Nanocrystal polymer composites and solar modules

Abstract

The present invention is directed to nanoparticle-polymer composites for efficient emission of light. Certain nanoparticle-polymer composites of the present invention have been found to exhibit higher photoluminescence quantum yield and narrower photoluminescence linewidth than the same materials disposed in liquid solvents. In some embodiments, the composites include quantum dots that have a first semiconductor core material made from CuInSexS2-x, CuInGaSexS2-x, AgInSexS2-x, AgInGaSexS2-x, PbS, PbSe, InAs, InP, Cd3P2, CdS, CdSe, and CdTe semiconductor compositions. In some embodiments the composites include a polyolefin elastomer polymer. Furthermore, the tunability of emission peaks from these novel fluorescent polymer composites make them suitable for down-conversion of visible and UV light into visible and NIR light. In some embodiments these nanoparticles are incorporated into solar modules to improve power conversion efficiency.

Description

[0001] NANOCRYSTAL POLYMER COMPOSITES AND SOLAR MODULES

[0002] CROSS REFERENCE TO RELATED APPLICATION(S)

[0003] This application claims priority to U.S. Application No. 63 / 725,911, filed November 27, 2024, the content of which is incorporated herein by reference in its entirety.

[0004] FIELD OF THE DISCLOSURE

[0005] The present invention is directed to nanoparticle-polymer composites for efficient emission of light. Certain nanoparticle-polymer composites of the present invention have been found to exhibit higher photoluminescence quantum yield (QY) and narrower photoluminescence linewidth (full width at half max, FWHM) than the same materials disposed in liquid solvents. Furthermore, the tunability of emission peaks from these novel fluorescent polymer composites make them suitable for down-conversion of visible and ultraviolet (UV) light into visible and near infrared (NIR) light. In some embodiments these nanoparticles are incorporated into solar modules to improve power conversion efficiency.

[0006] BACKGROUND OF THE DISCLOSURE

[0007] Typical nanocrystals / nanoparticles exhibit decreasing photoluminescence (PL) quantum yield (QY) and broadening linewidth when they are processed and blended into a polymer host matrix. In some cases, the polymer matrix is extruded by a compounding process, in other cases the nanoparticles may be mixed into a liquid polymer resin that is cured. The reduced performance (lower QY, broader FWHM) is typically attributed to damaging of the nanoparticle surfaces and / or nanoparticle aggregation during the process, or deleterious effects of combining organic materials with inorganic materials. Moreover, nanosized particles bring many advantages including easier processability in liquids and polymers and minimal scattering of light due to their small size.

[0008] Although the present invention focuses on this family of I-III-VI and II- VI semiconductors (e.g., CuInS2, CuInSe2, InAs, PbS, CdsP2, CdS, CdSe, and CdTe, etc.), the concept is applicable to many other combinations of semiconductors at the nanoscale, including groups IV, III-V, other I-III-VI, other II- VI, perovskite, and other semiconductors known in the art. SUMMARY OF THE DISCLOSURE

[0009] Few materials can emit near-infrared (NIR) light efficiently and they often have broad photoluminescence FWHM. Some solar cells suffer from lower spectral efficiency at higher photon energies than in the NIR, and further some solar cells have narrow spectral responses in the NIR. Also, many solar modules suffer from ultraviolet (UV) or visible light degradation. Materials that efficiently down-convert visible and / or UV light to NIR light remain needed in various applications, especially in solar modules.

[0010] In one aspect of the present invention, CuInSeS / ZnS quantum dots (QDs) and related compounds are mixed into extruded polymers with a surprising result, a higher QY and a narrower FWHM than when suspended in solvents.

[0011] In another aspect of the present invention, type II band offset core / shell structures, such as CdSe / CdTe and related nanocrystal heterostructures are mixed into extruded polymers and exhibit higher QY and narrower FWHM than when suspended in solvents.

[0012] In another aspect of the present invention, III-V semiconductors, such as InAs, InP, GaAs, and related nanocrystal heterostructures are mixed into extruded polymers and exhibit higher QY and narrower FWHM than when suspended in solvents.

[0013] In another aspect of the present invention, the quantum dots of the present invention are combined with photovoltaic modules for improving the light harvesting efficiency by down-conversion of visible photons into near-infrared (NIR) light that is more efficiently harvested by solar cells. This combination can improve the photocurrent, particularly for bifacial CdTe modules.

