bottom flask. Air was removed from the flask by vacuum, and argon gas was subsequently introduced; this cycle was repeated three times. Then, Pd(PPh3)4 (83.0 mg, 0.04 mmol, 0.15 equiv) was added under a counterflow of argon, followed by the addition of the degassed THF / H2O [2:1] mixture (20 mL). The reaction mixture was refluxed at 70 °C for 18 hours. After cooling to room temperature, the reaction was added water (20 mL) and ethyl acetate (20 mL) before transferring and separating the organic layer. The aqueous layer was washed with an additional 20 mL ethyl acetate, followed by dichloromethane (20 mL), dried over magnesium sulfate, and solvent removed under reduced pressure, yielding a brownish solid. The resultant crude residue was purified twice by column chromatography; 1st (20% EtOAc in hexanes) then CH2Cl2 / MeOH (100% DCM, to 5% MeOH) yielding a bright orange solid. Compound 6 (0.145 g, 46%). 1 H-NMR (500 MHz, CDCI3) 5 7.98-7.97 (m, 2H), 7.96 (d, J = 1.7 Hz, 2H), 7.86 (s, 2H), 7.73 (dd, J = 7.6, 0.9 Hz, 2H), 7.63 (d, J = 8.4 Hz, 2H), 6.77 (d, J = 2.4 Hz, 2H), 6.71 (dd, J = 8.4, 2.4 Hz, 2H), 3.47 (q, J = 7.1 Hz, 8H), 1.58 (s, 12H), 1.25 (t, J = 7.1 Hz, 12H). 13C-NMR (126 MHz, CDCI3) 5 156.21 , 154.53,Attorney Docket No. 6550-000525-WO-POA153.20, 148.15, 140.50, 134.28, 133.53, 128.43, 127.82, 126.91 , 123.32, 121.43, 118.51 , 110.85, 105.77, 77.42, 77.36, 77.16, 76.91 , 47.02, 44.86, 27.76, 12.84. HRMS (ESI+): calcd. for C44H47N4S [M+2H]2+: 332.1794, found 332.1774.

[0216] DAD1 was prepared from an adaptation of a previously reported procedure: Naeem, K. C.; Neenu, K.; Nair, V. C. Effect of Differential Self-Assembly on Mechanochromic Luminescence of Fluorene-Benzothiadiazole-Based Fluorophores. ACS Omega 2017, 2 (12), 9118-9126, which is incorporated herein by reference in its entirety.

[0217] FIGS. 11 A-11 C illustrate a synthetic Scheme for Synthesis of DAD2.

[0218] The donor-acceptor-donor was synthesized in 6 steps, starting from Compound 1. Initial treatment of 1 with nitrating mixture (HNO3 / TfOH) yielded Compound 6. Dinitro reduction in the presence of iron dust and acetic acid yielded the free diamine Compound 7. Bisbenzothiadiazole 8 was then obtained via annulation of 7 with SOCI2, generating acceptor 8. Carbazole donor was synthesized from initial N-alkylation of commercially available 2-bromo-9H-carbazole yielding 9, followed by subsequent borylation of the C2-bromo afforded donor 10. Suzuki coupling between acceptor 8 & donor 10 produced DAD2 in 30% yield.

[0219] FIG. 11 D illustrates synthesis of Compound 6: 4,7-dibromo-5,6-dinitrobenzo[c][1 ,2,5]thiadiazole.

[0220] To a 2-neck round bottom flask, was added fuming nitric acid (1.0 mL, 23.8 mmol) followed by trifluoromethanesulfonic acid (8.8 mL, 100 mmol) and the mixture was cooled for 20 minutes to 0 °C. Then, Compound 1 (2.5 g, 8.50 mmol, 1 equiv) was added portion wise over a period of 30-45 min to the cold mixture. Following addition, the mixture was heated to 50 °C, for 12 hours, and monitored by TLC. After cooling the reaction mixture, it was poured into ice water. The precipitate was filtered and washed with cold water, then purified by recrystallization from ethanol and acetone, yielding a bright yellow solid. Compound 6, (4.80 g, 73%). 1 H-NMR: No 1 H-NMR signals were observed. 13C-NMR (125 MHz,CDCI3) 5 ppm: 151.36, 127.49, 110.29.

[0221] Compound 6 was synthesized according to a previously reported procedure: Murali, M. G.; Rao, A. D.; Ramamurthy, P. C. New Low Band Gap 2-(4-(Trifluoromethyl)Phenyl)-1 H-Benzo[d]lmidazole and Benzo[1 ,2-c;4,5- C']Bis[1 ,2,5]Thiadiazole Based Conjugated Polymers for Organic Photovoltaics. RSC Advances. 2014, 4, 44902-44910, which is incorporated herein by reference in its entirety.Attorney Docket No. 6550-000525-WO-POA

[0222] FIG. 11 E illustrates synthesis of Compound 7: 4,7-dibromobenzo[c][1 ,2,5]thiadiazole-5,6-diamine.

[0223] To a stirred solution of Compound 6 (2.0 g, 5.23 mmol) in glacial acetic acid (40 ml), was added iron dust (3.51 g, 62.76 mmol) was added portion wise at 0 °C. The reaction mixture was stirred at ambient temperature for 12 h. Then the reactant was poured into ice cold water and the precipitate was filtered off. The obtained product was washed with water, followed by a small amount of cold, methanol to get yellow solid as a yellow-brown solid. Compound 7 (1.0 g, 60%). 1 H-NMR (500 MHz, dmso-d6) 56.36 (s, 4H). 13C-NMR (126 MHz, dmso-d6) 5 148.29, 140.45, 88.95.

[0224] Compound 7 was synthesized according to a previously reported procedure (see Murali et al. for Compound 6).

[0225] FIG. 11 F illustrates synthesis of Compound 8: 4,8-dibromo-1 H,5H-benzo[1 ,2-c :4,5-c'] bis([ 1 ,2,5]thiadiazole).

[0226] To a two neck round bottom flask under an inert atmosphere, was added a solution of Compound 7 (0.400 g, 1.24 mmol) in dry dichloromethane (8 ml), followed by triethylamine (0.7 ml, 4.94 mmol). To this stirred solution, anhydrous thionyl chloride (0.18 mL, 2.48 mmol) was added drop wise at 0 °C. The reaction mixture was stirred at 50 °C for 12 h. After completion of the reaction, the reactant was poured into ice cold water and acidified with concentrated HCI. The obtained solid product was filtered off, washed with water and followed by methanol. The crude product was purified by column chromatography using hexane-ethyl acetate (10 :2) as the eluent. The pure product was obtained as dark red solid. Compound 8 (0.320 g, 74%) 1 H-NMR: No 1 H-NMR signals were observed. 13C-NMR: Due to poor solubility in common deuterated solvents, no 13C-NMR was obtained.

