Singlet fission for photovoltaic devices

Abstract

Disclosed herein are photovoltaic precursor devices which may exhibit improved efficiency. In particular, disclosed herein photovoltaic precursor devices comprising a singlet fission compound, methods of making a photovoltaic precursor devices comprising a singlet fission compound, and uses thereof.

Description

" SINGLET FISSION FOR PHOTOVOLTAIC DEVICES" CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] The present application claims priority from Australian Provisional Patent Application No 2024903895 filed on 26 November 2024, the contents of which are incorporated herein by reference in their entirety.TECHNICAL FIELD

[0002] This disclosure generally relates to photovoltaic precursor devices which may exhibit improved efficiency. In particular, the disclosure relates to a photovoltaic precursor devices comprising a singlet fission compound. In addition, the present disclosure relates to methods of making a photovoltaic precursor devices comprising a singlet fission compound, and uses thereof.BACKGROUND

[0003] Silicon-based solar cells dominate the photovoltaic market due to their proven performance, abundance, and long-term stability. These cells primarily rely on crystalline silicon, available in two main forms: monocrystalline and polycrystalline. Monocrystalline silicon solar cells typically achieve higher efficiencies, ranging from 20% to 28%, due to their uniform crystal structure, which facilitates better electron mobility. In contrast, poly crystalline cells, though less efficient (around 15% to 20%), are more cost-effective and easier to produce.

[0004] The efficiency of silicon solar cells is determined by several factors, including light absorption, charge carrier separation, and the reduction of recombination losses. Advances in technology have driven improvements in efficiency over time. Innovations such as passivated emitter and rear cell (PERC) technology enhance light capture and reduce recombination, boosting cell efficiencies beyond traditional limits. Additionally, the development of bifacial solar cells, which harvest light from both sides, further enhances energy generation.

[0005] However, silicon solar cells face theoretical limits to efficiency, primarily defined by the Shockley-Queisser limit of around 29% for single-junction cells.Strategies to overcome this include tandem solar cells, where silicon is combined with materials like perovskites to harness a broader spectrum of light.

[0006] Singlet fission is a process that splits a singlet excited state (electron-hole pair) into two triplet excited states (electron-hole pairs) spontaneously in some molecules. This multiple exciton generation has potential to boost silicon photovoltaic efficiencies from 29% for a standard Si PV to 42% for a singlet fission silicon photovoltaic devices. However, to date, singlet fission and triplet energy transfer to silicon photovoltaic cell has only been demonstrated for the light unstable tetracene.

[0007] Therefore, it is desirable to provide alternative device architectures, which can incorporate light stable singlet fission compounds, to provide alternative silicon based photovoltaic devices within increased efficient. It is also desirable to provide alternative methods for the producing photovoltaic devices with increased efficiency.SUMMARY

[0008] In an aspect of the present disclosure, disclosed herein is a photovoltaic precursor device, the photovoltaic precursor device comprising:a)a light absorbing semiconductor layer;a singlet fission layer; andat least one of a metal oxide layer and a passivation layer,wherein optionally:if present, at least one metal oxide layer is disposed between the light absorbing semiconductor layer and the singlet fission layer; and if at least one passivation layer is present, the singlet fission layer is disposed between the light absorbing semiconductor layer and the at least one passivation layer; orb)a light absorbing semiconductor layer;a singlet fission layer; andat least one of a metal oxide layer and a passivation layer,wherein optionally:- if present, at least one metal oxide layer is disposed between the light absorbing semiconductor layer and the singlet fission layer; andif at least one passivation layer is present, the at least one passivation layer is disposed between the semiconductor layer and the singlet fission layer; andthe singlet fission layer comprises at least one singlet fission compound of Formula (I), or a dimer or trimer thereof as described herein, or an oligomer thereof, as described herein, or a compound of Formula (IV) as described herein or a compound of Formula (V) as described herein.

[0009] In one embodiment a compound of Formula (I) is replaced with a compound of Formula (VI) as defined herein.

[0010] In another aspect, disclosed herein is a photovoltaic device comprising: a)a light absorbing semiconductor layer;a singlet fission layer; andat least one of a metal oxide layer and a passivation layer,wherein optionally:if present, at least one metal oxide layer is disposed between the light absorbing semiconductor layer and the singlet fission layer; and if at least one passivation layer is present, the singlet fission layer is disposed between the light absorbing semiconductor layer and the at least one passivation layer; orb)a light absorbing semiconductor layer;a singlet fission layer; andat least one of a metal oxide layer and a passivation layer,wherein optionally:- if present, at least one metal oxide layer is disposed between the light absorbing semiconductor layer and the singlet fission layer; andif at least one passivation layer is present, the at least one passivation layer is disposed between the semiconductor layer and the singlet fission layer;andthe singlet fission layer comprises at least one singlet fission compound of Formula (I), or a dimer or trimer thereof as described herein, or an oligomer thereof, as described herein, or a compound of Formula (IV) as described herein or a compound of Formula (V) as described herein.

[0011] In one embodiment a compound of Formula (I) is replaced with a compound of Formula (VI) as defined herein.

[0012] In another aspect, disclosed herein is a method of forming an article, for use in a photovoltaic device, the method comprising:depositing a singlet fission layer compound on a substrate comprising a light absorbing semiconductor layer,wherein:the singlet fission layer comprises at least at least one singlet fission compound of Formula (I), or a dimer or trimer thereof as described herein, or an oligomer thereof, as described herein, or a compound of Formula (IV) as described herein or a compound of Formula (V) as described herein.

[0013] In one embodiment for a method or used as defined herein, a compound of Formula (I) is replaced with a compound of Formula (VI) as defined herein.

[0014] In an embodiment of the present disclosure, there is provided a method as described herein, wherein the article is a device as described herein.

[0015] In another aspect of the present disclosure, there is provided use of the device described herein in a photovoltaic device.

[0016] In another aspect of the present disclosure, there is provided an article produced according to the method as described herein.

[0017] In another aspect of the present disclosure, there is provided a photovoltaic device comprising the device as described herein.

[0018] In another aspect of the present disclosure, there is provided a use of the device as described herein in the manufacture of a photovoltaic device.

[0019] The present inventors have demonstrated the potential integration of organic singlet fission compounds into silicon based photovoltaic devices.BRIEF DESCRIPTION OF DRAWINGS

[0020] Preferred embodiments of the present disclosure will be further described and illustrated, by way of example only, with reference to the accompanying drawings in which:

[0021] Figure 1: AFM image of the thermally evaporated DPND-2 ‘islands’ on n-type Si.

[0022] Figure 2: Absorption (abs) and photoluminescence (PL) of DPND-2 and DPND-7, these show minimal change between the two DPNDs in CH2Cl2, indicating that the optical properties are unaffected by chain length.

[0023] Figure 3: ns-TA of thermally evaporated films of DPND-2 and DPND-7, these show significant differences in spectral shape in the first ps.

[0024] Figure 4: PL yield of Si with a DPND-7 layer deposition, this shows the PL yield of Si is dependent on magnetic field, indicating triplets are being transferred from DPND-7.DESCRIPTION OF EMBODIMENTS

[0025] The present disclosure describes the following various non-limiting embodiments, which relate to the present disclosure.Definitions

[0026] In the following description, reference is made, where needed, to any accompanying drawings which form a part hereof, and which is shown, by way of illustration, several embodiments. It is understood that other embodiments may be used, and structural changes may be made without departing from the scope of the present disclosure.

[0027] With regards to the definitions provided herein, unless stated otherwise, or implicit from context, the defined terms and phrases include the provided meanings. Unless explicitly stated otherwise, or apparent from context, the terms and phrases below do not exclude the meaning that the term or phrase has acquired by a person skilled in the relevant art. The definitions are provided to aid in describing particular embodiments, and are not intended to limit the claimed invention, because the scope of the invention islimited only by the claims. Furthermore, unless otherwise required by context, singular terms shall include pluralities and plural terms shall include the singular.

[0028] All publications discussed and / or referenced herein are incorporated herein in their entirety.

[0029] Throughout this disclosure, unless specifically stated otherwise or the context requires otherwise, reference to a single step, composition of matter, group of steps or group of compositions of matter shall be taken to encompass one and a plurality (i.e., one or more) of those steps, compositions of matter, groups of steps or groups of compositions of matter. Thus, as used herein, the singular forms “a”, “an” and “the” include plural aspects unless the context clearly dictates otherwise. For example, reference to “a” includes a single as well as two or more; reference to “an” includes a single as well as two or more; reference to “the” includes a single as well as two or more and so forth.

[0030] Those skilled in the art will appreciate that the disclosure herein is susceptible to variations and modifications other than those specifically described. It is to be understood that the disclosure includes all such variations and modifications. The disclosure also includes all of the examples, steps, features, methods, processes, and compositions, referred to or indicated in this specification, individually or collectively, and any and all combinations or any two or more of said steps or features.

[0031] The term “and / or”, e.g., “X and / or Y” shall be understood to mean either “X and Y” or “X or Y” and shall be taken to provide explicit support for both meanings or for either meaning.

[0032] Unless otherwise indicated, the terms “first,” “second,” etc. are used herein merely as labels, and are not intended to impose ordinal, positional, or hierarchical requirements on the items to which these terms refer. Moreover, reference to a “second” item does not require or preclude the existence of lower-numbered item (e.g., a “first” item) and / or a higher-numbered item (e.g., a “third” item).

[0033] As used herein, the phrase “at least one of’, when used with a list of items, means different combinations of one or more of the listed items may be used and only one of the items in the list may be needed. The item may be a particular object, thing, or category. In other words, “at least one of’ means any combination of items or number ofitems may be used from the list, but not all of the items in the list may be required. For example, “at least one of item A, item B, and item C” may mean item A; item A and item B; item B; item A, item B, and item C; or item B and item C. In some cases, “at least one of item A, item B, and item C” may mean, for example and without limitation, two of item A, one of item B, and ten of item C; four of item B and seven of item C; or some other suitable combination.

[0034] As used herein, the term “about”, unless stated to the contrary, typically refers to a range of up to + / - 10% of the designated value, and includes smaller ranges therein, for example + / - 5% or + / - 1% of the designated value.

[0035] It is to be appreciated that certain features that are, for clarity, described herein in the context of separate embodiments, may also be provided in combination in a single embodiment. Conversely, various features that are, for brevity, described in the context of a single embodiment, may also be provided separately or in any sub-combination.

[0036] Throughout the present specification, various aspects and components of the invention can be presented in a range format. The range format is included for convenience and should not be interpreted as an inflexible limitation on the scope of the invention. Accordingly, the description of a range should be considered to have specifically disclosed all the possible sub-ranges as well as individual numerical values within that range, unless specifically indicated. For example, description of a range such as from 1 to 5 should be considered to have specifically disclosed sub-ranges such as from 1 to 3, from 1 to 4, from 1 to 5, from 2 to 4, from 2 to 5, from 3 to 5 etc., as well as individual and partial numbers within the recited range, for example, 1, 2, 3, 4, 4.5, 4.75, and 5, unless where integers are required or implicit from context. This applies regardless of the breadth of the disclosed range. Where specific values are required, these will be indicated in the specification.

[0037] Throughout this specification the word "comprise", or variations such as "comprises" or "comprising", will be understood to imply the inclusion of a stated element, integer or step, or group of elements, integers or steps, but not the exclusion of any other element, integer or step, or group of elements, integers or steps.

[0038] Throughout this specification, the term "consisting essentially of' is intended to exclude elements which would materially affect the properties of the claimed composition, method or process.

[0039] The terms "comprising", "comprise" and "comprises" herein are intended to be optionally substitutable with the terms "consisting essentially of', "consist essentially of, "consists essentially of, "consisting of, "consist of and "consists of, respectively, in every instance.

[0040] As used herein, “Cato 0,” or “Ca-b” in which “a” and “b” are integers refer to the number of carbon atoms in the specified group. That is, the group can contain from “a” to “b”, inclusive, carbon atoms. Thus, for example, a “Ci to C4alkyl” or “Ci_4alkyl” group refers to all alkyl groups having from 1 to 4 carbons, that is, CH3-, CH3CH2-, CH3CH2CH2-, (CH3)2CH-, CH3CH2CH2CH2-, CH3CH2CH(CH3)- and (CH3)3C-.

[0041] Herein a “hydrocarbon” refers to any chemical group comprising hydrogen and carbon. In some embodiments, a hydrocarbon consists of hydrogen and carbon, which may comprise form 1 to 35 carbon atoms, for example the hydrocarbon may comprise or at least comprise: 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, or 35 carbon atoms. A hydrocarbon may be substituted or unsubstituted. A hydrocarbon may be unsaturated, saturated, branched, unbranched, cyclic, or polycyclic. Illustrative hydrocarbons include, for example, methyl, ethyl, n-propyl, iso-propyl, cyclopropyl, allyl, vinyl, n-butyl, tert-butyl, ethynyl, cyclohexyl, methoxy, diethylamino, and the like. The hydrocarbon may be monovalent or bivalent. In one embodiment one or more hydrocarbons may be an optionally substituted alkyl group. In one embodiment one or more hydrocarbons may be an optionally substituted alkenyl group. In one embodiment one or more hydrocarbons may be an optionally substituted alkynyl group. In one embodiment one or more hydrocarbons may be an optionally substituted alkynyl group. In one embodiment one or more hydrocarbons may be an optionally substituted carbocyclyl group. In one embodiment one or more hydrocarbons may be an optionally substituted aromatic group. In one embodiment one or more hydrocarbons may be an optionally substituted aryl group.

[0042] As used herein, “alkyl” refers to a straight or branched hydrocarbon chain that is fully saturated (i.e., contains no double or triple bonds). The alkyl group may have 1to 35 carbon atoms (whenever it appears herein, a numerical range such as “1 to 35” refers to each integer in the given range; e.g., “1 to 35 carbon atoms” means that the alkyl group may consist of 1 carbon atom, 2 carbon atoms, 3 carbon atoms, etc., up to and including 35 carbon atoms, although the present definition also covers the occurrence of the term “alkyl” where no numerical range is designated). By way of example only, “Ci.4alkyl” indicates that there are one to four carbon atoms in the alkyl chain, e.g., the alkyl chain is selected from the group consisting of methyl, ethyl, propyl, iso-propyl, n-butyl, iso-butyl, sec-butyl, and tert-butyl. Typical alkyl groups include, but are in no way limited to, methyl, ethyl, propyl, isopropyl, butyl, isobutyl, tertiary butyl, pentyl, hexyl, and the like.

[0043] As used herein, “heteroalkyl” refers to a straight or branched hydrocarbon chain containing one or more heteroatoms, that is, an element other than carbon, including but not limited to, nitrogen, oxygen and sulfur, in the chain backbone. The heteroalkyl group may have 1 to 35 carbon atom, although the present definition also covers the occurrence of the term “heteroalkyl” where no numerical range is designated. The heteroalkyl group may contain one or more heteroatoms. By way of example only, “Ci_4heteroalkyl” indicates that there are one to four carbon atoms in the heteroalkyl chain and additionally one or more heteroatoms in the backbone of the chain.

[0044] As used herein, “alkenyl” refers to a straight or branched hydrocarbon chain containing one or more double bonds. The alkenyl group may have 2 to 35 carbon atoms, although the present definition also covers the occurrence of the term “alkenyl” where no numerical range is designated. By way of example only, “C2.4alkenyl” indicates that there are two to four carbon atoms in the alkenyl chain, e.g., the alkenyl chain is selected from the group consisting of ethenyl, propen- 1-yl, propen-2 -yl, propen-3 -yl, buten-l-yl, buten-2-yl, buten-3-yl, buten-4-yl, 1-methyl-propen-l-yl, 2-methyl-propen-l-yl, 1-ethyl-ethen-l-yl, 2-methyl-propen-3-yl, buta-l,3-dienyl, buta-l,2,-dienyl, and buta-l,2-dien-4-yl. Typical alkenyl groups include, but are in no way limited to, ethenyl, propenyl, butenyl, pentenyl, and hexenyl, and the like.

[0045] As used herein, “alkynyl” refers to a straight or branched hydrocarbon chain containing one or more triple bonds. The alkynyl group may have 2 to 35 carbon atoms, although the present definition also covers the occurrence of the term “alkynyl” whereno numerical range is designated. By way of example only, “C2.4 alkynyl” indicates that there are two to four carbon atoms in the alkynyl chain, e.g., the alkynyl chain is selected from the group consisting of ethynyl, propyn-l-yl, propyn-2-yl, butyn-l-yl, butyn-3-yl, butyn-4-yl, and 2-butynyl. Typical alkynyl groups include, but are in no way limited to, ethynyl, propynyl, butynyl, pentynyl, and hexynyl, and the like. As used herein, “carbocyclyl” means a non-aromatic cyclic ring or ring system containing only carbon atoms in the ring system backbone. When the carbocyclyl is a ring system, two or more rings may be joined together in a fused, bridged or spiro-connected fashion. Carbocyclyls may have any degree of saturation provided that at least one ring in a ring system is not aromatic. Thus, carbocyclyls include cycloalkyls, cycloalkenyls, and cycloalkynyls. The carbocyclyl group may have 3 to 20 carbon atoms, although the present definition also covers the occurrence of the term “carbocyclyl” where no numerical range is designated. The carbocyclyl group may also be a medium size carbocyclyl having 3 to 10 carbon atoms. The carbocyclyl group could also be a carbocyclyl having 3 to 6 carbon atoms. The carbocyclyl group may be designated as “C3.6carbocyclyl” or similar designations. Examples of carbocyclyl rings include, but are not limited to, cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, cyclohexenyl, 2,3 -dihydro-indene, bicycle[2.2.2]octanyl, adamantyl, and spiro[4.4]nonanyl.