[0014] BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Fig. 1 shows the photoluminescence quantum yield (PL QY) of CuInSexS2-x / ZnS QDs (0 < x < 2) in polyolefin elastomers (POE) versus those same QDs in organic solvent (typically toluene or hexane). The diagonal line shows where the PL QY would be equal before (in solvent) and after (in POE). Nearly all data points indicate an increase in PL QY, approaching 100% in several instances. This surprising result indicates that a synergistic effect between the QDs and POE. Fig. 2 shows the photoluminescence full width at half max (FWHM) of CuTnSexSz-x / ZnS QDs (0 < x < 2) in polyolefin elastomers (POE) versus those same QDs in organic solvent. The diagonal line shows where the FWHM would be equal before (in solvent) and after (in POE). Nearly all data points indicate a decrease in FWHM upon compounding in POE. This surprising result indicates that a synergistic effect between the QDs and POE.

[0016] DEFINITIONS AND ABBREVIATIONS

[0017] Colloidal suspension: A mixture consisting of a disperse phase (the suspended particles) and a continuous phase (the liquid medium of suspension), wherein the mixture either does not settle, or would take a very long time to settle appreciably.

[0018] Dispersibility: The ability of QDs to form a colloidal suspension.

[0019] Emission spectrum: Those portions of the electromagnetic spectrum over which QDs (or a composition containing them) exhibit PL (in response to excitation by a light source) whose amplitude is at least 1% of the peak PL emission.

[0020] Nanoparticle: A nanoscale particle of a solid material. The nanoparticles disclosed herein are preferably crystalline and have a size of less than 500 nanometers in dimension. The nanoparticles disclosed herein may form a colloidal suspension. Embodiments of the disclosed nanoparticles may be of a single material or may include an inner core and an outer shell of differing materials. The nanoparticles may further include a plurality of ligands bound to the nanoparticle outer surface. Exemplary nanoparticles which may be utilized in the compositions, systems and methodologies described herein may comprise metals, metal oxides, metal chalcogenides, semiconductors, and insulators. Nanoparticles may be crystalline (i.e., nanocrystals), amorphous, or mixtures thereof.

[0021] Photoluminescence (PL): The emission of light (electromagnetic radiation, in the form of photons) after the absorption of light. It is one form of luminescence (light emission) and is initiated by photoexcitation (excitation by photons). Polar solvents: A polar solvent is any solvent containing an electric dipole. Exemplary polar solvents include acetone, ethanol, water, ethanol / water mixtures, isopropanol, isopropanol / water mixtures, methanol, methanol / water mixtures, dimethyl sulfoxide, diethyl sulfoxide, tetrahydrofuran, and tetrahydrofuran / water mixtures.

[0022] Polymers (as well as polar polymers): A large molecule, or macromolecule, composed of many repeating subunits. Polymers range from familiar synthetic plastics such as polystyrene or poly (methyl methacrylate) (PMMA), to natural biopolymers such as DNA and proteins that are fundamental to biological structure and function. Polymers, both natural and synthetic, are created via polymerization of many smaller molecules, e.g., monomers. Exemplary polymers include poly (methyl methacrylate) (PMMA), polystyrene, silicones, epoxy resins and the like.

[0023] Polar polymers: Polymers containing only carbon and hydrogen atoms are non-polar polymers. Polar polymers typically contain other atoms such as chlorine, fluorine, oxygen, nitrogen, and sulfur whereby the polymer will contain a permanent electric dipole called a polar polymer. Exemplary polar polymers include poly vinyl alcohol, an ethylene vinyl alcohol copolymer, polyvinyl acetate, polyurethane, polyolefin elastomer, ethylene vinyl acetate, an acrylic polymer, polyvinyl butyral, and polyamides, e.g., nylons.