[0227] Compound 8 was synthesized according to a previously reported procedure (see Murali et al. for Compound 6).

[0228] FIG. 11G illustrates synthesis of Compound 9: 2-bromo-9-hexyl-9H-carbazole.

[0229] A mixture of 2-bromo-9H-carbazole (2.0 g, 8.50 mmol, 1 equiv), 1-bromohexane (1.2 mL, 8.56 mmol, 1.1 equiv) TEBA [benzyltriethylammonium chloride] (186 mg, 0.82 mmol, 0.1 equiv ), was dissolved in toluene (20 mL) and subsequently, an NaOH solution (0.25 g in 0.5 mL water) was added, and the mixture stirred at 80 °C for 14 h. The reaction was then cooled to room temperature, poured into 30 mL of water and acidified with 10% hydrochloric acid to pH of about 2 (about 5 mL). The organic layer wasAttorney Docket No. 6550-000525-WO-POAseparated, and water layer additionally extracted with toluene (2 x 30 mL). Combined extracts were washed with water (2 x 15 mL), dried over Na2SO4, filtered and evaporated to dryness. The obtained crude products of the alkylation reaction were purified by column chromatography (100% hexanes) yielding a white solid. Compound 9, (2.4 g, 90 %).1H-NMR: (500 MHz, Chloroform-d) 5 8.06 (d, J = 7.8 Hz, 1 H), 7.94 (d, J = 8.3 Hz, 1 H), 7.54 (d, J = 1.7 Hz, 1 H), 7.48 (ddd, J = 8.2, 7.0, 1.2 Hz, 1 H), 7.40 (d, J = 8.5 Hz, 1 H), 7.32 (dd, J = 8.3, 1.7 Hz, 1 H), 7.26 - 7.19 (m, 1 H), 4.25 (t, J = 7.3 Hz, 2H), 1.85 (t, J = 7.5 Hz, 2H), 1.41 - 1.17 (m, 6H), 0.87 (t, J = 7.0 Hz, 3H). 13C-NMR: (126 MHz, CDCI3): 5 141.24, 140.57, 126.04, 122.31 , 121.87, 121.78, 121.48, 120.35, 119.29, 119.21 , 111.75, 108.90, 43.22, 31.56, 28.86, 26.93, 22.56, 14.03.

[0230] Compound 9 was prepared according to a previously reported procedure: Jursenas et al. Heterocyclic heptacene analogs e 8H-16,17-epoxydinaphto[2,3-c:20,30g]carbazoles as charge transport materials. Dyes & Pigments, 2016, 124, 133-144, which is incorporated herein by reference in its entirety.

[0231] FIG. 11 H illustrates synthesis of Compound 10: 9-hexyl-2-(4, 4,5,5-tetramethyl-1 ,3,2-dioxaborolan-2-yl)-9H-carbazole.

[0232] Compound 9 (2.5 g, 7.57 mmol), B2Pin2 (2.1 g, 8.33 mmol), Pd2(dppf)Cl2 (277 mg, 0.38 mmol) and K2CO3 (2.23 g, 22.7 mmol) were dissolved in anhydrous1 ,4 dioxane (75 mL), and the stirred mixture was heated at 85° C under argon for 22 hours. After being cooled to room temperature, EtOAc (200 mL) was added, the mixture transferred to a separatory funnel, and subsequently washed with water (100 mL), brine (100 mL), and dried over anhydrous sodium sulfate before loaded on silica gel and purified by flash column (100% hexanes--> 5% EtOAc / Hexanes, yielding a white solid. Compound 10 (2.20 g, 77%). 1 H-NMR: (500 MHz, Chloroform-d) 58.14 - 8.09 (m, 2H), 7.88 (s, 1 H), 7.69 (d, J = 7.7 Hz, 1 H), 7.50 - 7.47 (m, 1 H), 7.43 (m, 2H), 7.22 (t, J = 7.4 Hz, 1 H), 4.35 (t, J = 7.3 Hz, 2H), 1.93 - 1.77 (m, 2H), 1.41 (s, 12H), 1.32 - 1.23 (m, 6H), 0.88 (t, J = 6.8 Hz, 3H).13C-NMR: (126 MHz, CDCI3): 5 140.97, 139.97, 126.20, 125.37, 124.98, 122.62, 120.82, 119.65, 118.70, 115.08, 108.87, 83.79, 42.99, 31.65, 29.10, 26.95, 24.98, 22.63, 14.11.

[0233] Compound 10 was synthesized based on a previous report (see Sun et al. for Compound 2).

[0234] Compound 10 (73 mg, 0.19 mmol, 2.0 equiv), and Compound 8 (34 mg, 0.1 mmol, 1.0 equiv), followed by K2CO3 (133 mg, 0.97 mmol, 10.0 equiv) added to a sealed tube which was pre-purged with argon. Then, Pd(PPhs)4 (16 mg, 0.014 mmol,Attorney Docket No. 6550-000525-WO-POA0.15 equiv), followed by the addition of the degassed mixture THF / H2O [(2:1 ), 2 mL] was added and the reaction mixture was refluxed at 70 °C for 18 hours, before cooling to room temperature. Dichloromethane was added, and the organic layer was separated. The aqueous layer was washed with DCM (5 mL, x 3) and dried over anhydrous sodium sulfate. The crude residue was purified by column chromatography (DCM / MeOH, 99:1). The dark blue-green product containing fractions, identified by sampling on ESI-MS (M2+= 346) were combined and dried. To the residue, methanol was added, followed by brief sonication before adding DCM dropwise, followed by subsequent sonication, until a dark yellow / green color filtrate was observed. The solid was transferred to a funnel with a cotton plug, where additional portions of MeOH / DCM were added until no color remained from rinsing the solid. The resultant purified solid was then dissolved in DCM and evaporated, yielding a dark blue residue. DAD2 (0.065 g, 30%). 1 H-NMR (500 MHZ,CDCI3) 58.36 (d, J = 8.1 Hz, 2H), 8.33 (d, J = 1.4 Hz, 2H), 8.20 (d, J = 7.5 Hz, 2H), 8.12 (dd, J = 8.0, 1.4 Hz, 2H), 7.54 - 7.51 (m, 2H), 7.48 (d, J = 8.1 Hz, 2H), 7.29 (dd, J = 7.9, 7.1 Hz, 2H), 4.42 (t, J = 7.2 Hz, 2H), 1.96 (p, 2H), 1.45 (td, J = 8.8, 4.2 Hz, 2H), 1.36 - 1.29 (m, 4H), 0.86 (t, J = 7.0 Hz, 3H).13C-NMR (126 MHz, CDCI3) 5 153.18, 141.44, 140.47, 132.30, 126.17, 123.53, 122.75, 122.68, 122.35, 120.81 , 120.14, 119.00, 112.64, 108.83, 43.31 , 31.64, 29.09, 27.08, 22.57, 14.07. HRMS (ESI+): calcd. for C42H4ON6S2 [M+H]: 693.2829; found 693.2825.