[0046] As used herein, “heterocyclyl” means a non-aromatic cyclic ring or ring system containing at least one heteroatom in the ring backbone. Heterocyclyls may be joined together in a fused, bridged or spiro-connected fashion. Heterocyclyls may have any degree of saturation provided that at least one ring in the ring system is not aromatic. The heteroatom(s) may be present in either a non-aromatic or aromatic ring in the ring system. The heterocyclyl group may have 3 to 20 ring members (i.e., the number of atoms making up the ring backbone, including carbon atoms and heteroatoms ), although the present definition also covers the occurrence of the term “heterocyclyl” where no numerical range is designated. The heterocyclyl group may also be a medium size heterocyclyl having 3 to 10 ring members. The heterocyclyl group could also be a heterocyclyl having 3 to 6 ring members. The heterocyclyl group may be designated as “3-6 membered heterocyclyl” or similar designations. In preferred six membered monocyclic heterocyclyls, the heteroatom(s) are selected from one up to three of O, N or S, and inpreferred five membered monocyclic heterocyclyls, the heteroatom(s) are selected from one or two heteroatoms selected from O, N, or S. Examples of heterocyclyl rings include, but are not limited to, azepinyl, acridinyl, carbazolyl, cinnolinyl, dioxolanyl, imidazolinyl, imidazolidinyl, morpholinyl, oxiranyl, oxepanyl, thiepanyl, piperidinyl, piperazinyl, dioxopiperazinyl, pyrrolidinyl, pyrrolidonyl, pyrrolidionyl, 4-piperidonyl, pyrazolinyl, pyrazolidinyl, 1,3-dioxinyl, 1,3-dioxanyl, 1,4-dioxinyl, 1,4-dioxanyl, 1,3-oxathianyl, 1,4-oxathiinyl, 1,4-oxathianyl, 2 / 7-1, 2-oxazinyl, trioxanyl, hexahydro- 1,3, 5-triazinyl, 1,3-dioxolyl, 1,3 -dioxolanyl, 1,3 -dithiolyl, 1,3-dithiolanyl, isoxazolinyl, isoxazolidinyl, oxazolinyl, oxazolidinyl, oxazolidinonyl, thiazolinyl, thiazolidinyl, 1,3-oxathiolanyl, indolinyl, isoindolinyl, tetrahydrofuranyl, tetrahydropyranyl, tetrahydrothiophenyl, tetrahydrothiopyranyl, tetrahydro-l,4-thiazinyl, thiamorpholinyl, dihydrobenzofuranyl, benzimidazolidinyl, and tetrahydroquinoline.

[0047] A heterocyclyl group may, for example, be monocyclic or polycyclic (e.g. bicyclic). A polycyclic heterocyclyl may for example contain fused rings. In a bicyclic heterocyclyl group there may be one or more heteroatoms in each ring, or heteroatoms only in one of the rings. In one example, the heterocyclyl group is of three to ten atoms (i.e. 3-10 membered heterocyclyl). Examples of monocyclic non-aromatic heterocyclyl groups include aziridinyl, azetidinyl, pyrrolidinyl, imidazolidinyl, pyrazolidinyl, piperidinyl, piperazinyl, tetrahydrofuranyl, tetrahydropyranyl, morpholinyl, thiomorpholinyl and azepanyl. Examples of bicyclic heterocyclyl groups in which one of the rings is non-aromatic include dihydrobenzofuranyl, indanyl, indolinyl, isoindolinyl, tetrahydroisoquinolinyl, tetrahydroquinolyl, and benzoazepanyl.

[0048] The term “aromatic” refers to a ring or ring system having a conjugated pi electron system and includes both carbocyclic aromatic (e.g., phenyl) and heterocyclic aromatic groups (e.g., pyridine). The term includes monocyclic or fused-ring polycyclic (i.e., rings which share adjacent pairs of atoms) groups provided that the entire ring system is aromatic.

[0049] As used herein, “aryl” refers to an aromatic ring or ring system (i.e., two or more fused rings that share two adjacent carbon atoms) containing only carbon in the ring backbone. When the aryl is a ring system, every ring in the system is aromatic. The aryl group may have 6 to 18 carbon atoms, although the present definition also covers theoccurrence of the term “aryl” where no numerical range is designated. In some embodiments, the aryl group has 6 to 10 carbon atoms. The aryl group may be designated as “C6.io aryl,” “C6or Cio aryl,” or similar designations. Examples of aryl groups include, but are not limited to, phenyl, naphthyl, azulenyl, and anthracenyl.

[0050] As used herein, “heteroaryl” refers to an aromatic ring or ring system (i.e., two or more fused rings that share two adjacent atoms) that contain(s) one or more heteroatoms, that is, an element other than carbon, including but not limited to, nitrogen, oxygen and sulfur, in the ring backbone. When the heteroaryl is a ring system, every ring in the system is aromatic. The heteroaryl group may have 5-18 ring members (i.e., the number of atoms making up the ring backbone, including carbon atoms and heteroatoms), although the present definition also covers the occurrence of the term “heteroaryl” where no numerical range is designated. In some embodiments, the heteroaryl group has 5 to 10 ring members or 5 to 7 ring members. The heteroaryl group may be designated as “5-7 membered heteroaryl,” “5-10 membered heteroaryl,” or similar designations. Examples of heteroaryl rings include, but are not limited to, furyl, thienyl, phthalazinyl, pyrrolyl, oxazolyl, thiazolyl, imidazolyl, pyrazolyl, isoxazolyl, isothiazolyl, triazolyl, thiadiazolyl, pyridinyl, pyridazinyl, pyrimidinyl, pyrazinyl, triazinyl, quinolinyl, isoquinlinyl, benzimidazolyl, benzoxazolyl, benzothiazolyl, indolyl, isoindolyl, and benzothienyl.

[0051] A heteroaryl group may, for example, be monocyclic or polycyclic (e.g. bicyclic). A polycyclic heteroaryl may for example contain fused rings. In a bicyclic heteroaryl group there may be one or more heteroatoms in each ring, or heteroatoms only in one of the rings. Examples of monocyclic heteroaryl groups include furanyl, thienyl, pyrrolyl, oxazolyl, thiazolyl, imidazolyl, oxadiazolyl, thiadiazolyl, pyridyl, triazolyl, triazinyl, pyridazyl, isothiazolyl, isoxazolyl, pyrazinyl, pyrazolyl, and pyrimidinyl. Examples of bicyclic heteroaryl groups include quinoxalinyl, quinazolinul, pyridopyrazinyl, benzoxazolyl, benzothiophenyl, benzimidazolyl, naphthyridinyl, quinolinyl, benzofuranyl, indolyl, indazolyl, benzothiazolyl, oxazolyl[4,5-b]pyridyl, pyridopyrimidinyl, isoquinolinyl, and benzohydroxazole.

[0052] As used herein, a substituted group is derived from the unsubstituted parent group in which there has been an exchange of one or more hydrogen atoms for anotheratom or group. Unless otherwise indicated, when a group is deemed to be “substituted,” it is meant that the group is substituted with one or more substituents independently selected from Ci-C6alkyl, C2-C6alkenyl, C2-C6alkynyl, Ci-C6heteroalkyl, C3-C7carbocyclyl (optionally substituted with halo, Ci-C6alkyl, Ci-C6alkoxy, Ci-C6haloalkyl, and Ci-C6haloalkoxy), Cs-C -carbocyclyl-Cx-Ce-alkyl (optionally substituted with halo, Ci-C6alkyl, Ci-C6alkoxy, Ci-C6haloalkyl, and Ci-C6haloalkoxy), 5-10 membered heterocyclyl (optionally substituted with halo, Ci-C6alkyl, Ci-C6alkoxy, Ci-C6haloalkyl, and Ci-C6haloalkoxy), 5-10 membered heterocyclyl-Ci-C6-alkyl (optionally substituted with halo, Ci-C6alkyl, Ci-C6alkoxy, Ci-C6haloalkyl, and Ci-C6haloalkoxy), aryl (optionally substituted with halo, Ci-C6alkyl, Ci-C6alkoxy, Ci-C6haloalkyl, and Ci-C6haloalkoxy), aryl(C!-C6)alkyl (optionally substituted with halo, C C6alkyl, Ci-C6alkoxy, Ci-C6haloalkyl, and Ci-C6haloalkoxy), 5-10 membered heteroaryl (optionally substituted with halo, Ci-C6alkyl, Ci-C6alkoxy, Ci-C6haloalkyl, and Ci-C6haloalkoxy), 5-10 membered heteroaryl(Ci-C6)alkyl (optionally substituted with halo, Ci-C6alkyl, Ci-C6alkoxy, Ci-C6haloalkyl, and Ci-C6haloalkoxy), halo, cyano, hydroxy, Ci-C6alkoxy, Ci-C6alkoxy(C!-C6)alkyl (i.e., ether), aryloxy, sulfhydryl (mercapto), halo(C!-C6)alkyl (e.g., -CF3), halo(C!-C6)alkoxy (e.g., -OCF3), Ci-C6alkylthio, arylthio, amino, amino(C!-C6)alkyl, nitro, O-carbamyl, N-carbamyl, O-thiocarbamyl, N-thiocarbamyl, C-amido, N-amido, S-sulfonamido, N-sulfonamido, C-carboxy, O-carboxy, acyl, cyanato, isocyanato, thiocyanato, isothiocyanato, sulfinyl, sulfonyl, and oxo (=0). Wherever a group is described as “optionally substituted” that group can be substituted with the above substituents.

[0053] The term “halogen” or “halo,” as used herein, means any one of the radio-stable atoms of column 7 of the Periodic Table of the Elements, e.g., fluorine, chlorine, bromine, or iodine, with fluorine and chlorine being preferred.

[0054] It is to be understood that the substituents and moieties described herein (e.g. alkyl, alkenyl and / or alkynyl) can include either a mono-radical or a di-radical, depending on the context. For example, where a substituent requires two points of attachment to the rest of the molecule, it is understood that the substituent is a di-radical. For example, a substituent identified as alkyl that requires two points of attachment includes di-radicals such as -CH2- -CH2CH2- -CH2CH(CH3)CH2- and the like. Foran alkenyl the diradical may be in the structure of -C=C- or -C=C-X1-C=C- wherein Xx is absent or is a diradical alkyl as defined herein.

[0055] Herein “weight %” may be abbreviated to as “wt%” or “wt.%”. The weight % may be w / w or w / v, unless specifically indicated or clear from context.

[0056] Herein, unless specifically defined a “device” may refer to a “photovoltaic precursor device” or a “photovoltaic device”.Photovoltaic precursor device

[0057] Disclosed herein is a photovoltaic precursor device, the photovoltaic precursor device comprising:a light absorbing semiconductor layer;a singlet fission layer; andat least one of a metal oxide layer and a passivation layer,wherein optionally:- if present, at least one metal oxide layer is disposed between the light absorbing semiconductor layer and the singlet fission; and- if at least one passivation layer is present, the singlet fission layer is disposed between the light absorbing semiconductor layer and the at least one passivation layer; andthe singlet fission layer comprises at least one singlet fission compound, as described herein.

[0058] In an alternative embodiment of the present disclosure, disclosed herein is a photovoltaic precursor device, the photovoltaic precursor device comprising:a light absorbing semiconductor layer;a singlet fission layer; andat least one of a metal oxide layer and a passivation layer,wherein optionally:- if present, at least one metal oxide layer is disposed between the light absorbing semiconductor layer and the singlet fission; and- if present, at least one passivation layer is disposed between the light absorbing semiconductor layer and the singlet fission layer; andthe singlet fission layer comprises at least one singlet fission compound, as described herein.

[0059] Disclosed herein is a photovoltaic device comprising:a light absorbing semiconductor layer;a singlet fission layer; andat least one of a metal oxide layer and a passivation layer,wherein optionally:if present, at least one metal oxide layer is disposed between the light absorbing semiconductor layer and the singlet fission layer; andif at least one passivation layer is present, the singlet fission layer is disposed between the light absorbing semiconductor layer and the at least one passivation layer; andthe singlet fission layer comprises at least one singlet fission compound.

[0060] In an alternative embodiment of the present disclosure, disclosed herein is a photovoltaic device comprising:a light absorbing semiconductor layer;a singlet fission layer; andat least one of a metal oxide layer and a passivation layer,wherein optionally:if present, at least one metal oxide layer is disposed between the light absorbing semiconductor layer and the singlet fission layer; andif at least one passivation layer is present, at least one passivation layer is disposed between the light absorbing semiconductor layer and the singlet fission layer; andthe singlet fission layer comprises at least one singlet fission compound.

[0061] In one or more embodiments, there is provided a photovoltaic precursor device, or a photovoltaic device, the photovoltaic precursor device or photovoltaic device comprising:a light absorbing semiconductor layer;a singlet fission layer; andat least one of a metal oxide layer and a passivation layer,wherein optionally:- if present, at least one metal oxide layer is disposed between the light absorbing semiconductor layer and the singlet fission layer; and- if at least one passivation layer is present, the singlet fission layer is disposed between the light absorbing semiconductor layer and the at least one passivation layer; andthe singlet fission layer comprises at least one singlet fission compound of Formula (I) or a dimer or trimer thereof:O R1Formula (I)wherein:the dimer of Formula (I) is a compound of Formula (II) or Formula (Ila);Formula (Ila);andthe trimer of Formula (I) is a compound of Formula (III) or Formula (Illa):Formula (III)Formula (Illa)wherein:R1, R2, R3, R4, R5, R6, R7, and R8are independently selected from: a bond, H, or optionally substituted C1.35 hydrocarbon.

[0062] In one or more embodiments, there is provided a photovoltaic precursor device, or a photovoltaic device, the photovoltaic precursor device or photovoltaic precursor device comprising:a light absorbing semiconductor layer;a singlet fission layer; andat least one of a metal oxide layer and a passivation layer,wherein optionally:- if present, at least one metal oxide layer is disposed between the light absorbing semiconductor layer and the singlet fission layer; and- if at least one passivation layer is present, the singlet fission layer is disposed between the light absorbing semiconductor layer and the at least one passivation layer; andthe singlet fission layer comprises at least one singlet fission compound of Formula (I) or a dimer or trimer thereof:O R1Formula (I)wherein:the dimer of Formula (I) is a compound of Formula (II);Formula (II);andthe trimer of Formula (I) is a compound of Formula (III):Formula (III)wherein:- R1, R2, R4, R5, R7, and R8are independently selected from: H, C1.25 alkyl, C2-25 alkenyl, C2.25 alkynyl, each of which is optionally substituted with one or more substituents selected from CMO alkyl, C2-io alkenyl, and C2.10alkynyl; and- R3and R6are independently selected from a bond, C1.25 alkyl, C2.25 alkenyl, C2.25 alkynyl, C3.6carbocyclyl, C3.6aryl, each of which is optionally substituted with one or more substituents selected from CMO alkyl, C2.io alkenyl, and C2-io alkynyl.

[0063] In one or more embodiments, there is provided a photovoltaic precursor device, or a photovoltaic device, the photovoltaic precursor device or photovoltaic precursor device comprising:a light absorbing semiconductor layer;a singlet fission layer; andat least one of a metal oxide layer and a passivation layer,wherein optionally:- if present, at least one metal oxide layer is disposed between the light absorbing semiconductor layer and the singlet fission layer; and- if at least one passivation layer is present, the singlet fission layer is disposed between the light absorbing semiconductor layer and the at least one passivation layer; andthe singlet fission layer comprises at least one singlet fission compound of Formula (I) or a dimer or trimer thereof:O R1Formula (I)wherein:the dimer of Formula (I) is a compound of Formula (Ila);Formula (Ila);andthe trimer of Formula (I) is a compound of Formula (Illa):Formula (Illa)wherein:- R1, R2, R4, R5, R7, and R8are independently selected from: H, C1.25 alkyl, C2-25 alkenyl, C2.25 alkynyl, each of which is optionally substituted with one or more substituents selected from CMO alkyl, C2-io alkenyl, and C2.10alkynyl; and- R3and R6are independently selected from a bond, C1.25 alkyl, C2.25 alkenyl, C2.25 alkynyl, C3.6carbocyclyl, C3.6aryl, each of which isoptionally substituted with one or more substituents selected from CM0alkyl, C2.io alkenyl, and C2-io alkynyl.

[0064] In one embodiment a compound of Formula (I) is replaced with a compound of Formula (VI)

[0065] Herein a compound of Formula (VI) has the following structure:OFormula (VI)wherein p is an integer of 5 to 100.

[0066] In one embodiment, for a compound of Formula (VI), at least one CH2group in (CH2)Pmay be exchanged for O or NR9, wherein each R9is selected from H, optionally substituted CMO alkyl, optionally substituted C2-io alkenyl, optionally substituted C2.io alkynyl, and optionally substituted C5.6aryl. In another embodiment, (CH2)pin Formula (VI), is replaced with -(CH2)x-O-(CH2)y-, wherein each of x and y is an integer, and x +y is an integer between 4 and 100. In another embodiment, (CH2)pin Formula (VI), is replaced with -(CH2)x-NR9-(CH2)y-, wherein each of x and y is an integer, and x +y is an integer between 4 and 100, and R9is selected from H, optionally substituted CMO alkyl, optionally substituted C2.10alkenyl, optionally substituted C2.10alkynyl, and optionally substituted C5.6aryl.

[0067] In one embodiment, for a compound of Formula (VI), p is 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53, 54, 55, 56, 57, 58, 59, 60, 61, 62, 63, 64, 65, 66, 67, 68, 69, 70, 71, 72, 73, 74, 75, 76, 77, 78, 79, 80, 81, 82, 83, 84, 85, 86, 87, 88, 89, 90, 91, 92, 93, 94, 95, 96, 97, 98, 99, 100, or in a range of any two of these values.

[0068] In one embodiment, for a compound of Formula (VI), p is 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, or in a range of any two of these values.

[0069] In one embodiment, for a compound of Formula (VI), p is 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, or in a range of any two of these values.Light absorbing semiconductor layer

[0070] In one or more embodiments, the light absorbing semiconductor layer is a n-type semiconductor layer. In one or more embodiments, n-type semiconductor layer comprises silicon. In one or more embodiments, the n-type semiconductor layer

[0071] In one or more embodiments, the light absorbing semiconductor layer is a n-type semiconductor layer. In one or more embodiments, n-type semiconductor layer comprises silicon. In one or more embodiments, the n-type semiconductor layer substantially consists of a n-type silicon. In one or more embodiments, the n-type silicon comprises silicon doped with phosphorus, arsenic, antimony, and mixtures thereof. In one or more embodiments, the n-type silicon comprises silicon doped with phosphorus. In one or more embodiments, the n-type silicon substantially consists of silicon doped with phosphorus.

[0072] In one or more embodiments, the light absorbing semiconductor layer is a p-type semiconductor layer. In one or more embodiments, p-type semiconductor layer comprises silicon. In one or more embodiments, the p-type semiconductor layer substantially consists of a p-type silicon. In one or more embodiments, the p-type silicon comprises silicon doped with boron, aluminium, gallium, indium, and mixtures thereof. In one or more embodiments, the p-type silicon comprises silicon doped with boron. In one or more embodiments, the p-type silicon substantially consists of silicon doped with boron.