[0024] Quantum Dots: A nanoparticle that exhibits size dependent electronic and optical properties due to quantum confinement. The quantum dots disclosed herein preferably have at least one dimension less than about 50 nanometers. The disclosed quantum dots may be colloidal quantum dots. Some of the quantum dots which may be utilized in the compositions, systems and methodologies described herein are made from a binary semiconductor material having a formula MX where M is a metal and X is typically selected from sulfur, selenium, tellurium, nitrogen, phosphorus, arsenic, antimony, or mixtures thereof. Exemplary binary quantum dots which may be used in the compositions, systems and methodologies described herein include CdS, CdSe, CdTe, Cd3P2, PbS, PbSe, PbTe, ZnS, ZnSe, ZnTe, InP, InAs, GaP, GaAs, InGaAs, GaS, GaSe, Cu2S, SiC>2, and In2S3. Other quantum dots which may be utilized in the compositions, systems and methodologies described herein are binary, ternary, quaternary, and / or alloyed quantum dots including, but not limited to, Si, ZnSSe, ZnSeTe,ZnSTe, CdSSe, CdSeTe, HgSSe, HgSeTe, HgSTe, ZnCdS, ZnCdSe, ZnCdTe, ZnHgS, ZnHgSe, ZnHgTe, CdHgS, CdHgSe, CdHgTe, ZnCdSSe, ZnCdSeTe, ZnHgSeTe, ZnHgS Se, CdHgS Se, CdHgSeTe, C11AIS2, CuAlSe2, CuFeSe2, CuFeSe2, CuInS2, CuAlSexS2-x, CuInS2, CuInSe2, CuInGaSe2, CuInZnS2, CuZnSnSe2, CuInSexS2- x, CuInZnSexS2 x, AgInS2, AgInSe2, AgInGaSexS2-x, and AgInSexS2 xwhere 0 < x < 2. Embodiments of the disclosed quantum dots may be of a single material or may include an inner core and an outer shell of differing materials. The outer shell may be a thin shell or layer formed by any suitable method, such as cation exchange. The quantum dots further include a plurality of ligands bound to the quantum dot surface.

[0025] Ligand: A ligand is an ion or molecule that binds to another, usually larger, molecule. In general, a ligand bonds to a metal atom, which in the case of the present disclosure, is part of a quantum dot and / or nanoparticle. A ligand may be configured to bind to a particular receptor, interact with various types of matter in prescribed ways, and / or the like. Capping ligands are configured to stabilize the interface where nanoparticles, such as quantum dots, interact with their surrounding medium.

[0026] Solar module: An optical device that converts sunlight into electricity using photovoltaics (PVs) made from at least one semiconductor material. Often these are planar devices with one face facing the sun, but in some cases they are not planar. Solar modules typically include polymers and / or glass elements for encapsulation. Some kinds of solar modules are bifacial, wherein they can convert light from both sides of the device (the sun-facing side and the ground facing side). A solar module may sometimes be referred to as a photovoltaic module. Generally, PV cells in a solar module may be crystalline, semi-crystalline, or amorphous, and they are safely packaged in multiple protective layers including front cover, encapsulate, and back sheet. They may be thin films of less than about five microns or larger layers of greater than about 100 microns. The encapsulate layer is typically a polymeric material to protect against weather, corrosive environment, UV radiation, low mechanical stress, and low energy impacts. Most often polymeric encapsulate materials include ethylene vinyl acetate (EVA), polyurethanes, polyolefin elastomers (POE), or epoxies. Solubility: When used in reference to QDs, the ability of QDs to form a clear colloidal suspension without haze caused by formation of aggregates.

[0027] Type II Heterostructures: The introduction of heterostructures, which is the combination of two different semiconductors, has not only allowed enhanced performance and stability (e.g., straddling type I band-offset core / shell heterostructures) but also led to additional desirable effects. In particular, staggered “type II” band-offset heterojunctions can impart spatial separation of electrons and holes with low wavefunction overlap. A type II band offset occurs when both the conduction and valence band levels of a semiconductor are both at higher energy levels than the conduction and valence bands respectively of the attached different semiconductor. This feature of type II QD heterostructures can lead to increased carrier lifetimes that can facilitate carrier extraction, suppression of Auger recombination, modulation of biexciton lifetimes, and Stokes- shifted emission, among several benefits. Core / shell and rod / rod / rod structures consisting of CdS / ZnSe or CdSe / CdTe heterojunctions have been the most frequently explored type II colloidal heterostructures.

[0028] The following explanations of terms and abbreviations are provided to better describe the present disclosure and to guide those of ordinary skill in the art in the practice of systems, methodologies and compositions disclosed herein.