[0235] FIG. 111 illustrates synthesis of DAD2. DAD2 was synthesized in an analogous manner to DAD1.H. Supplementary Text

[0236] Materials and Methods.

[0237] DAD1 , DAD2, and BODIPY lightguides.

[0238] DAD1 and DAD2 solutions were prepared in toluene, while BODIPY solutions were prepared in DCM. To prepare the LSCs, the solutions were prepared with the desired concentrations, then mixed with mounting medium (Shandon, Thermo Fisher Scientific) at a volume ratio of 1 :2. The mixtures were well-mixed and then drop-casted on 50.8 mm x 50.8 mm x 3.175 mm borosilicate glass sheets and allowed to dry for 6 h in a glovebox filled with nitrogen gas (02, H2O < 1 ppm).

[0239] Single component and Ternary LSCs.

[0240] The edge-mounted GaAs PVs (Alta Devices) were used as received. Optically transparent refractive index matching gel (Thorlabs) was used to bind the attach GaAs PV with one edge of the LSC. The other three edges were blackened and maskedAttorney Docket No. 6550-000525-WO-POAwith black tape. To block any direct illuminations, a black mask with a well-defined area was also placed right above the PV-mounted edge of LSC. Correcting the raw data to account for 4 cell integration was done according to the standardized protocols reported elsewhere.1 Based on the single-luminophore LSC results, the 3-LSC is built as follows: 4 mg / mL (UV-VIS1), 1 mg / mL DAD2 (VIS2), and 0.2 mg / mL BODIPY (NIR). To avoid reabsorption losses, an airgap of ca. 50pm was kept between each waveguide using surlyn spacer.

[0241] Optical Characterization.

[0242] The specular transmittance (T(A)) of LSCs was measured using a dualbeam Lambda 800 UV / VIS spectrometer in transmission mode. No comparative sample was situated on the reference beam segment for assessing the transmittance of solidfilm LSCs. The reflectance (R(A)) of the LSCs was also quantified using a Lambda 800 UV / VIS spectrometer, employing the 6° specular accessory affixed to the sample beam side. Photoluminescence (PL) of luminophores within the polymer matrix were measured using a PTI QuantaMaster 40 spectrofluorometer. PLQY of DAD1 , DAD2, and BODIPY were determined utilizing a Hamamatsu Quantaurus fluorometer.

[0243] Photovoltaic Characterization.

[0244] J-V characteristics were acquired utilizing a Keithley 2420 SourceMeter. The surface of the LSCs was illuminated using AM 1 ,5G solar simulator with irradiance of 100 mWcm-2. To ensure precise light intensity measurements, calibration was performed using an NREL-certified Silicon (Si) reference diode fitted with a KG5 filter. For position-dependent EQE measurements, a QTH lamp, along with calibrated Si detector, monochromator, chopper, and lock-in amplifier, was employed. The measured EQE(A) at different distances (d) was adjusted using a correction factor g = n7tan-1(L / 2d), which accounts for the varying angle at which the edge-mounted PV is illuminated at different excitation distances (d), where L represents the LSC waveguide length. Integrated JSC from EQE(A) spectra was employed to confirm the JSC from the corresponding J-V characteristics of the same device. A matte black background was positioned behind the LSC device in order to avoid direct illumination or reflection (double-pass) during J-V and EQE measurements.

[0245] Note S1 : Mismatch Factor (M).

[0246] For each device with distinct EQE, the spectral mismatch factor, M, is calculated as follows:Attorney Docket No. 6550-000525-WO-POAwhere ERef is the reference spectral irradiance (AM1.5G), ES is the source spectral irradiance (solar simulator lamp), SR is the reference spectral responsivity (Newport-calibrated Si diode), and ST is the device spectral responsivity (device EQE).

[0247] Note S2: Overlap integral (Ol).

[0248] The overlap integral is a convenient metric to quantify the reabsorption losses in LSCs, and it is calculated as follows [4],>

[0249] Where A(A) is the absolute absorption spectrum (1-T(A) -R(A), T(A) is the transmission and R(A) is the reflection) of the luminophore-LSC, and PL(A) is the normalized emission spectrum of the luminophore in the same conditions (same host material). As such, the Ol quantifies the degree of overlapping between the absorption and emission spectrum of the luminophore in the LSC host material, and depends on the luminophore concentration (or layer thickness).

[0250] The Ol is calculated for DAD1 , DAD2, and BODIPY with the optimal conditions, and presented in FIGS. 16A-16C.

[0251] FIG. 12 illustrates DAD1 absorption and emission spectra in different solvents: chloroform, O-xylene, and toluene.

[0252] FIG. 13 illustrates DAD1 absorption and emission spectra in different polymer matrices.

[0253] FIG. 14 illustrates DAD2 absorption and emission spectra in different solvents.

[0254] FIGS. 15A-15C related to optical simulation for the single component-LSCs scalability: Peak EQE of different luminophore concentration as a function of the LSC plate. FIG. 15A is for DAD1. FIG. 15B is for DAD2. FIG. 15C is for BODIPY.

[0255] FIGS. 16A-16D illustrate absorption and emission of the single luminophore-LSC in the optimal conditions with the calculated overlap integral (Ol). FIG.16A is for DAD1. FIG. 16B is for DAD2. FIG. 16C is for BODIPY. FIG. 16D is for LR305 as a reference luminophore.

[0256] FIG. 17 is a graph illustrating luminophore emissions in host material of DAD1 , DAD2, and BODIPY. The EQE of the edge-mounted GaAs is presented as the dotted line.Attorney Docket No. 6550-000525-WO-POA

[0257] FIGS. 18A-18D relate to J-V characteristics of a blank LSC-PV system . FIG. 18A shows a matte black background. FIG. 18B shows a specular reflector background. FIG. 18C shows a diffusive scatterer background. FIG. 18D is a graph illustrating J-V curves of a blank borosilicate glass void of any emitter with a black and a reflective silver background with a GaAs edge mounted PV on one side.