[0073] In one or more embodiments, the thickness of the light absorbing semiconductor layer (in pm) is about, or greater than about: 1, 2, 3, 4, 5, 10, 15, 20, 30, 40, 50, 60, 70, 80, 90, 100, 110, 120, 130, 140, 150, 200, 250, 300, 350, 400, 450, 500, 600, 700, 800, 900, 1000, 2000, 3000, 4000, or 5000. In one or more embodiments, the thickness of the light absorbing semiconductor layer (in pm) is less than about: 5000, 4000, 3000, 2000, 1000, 900, 800, 700, 600, 500, 450, 400, 350, 300, 250, 200, 150, 100, 95, 90, 85, 80, 75, 70, 65, 60, 55, 50, 45, 40, 35, 30, 25, 20, 15, 10, 5, 4, 3, 2, 1. The thickness of the light absorbing semiconductor layer (in pm) may be in a range provided by any two or more of these upper and / or lower amounts. In one or more embodiments, the thickness of the light absorbing semiconductor layer (in pm) is between about 1 to about 5000, or between about 100 to about 1000.Singlet fission layer

[0074] The photovoltaic precursor device or photovoltaic device of the present disclosure comprises a singlet fission layer. The singlet fission layer comprises at least one singlet fission compound. In singlet fission, absorption of a high-energy photon generates a singlet exciton that is then converted into two triplet excitons, hence generating two excitons from a single photon.Formula (I)

[0075] In one or more embodiments, the singlet fission layer comprises at least one singlet fission compound of Formula (I) or a dimer or trimer thereof as described herein, or an oligomer thereof, as described herein:R2Formula (I)wherein:- R1and R2are independently selected from: H, C1-35alkyl, C1-35heteroalkyl, C2-35alkenyl, C2-35alkynyl, C3-20carbocyclyl, C3-20heterocyclyl, C3-18aryl, and C5-18heteroaryl, each of which is optionally substituted with one or more substituents selected C1-10alkyl, C2-10alkenyl, C2-10alkynyl, halogen, -CN, -OR9, -SR9, -S(O)2R9, -NR9R10, - NO2, =(O), =(S), =(N)R9, =(N)R10, -C(O)R9, -C(O)NR9R10, -C(O)SR9or -C(O)OR9; or with one or more groups selected from C3.6carbocyclyl, C3.6heterocyclyl, C3.6aryl, and C5-12heteroaryl, each of which is optionally substituted with one or more substituents selected from C1-6alkyl, halogen, -CN, -OR9, -SR9, -S(O)2R9, -NR9R10, -NO2, =(O), =(S), =(N)R9, =(N)R10, -C(O)R9, -C(O)NR9R10, -C(O)SR9or -C(O)OR9; - wherein each R9is selected from H, optionally substituted C1-10alkyl, optionally substituted C2-10alkenyl, optionally substituted C2-10alkynyl, and optionally substituted C5.6aryl;- wherein each R10is selected from H, optionally substituted CM0alkyl, optionally substituted C2-io alkenyl, optionally substituted C2-io alkynyl, and optionally substituted C5.6aryl.

[0076] In one or more embodiments, the singlet fission layer comprises at least one singlet fission compound of Formula (I) or a dimer or trimer thereof as described herein, or an oligomer thereof, as described herein:O R1Formula (I)wherein:- R1and R2are independently selected from: H or optionally substituted Ci.35 hydrocarbons.Dimers

[0077] In one or more embodiments, the singlet fission layer comprises at least one singlet fission compound which is a dimer of Formula (I), wherein the dimer of Formula (I) is a compound of Formula (II);Formula (II)wherein:- R1, R2, R3, R4, and R5are independently selected from: a bond, H, Ci.35alkyl, Ci.35 heteroalkyl, C2.35alkenyl, C2.35alkynyl, C3.20carbocyclyl, C3.20heterocyclyl, C3.18aryl, and C5.18heteroaryl, each of which is optionally substituted with one or more substituents selected CM0alkyl, C2.10alkenyl, C2.10alkynyl, halogen, -CN, -OR9, -SR9, -S(O)2R9, -NR9R10, - NO2, =(O), =(S), =(N)R9, =(N)R10, -C(O)R9, -C(O)NR9R10, -C(O)SR9or -C(O)OR9; or with one or more groups selected from C3.6carbocyclyl, C3.6heterocyclyl, C3.6aryl, and C5.12heteroaryl, each of which isoptionally substituted with one or more substituents selected from Ci_6alkyl, halogen, -CN, -OR9, -SR9, -S(O)2R9, -NR9R10, -NO2, =(O), =(S), =(N)R9, =(N)R10, -C(O)R9, -C(O)NR9R10, -C(O)SR9or -C(O)OR9; - wherein each R9is selected from H, optionally substituted C1-10alkyl, optionally substituted C2.10alkenyl, optionally substituted C2.10alkynyl, and optionally substituted C5.6aryl;- wherein each R10is selected from H, optionally substituted C1-10alkyl, optionally substituted C2-io alkenyl, optionally substituted C2-io alkynyl, and optionally substituted C5.6aryl.

[0078] In one or more embodiments, the singlet fission layer comprises at least one singlet fission compound which is a dimer of Formula (I), wherein the dimer of Formula (I) is a compound of Formula (II);Formula (II)wherein:- R1, R2, R3, R4, and R5are independently selected from: a bond, H, or optionally substituted Cl -35 hydrocarbons.

[0079] In one or more embodiments, the singlet fission layer comprises at least one singlet fission compound which is a dimer of Formula (I), wherein the dimer of Formula (I) is a compound of Formula (Ila);Formula (Ila)wherein:- R1, R2, R3, R4, and R5are independently selected from: a bond, H, Ci.35alkyl, Ci.35 heteroalkyl, C2.35alkenyl, C2.35alkynyl, C3.20carbocyclyl, C3.20 heterocyclyl, C3.18aryl, and C5.18heteroaryl, each of which is optionally substituted with one or more substituents selected C1-10alkyl, C2-io alkenyl, C2-io alkynyl, halogen, -CN, -OR9, -SR9, -S(O)2R9, -NR9R10, - NO2, =(O), =(S), =(N)R9, =(N)R10, -C(O)R9, -C(O)NR9R10, -C(O)SR9or -C(O)OR9; or with one or more groups selected from C3.6carbocyclyl, C3.6heterocyclyl, C3.6aryl, and C5.12heteroaryl, each of which is optionally substituted with one or more substituents selected from Ci.6alkyl, halogen, -CN, -OR9, -SR9, -S(O)2R9, -NR9R10, -NO2, =(O), =(S), =(N)R9, =(N)R10, -C(O)R9, -C(O)NR9R10, -C(O)SR9or -C(O)OR9; - wherein each R9is selected from H, optionally substituted C1-10alkyl, optionally substituted C2.10alkenyl, optionally substituted C2.10alkynyl, and optionally substituted C5.6aryl;- wherein each R10is selected from H, optionally substituted CMO alkyl, optionally substituted C2-io alkenyl, optionally substituted C2.io alkynyl, and optionally substituted C5.6aryl.

[0080] In one or more embodiments, the singlet fission layer comprises at least one singlet fission compound which is a dimer of Formula (I), wherein the dimer of Formula (I) is a compound of Formula (Ila);Formula (Ila)wherein:- R1, R2, R3, R4, and R5are independently selected from: a bond, H, or optionally substituted Ci_35hydrocarbons.

[0081] In one or more embodiments, the singlet fission layer comprises at least one singlet fission compound which is a dimer of Formula (I), wherein the dimer of Formula (I) is a compound of Formula (lib);Formula (lib);wherein:- R1, R2and R5are independently selected from: a bond, H, C1.35 alkyl, C).35 heteroalkyl, C2.35 alkenyl, C2.35 alkynyl, C3.20 carbocyclyl, C3.20 heterocyclyl, C3.i8aryl, and C5.i8heteroaryl, each of which is optionally substituted with one or more substituents selected CM0alkyl, C2.io alkenyl, C2.io alkynyl, halogen, -CN, -OR9, -SR9, -S(O)2R9, -NR9R10, - NO2, =(O), =(S), =(N)R9, =(N)R10, -C(O)R9, -C(O)NR9R10, -C(O)SR9or -C(O)OR9; or with one or more groups selected from C3.6carbocyclyl, C3.6 heterocyclyl, C3.6aryl, and C5.12 heteroaryl, each of which is optionally substituted with one or more substituents selected from Ci_6alkyl, halogen, -CN, -OR9, -SR9, -S(O)2R9, -NR9R10, -NO2, =(O), =(S), =(N)R9, =(N)R10, -C(O)R9, -C(O)NR9R10, -C(O)SR9or -C(O)OR9; - wherein each R9is selected from H, optionally substituted C1-10alkyl, optionally substituted C2-io alkenyl, optionally substituted C2-io alkynyl, and optionally substituted C5.6aryl;- wherein each R10is selected from H, optionally substituted CM0alkyl, optionally substituted C2-io alkenyl, optionally substituted C2-io alkynyl, and optionally substituted C5.6aryl.

[0082] In one or more embodiments, the singlet fission layer comprises at least one singlet fission compound which is a dimer of Formula (I), wherein the dimer of Formula (I) is a compound of Formula (lib);Formula (lib);wherein:- R1, R2and R5are independently selected from: a bond, H, or optionally substituted C1.35 hydrocarbons.Trimers

[0083] In one or more embodiments, the singlet fission layer comprises at least one singlet fission compound which is a trimer of Formula (I), wherein the trimer of Formula (I) is a compound of Formula (III):Formula (III)wherein:R1, R2, R3, R4, R5, R6, R7, and R8are independently selected from: a bond, H, Ci -35 alkyl, Ci.35 heteroalkyl, C2.35 alkenyl, C2.35 alkynyl, C3.20 carbocyclyl, C3.2o heterocyclyl, C3.i8aryl, and C5.i8heteroaryl, each of which is optionally substituted with one or more substituents selected Ci.10 alkyl, C2.io alkenyl, C2-io alkynyl, halogen, -CN, -OR9, -SR9, - S(O)2R9, -NR9R10, -NO2, =(O), =(S), =(N)R9, =(N)R10, -C(O)R9, - C(O)NR9R10, -C(O)SR9or -C(O)OR9; or with one or more groups selected from C3.6carbocyclyl, C3.6heterocyclyl, C3.6aryl, and C5.12 heteroaryl, each of which is optionally substituted with one or more substituents selected from Ci_6alkyl, halogen, -CN, -OR9, -SR9, - S(O)2R9, -NR9R10, -NO2, =(O), =(S), =(N)R9, =(N)R10, -C(O)R9, - C(O)NR9R10, -C(O)SR9or-C(O)OR9;- wherein each R9is selected from H, optionally substituted C1-10alkyl, optionally substituted C2-io alkenyl, optionally substituted C2-io alkynyl, and optionally substituted C5.6aryl;- wherein each R10is selected from H, optionally substituted CMO alkyl, optionally substituted C2-io alkenyl, optionally substituted C2-io alkynyl, and optionally substituted C5.6aryl.

[0084] In one or more embodiments, the singlet fission layer comprises at least one singlet fission compound which is a trimer of Formula (I), wherein the trimer of Formula (I) is a compound of Formula (III):Formula (III)wherein:R1, R2, R3, R4, R5, R6, R7, and R8are independently selected from: a bond, H, or optionally substituted C1.35 hydrocarbons.

[0085] In one or more embodiments, the singlet fission layer comprises at least one singlet fission compound which is a trimer of Formula (I), wherein the trimer of Formula (I) is a compound of Formula (Illa):Formula (Illa)wherein:R1, R2, R3, R4, R5, R6, R7, and R8are independently selected from: a bond, H, Ci -35 alkyl, Ci.35 heteroalkyl, C2.35 alkenyl, C2.35 alkynyl, C3.20 carbocyclyl, C3.2o heterocyclyl, C3.i8aryl, and C5.i8heteroaryl, each of which is optionally substituted with one or more substituents selected Ci.10 alkyl, C2.io alkenyl, C2-io alkynyl, halogen, -CN, -OR9, -SR9, - S(O)2R9, -NR9R10, -NO2, =(O), =(S), =(N)R9, =(N)R10, -C(O)R9, - C(O)NR9R10, -C(O)SR9or -C(O)OR9; or with one or more groups selected from C3.6carbocyclyl, C3.6heterocyclyl, C3.6aryl, and C5.12 heteroaryl, each of which is optionally substituted with one or more substituents selected from Ci.6alkyl, halogen, -CN, -OR9, -SR9, -S(O)2R9, -NR9R10, -NO2, =(O), =(S), =(N)R9, =(N)R10, -C(O)R9, - C(O)NR9R10, -C(O)SR9or-C(O)OR9;- wherein each R9is selected from H, optionally substituted C1-10alkyl, optionally substituted C2.10alkenyl, optionally substituted C2.10alkynyl, and optionally substituted C5.6aryl;- wherein each R10is selected from H, optionally substituted C1-10alkyl, optionally substituted C2-io alkenyl, optionally substituted C2-io alkynyl, and optionally substituted C5.6aryl.

[0086] In one or more embodiments, the singlet fission layer comprises at least one singlet fission compound which is a trimer of Formula (I), wherein the trimer of Formula (I) is a compound of Formula (Illa):Formula (Illa)wherein:R1, R2, R3, R4, R5, R6, R7, and R8are independently selected from: a bond, H, or optionally substituted C1.35 hydrocarbons.

[0087] In one or more embodiments, the singlet fission layer comprises at least one singlet fission compound which is a trimer of Formula (I), wherein the trimer of Formula (I) is a compound of Formula (Illb):Formula (Illb)wherein:- R1, R2, R5and R8are independently selected from: a bond, H, Ci_35alkyl, C1.35 heteroalkyl, C2.35alkenyl, C2.35alkynyl, C3.20carbocyclyl, C3.20heterocyclyl, C3.i8aryl, and C5.i8heteroaryl, each of which is optionallysubstituted with one or more substituents selected CM0alkyl, C2.io alkenyl, C2-io alkynyl, halogen, -CN, -OR9, -SR9, -S(O)2R9, -NR9R10, - NO2, =(O), =(S), =(N)R9, =(N)R10, -C(O)R9, -C(O)NR9R10, -C(O)SR9or -C(O)OR9; or with one or more groups selected from C3.6carbocyclyl, C3.6heterocyclyl, C3.6aryl, and C5.12heteroaryl, each of which is optionally substituted with one or more substituents selected from Ci_6alkyl, halogen, -CN, -OR9, -SR9, -S(O)2R9, -NR9R10, -NO2, =(O), =(S), =(N)R9, =(N)R10, -C(O)R9, -C(O)NR9R10, -C(O)SR9or -C(O)OR9; - wherein each R9is selected from H, optionally substituted C1-10alkyl, optionally substituted C2.10alkenyl, optionally substituted C2.10alkynyl, and optionally substituted C5.6aryl;- wherein each R10is selected from H, optionally substituted C1-10alkyl, optionally substituted C2.io alkenyl, optionally substituted C2.io alkynyl, and optionally substituted C5.6aryl.In one or more embodiments, the singlet fission layer comprises at least one singlet fission compound which is a trimer of Formula (I), wherein the trimer of Formula (I) is a compound of Formula (Illb):Formula (Illb)wherein:- R1, R2, R5and R8are independently selected from: a bond, H, or optionally substituted Ci_35hydrocarbons.Oligomers

[0088] In one or more embodiments, the singlet fission layer comprises at least one singlet fission compound of Formula (IV):Formula (IV)wherein:- R1, R2, R3are independently selected from: a bond, H, Ci_35alkyl, Ci_35heteroalkyl, C2.35alkenyl, C2.35alkynyl, C3.20carbocyclyl, C3.20heterocyclyl, C3.i8aryl, and C5.i8heteroaryl, each of which is optionally substituted with one or more substituents selected C1-10alkyl, C2-io alkenyl, C2.10alkynyl, halogen, -CN, -OR9, -SR9, -S(O)2R9, -NR9R10, - NO2, =(O), =(S), =(N)R9, =(N)R10, -C(O)R9, -C(O)NR9R10, -C(O)SR9or -C(O)OR9; or with one or more groups selected from C3.6carbocyclyl, C3.6heterocyclyl, C3.6aryl, and C5-12heteroaryl, each of which is optionally substituted with one or more substituents selected from C1-6alkyl, halogen, -CN, -OR9, -SR9, -S(O)2R9, -NR9R10, -NO2, =(O), =(S), =(N)R9, =(N)R10, -C(O)R9, -C(O)NR9R10, -C(O)SR9or-C(O)OR9; or - R1and R2are independently selected from: H, or optionally substituted Ci.35hydrocarbons- wherein each R9is selected from H, optionally substituted C1-10alkyl, optionally substituted C2.10alkenyl, optionally substituted C2.10alkynyl, and optionally substituted C5.6aryl;- wherein each R10is selected from H, optionally substituted CMO alkyl, optionally substituted C2-io alkenyl, optionally substituted C2.io alkynyl, and optionally substituted C5.6aryl;- wherein — indicates a bond between repeat units; and- wherein n is between about 4 and about 100.

[0089] In one embodiment for a compound of Formula (IV), R1and R2are independently selected from: H, or optionally substituted Ci.35hydrocarbons.

[0090] In one embodiment, for a compound of Formula (IV), n is an integer of about or at least about: 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24,25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53, 54, 55, 56, 57, 58, 59, 60, 61, 62, 63, 64, 65, 66, 67, 68, 69, 70, 71, 72, 73, 74, 75, 76, 77, 78, 79, 80, 81, 82, 83, 84, 85, 86, 87, 88, 89, 90, 91, 92, 93, 94, 95, 96, 97, 98, 99, or 100. The integer may be in a range provided by any two or more of these amounts.

[0091] In one or more embodiments, the singlet fission layer comprises at least one singlet fission compound of Formula (V):Formula (V)wherein:- R1and R2are independently selected from: a bond, H, Ci.35alkyl, Ci.35heteroalkyl, C2.35alkenyl, C2.35alkynyl, C3.20carbocyclyl, C3.20heterocyclyl, C3.18aryl, and C5.18heteroaryl, each of which is optionally substituted with one or more substituents selected CM0alkyl, C2.10alkenyl, C2.10alkynyl, halogen, -CN, -OR9, -SR9, -S(O)2R9, -NR9R10, - NO2, =(O), =(S), =(N)R9, =(N)R10, -C(O)R9, -C(O)NR9R10, -C(O)SR9or -C(O)OR9; or with one or more groups selected from C3.6carbocyclyl, C3.6heterocyclyl, C3.6aryl, and C5.12heteroaryl, each of which is optionally substituted with one or more substituents selected from Ci_6alkyl, halogen, -CN, -OR9, -SR9, -S(O)2R9, -NR9R10, -NO2, =(O), =(S), =(N)R9, =(N)R10, -C(O)R9, -C(O)NR9R10, -C(O)SR9or-C(O)OR9; or - R1and R2are independently selected from: H, or optionally substituted Ci-35hydrocarbons- wherein each R9is selected from H, optionally substituted C1-10alkyl, optionally substituted C2.10alkenyl, optionally substituted C2.10alkynyl, and optionally substituted C5.6aryl;- wherein each R10is selected from H, optionally substituted CM0alkyl, optionally substituted C2-io alkenyl, optionally substituted C2-io alkynyl, and optionally substituted C5.6aryl;- wherein — indicates a bond between repeat units; and- wherein n is between about 4 and about 100.