[0029] As used herein, “comprising” means “including”, and the singular form “a” or “an” or “the” include plural references unless the context clearly indicates otherwise. Unless the context clearly indicates otherwise, the term “or” is inclusive, and thus refers to both a single element of stated alternative elements and a combination of two or more of those elements.

[0030] Unless explained otherwise, all technical and scientific terms used herein have the same meaning as commonly understood to one or ordinary skill in the art to which this disclosure relates. Suitable methods and compositions are described herein for the practice or testing of the systems, methodologies and compositions described herein. However, it is to be understood that other methods and materials similar, or equivalent to, those described herein may be used in the practice or testing of these systems, methodologies and compositions disclosed herein. Consequently, the systems, methodologies, compositions, and examples disclosed herein are illustrative only and are not intended to be limiting. Other features of the present disclosure will be apparent to those skilled in the art from the following detailed description and the appended claims.

[0031] Unless otherwise indicated, all numbers expressing quantities of components, percentages, temperatures, times, and so forth as used in the specification or claims are to be understood as being modified by the term “about”. Unless otherwise indicated, non-numerical properties such as colloidal, continuous, crystalline, and so forth as used in the specification or claims are to be understood as being modified by the term “substantially”, meaning to a great extent or degree. Accordingly, unless otherwise indicated implicitly or explicitly, the numerical parameter and / or non-numerical properties set forth herein are approximations, and the optimal values of these properties and parameters may depend on the desired properties sought, the limits of detection under standard test conditions or methods, the limitations of the processing methods, and / or the nature of the property or parameter. When directly and explicitly distinguishing embodiments from disclosed prior art, the embodiment numbers are not approximations unless the word “about” is recited.

[0032] DETAILED DESCRIPTION

[0033] The presently described invention relates to nanocrystals, nanoparticles, heterostructures, and quantum dots combined with polymers. In some embodiments those polymers are incorporated into photovoltai c / solar modules.

[0034] EXAMPLES

[0035] The following examples are non-limiting and are merely intended to further illustrate the compositions, systems, and methodologies described herein is as follows.

[0036] EXAMPLE 1

[0037] For more than 30 CuInSexS2-x / ZnS quantum dot (QD) batches, it was found that photoluminescence quantum yield (PLQY) is enhanced upon extrusion of the CuInSeS / ZnS QDs in POE polymer versus those same QDs in liquid toluene solvent. The enhancement ranging from 5% to 90% was observed (Fig. 1). It is hypothesized that the main reason for enhancement is that for the QDs, which are not perfectly passivated by ligands, POE polymer chains could act as an alternative passivation ligand, thus neutralizing dangling bonds, and effectively increasing passivation of the QDs' surface. As a result, probability for non-radiative recombination reduces, and PLQY increases. This is highly unusual and unexpected, typically QDs would have lower QY in a host polymer versus in toluene or other organic solvents.

[0038] EXAMPLE 2

[0039] More than 30 CuInSexS2-x / ZnS QD batched exhibited line narrowing effect upon extrusion in POE (Fig. 2) when compared with those same QDs in toluene. Similar effects was also observed in other polymers, such as EVA, LLDPE, TPU, and EVOH. While this effect can be understood for organic molecules, the explanation is more complicated for QDs. However, we can use similar approach at first approximation. In case of organic molecules, placing them in polymer (assuming good dispersion without aggregation) freezes free movement of the molecules in matrix, effectively reducing or removing inhomogeneous broadening due to Brownian motion. Furthermore, depending on the polymer polarity, the dipole-dipole interaction between the matrix and the molecules is reduced, further narrowing emission linewidth. This effect (dipole-dipole interaction) is more pronounced for non-polar polymers, such as EVA, and less pronounced for more polar polymers, such as EVOH. The effect is more pronounced in non-polar polymers, and less pronounced in polar polymers.