[0258] FIGS. 19A-19C relate to importance of the optical isolation as realized when no airgap is introduced between the three lightguides. FIG. 19A is a Schematic representation of the no-airgap architecture of the ternary LSC. FIG. 19B illustrates a J-V curve of the no-airgap architecture of the ternary LSC. FIG. 19C illustrates EQE of the no-airgap architecture of the ternary LSC.

[0259] FIGS. 20A-20C relate to simulated EQE for the ternary-LSC. FIG. 20A is BODIPY having a PLQY of 80%. FIG. 20B is DAD2 having a PLQY of 80%. FIG. 20C is DAD2 and BODIPY having 80% PLQY.

[0260] FIG. 21 relates to a photostability example of single-luminophore LSCs. Normalized peak values of absorption spectra A(A) for DAD1, B) DAD2, and BODIPY LSCs as a function of time under constant illumination.

[0261] Table 3. DAD1 optical characteristics in different solvents and polymer hosts.Attorney Docket No. 6550-000525-WO-POA

[0262] Table 4. DAD2 optical characteristics in different solvents and polymer hosts.

[0263] Table 5. DAD1 in Shandon photovoltaic parameters as a function of concentration.

[0264] Table 6. DAD2 in Shandon photovoltaic parameters as a function of concentration.Attorney Docket No. 6550-000525-WO-POA

[0265] Table 7. BODIPY in Shandon photovoltaic parameters as a function of concentration.

[0266] Table 8 Photovoltaic parameters of a blank LSC (50.8 x 50.8 x 3.125 mm3 borosilicate glass with GaAs as edge-mounted PV) with different backgrounds. The diffusive scattering background results show the direct scattered photons on the GaAs leading to ~0.9 mA / cm2, and this should not be considered as a reliable background for opaque measurements.Attorney Docket No. 6550-000525-WO-POA

[0267] Table 9. Simulated photovoltaics parameters of the ternary LSC considering a PLQY of 80% for BODIPY, DAD2, and both BODIPY and DAD2.

[0268] Tables 10(a)-10(b). Summary of published LSC data with reported PCE. The column max PCE (%) refers to the calculated / estimated maximum PCE to be obtained by the reported data about the LSC. The inventors believe that most of the results are disputed and offer a re-estimated PCE values of these results based on the accurate and correct way of calculating PCEs for LSC-PV systems. The ranking is from the highest calculated maximum PCE.Attorney Docket No. 6550-000525-WO-POA&&& &Attorney Docket No. 6550-000525-WO-POAAttorney Docket No. 6550-000525-WO-POA>Attorney Docket No. 6550-000525-WO-POA&&& &Attorney Docket No. 6550-000525-WO-POA<<<Attorney Docket No. 6550-000525-WO-POADisputed use of scattering backgroundWrong area** Disputed PCE calculation methodThe PCE(%) column refers to the reported PCE in the publications. The Max PCE(%) column refers to the PCE calculated by digitizing the data reported in these papers to calculate the maximum possible PCE giving all benefits of the doubt. If EQE is reported, the integrated JSC is calculated, then the VOC and FF of the edge mounted PV cell are used to get the PCE. If the transmittance, reflectance, or absorbance are reported of the LSC, these data are used to estimate the maximum possible EQE (if the PLQY of the luminophores is not reported, this example assumed a value of unity). If absorbance (a.u) is reported, this example assumed a 100% absorption at the maximum peak. All of the simulated and estimated EQEs assume no reabsorption losses. If the authors of theAttorney Docket No. 6550-000525-WO-POAliterature in Tables 10(a)-10(b) use the wrong area (the LSC edge area, or the edgemounted PV area instead of the active front LSC area), this example multiplied the reported JSC by the edge area, then divide it by the correct front area to correct the PCEs.Example 2

[0269] Summary of QDs device results.

[0270] In ternary LSC devices, the choice of the mid-layer components is based on two important parameters: a high PLQY, and an absorption profile that bridges the absorption of the UV1-VIS1 DAD1 and NIR BODIPY layers to ensure full spectrum harvesting. Noteworthy, CIS / ZnS QDs exhibit a broad-absorption profile in the 300 -700 nm range, an emission peak at 800nm, and a high PLQY of ~75%, therefore, serve as an excellent candidate to replace DAD2 proposed in the first approach.

[0271] First, the transmittance and photovoltaic performance of individual QD waveguides with varying QD concentrations of 0.40mg / mL, 0.8mg / mL, and 1.5mg / mL were recorded. Among these concentrations, 1.5mg / mL QDs demonstrated the highest PCE of 3.3% (black background), with the corresponding transmittance, JV , and EQE curves showcased in FIGS. 23A-23C. Analogous to the DAD waveguide scenario, further increase of QDs concentration was stopped due to the constraints posed by solubility. For maximum spectrum harvesting within the 300-750 nm wavelength range, QD-ternary LSC with 1.5mg / mL QDs waveguide was fabricated. Notably, the device achieves the EQE of ~28% at 630 nm due to the high PLQY of QDs while the EQE of DAD1 and BODIPY is similar to that observed in the case of DAD1 / DAD2 / BODIPY ternary device (FIG. 24B). JV curves show that the QDs-ternary LSC achieved the record PCE of 7.06% and 8.04% with black and reflective backgrounds, respectively (FIG. 24C). Notably, the integrated photo-current density (J_SCAlnt) derived from the EQE profiles of the QD-ternary LSC with black and reflective background is 9.10 mA / cm2and 10.2 mA / cm2with the corresponding mismatch factor (M) of 1.03 and 1.02, respectively. These values are in excellent agreement with the experimentally measured short-circuit current density (J_SCAmeas) obtained from the J-V curve. Lastly, a rigorous photon balance analysis was conducted to validate the experimental results. FIG. 24D presents the transmittance (T(A)), reflectance (R(A)), and EQE(A) spectra, demonstrating that the sum of these parameters is consistently less than or equal to unity. This confirms the accuracy of the reported performance metrics.

[0272] Fabrication summary:Attorney Docket No. 6550-000525-WO-POA

[0273] QD Waveguide: 0.4mg / mL, 0.8mg / mL, 1.5mg / mL CIS / ZnS (UbIQD Inc.) were dispersed in a monomer mixture of 80% lauryl methacrylate (LMA, Sigma Aldrich), 20% of the cross-linking agent ethylene glycol dimethacrylate (EGDM, Sigma Aldrich), and 0.6% of the UV-initiator Irgacure 651 (CIBA) by ultrasonic treatment. The resulting reaction mixtures were subsequently introduced into glass molds and subjected to polymerization within a nitrogen-controlled environment. Polymerization was initiated by irradiation with ultraviolet light at a wavelength of 400 nm for a duration of 3 minutes. Following this polymerization step, the resultant waveguiding plates with a thickness of 4 mm, were carefully extracted and cut into desired dimensions of 50.8 mm x 50.8 mm x 4 mm.