[0092] In one embodiment for a compound of Formula (V), R1and R2are independently selected from: H, or optionally substituted Ci.35hydrocarbons.

[0093] In one embodiment, for a compound of Formula (V), n is an integer of about or at least about: 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53, 54, 55, 56, 57, 58, 59, 60, 61, 62, 63, 64, 65, 66, 67, 68, 69, 70, 71, 72, 73, 74, 75, 76, 77, 78, 79, 80, 81, 82, 83, 84, 85, 86, 87, 88, 89, 90, 91, 92, 93, 94, 95, 96, 97, 98, 99, or 100. The integer may be in a range provided by any two or more of these amounts.

[0094] In one or more embodiments, the singlet fission layer comprises at least one singlet fission compound of Formula (I) or a dimer or trimer thereof:Formula (I)wherein:the dimer of Formula (I) is a compound of Formula (II);\R\'O IR2R5Formula (II);andthe trimer of Formula (I) is a compound of Formula (III):Formula (III)wherein:R1, R2, R3, R4, R5, R6, R7, and R8are independently selected from: a bond, H, or optionally substituted C1.35 hydrocarbons.

[0095] In one or more embodiments, the singlet fission layer comprises at least one singlet fission compound of Formula (I) or a dimer or trimer thereof:O R1Formula (I),wherein:the dimer of Formula (I) is a compound of Formula (Ila);Formula (Ila);andthe trimer of Formula (I) is a compound of Formula (Illa):(Formula Illa)wherein:R1, R2, R3, R4, R5, R6, R7, and R8are independently selected from: a bond, H, or optionally substituted C1.35 hydrocarbons.

[0096] In one or more embodiments, the R1, R2, R3, R4, R5, R6, R7, and R8are independently selected from: a bond, H, C1-35 branched or unbranched alkanes, alkenes, alkynes, aromatic hydrocarbons, cycloalkanes, cycloalkenes, polycyclic hydrocarbons, and combinations thereof.

[0097] In one or more embodiments, the singlet fission layer comprises at least one singlet fission compound of Formula (I) or a dimer or trimer thereof:O R1Formula (I),wherein:the dimer of Formula (I) is a compound of Formula (II);Formula (II);andthe trimer of Formula (I) is a compound of Formula (III):Formula (III)wherein:- R1, R2, R4, R5, R7, and R8are independently selected from: H, C1.25 alkyl, C2.25 alkenyl, C2.25 alkynyl, each of which is optionally substituted with one or more substituents selected from Cuo alkyl, C2-io alkenyl, and C2-io alkynyl; and- R3and R6are independently selected from C1.25 alkyl, C2.25 alkenyl, C2.25 alkynyl, C3.6 carbocyclyl, C3.6aryl, each of which is optionally substituted with one or more substituents selected from CMO alkyl, C2-io alkenyl, and C2-io alkynyl.

[0098] In one or more embodiments, the singlet fission layer comprises at least one singlet fission compound of Formula (I) or a dimer or trimer thereof:O R1Formula (I),wherein:the dimer of Formula (I) is a compound of Formula (Ila);Formula (Ila);andthe trimer of Formula (I) is a compound of Formula (Illa):Formula (Illa)wherein:- R1, R2, R4, R5, R7, and R8are independently selected from: H, C1.25 alkyl, C2.25 alkenyl, C2.25 alkynyl, each of which is optionally substituted with one or more substituents selected from Cuo alkyl, C2-io alkenyl, and C2-io alkynyl; and - R3and R6are independently selected from C1.25 alkyl, C2.25 alkenyl, C2.25 alkynyl, C3.6carbocyclyl, C3.6aryl, each of which is optionally substituted with one or more substituents selected from CMO alkyl, C2-io alkenyl, and C2-io alkynyl.

[0099] In one or more embodiments, the singlet fission layer comprises at least one singlet fission compound of Formula (I):O R1Formula (I),wherein:- R1, R2, R4, R5, R7, and R8are independently selected from: H, C1.25 alkyl, C2.25 alkenyl, C2.25 alkynyl, each of which is optionally substituted with one or more substituents selected from Cuo alkyl, C2-io alkenyl, and C2-io alkynyl.

[0100] In one or more embodiments, the singlet fission layer comprises at least one singlet fission compound of Formula (II):Formula (II);wherein:- R1, R2, R4, R5are independently selected from: H, C1.25 alkyl, C2.25 alkenyl, C2.25 alkynyl, each of which is optionally substituted with one or more substituents selected from CM0alkyl, C2-io alkenyl, and C2-io alkynyl; and- R3is selected from a bond, C1.25 alkyl, C2.25 alkenyl, C2.25 alkynyl, C3.6carbocyclyl, C3.6aryl, each of which is optionally substituted with one or more substituents selected from Cuo alkyl, C2-io alkenyl, and C2-io alkynyl.

[0101] In one or more embodiments, the singlet fission layer comprises at least one singlet fission compound of Formula (Ila):wherein:- R1, R2, R4, R5are independently selected from: H, C1.25 alkyl, C2.25 alkenyl, C2.25 alkynyl, each of which is optionally substituted with one or more substituents selected from CMO alkyl, C2-io alkenyl, and C2-io alkynyl; and- R3is selected from a bond, C1.25 alkyl, C2.25 alkenyl, C2.25 alkynyl, C3.6carbocyclyl, C3.6aryl, each of which is optionally substituted with one or more substituents selected from Cuo alkyl, C2-io alkenyl, and C2-io alkynyl.

[0102] In one or more embodiments, the singlet fission layer comprises at least one singlet fission compound of Formula (III):Formula (III)wherein:- R1, R2, R4, R5, R7, and R8are independently selected from: H, C1.25 alkyl, C2-25 alkenyl, C2.25 alkynyl, each of which is optionally substituted with one or more substituents selected from CMO alkyl, C2-io alkenyl, and C2.10 alkynyl; and- R3and R6are independently selected from a bond, C1.25 alkyl, C2.25 alkenyl, C2.25 alkynyl, C3.6carbocyclyl, C3.6aryl, each of which is optionally substituted with one or more substituents selected from CM0alkyl, C2.io alkenyl, and C2-io alkynyl.

[0103] In one or more embodiments, the singlet fission layer comprises at least one singlet fission compound of Formula (Illa):Formula (Illa)wherein:- R1, R2, R4, R5, R7, and R8are independently selected from: H, C1.25 alkyl, C2-25 alkenyl, C2.25 alkynyl, each of which is optionally substituted with one or more substituents selected from CM0alkyl, C2-io alkenyl, and C2.10alkynyl; and- R3and R6are independently selected from a bond, C1.25 alkyl, C2.25 alkenyl, C2.25 alkynyl, C3.6carbocyclyl, C3.6aryl, each of which is optionally substituted with one or more substituents selected from CMO alkyl, C2.io alkenyl, and C2-io alkynyl.

[0104] In one or more embodiments, at least one of R1, R2, R4, R5, R7, and R8, is selected from H, C1 7 alkyl, C2-i7 alkenyl, each of which is optionally substituted with one substituent selected from C1.5 alkyl.

[0105] In one or more embodiments, at least one of R3and R6, is selected from C2.5 alkynyl, and C3.6aryl, each of which is optionally substituted with one or more substituents selected from Ci_2alkyl.

[0106] In one or more embodiments, at least one of R1, R2, R4, R5, R7, and R8is selected from H, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, n-pentyl, 2-pentyl, 3-pentyl, isopentyl, neopentyl, 1 -methylbutyl, 2-methylbutyl, 3 -methylbutyl, tert-pentyl, n-hexyl, 2-hexyl, 3 -hexyl, 1 -methylpentyl, 2-methylpentyl, 3 -methylpentyl, 4-methylpentyl, 1,1 -dimethylbutyl, 1,2-dimethylbutyl, 1,3 -dimethylbutyl, 2,2-dimethylbutyl, 2,3-dimethylbutyl, 1-ethylbutyl, tert-hexyl, n-heptyl, 2-heptyl, 3-heptyl, 1 -methylhexyl, 2-methylhexyl, 3 -methylhexyl, 4-m ethylhexyl, 1,1 -dimethylpentyl, 1,2-dimethylpentyl, 1,3 -dimethylpentyl, 1,4-dimethylpentyl, 2,2-dimethylpentyl, 2,3-dimethylpentyl, 2,4-dimethylpentyl, 3,3-dimethylpentyl, 1 -ethylpentyl, 2-ethylpentyl,1.1.2-trimethylbutyl, 1,1, 3 -trimethylbutyl, 1,2,2-trimethylbutyl, 1,2,3-trimethylbutyl, n-octyl, 2-octyl, 3 -octyl, 1 -methylheptyl, 2-methylheptyl, 3 -methylheptyl, 4-methylheptyl, 1,1 -dimethylhexyl, 1,2-dimethylhexyl, 1,3 -dimethylhexyl, 1,4-dimethylhexyl, 2,2-dimethylhexyl, 2,3 -dimethylhexyl, 2,4-dimethylhexyl, 2,5-dimethylhexyl, 3,3-dimethylhexyl, 3,4-dimethylhexyl, 1 -ethylhexyl, 2-ethylhexyl, 1,1,2-trimethylpentyl, 1.1.3-trimethylpentyl, 1,2,2-trimethylpentyl, 1,2,3-trimethylpentyl, 1,3,3-trimethylpentyl.

[0107] In one or more embodiments, at least one of R1, R2, R4, R5, R7, and R8is selected from H, methyl, n-ethyl, n-propyl, n-pentyl, n-heptyl, n-heptadecyl, 8-heptadecenyl, and sec-butyl.

[0108] In one or more embodiments, R1, R2, and if present, R4, R5, R7, and R8are the same.

[0109] In one or more embodiments, at least one of R3and R6is selected from C2.25 alkynyl, and C3.6aryl, each of which is optionally substituted with one or more substituents selected from CM0alkyl.

[0110] In one or more embodiments, at least one of R3and R6is phenyl (1,4, 1,3 or 1,2 substitution), 1,4-diethynylbenzene, 1,3-diethynylbenzene, 1,2-diethynylbenzene, biphenyl, tetrafluor ophenyl, bicyclo[2.2.2]octane, cubane, any alkyl chain / fluorinated alkyl chain, an alkene, bistrifluoromethyl, ethylene glycol (and related oligomers), fused heterocycles like indole, benzimidazole, pyrrole, thiophene, ethynyl, or 2, 3,5,6-tetram ethylphenyl.

[0111] In one or more embodiments, at least one of R3and R6is ethynyl, or 2, 3,5,6-tetram ethylphenyl.

[0112] In one or more embodiments, R3and R6are the same.

[0113] In one or more embodiments, the singlet fission compound is a compound of Formula (I). In one or more embodiments, the singlet fission compound is selected from:O n-C, H / 7-C2H5 oDPND-0 DPND-1 DPND-2n-CjHy O n-C7H15O DPND-3 DPND-5 DPND-7DPND-S-3,1and mixtures thereof.

[0114] In one or more embodiments, the singlet fission compound is a compound of Formula (II). In one or more embodiments, the singlet fission compound is a compound of Formula (Ila). In one or more embodiments, the singlet fission compound is selected from:DPND-2 acetylene dimerDPND-7 acetylene dimerDPND-7 durene dimerand mixtures thereof.

[0115] In one or more embodiments, the singlet fission compound is selected from:thereof.

[0116] In one or more embodiments, the singlet fission compound is a compound of Formula (III). In one or more embodiments, the singlet fission compound is a compound of Formula (Illa). In one or more embodiments, the singlet fission compound is:DPND-2 acetylene trimer

[0117] In one or more embodiments, the singlet fission compound is selected from DPND-0, DPND-1, DPND-2, DPND-3, DPND-5, DPND-7, DPND-17, DPND-Z-17, DPND-E-17, DPND-5-3, 1, DPND-2 acetylene dimer, DPND-7 acetylene trimer, DPND-7 durene dimer, DPND-2 acetylene trimer, and mixtures thereof.

[0118] In one or more embodiments, the singlet fission compound is DPND-0. In one or more embodiments, the singlet fission compound is DPND-1. In one or more embodiments, the singlet fission compound is DPND-2. In one or more embodiments, the singlet fission compound is DPND-3. In one or more embodiments, the singlet fissioncompound is DPND-5. In one or more embodiments, the singlet fission compound is DPND-7. In one or more embodiments, the singlet fission compound is DPND-17. In one or more embodiments, the singlet fission compound is DPND-Z-17. In one or more embodiments, the singlet fission compound is DPND-E-17. In one or more embodiments, the singlet fission compound is DPND-5-3,1. In one or more embodiments, the singlet fission compound is DPND-2 acetylene dimer. In one or more embodiments, the singlet fission compound is DPND-7 acetylene trimer. In one or more embodiments, the singlet fission compound is DPND-7 durene dimer. In one or more embodiments, the singlet fission compound is DPND-2 acetylene trimer.

[0119] In one or more embodiments, the thickness of the singlet fission layer (in nm) is about, or greater than about: 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 15, 20, 25, 30, 35, 40, 45, 50, 55, 60, 65, 70, 75, 80, 85, 90, 95, or 100. In one or more embodiments, the thickness of the singlet fission layer (in nm) is less than about: 100, 95, 90, 85, 80, 75, 70, 65, 60, 55, 50, 45, 40, 35, 30, 25, 20, 15, 10, 9, 8, 7, 6, 5, 4, 3, 2, or 1. The thickness of the singlet fission layer (in nm) may be in a range provided by any two or more of these upper and / or lower amounts. In one or more embodiments, the thickness of the singlet fission layer (in nm) is between about 1 to about 100, between about 0.2 to about 5, or between about 20 to about 40.

[0120] In one or more embodiments, the singlet fission layer is a discontinuous layer. In one or more embodiments, the singlet fission layer comprises one or more discrete islands. In one or more embodiments, the one or more discrete islands as substantially homogeneously dispersed across the cross sectional are in the region of the device comprising the singlet fission layer.

[0121] In one or more embodiments, in at least a portion of the region of the device comprising the singlet fission layer, the percentage (%) of the cross sectional area of the device comprising the singlet fission layer is about, or greater than about: 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 15, 20, 25, 30, 35, 40, 45, 50, 55, 60, 65, 70, 75, 80, 85, 90, 95, or 100. In one or more embodiments, in at least a portion of the region of the device comprising the singlet fission layer, the percentage (%) of the cross sectional area of the device comprising the singlet fission layer is less than about: 100, 95, 90, 85, 80, 75, 70, 65, 60, 55, 50, 45, 40, 35, 30, 25, 20, 15, 10, 9, 8, 7, 6, 5, 4, 3, 2, or 1. In at least a portion of theregion of the device comprising the singlet fission layer, the percentage (%) of the cross sectional area of the device comprising the singlet fission layer may be in a range provided by any two or more of these upper and / or lower amounts. In one or more embodiments, in at least a portion of the region of the device comprising the singlet fission layer, the percentage (%) of the cross sectional area of the device comprising the singlet fission layer is between about 1 to about 100, between about 10 to about 95.

[0122] In one or more embodiments, in at least a portion of the region of the device comprising the singlet fission layer, the percentage (%) of the cross sectional area of the device comprising the singlet fission layer is at least about 20.Metal oxide layer

[0123] In one or more embodiments, the photovoltaic precursor device comprises a metal oxide layer. In one or more embodiments, the metal oxide layer is disposed between the light absorbing semiconductor layer and the singlet fission.

[0124] In one or more embodiments, the metal oxide layer comprises a transition metal. In one or more embodiments, the metal oxide layer comprises a material selected from: aluminium oxide (A1OX), titanium dioxide (TiOx), zinc oxide (ZnOx), tin oxide (SnOx), niobium oxide (btuOs), tungsten oxide (WCh), indium oxide (ImCh), molybdenum oxide (MoOs), vanadium oxide (V2O5), cobalt oxide (CO3O4), nickel oxide (NiO), chromium oxide (C Ch), aluminium-doped zinc oxide (AZO), indium tin oxide (ITO), copper oxide (CuxO), gallium-doped zinc oxide (GZO), and mixtures thereof.

[0125] In one or more embodiments, the metal oxide layer comprises a material selected from aluminium oxide (A1OX), indium tin oxide (ITO), zinc oxide (ZnOx), tin oxide (SnOx), aluminium-doped zinc oxide (AZO), copper oxide (CuxO), gallium-doped zinc oxide (GZO), and mixtures thereof.

[0126] In one or more embodiments, the metal oxide layer comprises tin oxide (SnOx).

[0127] In one or more embodiments, the thickness of the metal oxide layer (in nm) is about, or greater than about: 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 1, 1.1, 1.2, 1.3, 1.4, 1.5, 1.6, 1.7, 1.8, 1.9, 2, 3, 4, 5, 6, 7, 8, 9, 10, 15, 20, 25, 30, 35, 40, 45, or 50. In one or more embodiments, the thickness of the metal oxide layer (in nm) is less than about: 50, 45, 40, 35, 30, 25, 20, 15, 10, 9, 8, 7, 6, 5, 4, 3, 2, 1.9, 1.8, 1.7, 1.6, 1.5, 1.4, 1.3, 1.2, 1.1, 1, 0.9, 0.8, 0.7, 0.6, 0.5, 0.4, 0.3, 0.2, or 0.1. The thickness of the metal oxide layer (innm) may be in a range provided by any two or more of these upper and / or lower amounts. In one or more embodiments, the thickness of the metal oxide layer (in nm) is between about 0.1 to about 50, between about 0.2 to about 5, or between about 0.5 to about 1.5.Passivation layer

[0128] In one or more embodiments, the photovoltaic precursor device comprises a passivation layer. In one or more embodiments, the singlet fission layer is disposed between the light absorbing semiconductor layer and the passivation layer.

[0129] In one or more embodiments, the passivating layer substantially covers the singlet fission layer.

[0130] In one or more embodiments, at least a portion of the passivating layer is contiguous with the singlet fission layer.

[0131] In one or more embodiments, at least a portion of the passivating layer is contiguous with at least a portion of the metal oxide layer.

[0132] In one or more embodiments, at least a portion of the passivating layer is contiguous with at least a portion of the light absorbing semiconductor layer.