[0040] EXAMPLE 3

[0041] Mixing other kinds of QDs including CdS, CdSe, CdTe, Cd3P2, PbS, PbSe, PbTe, ZnS, ZnSe, ZnTe, InP, InAs, GaP, GaAs, InGaAs, Cu2S, In2S3, ZnSSe, ZnSeTe, ZnSTe, CdSSe, CdSeTe, HgSSe, HgSeTe, HgSTe, ZnCdS, ZnCdSe, ZnCdTe, ZnHgS, ZnHgSe, ZnHgTe, CdHgS, CdHgSe, CdHgTe, ZnCdSSe, ZnCdSeTe, ZnHgSeTe, ZnHgSSe, CdHgSSe, CdHgSeTe, CUA1S2, CuAlSe2, CuFeSe?, CuFeSe2, CuInS2, CuAlSexS2-x, CuInS2, CuInSe2, CuInGaSe?, CuInZnS2, CuZnSnSe2, CuInSexS2-x, CuInZnSexS2-x, AgInS2, AgInSe2, AgInGaSexS2-x, and AgInSexS2-x where 0 < x < 2 when mixed into POE will exhibit higher PL QY, approaching >90%, and narrower FWHM, than those same QDs in organic solvents or neat powders. The same principles apply to other kinds of QDs besides those described in examples 1 and 2. EXAMPLE 4

[0042] Relatively simple and widely accessible synthesis pathways to an array of tunable properties make colloidal QDs an ideal platform for discovering novel photophysics and developing nextgeneration photonics / electronics. In addition to the well-established wide spectral range of absorption and emission, many characteristics such as charge separation, polarized emission, and multi-exciton processes may be tuned with synthetic control over size and shape. The introduction of heterostructures has not only allowed enhanced performance and stability (e.g., straddling type I band-offset core / shell heterostructures) but also led to additional desirable effects. In particular, staggered type II band-offset heterojunctions can impart spatial separation of electrons and holes with low wavefunction overlap. This feature of type II QD heterostructures can lead to increased carrier lifetimes that can facilitate carrier extraction, suppression of Auger recombination, modulation of biexciton lifetimes, and massively Stokes-shifted emission, among several benefits. Core / shell and rod / rod / rod structures consisting of CdS / ZnSe or CdSe / CdTe heterojunctions have been the most frequently explored type II colloidal heterostructures. Although CdTe / CdSe core / shell QDs have shown promise with respect to deep red to near infrared (NIR) emission, achieving high photoluminescence quantum yields (PL QYs), narrow linewidths, and wide spectral tunability has been challenging. Therefore, the CdTe / CdSe core / shell system has fallen out of favor even for relatively straightforward applications such as light down-conversion.

[0043] Some of these difficulties may stem from starting with the CdTe core. While the inverse structure of CdSe / CdTe core / shell can exploit the exquisite control of size and size distribution established for CdSe QDs, terminating with CdTe shell often leads to stability issues with poor PL characteristics. Hence, most of these core / shell structures consist of CdTe cores. Known routes of synthesizing CdTe QDs lead to the zinc-blende structure with often limited maximum size and faceting, thereby limiting the range of hole confinement energies and potentially limiting CdSe shell growth.

[0044] An alternative solution towards developing a highly tunable, narrow emission and high PL QY CdSe and CdTe based QD heterostructures may be through scaffolding CdTe on CdSe QDs then growing a final, passivating CdSe shell, i.e., a CdSe / CdTe / CdSe core / shell / shell (CSS) structure. Similar structures have been achieved for type I or quasi-type II band offset materials. One of the earliest examples has been CdS / HgS / CdS quantum dot quantum wells. One of the desirable features of type II band offset heterostructures is the effective band gap, and therefore the emission energy, that is smaller than the band gap of either component semiconductor alone. While achieving longer wavelength emission through type II core / shell QDs is well established, simultaneously imparting narrow linewidths and high PL Qys needed for many applications has been challenging. For an ensemble of QDs, inhomogeneous broadening due to a size distribution is usually the main cause of line broadening. For the CdTe / CdSe core / shell QDs, starting with CdTe QDs as the core limits size and size distribution and therefore the PL linewidth compared to the prototypical CdSe QDs. The large lattice mismatch between CdTe and CdSe and the resulting lattice strain can also limit achievable size and size uniformity and / or induce undesirable defects, leading to limited control over spectral tunability, PL QY, and linewidth. Our approach to minimize the undesirable size distribution and lattice strain effects exploits high quality wurtzite CdSe QDs as the starting point for sequential epitaxial growth of CdTe and CdSe shells to achieve the CSS structure. A highly monodispersed ensemble of CdSe QDs provides initial narrow emission linewidth. The epitaxial growths of a thin CdTe inner shell and a final CdSe shell are then followed, leading to a CSS structure, where the electron and the hole wavefunctions are dictated by band structure and confinement imposed by the size of both CdSe and CdTe domains.