[0274] QD based Ternary LSCs: Like DAD1 / DAD2 / BODIPY ternary LSCs, QDs based ternary LSCs were prepared by stacking individual waveguides of DAD1 (4mg / mL), QDs(1.5mg / mL), and BPDIPY(0.2 mg / mL). The GaAs PV cell was attached to one edge of the LSCs in order to test photovoltaic performance. Correcting the raw data to account for 4 cell integration was done according to standardized protocols reported elsewhere.

[0275] Table 11. Photovoltaic performance metrics of QDs based individual QDs waveguides and ternary LSC.Attorney Docket No. 6550-000525-WO-POAExample 3A. Introduction to Donor-Acceptor-Donors

[0276] Organic luminophores have drawn significant interest in the realm of TPVs due to highly tunable and selective absorption bands, allowing for targeted NIR harvesting. Several donor-acceptor classes of small molecules, utilizing a combination of electron-rich and electron-poor moieties on the same molecule, have shown significant promise including acceptor-donor-acceptor compounds (ADA), which have demonstrated implementation as small-molecule acceptors for organic photovoltaic and TPV applications. In a conventional PV structure, ADA molecules utilize the local electron density distribution, which concentrates towards the outer acceptor moieties in the excited state, to better facilitate charge separation. This behavior showcases that the molecular orbitals in these donor and acceptor units still operate with some independence despite being chemically bonded.

[0277] In contrast to ADA molecules, donor-acceptor-donor (DAD) chromophores have begun to draw more interest for tunable and strong photoluminescent properties for purposes like imaging. One of the important features of this material class is the simplicity of synthesis, allowing several different types of donors and acceptors to be paired together via the Suzuki coupling method, enabling the synthesis of several NIR-emissive dyes with variable PLQY.

[0278] This example demonstrates performance of a high-PLQY DAD molecule in a high-performing visibly absorbing LSC. This example catalogs the optical properties of several novel DAD molecules and highlight how structural changes contribute to changes in optical properties including, primarily the absorption and emission positions and PLQY. This example uses these measurements to evaluate some of these compounds for use in TLSCs.

[0279] To simplify the discussion, the names are written as abbreviations of the different components pieced together with hyphens indicating the bonding between each unit: acceptor-t(thiophene if applicable)-donor-donor ligand. The nomenclature of the different pieces along with an example molecule is visualized in FIGS. 25A-25D, and the expanded names of the donors and acceptors associated with the abbreviations areAttorney Docket No. 6550-000525-WO-POAdescribed below. The DAD molecules explored in this example are generally symmetrical, such that the name of the donor only needs to be included once.

[0280] FIG. 25 is a chart detailing the different components. FIG. 25A shows a DAD molecule. FIG. 25B illustrates donors: Benzo-selenadiazolo-thiadiazole (BSDTD), Benzo-bis-thiadiazole (BBTD), Benzo-selenadiazole (BSD), Benzo-thiadiazole (BTD), Benzo-thiadiazolo-quinoxaline (BTDQ). BTD has a few functional groups — hydrogen, fluoride (F), and nitro (N) — which are added to the end of BTD in the name (when not hydrogen), and BTDQ can be functionalized with methyl (m), fluoride (F), trifluoromethyl (TFM), a set of fused phenyl rings (f), and 4-fluorophenyl (FPh) groups that are similiary added to the name. FIG. 250 illustrates acceptors: bromide (Br), triphenyl-amine (TPA), carbazole (Cbz), fluorene (Fl). There are some DADs where fluorene is modified such that the dimethyl is replaced by dioctyl (Flo). Cbz, Fl, and Flo are all functionalized by different functional groups, as shown in FIG. 25D, including hydrogen (H), dimethyl amine (dma), diethyl amine (dea), azetidine (az), pyrrolidine (pyr), and piperidine (pip). Finally, there will be some compounds where the donor and acceptor are spaced with a thiophene (t) group, as shown in FIG. 25A.B. Visibly Absorbing Donor-Acceptor-Donor LSC

[0281] FIGS. 26A-26C illustrate donor-acceptor-donor Structure and solvatochromism.

[0282] Table 12. Host Properties and Optical Properties of BTD-FI-dea in different host media.AbSmax PLmax StOkeHost 6 ErPLQY (nm) (nm) Shift (nm) Acetonitrile 5.8 37.5 460 - - < 1% Ethanol 4.3 24.5 462 - - < 1% DMSO 7.2 46.7 480 - - < 1 % Neat layer - - 488 675 187 ~ 10 % DOM 3.1 8.93 472 712 240 - 12 % Chloroform 4.1 4.81 472 677 205 - 30 % 1- 5.00 472 707 235 ~ 47% ChloronaphthaleneAttorney Docket No. 6550-000525-WO-POAPVP - 7.7 496 638 142 ~ 61 % O-xylene 2.5 2.57 472 616 144 ~ 73 % Hexane 0.1 1.88 462 581 119 - 75% PMMA - 3.64 472 603 131 - 76 % PBMA 476 592 116 ~ 93 % Toluene 2.4 2.38 474 616 142 ~ 96 % PLMA - 4.9 476 580 104 ~ 96 %

[0283] The first DAD molecule explored in this example is based on a benzothiadiazole (BTD) acceptor and diethyl amine-terminated fluorene donors (Fl-dea) (FIG.26A). These DAD molecules display significant sensitivity to the solvent or host environment with reports of notable increases in PLQY and solvatochromatic shifts in absorption and emission spectra, In this case, lower solvent polarity (5) and lower dielectric constant (er) seem to correlate with dramatic increases in PLQY. DAD molecules in the excited state undergo a twisting conformational change that facilitates the intramolecular charge transfer called twisted intramolecular charge transfer (TICT), enabling an uncommonly large Stokes shift (104-240 nm) compared to other organic chromophores like cyanine dyes with Stokes shifts of ~20 nm. In many common organic solvents — e.g., DOM, DMSO, chloroform — the PLQY o this BTD-FI-dea molecule is only moderate for a visibly emitting organic dye (at PLQY< 30%). However, as shown in Table 12, when dissolved in more nonpolar aromatic solvents (e.g., toluene), DAD molecules demonstrate a dramatic enhancement of PLQY, achieving near-unity PLQY. This DAD also demonstrates a blueshift in emission despite no change in the position of the absorption band, with solvent systems higher PLQY values being linked to more blue-shifted emission. These enhancements suggest that there is some interplay between the DAD and solvent that alters specifically the excited state dynamics, but it is currently unknown the exact photophysical reason for this strong effect.