[0133] In one or more embodiments, the passivating layer comprises a material selected from, but not limited to: silicon dioxide (SiCE), silicon nitride (SisN^, aluminium oxide (AI2O3), titanium dioxide (TiCE), hafnium oxide (HfCE), zinc oxide (ZnO), magnesium fluoride (MgF?), tantalum pentoxide (Ta2Os), zirconium oxide (ZrCE), gallium oxide (Ga2Os), graphene oxide, carbon nanotube (CNT) coatings, cadmium sulfide (CdS), lead iodide (PbL), barium titanate (BaTiCE), boron nitride (BN), molybdenum disulfide (M0S2), magnesium oxide (MgO), lithium fluoride (LiF), indium oxide (I112CE), caesium iodide (CsI), samarium oxide (SrmCE), lanthanum oxide (La2Os), vanadium oxide (V2O5), caesium fluoride (CsF), niobium oxide (btuCE), poly(3,4-ethylenedi oxy thiophene) polystyrene sulfonate (PEDOT), poly(3,4-ethylenedi oxy thiophene) polystyrene sulfonate (PEDOT: PSS), methylammonium lead iodide (MAPbE), nickel oxide (NiOx), tungsten oxide (WO3), calcium fluoride (CaF2), aluminium fluoride (AIF3), polyethylene dioxythiophene-co-pyrrole) (PEDOT-co-PPy), poly(9,9-dioctylfluorene-co-bithiophene) (F8T2), poly(anthraquinone thiophene) (PAQT), poly(isothianaphthene) (PITN), poly(dithienothiophene) (PDTT), poly(bis(thiophene)) derivatives, poly(p-phenylene) (PPP),poly(benzimidazobenzophenanthroline) (BBL), polycarbazole (PCz), polyindole (Pin), poly(benzothiadiazole) derivatives, poly(cyclopentadithiophene) derivatives, poly(pyridinium salts), poly(benzopyrene), poly(diketopyrrolopyrrole) (PDPP) derivatives, and combinations thereof. In one or more embodiments, the passivating layer comprises a material selected aluminium oxide (AI2O3), lithium fluoride (LiF), and combinations thereof.

[0134] In one or more embodiments, the passivating layer comprises a conductive polymer. In one or more embodiments, the passivating layer comprises poly(3,4-ethylenedi oxythiophene), poly(3,4-ethylenedi oxythiophene) polystyrene sulfonate (PEDOT: PSS), polyethylene dioxythiophene-co-pyrrole) (PEDOT-co-PPy), poly(9,9-dioctylfluorene-co-bithiophene) (F8T2), poly(anthraquinone thiophene) (PAQT), poly(isothianaphthene) (PITN), poly(dithienothiophene) (PDTT), poly(bis(thiophene)) derivatives, poly(p-phenylene) (PPP), poly(benzimidazobenzophenanthroline) (BBL), polycarbazole (PCz), Polyindole (Pin), poly(benzothiadiazole) derivatives, poly(cyclopentadithiophene) derivatives, poly(pyridinium salts), poly(benzopyrene), poly(diketopyrrolopyrrole) (PDPP) derivatives, and combinations thereof. In one or more embodiments, the passivating layer comprises poly(3,4-ethylenedioxythiophene). In one or more embodiments, the passivating layer comprises poly(3,4-ethylenedi oxy thiophene) polystyrene sulfonate (PEDOT: PSS).In one or more embodiments, the weight ratio of PEDOT to PSS in the passivating layer is about, or greater than about: 1:1, 1:2, 1:3, 1:4, 1:5, 1:6, 1:7, 1:8, 1:9, 1:10, 1:11, 1:12, 1:13, 1:14, 1:15, 1:16, 1:17, 1:18, 1:19, or 1:20. In one or more embodiments, the weight ratio of PEDOT to PSS in the passivating layer is less than about: 1:20, 1:19, 1:18, 1:17, 1:16, 1:15, 1:14, 1:13, 1:12, 1:11, 1:10, 1:9, 1:8, 1:7, 1:6, 1:5, 1:4, 1:3, 1:2, 1:1. The weight ratio of PEDOT to PSS in the passivating layer may be in a range provided by any two or more of these upper and / or lower amounts. In one or more embodiments, the weight ratio of PEDOT to PSS in the passivating layer is between about 1:1 to about 1:20, or between about 1:2 to about 1:10.

[0135] In one or more embodiments, the thickness of the passivating layer (in nm) is about, or greater than about: 1, 2, 3, 4, 5, 10, 15, 20, 30, 40, 50, 60, 70, 80, 90, 100, 110, 120, 130, 140, 150, 200, 250, 300, 350, 400, 450, or 500. In one or more embodiments,the thickness of the passivating layer (in nm) is less than about: 500, 450, 400, 350, 300, 250, 200, 150, 100, 95, 90, 85, 80, 75, 70, 65, 60, 55, 50, 45, 40, 35, 30, 25, 20, 15, 10, 5, 4, 3, 2, or 1. The thickness of the passivating layer (in nm) may be in a range provided by any two or more of these upper and / or lower amounts. In one or more embodiments, the thickness of the passivating layer (in nm) is between about 1 to about 500, between about 10 to about 200.Second passivation layer

[0136] In one or more embodiments, the photovoltaic precursor device comprises a second passivation layer. In one or more embodiments, the second passivating layer is on the opposite side of the light absorbing semiconductor layer to the singlet fission layer. In one or more embodiments, the second passivating layer is contiguous with the light absorbing semiconductor layer.

[0137] In one or more embodiments, the second passivating layer comprises a material selected from, but not limited to: silicon dioxide (SiCE), silicon nitride (SisN^, aluminum oxide (AI2O3), titanium dioxide (TiCE), hafnium oxide (HfCE), zinc oxide (ZnO), magnesium fluoride (MgF?), tantalum pentoxide (Ta2Os), zirconium oxide (ZrCE), gallium oxide (Ga2Os), graphene oxide, carbon nanotube (CNT) coatings, cadmium sulfide (CdS), lead iodide (PbL), barium titanate (BaTiCE), boron nitride (BN), molybdenum disulfide (M0S2), magnesium oxide (MgO), lithium fluoride (LiF), indium oxide (I112O3), caesium iodide (CsI), samarium oxide (SrmCE), lanthanum oxide (La2Os), vanadium oxide (V2O5), caesium fluoride (CsF), niobium oxide (btuCE), poly(3,4-ethylenedi oxy thiophene) polystyrene sulfonate (PEDOT), methylammonium lead iodide (MAPbL), nickel oxide (NiOx), tungsten oxide (WO3), calcium fluoride (CaF2), aluminum fluoride (AIF3), and combinations thereof.

[0138] In one or more embodiments, the second passivating layer comprises silicon nitride (SiNx).

[0139] In one or more embodiments, the thickness of the second passivating layer (in nm) is about, or greater than about: 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 15, 20, 25, 30, 35, 40, 45, 50, 55, 60, 65, 70, 75, 80, 85, 90, 95, or 100. In one or more embodiments, the thickness of the second passivating layer (in nm) is less than about: 100, 95, 90, 85, 80, 75, 70, 65, 60, 55, 50, 45, 40, 35, 30, 25, 20, 15, 10, 9, 8,7, 6, 5, 4, 3, 2, 1, 0.9, 0.8, 0.7, 0.6, 0.5, 0.4, 0.3, 0.2, or 0.1. The thickness of the second passivating layer (in nm) may be in a range provided by any two or more of these upper and / or lower amounts. In one or more embodiments, the thickness of the second passivating layer (in nm) is between about 0.1 to about 100, between about 1 to about 10.Method of Forming an Article

[0140] In another aspect of the present disclosure there is provided a method of forming an article, for use in a photovoltaic device, the method comprising:depositing a singlet fission layer compound on a substrate comprising a light absorbing semiconductor layer.

[0141] In one or more embodiments, the article is a photovoltaic precursor device as described herein.

[0142] In another aspect of the present disclosure there is provided a method of forming an article, for use in a photovoltaic device, the method comprising:depositing a singlet fission layer compound on a substrate comprising a light absorbing semiconductor layer,wherein:the singlet fission layer comprises at least one singlet fission compound of Formula (I), or a dimer or trimer thereof as described herein, or an oligomer thereof, as described herein, or a compound of Formula (IV) as described herein or a compound of Formula (V) as described herein. For example at least one singlet fission compound of Formula (I) or a dimer or trimer thereof:Formula (I),wherein:the dimer of Formula (I) is a compound of Formula (II);Formula (II);andthe trimer of Formula (I) is a compound of Formula (III):(Formula III)wherein:R1, R2, R3, R4, R5, R6, R7, and R8are independently selected from: a bond, H, or optionally substituted C1.35 hydrocarbons, or as defined herein.

[0143] In one embodiment, at least one of R2, R3, R5and / or R6, optionally for a dimer or trimer as described herein (e.g. a compound of Formula (II), Formula (Ila), formula (lib), Formula (III), Formula (Illa) and / or Formula (Illb)), is independently selected from:- (-CH2^ *4-C=C^- *wherein:* denotes a point of attachmentq is an integer of from 1 to 100; andeach of Ra, Rb, Rc, and Rd is independently selected from: H, C1.35 alkyl, C1.35 heteroalkyl, C2.35 alkenyl, C2.35 alkynyl, C3.20carbocyclyl, C3.20heterocyclyl, C3.18aryl, and C5.18heteroaryl, each of which is optionally substituted with one or more substituents selected C1-10alkyl, C2-10alkenyl, C2-10alkynyl,halogen, -CN, -OR9, -SR9, -S(O)2R9, -NR9R10, -NO2, =(O), =(S), =(N)R9, =(N)R10, -C(O)R9, -C(O)NR9R10, -C(O)SR9or -C(O)OR9; or with one or more groups selected from C3.6carbocyclyl, C3.6heterocyclyl, C3.6aryl, and C5.12heteroaryl, each of which is optionally substituted with one or more substituents selected from Ci_6alkyl, halogen, -CN, -OR9, -SR9, -S(O)2R9, - NR9R10, -NO2, =(O), =(S), =(N)R9, =(N)R10, -C(O)R9, -C(O)NR9R10, - C(O)SR9or-C(O)OR9.

[0144] In one embodiment each of Ra, Rb, Rc, and Rd is H

[0145] In one embodiment, at least one of R2, R3, R5and / or R6, optionally for a dimer or trimer as described herein (e.g. a compound of Formula (II), Formula (Ila), formula 'CH2’(lib), Formula (III), Formula (Illa) and / or Formula (Illb)), isq, where q is as defined herein.

[0146] In one embodiment, at least one of R2, R3, R5and / or R6, optionally for a dimer or trimer as described herein (e.g. a compound of Formula (II), Formula (Ila), formula *-(-C=C-)- *(lib), Formula (III), Formula (Illa) and / or Formula (Illb)), is, where * is a point of attachment.

[0147] In one embodiment, at least one of R2, R3, R5and / or R6, optionally for a dimer or trimer as described herein (e.g. a compound of Formula (II), Formula (Ila), formula (lib), Formula (III), Formula (Illa) and / or Formula (Illb)), is:wherein:* denotes a point of attachmenteach of Ra, Rb, Rc, and Rd is independently selected from: H, Ci.35alkyl, Ci.35heteroalkyl, C2.35alkenyl, C2.35alkynyl, C3.20carbocyclyl, C3.20heterocyclyl, C3.i8 aryl, and C5.18heteroaryl, each of which is optionally substituted with one or more substituents selected C1-10alkyl, C2-10alkenyl, C2-10alkynyl,halogen, -CN, -OR9, -SR9, -S(O)2R9, -NR9R10, -NO2, =(O), =(S), =(N)R9, =(N)R10, -C(O)R9, -C(O)NR9R10, -C(O)SR9or -C(O)OR9; or with one or more groups selected from C3.6carbocyclyl, C3.6heterocyclyl, C3.6aryl, and C5.12heteroaryl, each of which is optionally substituted with one or more substituents selected from Ci_6alkyl, halogen, -CN, -OR9, -SR9, -S(O)2R9, - NR9R10, -NO2, =(O), =(S), =(N)R9, =(N)R10, -C(O)R9, -C(O)NR9R10, - C(O)SR9or-C(O)OR9.

[0148] In one embodiment each of Ra, Rb, Rc, and Rd is H

[0149] In one embodiment, for a dimer or trimer as described herein (e.g. a compound of Formula (II), Formula (Ila), formula (lib), Formula (III), Formula (Illa) and / or Formula (Illb)) is each of Ra, Rb, Rc, and Rdis independently selected from: H or optionally substituted Ci.35alkyl (e.g. optionally substituted methyl, ethyl and / or propyl groups).

[0150] In one or more embodiments, q is an integer selected from: 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53, 54, 55, 56, 57, 58, 59, 60, 61, 62, 63, 64, 65, 66, 67, 68, 69, 70, 71, 72, 73, 74, 75, 76, 77, 78, 79, 80, 81, 82, 83, 84, 85, 86, 87, 88, 89, 90, 91, 92, 93, 94, 95, 96, 97, 98, 99, 100, or in a range of any two of these values. In another embodiment, q is an integer selected from: 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, or in a range of any two of these values. Thermal evaporating

[0151] In one or more embodiments, the depositing a singlet fission compound is by thermal evaporating.

[0152] In one or more embodiments, the absolute pressure (mbar x 10'7) at which the thermal evaporating is performed is about, or greater than about: 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 15, 20, 25, 30, 35, 40, 45, 50, 55, 60, 65, 70, 75, 80, 85, 90, 95, or 100. In one or more embodiments, the absolute pressure (mbar x 10'7) at which the thermal evaporating is performed is less than about: 100, 95, 90, 85, 80, 75, 70, 65, 60, 55, 50, 45, 40, 35, 30, 25, 20, 15, 10, 9, 8, 7, 6, 5, 4, 3, 2, 1, 0.9, 0.8, 0.7, 0.6, 0.5, 0.4, 0.3, 0.2, or 0.1. The absolute pressure (mbarx 10'7) at which the thermal evaporating is performed may be in a range provided by any two or more of these upperand / or lower amounts. In one or more embodiments, the absolute pressure (mbar x 10'7) at which the thermal evaporating is performed is between about 0.1 to about 100.

[0153] In one or more embodiments, the temperature (°C) at which thermal evaporating is performed is about, or greater than about: 50, 60, 70, 80, 90, 100, 110, 120, 130, 140, 150, 160, 170, 180, 190, or 200. In one or more embodiments, the temperature (°C) at which thermal evaporating performed is less than about:200, 190, 180, 170, 160, 150, 140, 130, 120, 110, 100, 90, 80, 70, 60, or 50. In one or more embodiments, the temperature (°C) at which thermal evaporating is performed may be in a range provided by any two or more of the upper and / or lower amounts. In one or more embodiments the temperature (°C) at which thermal evaporating is performed is between about 50 and about 200, or between about 100 to about 150.Spin coating

[0154] In one or more embodiments, wherein the depositing a singlet fission compound is by spin coating, wherein the spin coating comprises:dissolving the singlet fission compound in a solvent to form a mixture; depositing the mixture on the substrate; androtating the substrate to spread the mixture over at least a portion of the substrate.

[0155] In one or more embodiments, the method further comprises baking the substrate after the spin coating.

[0156] In one or more embodiments, the depositing the mixture on the substrate is achieved by dropwise addition of the mixture on the substrate. In one or more embodiments, the mixture is deposited in substantially the centre of the substrate. In one or more embodiments, during depositing the mixture on the substrate, the substate is rotated.

[0157] The solvent may be selected from any suitable solvent which can dissolve the required amount of the singlet fission compound. In one or more embodiments, the solvent is selected from 1,4-di oxane, 2-methyltetrahydrofuran, diethyl ether, dimethoxyethane, acetonitrile, dimethylformamide, dimethyl sulfoxide, toluene, hexane, tetrahydrofuran, di chloromethane, chloroform, chlorobenzene, 1,2-di chlorobenzene,1,2-di chloroethane, and mixtures thereof. In one or more embodiments, the solvent is tetrahydrofuran.

[0158] In one or more embodiments, the concentration (mg / ml) of the singlet fission compound in the mixture is about, or greater than about: 0.01, 0.02, 0.03, 0.04, 0.05, 0.06, 0.07, 0.08, 0.09, 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 1, 2, 3, 4, 5, 10, 15, 20, 25, 30, 35, 40, 45, or 50. In some embodiments, the concentration (mg / ml) of the singlet fission compound in the mixture is less than about: 50, 45, 40, 35, 30, 25, 20, 15, 10, 5, 4, 3, 2, 1, 0.9, 0.8, 0.7, 0.6, 0.5, 0.4, 0.3, 0.2, 0.1, 0.09, 0.08, 0.07, 0.06, 0.05, 0.04, 0.03, 0.02, or 0.01. The concentration (mg / ml) of the singlet fission compound in the mixture may be in a range provided by any two of these upper and / or lower values. In one or more embodiments, the concentration (mg / ml) of the singlet fission compound in the mixture is between about 0.01 and about 50, between about 0.1 to about 10, or between about 0.5 to about 2.

[0159] In one or more embodiments, the depositing the mixture on the substrate is dropwise.

[0160] In one or more embodiments, the rotating the substrate is performed at a rotation speed (rpm) of about, or greater than about: 500, 600, 700, 800, 900, 1000, 2000, 3000, 4000, 5000, 6000, 7000, 8000, 9000, or 10000. In one or more embodiments, the rotating the substrate is performed at a rotation speed (rpm) of less than about: 10000, 9000, 8000, 7000, 6000, 5000, 4000, 3000, 2000, 1000, 900, 800, 700, 600, or 500. In one or more embodiments, rotating the substrate is performed at a rotation speed (rpm) which may be in a range provided by any two of these upper and / or lower values. In one or more embodiments, the rotating the substrate is performed at a rotation speed (rpm) of between about 500 to about 10000, or between about 2000 and about 10000, or between about 4000 and about 6000.

[0161] In one or more embodiments, the rotating the substrate is performed for a period of time (seconds) of about, or greater than about: 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 30, 40, 50, 60, 70, 80, 90, 100, 110, 120. In one or more embodiments, the rotating the substrate is performed for a period of time (minutes) of less than about: 120, 110, 100, 90, 80, 70, 60, 50, 40, 30, 20, 19, 18, 17, 16, 15, 14, 13, 12, 11, 10, 9, 8, 7, 6, 5, 4, 3, 2, or 1. The contacting the article with a treatment gas isperformed for a period of time (minutes) which may be in a range provided by any two or more of these upper and / or lower amounts. In one or more embodiments, the contacting the article with a treatment gas is performed for a period of time (minutes) of between about 1 to about 120, between about 30 to about 90.

[0162] In one or more embodiments, the time (min) for which baking after the spin coating is performed after the spin coating is about, or greater than about: 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 30, 40, 50, or 60. In one or more embodiments, the time (min) for which baking after the spin coating performed is less than about: 60, 50, 40, 30, 20, 19, 18, 17, 16, 15, 14, 13, 12, 11, 10, 9, 8, 7, 6, 5, 4, 3, 2, or 1. In one or more embodiments, the time (min) for which baking after the spin coating is performed after the spin coating may be in a range provided by any two or more of the upper and / or lower amounts. In one or more embodiments the time (min) for which baking after the spin coating is performed after the spin coating is between about 1 and about 60, or between about 10 to about 30.