[0045] Type II nanocrystal heterostructures have electron and hole wavefunctions that are physically separated from one another, creating larger internal electric field (e g., dipole) strength. This makes these kinds of nanoparticles more sensitive to surface effects like those shown in examples 1 and 2. Incorporating type II structures with sub-bandgap emission will lead to even more pronounced linewidth narrowing and increase QY.

[0046] EXAMPLE 5

[0047] Alloyed semiconductors offer further tunability of bandgap and band alignment. For example, alloys of CdSe and CdTe can have a smaller bandgap than CdSe and CdTe owing to bandgap bowing. The minimal bandgap composition is roughly CdSeo.sTeo 7 (30% selenide, 70% telluride) according to literature, which has a bulk band gap of around 1.40eV, or 0. leV smaller than CdTe (https: / / doi.org / 10.1080 / 14686996.2018.1497403). The bulk ‘type II band gap’ for CdSe / CdTe (energy separation between CdSe conduction band and CdTe valence band) experimentally seems to be around 1.1-1.2 eV, which puts the lower limit of the alloyed type II bandgap to around 1.0- 1.1 eV, or 1240 nm at the reddest. This implies that with a CdSe / CdSeo.sTeo.v heterostructure, the emission wavelength could be as red as about 1240 nm. These kinds of nanoparticles will exhibit linewidth narrowing and increased QY in POE when compared with those same particles in organic solvents, similar to those QDs described in examples 1 and 2.

[0048] EXAMPLE 6

[0049] A solar module including nanoparticle-polymer composites that exhibit high PL QY above 80% is made by incorporating the nanoparticles into the encapsulation layer or layers by blend them into a polymer. In some cases these are the same QDs as those prepared in examples 1-5. In some embodiments the nanoparticles emit light with a peak emission at around 830 nm to 900 nm or out to beyond 1200 nm. The presence of these nanoparticles improves the power conversion efficiency of the solar module, which may further include a polymeric encapsulation layer around the solar module including a polymer selected from the group consisting of include ethylene vinyl acetate (EVA), polyurethanes, polyolefin elastomers (POE), or epoxies, and QDs comprising a core of a first semiconductor material and a shell layer of a second semiconductor material upon the core wherein the shell layer is of a different material than the core, wherein the shell layer is characterized as having a type II band offset from the core semiconductor material.

[0050] The solar module may contain QDs further characterized as having peak spectral emissions in the range of from about 600 nm to about 1240 nm, or from about 800 nm to 900 nm, with narrow FWHMs of about less than about 200 meV, or less than 100 nm, and photoluminescence quantum yields of at least 50%, and up to above 90%. In some cases the QDs are comprised of a core of a material selected from the group consisting of CuInSexS2-x, AgInSexS2-x, AgInGaSexS2-x, CdS, CdSe, and CdTe, and a shell layer upon the core wherein the first shell layer is of a different material than the core. The solar module would typically include solar cells made from semiconductors selected from the group consisting of CdS, CdSe, CdTe, Silicon, perovskite, CuInS2, and CuInSe2. The solar module may be a bifacial module further including QDs on the rear side (not facing the sun). The addition of fluorescent materials into the module encapsulation layer will increase the performance of the module by at least 0.1%, but in some cases greater than 1%, 2% or even 3%. In some cases, the front side performance is not affected, but the bifacial rear-side performance is increase by at least 10%, relative to the identical device without quantum dots.

[0051] Although the present invention has been described with reference to specific details, I is not intended that such details should be regarded as limitations upon the scope of the invention. Various modifications, substitutions, combinations, and ranges of parameters may be made or utilized in the compositions, and methodologies described herein.