[0284] The improvement in PLQY is also observed when the DAD is embedded in polymer films (FIG. 26C). There is a slight distinction in this case where DAD in PVP demonstrates a relatively proportional redshift in absorption and emission when compared to PMMA. The series of PMMA, PBMA, and PLMA, however, maintain a similar behavioral trend observed in the solvents where the absorption band isAttorney Docket No. 6550-000525-WO-POAunchanged and where the emission band is blueshifted with increasing PLQY. Utilizing the high PLQY of this visibly absorbing BTD-FI-dea molecule in polymer, a PLMA LSC was fabricated and the performance was measured with a GaAs edge-mounted PV because it can provide a higher voltage compared to Si and aligns well with the emission of BTD-FI-dea in PLMA.

[0285] The transmittance and device performance are plotted in FIGS. 27A-27C. The high PLQY results in a high photocurrent such that the EQE continues to increase with increasing concentration until it reaches the solubility limit. The large Stokes shift and high PLQY of this luminophore enable effective use in large-area devices. FIG. 28A plots the peak EQE of the LSCs of different concentrations with increasing module size. Interestingly, up to 0.030 wt%, the BTD-FI-dea enables an LSC with essentially no performance drop off with increasing module size. At higher concentrations, the performance begins to roll off with increasing module size as the tail absorption states start to red shift with increased concentration (Figure 27A).

[0286] Despite excellent performance metrics, BTD-FI-dea also shows susceptibility to photodegradation. Under constant 1-sun illumination, the BTD-FI-dea has a greater than 40% reduction in absorption in 11 days (FIG. 28B), resulting in a T50,dn of ~ 1700 hours or ~ 70 days. The decay behavior differs from that of Cy7 as there is also a notable blueshift in the absorption peak as the intensity drops, shifting more than 50 nm. Thus, while these results are promising, additional work may improve this DAD system for both high PLQY and lifetime.

[0287] Modification of Donor and Acceptor Units for the NIR.

[0288] Shifting to NIR-absorbing DAD luminophores, additional donor and acceptor units introduced in FIG. 25 are used to modify the DAD structure. Table 13, below, summarizes the optical characteristics (max absorption / emission wavelengths and PLQY) of each of the compounds tested. The compounds within the table are organized such that molecules with the same acceptor unit are grouped together, given that acceptor is the primary factor to determine the position of the absorption and emission bands. Utilizing the solvent results from the previous section, this example catalogs the optical properties for a range of DAD compounds in toluene as the primary screening method for determining potential use in LSC, with the PLQY of some compounds also reported in PBMA to more concretely demonstrate the potential LSC performance.Attorney Docket No. 6550-000525-WO-POA

[0289] This example demonstrates the expected decrease in PLQY paired with redshifts in absorption / emission. The most dramatic change in absorption and emission peaks results from changes in the conjugation of the acceptor unit. By increasing conjugation from the BTD acceptor to BTDQ to BBTD, the absorption and emission maxima redshift by up to ~ 300 nm (FIG. 29), followed by a sharp decline in PLQY from greater than 90% to ~1%. In FIG. 29, BTD-FI-dma (91% PLQY) absorption is shown at 2900 and BTD-FI-dma (91% PLQY) emission is shown at 2902. BTDQf-FI-dma (4% PLQY) absorption is shown at 2904 and BTDQf-FI-dma (4% PLQY) emission is shown at 2906. BBTD-FI-pyr (1% PLQY) absorption is shown at 2908 and BBTD-FI-pyr (1% PLQY) emission is shown at 2910.

[0290] Table 13. Optical Properties of DAD Compounds. *properties only measured in PBMA.AbSmax PLmax PLQYTOICompound PLQYPBMA (%)(nm) (nm) (%)BTD-FI-dea 474 616 96 93 BTD-FI-dma 462 602 91 85 BTD-TPA 462 593 90 85 BTD-Cbz-pyr 486 632 85 59 BTDF-FI-dma 450 601 80 71 BTDN-FI-az 526 - < 1BSD-FI-pyr 490* 614* - 34 BTDQm-FI-pip 536 655 24BTDQm-FI-H 512 634 89BTDQm-Cbz-pyr 594 821 17 20 BTDQFPh-FI-H 540 637 73 68 BTDQf-FI-dma 676 788 4BTDQf-Cbz-pyr 636 802 < 1BTDQPhTFM-TPA 656 795 < 1Attorney Docket No. 6550-000525-WO-POABBTD-Flo-az 722 886 3712BBTD-FI-pyr 885 1BBTD-Br 532 618 36BSDTD-FI-dma 778BSDTD-Br 616 676 7

[0291] Further studies have also looked at the inclusion of heavy atoms to further redshift these absorption and emission bands. Substituting the S atom on the acceptor unit with Se, this example demonstrates a further redshift without any additional modification to the conjugation of the acceptor but also with reductions in PLQY— resulting either through the introduction of additional nonradiative decay pathways or the suppression of previously efficient radiative decay pathways. In thermally activated delayed fluorescence emitters, the inclusion of Se as a heavy atom has been reported to lead to promotion of intersystem crossing and, thus, enhanced luminescent lifetime. The results from these reports, however, also report a similar redshift and drop in overall PLQY. This is most apparent with substitution of the donor groups with Br, where the Br atom is not a significant electron donating group nor does it affect the conjugation of the overall molecule. In this case, the redshift and PLQY drop can only be attributed to this atomic substitution.

[0292] The BTD and BTDQ-type acceptors are shown with a variety of different electron-withdrawing groups — e.g., F, NO2, trifluoro-methyl. The inclusion of these electron withdrawing groups typically yielded minor shifts in position of these absorption and emission bands with the nitro group providing the most significant direct change. A larger difference was observed on the BTDQ acceptors, which paired the electronwithdrawing groups with phenyl rings to further enhance the conjugation of the acceptor and, thus, further redshift the absorption and emission. Strong electron-withdrawing groups directly bonded to the acceptor appears to negatively impact the PLQY. However, this change is more dependent on the donor groups paired with these acceptors, making PLQY effects of electron-withdrawing groups more subtle than the natural trend of decreasing PLO / with decreasing bandgap.Attorney Docket No. 6550-000525-WO-POA

[0293] This series of luminophores utilized three primary classes of donors: fluorene (Fl), carbazole (Cbz), and triphenylamine (TPA). The Fl and Cbz donors allow for additional terminal groups to further alter the optical properties. In general, modification of these terminal groups provides relatively small changes in absorption characteristics with minor spectral shifts of < 20 nm. Hydrogen substitution for the terminal groups yielded the highest PLQY enhancement of the donor but also a subsequent blueshift due to reduced conjugation. Between the different terminal amino groups, the changes in PLQY are more subtle and marked primarily with ~ 10 nm spectral shifts.