[0163] In one or more embodiments, the temperature (°C) at which baking after the spin coating is performed after the spin coating is about, or greater than about: 30, 40, 50, 60, 70, 80, 90, 100, 110, 120, 130, 140, 150, 160, 170, 180, 190, or 200. In one or more embodiments, the temperature (°C) at which baking performed after the spin coating is less than about:200, 190, 180, 170, 160, 150, 140, 130, 120, 110, 100, 90, 80, 70, 60, 50, 40, or 30. In one or more embodiments, the temperature (°C) at which baking after the spin coating is performed after the spin coating may be in a range provided by any two or more of the upper and / or lower amounts. In one or more embodiments the temperature (°C) at which baking after the spin coating is performed after the spin coating is between about 30 and about 200, or between about 60 to about 100.Metal oxide deposition

[0164] In one or more embodiments, the method further comprises depositing a metal oxide layer on the substrate prior to deposition of the singlet fission compound, such that the metal oxide layer is disposed between the light absorbing semiconductor layer and the singlet fission compound.

[0165] In one or more embodiments, the depositing a metal oxide layer is by chemical vapour deposition. In one or more embodiments, the depositing a metal oxide layer is by atomic layer deposition.Passivating layer

[0166] In one or more embodiments, the method further comprises depositing a passivating layer on the substrate, such that the singlet fission layer is disposed between the substrate and the passivation layer.

[0167] The passivation layer may be deposited on the substrate by any suitable method known in the art. In one or more embodiments, the depositing the passivation layer on the substrate is by solution deposition. In one or more embodiments, the depositing the passivation layer on the substrate is by solution deposition selected from doctor blading, slot-die coating, inkjet printing; and spin coating.

[0168] In one or more embodiments, the depositing a passivating layer is by a passivating spin coating, wherein the passivating spin coating comprises:obtaining a passivating layer precursor;depositing the passivating layer precursor on the substrate; androtating the substrate to spread the passivating layer precursor over at least a portion of the substrate.

[0169] In one or more embodiments, the method further comprises baking the substrate after the passivating spin coating.

[0170] In one or more embodiments, the rotating the substrate is performed at a rotation speed (rpm) of about, or greater than about: 500, 600, 700, 800, 900, 1000, 2000, 3000, 4000, 5000, 6000, 7000, 8000, 9000, or 10000. In one or more embodiments, the rotating the substrate is performed at a rotation speed (rpm) of less than about: 10000, 9000, 8000, 7000, 6000, 5000, 4000, 3000, 2000, 1000, 900, 800, 700, 600, or 500. In one or more embodiments, rotating the substrate is performed at a rotation speed (rpm) which may be in a range provided by any two of these upper and / or lower values. In one or more embodiments, the rotating the substrate is performed at a rotation speed (rpm) of between about 500 to about 10000, between about 1000 and about 5000, or between about 2000 and about 4000.

[0171] In one or more embodiments, the rotating the substrate is performed for a period of time (seconds) of about, or greater than about: 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 30, 40, 50, 60, 70, 80, 90, 100, 110, 120. In one or more embodiments, the rotating the substrate is performed for a period of time (minutes) of less than about: 120, 110, 100, 90, 80, 70, 60, 50, 40, 30, 20, 19, 18, 17, 16, 15, 14, 13, 12, 11, 10, 9, 8, 7, 6, 5, 4, 3, 2, or 1. The contacting the article with a treatment gas is performed for a period of time (minutes) which may be in a range provided by any two or more of these upper and / or lower amounts. In one or more embodiments, the contacting the article with a treatment gas is performed for a period of time (minutes) of between about 1 to about 120, between about 30 to about 90.

[0172] In one or more embodiments, the method further comprises baking the substrate after the passivating spin coating.

[0173] In one or more embodiments, the time (min) for which baking after the passivating spin coating is performed is about, or greater than about: 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 30, 40, 50, or 60. In one or more embodiments, the time (min) for which baking after the passivating spin coating performed is less than about: 60, 50, 40, 30, 20, 19, 18, 17, 16, 15, 14, 13, 13, 12, 11, 10, 9, 8, 7, 6, 5, 4, 3, 2, or 1. In one or more embodiments, the time (min) for which baking after the passivating spin coating is performed may be in a range provided by any two or more of the upper and / or lower amounts. In one or more embodiments the time (min) for which baking after the passivating spin coating is performed is between about 1 and about 60, or between about 10 to about 30.

[0174] In one or more embodiments, the temperature (°C) at which baking after the passivating spin coating is performed is about, or greater than about: 50, 60, 70, 80, 90, 100, 110, 120, 130, 140, 150, 160, 170, 180, 190, or 200. In one or more embodiments, the temperature (°C) at which baking after the passivating spin coating performed is less than about:200, 190, 180, 170, 160, 150, 140, 130, 120, 110, 100, 90, 80, 70, 60, or 50. In one or more embodiments, the temperature (°C) at which baking after the passivating spin coating is performed may be in a range provided by any two or more of the upper and / or lower amounts. In one or more embodiments the temperature (°C) at which bakingafter the passivating spin coating is performed is between about 50 and about 200, or between about 100 to about 150.Second passivating layer

[0175] In one or more embodiments, the method further comprises depositing a second passivating layer of the substrate on the opposite side of the substrate to the singlet fission layer.Uses

[0176] In an aspect of the present disclosure, there is provided an article produced by the method described herein.

[0177] In an aspect of the present disclosure, there is provided a photovoltaic device comprising the photovoltaic precursor device as described herein.

[0178] In an aspect of the present disclosure, there is provided a use of the photovoltaic precursor device as described herein in a photovoltaic device.

[0179] In an aspect of the present disclosure, there is provided a use of the photovoltaic precursor device as described herein in the manufacture of a photovoltaic device.

[0180] In an aspect of the present disclosure, there is provided a use of the photovoltaic precursor device as described herein produced by the method described herein in a photovoltaic device.

[0181] In an aspect of the present disclosure, there is provided a use of the photovoltaic precursor device as described herein produced by the method described herein in the manufacture of a photovoltaic device.EXAMPLE EMBODIMENTS