Claims

WHAT IS CLAIMED IS:Claim 1 : A composition including a quantum dot comprising a core of a first semiconductor material and at least one outer shell material upon the core, and further comprising a polyolefin elastomer.Claim 2. The composition of claim 1 further characterized as having peak spectral emissions in the range of from about 600 nm to about 1240 nm, or from about 800 nm to 900 nm, with a photoluminescence quantum yield of at least 80%.Claim 3. The composition of claim 1 further characterized as having peak spectral emissions in the range of from about 600 nm to about 1240 nm, or from about 800 nm to 900 nm, with narrow FWHMs of about less than about 200 meV, or less than 100 nm.Claim 4: The composition of claim 1 wherein said first semiconductor material includes a semiconductor selected from the group consisting of CUA1S2, CuAlSe2, CuFeSe2, CuFeSe2, CuInS2, CuAlSexS2-x, CuInS2, CuInSe2, CuInGaSe2, CuInZnS2, CuZnSnSe2, CuInSexS2-x, CuInZnSexS2-x, A InS2, AgInSe2, AgInGaSexS2-x, and AgInSexS2-x where 0 < x < 2.Claim 5: The composition of claim 1 wherein said first semiconductor material includes a semiconductor selected from the group consisting of CdS, CdSe, CdTe, CdaP2, PbS, PbSe, PbTe, ZnS, ZnSe, ZnTe, InP, InAs, GaP, GaAs, and InGaAs.Claim 6: The composition of claim 1 wherein said quantum dot material includes a type II heterostructure.Claim 7: The composition of claim 1 wherein said outer shell material includes a material selected from the group of ZnS, ZnSe, GaP, GaS, GaSe, and SiCh.Claim 8: The composition of claim 1 wherein said quantum dot further comprises organic ligands.Claim 9: The composition of claim 1 wherein the emission of light includes photons with less energy than the band gap, including any quantum confinement or strain effects, of any individual constituent materials, whether a core or a shell.Claim 10: The composition of claim 1 wherein at least one of said semiconductor materials is an alloyed composition composed of combinations of sulfide, selenide, and telluride, either as a composition gradient or homogeneous composition.Claim 11 : A solar module comprising a polymeric encapsulation layer around the solar module including a polymer selected from the group consisting of ethylene vinyl acetate, polyolefin elastomers, polyurethane, and epoxy and quantum dots comprising at least one semiconductor material, wherein the encapsulation layer has a higher quantum yield (QY) and a narrower full width at half maximum (FWHM) than the same quantum dots disposed in a solvent.Claim 12. The solar module of claim 11 wherein the quantum dots are further characterized as having peak spectral emissions in the range of from about 600 nm to about 1240 nm, or from about 800 nm to 900 nm, with narrow FWHMs of about less than about 200 meV, or less than 100 nm, and photoluminescence quantum yields of at least 50%, and up to about 90%.Claims 13. The solar module of claim 11 wherein the quantum dots are comprised of a semiconductor selected from the group consisting of CUA1S2, CuAlSe2, CuFeSe2, CuFeSe2, CuInS2, CuAlSexS2-x, CuInS2, CuInSe2, CuInGaSe2, CuInZnS2, CuZnSnSe2, CuInSexS2-x, CuInZnSexS2-x, A InS2, AgInSe2, AgInGaSexS2-x, and AgInSexS2-xwhere 0 < x < 2.Claim 14: The solar module of claim 11 wherein the quantum dots are comprised of a semiconductor selected from the group consisting of CdS, CdSe, CdTe, CdaP2, PbS, PbSe, PbTe, ZnS, ZnSe, ZnTe, InP, InAs, GaP, GaAs, InGaAs, ZnS, ZnSe, GaP, GaS, GaSe, and SiCh, and alloys thereof.Claim 15 : The solar module of claims 11 where the quantum dots are compounded into an extruded layer of polyolefin elastomer.Claim 16: The solar module of claim 11 wherein the solar cell includes semiconductors selected from the group consisting of CdS, CdSe, CdTe, Silicon, CuInS2, and CuInSe2.Claim 17: The solar module of claim 11, wherein the quantum dots further comprise an outer shell of a semiconductor material that is different from the core semiconductor material.Claim 18: The solar module of claim 11, wherein the photovoltaic performance of the module is at least 0.1% higher than the same device made without the quantum dots.Claim 19. A bifacial solar module including fluorescent quantum dots within a polyolefin elastomer encapsulation layer, wherein the device exhibits an increased power conversion efficiency, and specifically a relative rear side performance increase of at least 5%.Claim 20. The solar module of claim 19 wherein the quantum dots are further characterized as having peak spectral emissions in the range of from about 600 nm to about 1240 nm, or from about 800 nm to 900 nm, with narrow full width at half maximums (FWHMs) of about less than about 200 meV, or less than 100 nm, and photoluminescence quantum yields of at least 50%, and up to about 90%.

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