[0294] The donors used in this section are all quite different, making direct comparison more convoluted. It is likely that the structure of these donors plays a role in further modulation of the excited state dynamics, potentially restricting or promoting TICT. Such effects require more in-depth photophysical studies including some form of transient photoluminescence paired potentially with computational simulations to better understand how each donor component contributes to modification of the emission peak and PLQY.

[0295] Thiophene Bridging between Donor-Acceptor

[0296] In addition to the modification of the core donor and acceptor units, studies into DAD molecules have utilized a bridging thiophene group to further affect the photophysical properties of the DAD molecules. Previous studies have reported the effects of thiophene bridging in donor-acceptor systems where the inclusion of thiophene expanded the conjugated network, resulting in a red shift in absorption and emission characteristics, and further promoting TT-stacking in the solid state. This example studied a range of modified BTD and BTDQ-based DAD with added thiophenes between the donors and acceptor to extend conjugation. Table 14 summarizes the optical characteristics of various thiophene-bridged DAD molecules tested with BTD-FI-dma from Table 13 included for comparison.

[0297] Table 14. Impact of Thiophene Bridging on Optical Characteristics of DAD.AbSmax PLmax PLQYpBMA Compound PLQYTOI(%)(nm) (nm) (%) BTD-FI-dma 462 602 91 85BTD-t-FI-dma 538 639 72Attorney Docket No. 6550-000525-WO-POABTD-t-FI-H 511 609 82BTD-t-FI-az 538 652 72BTD-t-Flo-az 535 638 64 65 BSD-t-FI-H 546 688 51 52 BTDQPh-t-Cbz-H 690 815 3BTDQPh-t-Cbz-pyr 800 853 2

[0298] The thiophene bridging results in notable red-shifting in the absorption maxima by up to 76 for the BTD-based DAD but with a notably smaller shift in the emission maxima of ~ 37 nm relative to the DAD without thiophene (FIG. 30). In FIG. 30, BTD-FI-dma (91% PLQY) absorption is shown at 3000 and BTD-FI-dma (91% PLQY) emission is shown at 3002. BTD-t-FI-dma (71% PLQY) absorption is shown at 3004 and BTD-t-FI-dma (71% PLQY) emission is shown at 3006. BTDQm-Cbz-pyr (<1% PLQY) absorption is shown at 3008 and BTDQm-Cbz-pyr (<1% PLQY) emission is shown at 3010. BTDQPh-t-Cbz-pyr (2% PLQY) absorption is shown at 3012 and BTDQPh-t-Cbz-pyr (2% PLQY) emission is shown at 3014. Addition of thiophene bridges does not result in consistent spectral shifts between from the donor-acceptor pairings observed in Table 13, further convoluting these DAD characteristics. Further studies may be useful to determine how thiophene bridging impacts photophysical behavior and intermolecular interactions to better guide rational molecular design for deeper NIR DAD molecules.C. Near-Infrared DAD TLSC Performance

[0299] Despite relatively low PLQY of the DAD compounds in the NIR, this example demonstrates the performance of these compounds in 2 in by 2 in LSCs. FIGS.31 A-31 F show a range of DADs used in LSCs with the device transmittance, EQE, and J-V. The performance metrics of these devices are summarized in Table 15, below. The devices are mounted with either a GaAs or Si PV, dependent on the position of the emission band of the DAD luminophore. BBTD-Cbz-dPha (bis-benzo-thiadiazole-carbazole-diphenylamine) benefits the most from the switch to Si generating nearly twice as much current as any other dye in this series, due to Si smaller bandgap enabling the long emissive tail characteristic of the DAD molecules. The compounds paired with SiAttorney Docket No. 6550-000525-WO-POApresent significantly lower PCE compared to the GaAs-paired dyes due to the lower voltage of the edge-mounted Si cell.

[0300] Table 15. NIR DAD LSC Performance Metrics.CompoundBTDQFPh-FI-dma -0.26 (-0.45) 0.97 81 0.20BTDQFPh-TPA -0.24 (-0.22) 0.97 81 0.19BTDQPhTFM-TPA -0.26 (-0.22) 0.97 81 0.20BBTD-FI-pyr -0.06 (-0.07) 0.40 56 0.06BBTD-Flo-az -0.06 (-0.16) 0.40 56 0.05BBTD-Cbz-dPha -0.44 (-0.35) 0.44 57 0.11

[0301] The PLQY can be estimated for these compounds by comparing absorption and EQE. For the BTDQPhTFM-TPA LSC, the DAD has a peak absorption of -30% with a peak EQE of - 0.015. When accounting for the -95% EQE of GaAs at the emission of the DAD and a waveguiding efficiency of 0.75, the estimated PLQY in PBMA is -6%. Applying the same methodology to the BBTD-Cbz-dPha, and adjusting for a 90% EQE of Si, the estimated PLQY'is - 7% for BBTD-Cbz-dPha.

[0302] While all the devices would benefit from increased absorption — by increasing DAD concentration, the device performance is ultimately capped by the PLQY of these NIR DAD, which falls below 10%, far below the performance of the visibly absorbing DAD presented earlier.D. Conclusion

[0303] In conclusion, this example demonstrates a high-efficiency visibly absorbing DAD-based molecular emitter, with suitable PLQY and low overlap between absorption and emission, that has the potential to be an important molecular platform for high-performance opaque LSC while also providing a potential route to high-efficiency NIR emitters. This example investigates the effects of changing solvent environment onAttorney Docket No. 6550-000525-WO-POAthis visibly absorbing DAD compound. This example then explored a variety of different DAD molecules utilizing different acceptor and donor units to initiate understanding in how structural changes affect the optical characteristics of this DAD class. This example finds that increased conjugation plays the most significant role in the position of the absorption bands while interaction with the solvent environment plays a more significant role in the emission characteristics. Further optimization of these DAD emitters will require in-depth photophysical studies to more clearly understand the solvent-structure interaction. This example demonstrates several NIR DAD molecular emitters and incorporates them into LSCs, highlighting how further studies may be useful to optimize the emissive characteristics of these NIR DAD — by reducing nonradiative losses — to further improve performance and aesthetics of TLSCs.