[0182] The present disclosure may be described by one or more example embodiments.1. A photovoltaic precursor device, the photovoltaic precursor device comprising: a)a light absorbing semiconductor layer;a singlet fission layer; andat least one of a metal oxide layer and a passivation layer,wherein optionally:if present, at least one metal oxide layer is disposed between the light absorbing semiconductor layer and the singlet fission layer; andif at least one passivation layer is present, the singlet fission layer is disposed between the light absorbing semiconductor layer and the at least one passivation layer; ora light absorbing semiconductor layer;a singlet fission layer; andat least one of a metal oxide layer and a passivation layer,wherein optionally:- if present, at least one metal oxide layer is disposed between the light absorbing semiconductor layer and the singlet fission layer; and - if at least one passivation layer is present, the at least one passivation layer is disposed between the semiconductor layer and the singlet fission layer; andthe singlet fission layer comprises at least one singlet fission compound of Formula (I), or a dimer or trimer thereof, or an oligomer thereof, or a compound of Formula (IV), or a compound of Formula (V),wherein:when a compound of Formula (I) is present:Formula (I),- R1and R2are independently selected from: H, Ci_35alkyl, Ci_35heteroalkyl, C2.35alkenyl, C2.35alkynyl, C3.20carbocyclyl, C3.20heterocyclyl, C3.i8aryl, and C5.i8heteroaryl, each of which is optionally substituted with one or more substituents selected C1-10alkyl, C2-10alkenyl, C2-10alkynyl, halogen, -CN, -OR9, -SR9, -S(O)2R9, -NR9R10, -NO2, =(O), =(S), =(N)R9, =(N)R10, -C(O)R9, -C(O)NR9R10, -C(O)SR9or -C(O)OR9; or with one or more groups selected from C3-6carbocyclyl, C3-6heterocyclyl, C3-6aryl, and C5-12heteroaryl, each of which is optionally substituted with one or more substituents selected from C1-6alkyl, halogen, -CN, -OR9, -SR9, -S(O)2R9, -NR9R10, -NO2, =(O), =(S), =(N)R9, =(N)R10, -C(O)R9, -C(O)NR9R10, -C(O)SR9or -C(O)OR9; - wherein each R9is selected from H, optionally substituted C1-10alkyl, optionally substituted C2-10alkenyl, optionally substituted C2-10alkynyl, and optionally substituted C5-6aryl;- wherein each R10is selected from H, optionally substituted C1-10alkyl, optionally substituted C2.10alkenyl, optionally substituted C2.10alkynyl, and optionally substituted C5.6aryl;or- R1and R2are independently selected from: H or optionally substituted Ci.35 hydrocarbons,orwhen a dimer of Formula (I), is present the compound is optionally a compound of Formula (II), Formula (Ila) or Formula (lib); wherein for a compound of Formula (II):Formula (II)- R1, R2, R3, R4, and R5are independently selected from: a bond, H, C1-35alkyl, C1-35heteroalkyl, C2-35alkenyl, C2-35alkynyl, C3-20carbocyclyl, C3-20heterocyclyl, C3-18aryl, and C5-18heteroaryl, each of which is optionally substituted with one or more substituents selected C1-10alkyl, C2-10alkenyl, C2-10alkynyl, halogen, -CN, -OR9, -SR9, -S(O)2R9, -NR9R10, -NO2, =(O), =(S), =(N)R9, =(N)R10, -C(O)R9, -C(O)NR9R10, -C(O)SR9or -C(O)OR9; or with one or more groups selected from C3-6carbocyclyl, C3-6heterocyclyl, C3-6aryl, and C5-12heteroaryl, each of which is optionally substituted with one or more substituents selected from C1-6alkyl, halogen, -CN, -OR9, -SR9, -S(O)2R9, -NR9R10, -NO2, =(O), =(S), =(N)R9, =(N)R10, -C(O)R9, -C(O)NR9R10, -C(O)SR9or -C(O)OR9;- wherein each R9is selected from H, optionally substituted C1-10alkyl, optionally substituted C2-10alkenyl, optionally substituted C2-10alkynyl, and optionally substituted C5-6aryl;- wherein each R10is selected from H, optionally substituted C1-10alkyl, optionally substituted C2-10alkenyl, optionally substituted C2-10alkynyl, and optionally substituted C5-6aryl,or- R1, R2, R3, R4, and R5are independently selected from: a bond, H, or optionally substituted C1.35 hydrocarbons.wherein for a compound of Formula (Ila):Formula (Ila)- R1, R2, R3, R4, and R5are independently selected from: a bond, H, C1-35alkyl, C1-35heteroalkyl, C2-35alkenyl, C2-35alkynyl, C3-20carbocyclyl, C3-20heterocyclyl, C3-18aryl, and C5-18heteroaryl, each of which is optionally substituted with one or more substituents selected C1-10alkyl, C2-10alkenyl, C2-10alkynyl, halogen, -CN, -OR9, -SR9, -S(O)2R9, -NR9R10, -NO2, =(O), =(S), =(N)R9, =(N)R10, -C(O)R9, -C(O)NR9R10, -C(O)SR9or -C(O)OR9; or with one or more groups selected from C3-6carbocyclyl, C3-6heterocyclyl, C3-6aryl, and C5-12heteroaryl, each of which is optionally substituted with one or more substituents selected from C1-6alkyl, halogen, -CN, -OR9, -SR9, -S(O)2R9, -NR9R10, -NO2, =(O), =(S), =(N)R9, =(N)R10, -C(O)R9, -C(O)NR9R10, -C(O)SR9or -C(O)OR9; - wherein each R9is selected from H, optionally substituted C1-10alkyl, optionally substituted C2-10alkenyl, optionally substituted C2-10alkynyl, and optionally substituted C5-6aryl;- wherein each R10is selected from H, optionally substituted C1-10alkyl, optionally substituted C2.10alkenyl, optionally substituted C2.10alkynyl, and optionally substituted C5.6aryl,or- R1, R2, R3, R4, and R5are independently selected from: a bond, H, or optionally substituted C1.35 hydrocarbons.wherein for a compound of Formula (lib):Formula (lib);- R1, R2and R5are independently selected from: a bond, H, C1.35 alkyl, Ci.35heteroalkyl, C2.35 alkenyl, C2.35 alkynyl, C3.20carbocyclyl, C3.20heterocyclyl, C3.18aryl, and C5.18heteroaryl, each of which is optionally substituted with one or more substituents selected C1-10alkyl, C2-io alkenyl, C2.io alkynyl, halogen, -CN, -OR9, -SR9, -S(O)2R9, -NR9R10, - NO2, =(O), =(S), =(N)R9, =(N)R10, -C(O)R9, -C(O)NR9R10, -C(O)SR9or -C(O)OR9; or with one or more groups selected from C3.6carbocyclyl, C3.6heterocyclyl, C3.6aryl, and C5.12heteroaryl, each of which is optionally substituted with one or more substituents selected from Ci_6alkyl, halogen, -CN, -OR9, -SR9, -S(O)2R9, -NR9R10, -NO2, =(O), =(S), =(N)R9, =(N)R10, -C(O)R9, -C(O)NR9R10, -C(O)SR9or -C(O)OR9; - wherein each R9is selected from H, optionally substituted C1-10alkyl, optionally substituted C2-io alkenyl, optionally substituted C2-io alkynyl, and optionally substituted C5.6aryl;- wherein each R10is selected from H, optionally substituted CMO alkyl, optionally substituted C2-io alkenyl, optionally substituted C2-io alkynyl, and optionally substituted C5.6aryl,or- R1, R2and R5are independently selected from: a bond, H, C1-35 hydrocarbons;orwhen a trimer of Formula (I), is present the compound is optionally a compound of Formula (III), Formula (Illa) or Formula (Illb);wherein for a compound of Formula (III):(Formula III)R1, R2, R3, R4, R5, R6, R7, and R8are independently selected from: a bond, H, Ci -35 alkyl, Ci.35 heteroalkyl, C2.35 alkenyl, C2.35 alkynyl, C3.20 carbocyclyl, C3.2o heterocyclyl, C3.i8aryl, and C5.i8heteroaryl, each of which is optionally substituted with one or more substituents selected Ci.10 alkyl, C2.io alkenyl, C2-io alkynyl, halogen, -CN, -OR9, -SR9, - S(O)2R9, -NR9R10, -NO2, =(O), =(S), =(N)R9, =(N)R10, -C(O)R9, - C(O)NR9R10, -C(O)SR9or -C(O)OR9; or with one or more groups selected from C3.6carbocyclyl, C3.6heterocyclyl, C3.6aryl, and C5.12 heteroaryl, each of which is optionally substituted with one or more substituents selected from Ci.6alkyl, halogen, -CN, -OR9, -SR9, - S(O)2R9, -NR9R10, -NO2, =(O), =(S), =(N)R9, =(N)R10, -C(O)R9, - C(O)NR9R10, -C(O)SR9or-C(O)OR9;- wherein each R9is selected from H, optionally substituted C1-10alkyl, optionally substituted C2-io alkenyl, optionally substituted C2-io alkynyl, and optionally substituted C5.6aryl;- wherein each R10is selected from H, optionally substituted C1 0 alkyl, optionally substituted C2-io alkenyl, optionally substituted C2-io alkynyl, and optionally substituted C5.6aryl,orR1, R2, R3, R4, R5, R6, R7, and R8are independently selected from: a bond, H, or optionally substituted C1.35 hydrocarbons.wherein for a compound of Formula (Illa):Formula (Illa)R1, R2, R3, R4, R5, R6, R7, and R8are independently selected from: a bond, H, Ci -35 alkyl, Ci.35 heteroalkyl, C2.35 alkenyl, C2.35 alkynyl, C3.20 carbocyclyl, C3.20 heterocyclyl, C3.i8aryl, and C5.i8heteroaryl, each of which is optionally substituted with one or more substituents selected Ci.10 alkyl, C2.io alkenyl, C2-io alkynyl, halogen, -CN, -OR9, -SR9, - S(O)2R9, -NR9R10, -NO2, =(O), =(S), =(N)R9, =(N)R10, -C(O)R9, - C(O)NR9R10, -C(O)SR9or -C(O)OR9; or with one or more groups selected from C3.6carbocyclyl, C3.6heterocyclyl, C3.6aryl, and C5.12 heteroaryl, each of which is optionally substituted with one or more substituents selected from Ci_6alkyl, halogen, -CN, -OR9, -SR9, - S(O)2R9, -NR9R10, -NO2, =(O), =(S), =(N)R9, =(N)R10, -C(O)R9, - C(O)NR9R10, -C(O)SR9or-C(O)OR9;- wherein each R9is selected from H, optionally substituted C1-10alkyl, optionally substituted C2-io alkenyl, optionally substituted C2-io alkynyl, and optionally substituted C5.6aryl;- wherein each R10is selected from H, optionally substituted CMO alkyl, optionally substituted C2-io alkenyl, optionally substituted C2-io alkynyl, and optionally substituted C5.6aryl,orR1, R2, R3, R4, R5, R6, R7, and R8are independently selected from: a bond, H, or optionally substituted C1.35 hydrocarbons.wherein for a compound of Formula (Illb):Formula (Illb)- R1, R2, R5and R8are independently selected from: a bond, H, C1.35 alkyl, C1.35 heteroalkyl, C2.35 alkenyl, C2.35 alkynyl, C3.20 carbocyclyl, C3.20 heterocyclyl, C3.18aryl, and C5.18heteroaryl, each of which is optionally substituted with one or more substituents selected CM0alkyl, C2.io alkenyl, C2-io alkynyl, halogen, -CN, -OR9, -SR9, -S(O)2R9, -NR9R10, - NO2, =(O), =(S), =(N)R9, =(N)R10, -C(O)R9, -C(O)NR9R10, -C(O)SR9or -C(O)OR9; or with one or more groups selected from C3.6carbocyclyl, C3.6 heterocyclyl, C3.6aryl, and C5.12 heteroaryl, each of which is optionally substituted with one or more substituents selected from Ci_6alkyl, halogen, -CN, -OR9, -SR9, -S(O)2R9, -NR9R10, -NO2, =(O), =(S), =(N)R9, =(N)R10, -C(O)R9, -C(O)NR9R10, -C(O)SR9or -C(O)OR9; - wherein each R9is selected from H, optionally substituted C1-10alkyl, optionally substituted C2-io alkenyl, optionally substituted C2-io alkynyl, and optionally substituted C5.6aryl;- wherein each R10is selected from H, optionally substituted CMO alkyl, optionally substituted C2-io alkenyl, optionally substituted C2-io alkynyl, and optionally substituted C5.6aryl,- R1, R2, R5and R8are independently selected from: a bond, H, or optionally substituted C1.35 hydrocarbons; or- when an oligomer of Formula (I), is present the oligomer is optionally a compound of Formula (IV) or Formula (V), wherein:- when a compound of Formula (IV) is present:Formula (IV)- R1, R2, R3are independently selected from: a bond, H, C1.35 alkyl, C1.35 heteroalkyl, C2.35 alkenyl, C2.35 alkynyl, C3.20carbocyclyl, C3.20heterocyclyl, C3.18aryl, and C5.18heteroaryl, each of which is optionally substituted with one or more substituents selected C1-10alkyl, C2-ioalkenyl, C2.10alkynyl, halogen, -CN, -OR9, -SR9, -S(O)2R9, -NR9R10, - NO2, =(O), =(S), =(N)R9, =(N)R10, -C(O)R9, -C(O)NR9R10, -C(O)SR9or -C(O)OR9; or with one or more groups selected from C3.6carbocyclyl, C3.6heterocyclyl, C3.6aryl, and C5.12heteroaryl, each of which is optionally substituted with one or more substituents selected from Ci.6alkyl, halogen, -CN, -OR9, -SR9, -S(O)2R9, -NR9R10, -NO2, =(O), =(S), =(N)R9, =(N)R10, -C(O)R9, -C(O)NR9R10, -C(O)SR9or-C(O)OR9; or - R1and R2are independently selected from: H, or optionally substituted Ci_35hydrocarbons,- wherein each R9is selected from H, optionally substituted C1-10alkyl, optionally substituted C2.io alkenyl, optionally substituted C2.io alkynyl, and optionally substituted C5.6aryl;- wherein each R10is selected from H, optionally substituted C O alkyl, optionally substituted C2.io alkenyl, optionally substituted C2.io alkynyl, and optionally substituted C5.6aryl;- wherein — indicates a bond between repeat units; and- wherein n is between about 4 and about 100;orwhen a compound of Formula (V) is present,Formula (V)- R1and R2are independently selected from: a bond, H, Ci.35alkyl, Ci.35heteroalkyl, C2.35alkenyl, C2.35alkynyl, C3.20carbocyclyl, C3.20heterocyclyl, C3.18aryl, and C5.18heteroaryl, each of which is optionally substituted with one or more substituents selected C O alkyl, C2.io alkenyl, C2.10alkynyl, halogen, -CN, -OR9, -SR9, -S(O)2R9, -NR9R10, - NO2, =(O), =(S), =(N)R9, =(N)R10, -C(O)R9, -C(O)NR9R10, -C(O)SR9or -C(O)OR9; or with one or more groups selected from C3.6carbocyclyl, C3.6 heterocyclyl, C3.6aryl, and C5.12 heteroaryl, each of which is optionally substituted with one or more substituents selected from Ci_6alkyl, halogen, -CN, -OR9, -SR9, -S(O)2R9, -NR9R10, -NO2, =(O), =(S), =(N)R9, =(N)R10, -C(O)R9, -C(O)NR9R10, -C(O)SR9or-C(O)OR9; or - R1and R2are independently selected from: H, or optionally substituted Ci.35 hydrocarbons- wherein each R9is selected from H, optionally substituted C1-10alkyl, optionally substituted C2.10alkenyl, optionally substituted C2.10alkynyl, and optionally substituted C5.6aryl;- wherein each R10is selected from H, optionally substituted C1 0 alkyl, optionally substituted C2-io alkenyl, optionally substituted C2-io alkynyl, and optionally substituted C5.6aryl;- wherein — indicates a bond between repeat units; and- wherein n is between about 4 and about 100.2. A photovoltaic device comprising:a)a light absorbing semiconductor layer;a singlet fission layer; andat least one of a metal oxide layer and a passivation layer,wherein optionally:if present, at least one metal oxide layer is disposed between the light absorbing semiconductor layer and the singlet fission layer; and if at least one passivation layer is present, the singlet fission layer is disposed between the light absorbing semiconductor layer and the at least one passivation layer; orb)a light absorbing semiconductor layer;a singlet fission layer; andat least one of a metal oxide layer and a passivation layer,wherein optionally:- if present, at least one metal oxide layer is disposed between the light absorbing semiconductor layer and the singlet fission layer; andif at least one passivation layer is present, the at least one passivation layer is disposed between the semiconductor layer and the singlet fission layer; andthe singlet fission layer comprises at least one singlet fission compound of Formula (I), or a dimer or trimer thereof, or an oligomer thereof, or a compound of Formula (IV), or a compound of Formula (V),wherein:when a compound of Formula (I) is present:O R1Formula (I),- R1and R2are independently selected from: H, Ci_35alkyl, Ci_35heteroalkyl, C2.35alkenyl, C2.35alkynyl, C3.20carbocyclyl, C3.20heterocyclyl, C3.i8aryl, and C5.i8heteroaryl, each of which is optionally substituted with one or more substituents selected CM0alkyl, C2.10alkenyl, C2.10alkynyl, halogen, -CN, -OR9, -SR9, -S(O)2R9, -NR9R10, - NO2, =(O), =(S), =(N)R9, =(N)R10, -C(O)R9, -C(O)NR9R10, -C(O)SR9or -C(O)OR9; or with one or more groups selected from C3.6carbocyclyl, C3.6heterocyclyl, C3.6aryl, and C5.12heteroaryl, each of which is optionally substituted with one or more substituents selected from Ci.6alkyl, halogen, -CN, -OR9, -SR9, -S(O)2R9, -NR9R10, -NO2, =(O), =(S), =(N)R9, =(N)R10, -C(O)R9, -C(O)NR9R10, -C(O)SR9or -C(O)OR9; - wherein each R9is selected from H, optionally substituted C1-10alkyl, optionally substituted C2-io alkenyl, optionally substituted C2-io alkynyl, and optionally substituted C5.6aryl;- wherein each R10is selected from H, optionally substituted CMO alkyl, optionally substituted C2.io alkenyl, optionally substituted C2.io alkynyl, and optionally substituted C5.6aryl;or- R1and R2are independently selected from: H or optionally substituted Ci.35hydrocarbons,orwhen a dimer of Formula (I), is present the compound is optionally a compound of Formula (II), Formula (Ila) or Formula (lib); wherein for a compound of Formula (II):Formula (II)- R1, R2, R3, R4, and R5are independently selected from: a bond, H, C1.35 alkyl, C1.35 heteroalkyl, C2.35 alkenyl, C2.35 alkynyl, C3.2o carbocyclyl, C3.20 heterocyclyl, C3.18aryl, and C5.18heteroaryl, each of which is optionally substituted with one or more substituents selected C1-10alkyl, C2-io alkenyl, C2.io alkynyl, halogen, -CN, -OR9, -SR9, -S(O)2R9, -NR9R10, - NO2, =(O), =(S), =(N)R9, =(N)R10, -C(O)R9, -C(O)NR9R10, -C(O)SR9or -C(O)OR9; or with one or more groups selected from C3.6carbocyclyl, C3.6heterocyclyl, C3.6aryl, and C5.12heteroaryl, each of which is optionally substituted with one or more substituents selected from Ci_6alkyl, halogen, -CN, -OR9, -SR9, -S(O)2R9, -NR9R10, -NO2, =(O), =(S), =(N)R9, =(N)R10, -C(O)R9, -C(O)NR9R10, -C(O)SR9or -C(O)OR9; - wherein each R9is selected from H, optionally substituted C1-10alkyl, optionally substituted C2-io alkenyl, optionally substituted C2-io alkynyl, and optionally substituted C5.6aryl;- wherein each R10is selected from H, optionally substituted CMO alkyl, optionally substituted C2-io alkenyl, optionally substituted C2-io alkynyl, and optionally substituted C5.6aryl,or- R1, R2, R3, R4, and R5are independently selected from: a bond, H, or optionally substituted C1.35 hydrocarbons.wherein for a compound of Formula (Ila):Formula (Ila)- R1, R2, R3, R4, and R5are independently selected from: a bond, H, C1.35 alkyl, Ci.35 heteroalkyl, C2.35 alkenyl, C2.35 alkynyl, C3.20 carbocyclyl, C3.20 heterocyclyl, C3.i8aryl, and C5.i8heteroaryl, each of which is optionally substituted with one or more substituents selected CM0alkyl, C2.io alkenyl, C2-io alkynyl, halogen, -CN, -OR9, -SR9, -S(O)2R9, -NR9R10, - NO2, =(O), =(S), =(N)R9, =(N)R10, -C(O)R9, -C(O)NR9R10, -C(O)SR9or -C(O)OR9; or with one or more groups selected from C3.6carbocyclyl, C3.6 heterocyclyl, C3.6aryl, and C5.12 heteroaryl, each of which is optionally substituted with one or more substituents selected from Ci.6alkyl, halogen, -CN, -OR9, -SR9, -S(O)2R9, -NR9R10, -NO2, =(O), =(S), =(N)R9, =(N)R10, -C(O)R9, -C(O)NR9R10, -C(O)SR9or-C(O)OR9; - wherein each R9is selected from H, optionally substituted C1-10alkyl, optionally substituted C2-io alkenyl, optionally substituted C2-io alkynyl, and optionally substituted C5.6aryl;- wherein each R10is selected from H, optionally substituted C1 0 alkyl, optionally substituted C2-io alkenyl, optionally substituted C2-io alkynyl, and optionally substituted C5.6aryl,or- R1, R2, R3, R4, and R5are independently selected from: a bond, H, or optionally substituted C1.35 hydrocarbons.wherein for a compound of Formula (lib):Formula (lib);- R1, R2and R5are independently selected from: a bond, H, C1.35 alkyl, Ci.35 heteroalkyl, C2.35 alkenyl, C2.35 alkynyl, C3.20 carbocyclyl, C3.20 heterocyclyl, C3.18aryl, and C5.18heteroaryl, each of which is optionally substituted with one or more substituents selected CM0alkyl, C2.io alkenyl, C2-io alkynyl, halogen, -CN, -OR9, -SR9, -S(O)2R9, -NR9R10, - NO2, =(O), =(S), =(N)R9, =(N)R10, -C(O)R9, -C(O)NR9R10, -C(O)SR9or -C(O)OR9; or with one or more groups selected from C3.6carbocyclyl, C3.6 heterocyclyl, C3.6aryl, and C5.12 heteroaryl, each of which is optionally substituted with one or more substituents selected from Ci_6alkyl, halogen, -CN, -OR9, -SR9, -S(O)2R9, -NR9R10, -NO2, =(O), =(S), =(N)R9, =(N)R10, -C(O)R9, -C(O)NR9R10, -C(O)SR9or -C(O)OR9; - wherein each R9is selected from H, optionally substituted C1-10alkyl, optionally substituted C2-io alkenyl, optionally substituted C2-io alkynyl, and optionally substituted C5.6aryl;- wherein each R10is selected from H, optionally substituted C1 0 alkyl, optionally substituted C2-io alkenyl, optionally substituted C2-io alkynyl, and optionally substituted C5.6aryl,or- R1, R2and R5are independently selected from: a bond, H, C1-35 hydrocarbons;orwhen a trimer of Formula (I), is present the compound is optionally a compound of Formula (III), Formula (Illa) or Formula (Illb); wherein for a compound of Formula (III):Formula (III)R1, R2, R3, R4, R5, R6, R7, and R8are independently selected from: a bond, H, C1.35 alkyl, C1.35 heteroalkyl, C2.35 alkenyl, C2.35 alkynyl, C3.2o carbocyclyl, C3.20 heterocyclyl, C3.i8aryl, and C5.i8heteroaryl, each ofwhich is optionally substituted with one or more substituents selected Ci.10 alkyl, C2.io alkenyl, C2-io alkynyl, halogen, -CN, -OR9, -SR9, - S(O)2R9, -NR9R10, -NO2, =(O), =(S), =(N)R9, =(N)R10, -C(O)R9, - C(O)NR9R10, -C(O)SR9or -C(O)OR9; or with one or more groups selected from C3.6carbocyclyl, C3.6heterocyclyl, C3.6aryl, and C5-12heteroaryl, each of which is optionally substituted with one or more substituents selected from C1-6alkyl, halogen, -CN, -OR9, -SR9, - S(O)2R9, -NR9R10, -NO2, =(O), =(S), =(N)R9, =(N)R10, -C(O)R9, - C(O)NR9R10, -C(O)SR9or-C(O)OR9;- wherein each R9is selected from H, optionally substituted C1-10alkyl, optionally substituted C2-10alkenyl, optionally substituted C2-10alkynyl, and optionally substituted C5.6aryl;- wherein each R10is selected from H, optionally substituted CMO alkyl, optionally substituted C2.io alkenyl, optionally substituted C2.io alkynyl, and optionally substituted C5.6aryl,orR1, R2, R3, R4, R5, R6, R7, and R8are independently selected from: a bond, H, or optionally substituted Ci.35hydrocarbons.wherein for a compound of Formula (Illa):Formula (Illa)R1, R2, R3, R4, R5, R6, R7, and R8are independently selected from: a bond, H, C3-35 alkyl, Ci _35heteroalkyl, C2.35alkenyl, C2.35alkynyl, C3.20carbocyclyl, C3.20heterocyclyl, C3.i8aryl, and C5.i8heteroaryl, each of which is optionally substituted with one or more substituents selected C3.10 alkyl, C2.io alkenyl, C2.io alkynyl, halogen, -CN, -OR9, -SR9, - S(O)2R9, -NR9R10, -NO2, =(O), =(S), =(N)R9, =(N)R10, -C(O)R9, - C(O)NR9R10, -C(O)SR9or -C(O)OR9; or with one or more groups selected from C3.6carbocyclyl, C3.6heterocyclyl, C3.6aryl, and C5.i2heteroaryl, each of which is optionally substituted with one or more substituents selected