Claims

Attorney Docket No. 6550-000525-WO-POACLAIMSWhat is claimed is:

1. A luminescent solar concentrator (LSC) device comprising:a first waveguide including,a first substrate, anda first luminophore on the first substrate, embedded in the first substrate, or both on the first substrate and embedded in the first substrate;a second waveguide including,a second substrate, anda second luminophore on the second substrate, embedded in the second substrate, or both on the second substrate and embedded in the second substrate; a third waveguide including,a third substrate, anda third luminophore on the third substrate, embedded in the third substrate, or both on the third substrate and embedded in the third substrate; anda photovoltaic cell coupled to the first waveguide, the second waveguide, and the third waveguide, whereinthe second waveguide is between the first waveguide and the third waveguide, andthe LSC device is configured to receive light in a direction defined from the first waveguide to the third waveguide.

2. The LSC device of claim 1 , wherein the LSC device has a power conversion efficiency (PCE) of greater than or equal to 5%.

3. The LSC device of claim 1 , wherein the PCE is greater than or equal to 7.5%.

4. The LSC device of claim 1 , wherein the LSC device has an external quantum efficiency (EQE) of greater than or equal to about 60%.

5. The LSC device of claim 1 , wherein the LSC device has a fill factor of greater than or equal to 0.7 and an open circuit voltage of greater than or equal to 1 V.Attorney Docket No. 6550-000525-WO-POA6. The LSC device of claim 1 , wherein the photovoltaic cell is coupled to a first edge surface of the first waveguide, a second edge surface of the second waveguide, and a third edge surface of the third waveguide.

7. The LSC device of claim 6, whereinthe first luminophore has a first photoluminescent quantum yield (PLQY), the second luminophore has a second PLQY less than the first PLQY, and the third luminophore has a third PLQY less than the second PLQY.

8. The LSC device of claim 7, whereinthe first PLQY ranges from 80% to 98%,the second PLQY ranges from 30% to 80%, andthe third PLQY ranges from 20% to 70%.

9. The LSC device of claim 6, whereinthe first waveguide and the second waveguide define a first airgap therebetween, andthe second waveguide and the third waveguide define a second airgap therebetween.

10. The LSC device of claim 9, whereina first distance between the first waveguide and the second waveguide is less than or equal to 150 pm, anda second distance between the second waveguide and the third waveguide is less than or equal to 150 pm.

11. The LSC device of claim 6, whereinthe first waveguide and the second waveguide define a first layer therebetween, the first layer having an index of refraction ranging from 1 to 1.35, andthe second waveguide and the third waveguide define a second layer therebetween, the second layer having an index of refraction ranging from 1 to 1.35.

12. The LSC device of claim 11 , whereina first thickness of the first layer ranges from 1 micrometer (pm) to 150 pm, andAttorney Docket No. 6550-000525-WO-POAa second thickness of the second layer ranges from 1 pm to 150 pm.

13. The LSC device of claim 6, whereinthe first waveguide is in direct contact with the second waveguide, andthe second waveguide is in direct contact with the third waveguide.

14. The LSC device of claim 1 , whereinthe first luminophore has a first peak absorbance between 300 nanometers (nm) and 500 nm,the second luminophore has a second peak absorbance of between 500 nm and 700 nm, andthe third luminophore has a third peak absorbance of between 700 nm and 1000 nm.

15. The LSC device of claim 1 , wherein one of the first luminophore, the second luminophore, or the third luminophore includes a benzothiadiazole donor-acceptor-donor having the structure:Y includes C(A2), N-A, or a combination thereof, andA is an alkyl.

16. The LSC device of claim 1 , wherein one of the first luminophore, the second luminophore, and the third luminophore is a benzothiadiazole donor-acceptor-donor having the structure:Attorney Docket No. 6550-000525-WO-POA17. The LSC device of claim 1 , one of the first luminophore, the second luminophore, and the third luminophore is a benzothiadiazole donor-acceptor-donor having the structure:

18. The LSC device of claim 1 , whereinthe first luminophore includes a benzothiadiazole donor-acceptor-donor having the structure:the third luminophore includes a BODIPY derivative having the structure:

19. The LSC device of claim 18, wherein the second luminophore includes a benzothiadiazole donor-acceptor-donor having the structure:Attorney Docket No. 6550-000525-WO-POA20. The LSC device of claim 18, wherein the second luminophore includes CIS / ZnS quantum dots.

21. The LSC device of claim 1 , wherein the LSC is visually opaque.

22. A luminescent solar concentrator (LSC) device comprising:a waveguide including,a first luminophore,a second luminophore, anda third luminophore; anda photovoltaic cell coupled to the waveguide, whereinthe LSC device is visually opaque, andthe LSC device has a power conversion efficiency (PCE) of greater than or equal to 7%.

23. The LSC device of claim 22, wherein the LSC device has a peak external quantum efficiency (EQE) of greater than 60%.

24. The LSC device of claim 22, wherein the LSC device has a fill factor of greater than or equal to 0.7 and an open circuit voltage of greater than or equal to 1 V.

25. The LSC device of claim 22, wherein the LSC device has an optical quantum efficiency of greater than 50%.

26. The LSC device of claim 22, wherein the waveguide includes,a first waveguide including a first substrate and the first luminophore,Attorney Docket No. 6550-000525-WO-POAa second waveguide including a second substrate and the second luminophore, anda third waveguide including a third substrate and the third luminophore.

21. The LSC device of claim 22, wherein the waveguide includes,a substrate,the first luminophore embedded in the substrate, on a surface of the substrate, or both embedded in the substrate and on a surface of the substrate,the second luminophore embedded in the substrate, on a surface of the substrate, or both embedded in the substrate and on a surface of the substrate, andthe third luminophore embedded in the substrate, on a surface of the substrate, or both embedded in the substrate and on a surface of the substrate.

28. The LSC device of claim 22, wherein the waveguide further includes a fourth luminophore.

29. A solar panel comprising a benzothiadiazole donor-acceptor-donor having the structure:Y includes C(A2), N-A, or a combination thereof, andA is an alkyl.

30. The solar panel of claim 29, wherein the benzothiadiazole donor-acceptor-donor includes:Attorney Docket No. 6550-000525-WO-POA31. The solar panel of claim 29, wherein the solar panel has a peak external quantum efficiency (EQE) of greater than 60%.

32. The solar panel of claim 29, wherein the solar panel has a fill factor of greater than or equal to 0.7 and an open circuit voltage of greater than or equal to 1 V.

33. A solar panel comprising a benzothiadiazole donor-acceptor-donor having the structure:

34. A solar panel comprising a benzothiadiazole donor-acceptor-donor having the structure:

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