from Ci.6alkyl, halogen, -CN, -OR9, -SR9, - S(O)2R9, -NR9R10, -NO2, =(O), =(S), =(N)R9, =(N)R10, -C(O)R9, - C(O)NR9R10, -C(O)SR9or-C(O)OR9;- wherein each R9is selected from H, optionally substituted C1-10alkyl, optionally substituted C2.10alkenyl, optionally substituted C2.10alkynyl, and optionally substituted C5.6aryl;- wherein each R10is selected from H, optionally substituted C1-10alkyl, optionally substituted C2-10alkenyl, optionally substituted C2-10alkynyl, and optionally substituted C5.6aryl,orR1, R2, R3, R4, R5, R6, R7, and R8are independently selected from: a bond, H, or optionally substituted Ci_35hydrocarbons.wherein for a compound of Formula (Illb):Formula (Illb)- R1, R2, R5and R8are independently selected from: a bond, H, Ci_35alkyl, Ci_35heteroalkyl, C2.35alkenyl, C2.35alkynyl, C3.20carbocyclyl, C3.20heterocyclyl, C3.i8aryl, and C5.i8heteroaryl, each of which is optionally substituted with one or more substituents selected CM0alkyl, C2.10alkenyl, C2.10alkynyl, halogen, -CN, -OR9, -SR9, -S(O)2R9, -NR9R10, - NO2, =(O), =(S), =(N)R9, =(N)R10, -C(O)R9, -C(O)NR9R10, -C(O)SR9or -C(O)OR9; or with one or more groups selected from C3.6carbocyclyl, C3.6heterocyclyl, C3.6aryl, and C5.12heteroaryl, each of which is optionally substituted with one or more substituents selected from Ci.6alkyl, halogen, -CN, -OR9, -SR9, -S(O)2R9, -NR9R10, -NO2, =(O), =(S), =(N)R9, =(N)R10, -C(O)R9, -C(O)NR9R10, -C(O)SR9or -C(O)OR9;- wherein each R9is selected from H, optionally substituted C1-10alkyl, optionally substituted C2-10alkenyl, optionally substituted C2-10alkynyl, and optionally substituted C5-6aryl;- wherein each R10is selected from H, optionally substituted C1-10alkyl, optionally substituted C2-10alkenyl, optionally substituted C2-10alkynyl, and optionally substituted C5-6aryl,- R1, R2, R5and R8are independently selected from: a bond, H, or optionally substituted Ci_35hydrocarbons; or- when an oligomer of Formula (I), is present the oligomer is optionally a compound of Formula (IV) or Formula (V), wherein:- when a compound of Formula (IV) is present:Formula (IV)- R1, R2, R3are independently selected from: a bond, H, Ci_35alkyl, Ci_35heteroalkyl, C2.35alkenyl, C2.35alkynyl, C3.20carbocyclyl, C3.20heterocyclyl, C3.i8aryl, and C5.i8heteroaryl, each of which is optionally substituted with one or more substituents selected CM0alkyl, C2.10alkenyl, C2.10alkynyl, halogen, -CN, -OR9, -SR9, -S(O)2R9, -NR9R10, - NO2, =(O), =(S), =(N)R9, =(N)R10, -C(O)R9, -C(O)NR9R10, -C(O)SR9or -C(O)OR9; or with one or more groups selected from C3.6carbocyclyl, C3.6heterocyclyl, C3.6aryl, and C5.12heteroaryl, each of which is optionally substituted with one or more substituents selected from Ci.6alkyl, halogen, -CN, -OR9, -SR9, -S(O)2R9, -NR9R10, -NO2, =(O), =(S), =(N)R9, =(N)R10, -C(O)R9, -C(O)NR9R10, -C(O)SR9or-C(O)OR9; or - R1and R2are independently selected from: H, or optionally substituted Ci_35hydrocarbons,- wherein each R9is selected from H, optionally substituted C1-10alkyl, optionally substituted C2-io alkenyl, optionally substituted C2-io alkynyl, and optionally substituted C5.6aryl;- wherein each R10is selected from H, optionally substituted CM0alkyl, optionally substituted C2.io alkenyl, optionally substituted C2.io alkynyl, and optionally substituted C5.6aryl;- wherein — indicates a bond between repeat units; and- wherein n is between about 4 and about 100;orwhen a compound of Formula (V) is present,Formula (V)- R1and R2are independently selected from: a bond, H, C1.35 alkyl, C1.35 heteroalkyl, C2.35alkenyl, C2.35alkynyl, C3.20carbocyclyl, C3.20heterocyclyl, C3.18aryl, and C5.18heteroaryl, each of which is optionally substituted with one or more substituents selected C1-10alkyl, C2.i0alkenyl, C2.10alkynyl, halogen, -CN, -OR9, -SR9, -S(O)2R9, -NR9R10, - NO2, =(O), =(S), =(N)R9, =(N)R10, -C(O)R9, -C(O)NR9R10, -C(O)SR9or -C(O)OR9; or with one or more groups selected from C3.6carbocyclyl, C3.6 heterocyclyl, C3.6aryl, and C5.i2heteroaryl, each of which is optionally substituted with one or more substituents selected from Ci_6alkyl, halogen, -CN, -OR9, -SR9, -S(O)2R9, -NR9R10, -NO2, =(O), =(S), =(N)R9, =(N)R10, -C(O)R9, -C(O)NR9R10, -C(O)SR9or-C(O)OR9; or - R1and R2are independently selected from: H, or optionally substituted C1.35 hydrocarbons- wherein each R9is selected from H, optionally substituted C1-10alkyl, optionally substituted C2-io alkenyl, optionally substituted C2-io alkynyl, and optionally substituted C5.6aryl;- wherein each R10is selected from H, optionally substituted CM0alkyl, optionally substituted C2.io alkenyl, optionally substituted C2.io alkynyl, and optionally substituted C5.6aryl;- wherein — indicates a bond between repeat units; and- wherein n is between about 4 and about 100.3. The device of any one of the preceding example embodiments, wherein at least one of R1, R2, R4, R5, R7, and R8, is selected from H, CM7alkyl, C2.17alkenyl, each of which is optionally substituted with one substituent selected from Ci.5alkyl.4. The device of any one of the preceding example embodiments, wherein at least one of R3and R6, is selected from C2.5alkynyl, and C3.6aryl, each of which is optionally substituted with one or more substituents selected from Ci.2alkyl.5. The device of any one of the preceding example embodiments, wherein at least one of R1, R2, R4, R5, R7, and R8is selected from H, methyl, n-propyl, n-pentyl, n-heptadecyl, 8-heptadecenyl.6. The device of any one of the preceding example embodiments, wherein R1, R2, and if present, R4, R5, R7, and R8are the same.7. The device of any one of the preceding example embodiments, wherein at least one of R3and R6is selected from C2.25alkynyl, and C3.6aryl, each of which is optionally substituted with one or more substituents selected from CM0alkyl.8. The device of any one of the preceding example embodiments, wherein at least one of R3and R6is ethynyl, 2, 3, 5, 6-tetram ethylphenyl.9. The device of any one of the preceding example embodiments, wherein R3and R6are the same.10. The device of any one of the preceding example embodiments, wherein singlet fission compound is a compound of Formula (I).11. The device of any one of the preceding example embodiments, wherein singlet fission compound is selected from:and mixtures thereof.12. The device of any one of the preceding example embodiments, wherein singlet fission compound is a compound of Formula (II).13. The device of any one of the preceding example embodiments, wherein singlet fission compound is selected from:and mixtures thereof.14. The device of any one of the preceding example embodiments, wherein singlet fission compound is a compound of Formula (III).15. The device of any one of the preceding example embodiments, wherein singlet fission compound is selected from:16. The device of any one of the preceding example embodiments, wherein the thickness (nm) of at least a portion of the singlet fission layer is between about 5 to about 100.17. The device of any one of the preceding example embodiments, wherein the thickness (nm) of at least a portion of the singlet fission layer is between about 10 to about 50.18. The device of any one of the preceding example embodiments, wherein the singlet fission layer is a discontinuous layer.19. The device of any one of the preceding example embodiments, wherein the singlet fission layer comprises one or more discrete islands.20. The device of any one of the preceding example embodiments, wherein the one or more discrete islands as substantially homogeneously dispersed across the cross sectional are in the region of the device comprising the singlet fission layer.21. The device of any one of the preceding example embodiments, wherein, in at least a portion of the region of the device comprising the singlet fission layer, the percentage of the cross sectional area of the device comprising the singlet fission layer is between about 10 to about 95.22. The device of any one of the preceding example embodiments, wherein, in at least a portion of the region of the device comprising the singlet fission layer, the percentage of the cross sectional area of the device comprising the singlet fission layer is at least about 20.23. The device of any one of the preceding example embodiments, wherein the device comprises the metal oxide layer.24. The device of any one of the preceding example embodiments, wherein the singlet fission layer is contiguous with at least a portion of the metal oxide layer.25. The device of any one of the preceding example embodiments, wherein the metal oxide comprises a material selected from aluminium oxide (A1OX), indium tin oxide (ITO), zinc oxide (ZnOx), tin oxide (SnOx), aluminum-doped zinc oxide (AZO), copper oxide (CuxO), gallium-doped zinc oxide (GZO), and mixtures thereof.26. The device of any one of the preceding example embodiments, wherein the metal oxide layer comprises tin oxide (SnOx).27. The device of any one of the preceding example embodiments, wherein the thickness (nm) of the metal oxide layer is between about 0.1 to about 5.28. The device of any one of the preceding example embodiments, wherein the thickness (nm) of the metal oxide layer is between about 0.5 to about 1.5.29. The device of any one of the preceding example embodiments, wherein the device comprises the passivating layer.30. The device of any one of the preceding example embodiments, wherein the passivating layer comprises a conductive polymer.31. The device of any one of the preceding example embodiments, wherein the passivating layer comprises poly(3,4-ethylenedioxythiophene) polystyrene sulfonate (PEDOT: PSS).32. The device of any one of the preceding example embodiments, wherein the weight ratio of PEDOT to PSS in the passivating layer is between about 1:1 to about 1:20.33. The device of any one of the preceding example embodiments, wherein the weight ratio of PEDOT to PSS in the passivating layer is between about 1:2 to about 1:10.34. The device of any one of the preceding example embodiments, wherein the thickness (nm) of the passivating layer is between about 1 to about 500.35. The device of any one of the preceding example embodiments, wherein the thickness (nm) of the passivating layer is between about 10 to about 200.36. The device of any one of the preceding example embodiments, wherein the passivating layer substantially covers the singlet fission layer.37. The device of any one of the preceding example embodiments, wherein at least a portion of the passivating layer is contiguous with the singlet fission layer.38. The device of any one of the preceding example embodiments, wherein at least a portion of the passivating layer is contiguous with at least a portion of the metal oxide layer.39. The device of any one of the preceding example embodiments, wherein at least a portion of the passivating layer is contiguous with at least a portion of the light absorbing semiconductor layer.40. The device of any one of the preceding example embodiments, the singlet fission layer is contiguous with at least a portion of the light absorbing semiconductor layer.41. The device of any one of the preceding example embodiments, the singlet fission layer is contiguous with at least a portion of the metal oxide layer.42. The device of any one of the preceding example embodiments, wherein the device further comprises a second passivating layer on the opposite side of the light absorbing semiconductor layer to the singlet fission layer.43 The device of any one of the preceding example embodiments, wherein the second passivation layer comprises silicon nitride (SiNx).44. The device of any one of the preceding example embodiments, wherein the light absorbing semiconductor layer is a n-type semiconductor layer.45. The device of example embodiment 44, wherein the n-type semiconductor layer comprises silicon.46. The device of example embodiment 44 or example embodiment 45, wherein the n-type semiconductor layer substantially consists of a n-type silicon.47. The device of any one of the preceding example embodiments, wherein the light absorbing semiconductor layer is a p-type semiconductor layer.48. The device of example embodiment 47, wherein the p-type semiconductor layer comprises silicon.49. The device of example embodiment 47 or example embodiment 48, wherein the n-type semiconductor layer substantially consists of a p-type silicon.50. A method of forming an article, for use in a photovoltaic device, the method comprising:depositing a singlet fission layer compound on a substrate comprising a light absorbing semiconductor layer,wherein the singlet fission layer comprises at least one singlet fission compound of Formula (I), or a dimer or trimer thereof, or an oligomer thereof, or a compound of Formula (IV), or a compound of Formula (V),wherein:when a compound of Formula (I) is present:O R1Formula (I),- R1and R2are independently selected from: H, Ci.35alkyl, Ci.35heteroalkyl, C2.35alkenyl, C2.35alkynyl, C3.20carbocyclyl, C3.20heterocyclyl, C3.18aryl, and C5.18heteroaryl, each of which is optionally substituted with one or more substituents selected C1-10alkyl, C2-io alkenyl, C2.10alkynyl, halogen, -CN, -OR9, -SR9, -S(O)2R9, -NR9R10, - NO2, =(O), =(S), =(N)R9, =(N)R10, -C(O)R9, -C(O)NR9R10, -C(O)SR9or -C(O)OR9; or with one or more groups selected from C3.6carbocyclyl, C3.6heterocyclyl, C3.6aryl, and C5.12heteroaryl, each of which is optionally substituted with one or more substituents selected from Ci_6alkyl, halogen, -CN, -OR9, -SR9, -S(O)2R9, -NR9R10, -NO2, =(O), =(S), =(N)R9, =(N)R10, -C(O)R9, -C(O)NR9R10, -C(O)SR9or -C(O)OR9; - wherein each R9is selected from H, optionally substituted C1-10alkyl, optionally substituted C2.io alkenyl, optionally substituted C2.io alkynyl, and optionally substituted C5.6aryl;- wherein each R10is selected from H, optionally substituted CM0alkyl, optionally substituted C2.io alkenyl, optionally substituted C2.io alkynyl, and optionally substituted C5.6aryl;or- R1and R2are independently selected from: H or optionally substituted Ci.35hydrocarbons,orwhen a dimer of Formula (I), is present the compound is optionally a compound of Formula (II), Formula (Ila) or Formula (lib); wherein for a compound of Formula (II):Formula (II)- R1, R2, R3, R4, and R5are independently selected from: a bond, H, Ci.35alkyl, Ci _35heteroalkyl, C2.35alkenyl, C2.35alkynyl, C3.20carbocyclyl, C3.20heterocyclyl, C3.i8aryl, and C5.i8heteroaryl, each of which is optionally substituted with one or more substituents selected C1-10alkyl, C2.i0alkenyl, C2.10alkynyl, halogen, -CN, -OR9, -SR9, -S(O)2R9, -NR9R10, -N02, =(0), =(S), =(N)R9, =(N)R10, -C(O)R9, -C(O)NR9R10, -C(O)SR9or -C(O)OR9; or with one or more groups selected from C3.6carbocyclyl, C3.6heterocyclyl, C3.6aryl, and C5.12heteroaryl, each of which is optionally substituted with one or more substituents selected from Ci_6alkyl, halogen, -CN, -OR9, -SR9, -S(O)2R9, -NR9R10, -NO2, =(O), =(S), =(N)R9, =(N)R10, -C(O)R9, -C(O)NR9R10, -C(O)SR9or -C(O)OR9; - wherein each R9is selected from H, optionally substituted C1-10alkyl, optionally substituted C2-io alkenyl, optionally substituted C2-io alkynyl, and optionally substituted C5.6aryl;- wherein each R10is selected from H, optionally substituted C O alkyl, optionally substituted C2.io alkenyl, optionally substituted C2.io alkynyl, and optionally substituted C5.6aryl,or- R1, R2, R3, R4, and R5are independently selected from: a bond, H, or optionally substituted Ci.35hydrocarbons,wherein for a compound of Formula (Ila):Formula (Ila)- R1, R2, R3, R4, and R5are independently selected from: a bond, H, Ci.35alkyl, Ci _35heteroalkyl, C2.35alkenyl, C2.35alkynyl, C3.20carbocyclyl, C3.20heterocyclyl, C3.i8aryl, and C5.i8heteroaryl, each of which is optionally substituted with one or more substituents selected C O alkyl, C2.io alkenyl, C2.10alkynyl, halogen, -CN, -OR9, -SR9, -S(O)2R9, -NR9R10, - NO2, =(O), =(S), =(N)R9, =(N)R10, -C(O)R9, -C(O)NR9R10, -C(O)SR9or -C(O)OR9; or with one or more groups selected from C3.6carbocyclyl, C3.6heterocyclyl, C3.6aryl, and C5.i2heteroaryl, each of which is optionally substituted with one or more substituents selected from Ci_6alkyl, halogen, -CN, -OR9, -SR9, -S(O)2R9, -NR9R10, -NO2, =(O), =(S), =(N)R9, =(N)R10, -C(O)R9, -C(O)NR9R10, -C(O)SR9or -C(O)OR9;- wherein each R9is selected from H, optionally substituted C1-10alkyl, optionally substituted C2-10alkenyl, optionally substituted C2-10alkynyl, and optionally substituted C5-6aryl;- wherein each R10is selected from H, optionally substituted C1-10alkyl, optionally substituted C2-10alkenyl, optionally substituted C2-10alkynyl, and optionally substituted C5-6aryl,or- R1, R2, R3, R4, and R5are independently selected from: a bond, H, or optionally substituted C1.35 hydrocarbons,wherein for a compound of Formula (lib):Formula (lib);- R1, R2and R5are independently selected from: a bond, H, C1.35 alkyl, Ci.35heteroalkyl, C2.35alkenyl, C2.35alkynyl, C3.20carbocyclyl, C3.20heterocyclyl, C3.18aryl, and C5.18heteroaryl, each of which is optionally substituted with one or more substituents selected C1-10alkyl, C2.i0alkenyl, C2.10alkynyl, halogen, -CN, -OR9, -SR9, -S(O)2R9, -NR9R10, - NO2, =(O), =(S), =(N)R9, =(N)R10, -C(O)R9, -C(O)NR9R10, -C(O)SR9or -C(O)OR9; or with one or more groups selected from C3.6carbocyclyl, C3.6heterocyclyl, C3.6aryl, and C5.12heteroaryl, each of which is optionally substituted with one or more substituents selected from Ci_6alkyl, halogen, -CN, -OR9, -SR9, -S(O)2R9, -NR9R10, -NO2, =(O), =(S), =(N)R9, =(N)R10, -C(O)R9, -C(O)NR9R10, -C(O)SR9or -C(O)OR9; - wherein each R9is selected from H, optionally substituted C1-10alkyl, optionally substituted C2.io alkenyl, optionally substituted C2.io alkynyl, and optionally substituted C5.6aryl;- wherein each R10is selected from H, optionally substituted CMO alkyl, optionally substituted C2.io alkenyl, optionally substituted C2.io alkynyl, and optionally substituted C5.6aryl,or- R1, R2and R5are independently selected from: a bond, H, C1-35 hydrocarbons;orwhen a trimer of Formula (I), is present the compound is optionally a compound of Formula (III), Formula (Illa) or Formula (Illb); wherein for a compound of Formula (III):Formula (III)R1, R2, R3, R4, R5, R6, R7, and R8are independently selected from: a bond, H, Ci -35 alkyl, Ci.35 heteroalkyl, C2.35 alkenyl, C2.35 alkynyl, C3.20 carbocyclyl, C3.2o heterocyclyl, C3.i8aryl, and C5.i8heteroaryl, each of which is optionally substituted with one or more substituents selected Ci.10 alkyl, C2.io alkenyl, C2-io alkynyl, halogen, -CN, -OR9, -SR9, - S(O)2R9, -NR9R10, -NO2, =(O), =(S), =(N)R9, =(N)R10, -C(O)R9, - C(O)NR9R10, -C(O)SR9or -C(O)OR9; or with one or more groups selected from C3.6carbocyclyl, C3.6heterocyclyl, C3.6aryl, and C5.12 heteroaryl, each of which is optionally substituted with one or more substituents selected from Ci.6alkyl, halogen, -CN, -OR9, -SR9, - S(O)2R9, -NR9R10, -NO2, =(O), =(S), =(N)R9, =(N)R10, -C(O)R9, - C(O)NR9R10, -C(O)SR9or-C(O)OR9;- wherein each R9is selected from H, optionally substituted C1-10alkyl, optionally substituted C2-io alkenyl, optionally substituted C2-io alkynyl, and optionally substituted C5.6aryl;- wherein each R10is selected from H, optionally substituted CMO alkyl, optionally substituted C2-io alkenyl, optionally substituted C2-io alkynyl, and optionally substituted C5.6aryl,orR1, R2, R3, R4, R5, R6, R7, and R8are independently selected from: a bond, H, or optionally substituted C1.35 hydrocarbons,wherein for a compound of Formula (Illa):Formula (Illa)R1, R2, R3, R4, R5, R6, R7, and R8are independently selected from: a bond, H, Ci -35 alkyl, Ci.35 heteroalkyl, C2.35 alkenyl, C2.35 alkynyl, C3.20 carbocyclyl, C3.20 heterocyclyl, C3.i8aryl, and C5.i8heteroaryl, each of which is optionally substituted with one or more substituents selected Ci.10 alkyl, C2.io alkenyl, C2-io alkynyl, halogen, -CN, -OR9, -SR9, - S(O)2R9, -NR9R10, -NO2, =(O), =(S), =(N)R9, =(N)R10, -C(O)R9, - C(O)NR9R10, -C(O)SR9or -C(O)OR9; or with one or more groups selected from C3.6carbocyclyl, C3.6heterocyclyl, C3.6aryl, and C5.12 heteroaryl, each of which is optionally substituted with one or more substituents selected from Ci_6alkyl, halogen, -CN, -OR9, -SR9, - S(O)2R9, -NR9R10, -NO2, =(O), =(S), =(N)R9, =(N)R10, -C(O)R9, - C(O)NR9R10, -C(O)SR9or-C(O)OR9;- wherein each R9is selected from H, optionally substituted C1-10alkyl, optionally substituted C2-io alkenyl, optionally substituted C2-io alkynyl, and optionally substituted C5.6aryl;- wherein each R10is selected from H, optionally substituted CMO alkyl, optionally substituted C2-io alkenyl, optionally substituted C2-io alkynyl, and optionally substituted C5.6aryl,orR1, R2, R3, R4, R5, R6, R7, and R8are independently selected from: a bond, H, or optionally substituted C1.35 hydrocarbons,wherein for a compound of Formula (Illb):Formula (Illb)- R1, R2, R5and R8are independently selected from: a bond, H, C1.35 alkyl, C1.35 heteroalkyl, C2.35 alkenyl, C2.35 alkynyl, C3.20 carbocyclyl, C3.20 heterocyclyl, C3.18aryl, and C5.18heteroaryl, each of which is optionally substituted with one or more substituents selected CM0alkyl, C2.io alkenyl, C2-io alkynyl, halogen, -CN, -OR9, -SR9, -S(O)2R9, -NR9R10, - NO2, =(O), =(S), =(N)R9, =(N)R10, -C(O)R9, -C(O)NR9R10, -C(O)SR9or -C(O)OR9; or with one or more groups selected from C3.6carbocyclyl, C3.6 heterocyclyl, C3.6aryl, and C5.12 heteroaryl, each of which is optionally substituted with one or more substituents selected from Ci_6alkyl, halogen, -CN, -OR9, -SR9, -S(O)2R9, -NR9R10, -NO2, =(O), =(S), =(N)R9, =(N)R10, -C(O)R9, -C(O)NR9R10, -C(O)SR9or -C(O)OR9; - wherein each R9is selected from H, optionally substituted C1-10alkyl, optionally substituted C2-io alkenyl, optionally substituted C2-io alkynyl, and optionally substituted C5.6aryl;- wherein each R10is selected from H, optionally substituted CM0alkyl, optionally substituted C2-io alkenyl, optionally substituted C2-io alkynyl, and optionally substituted C5.6aryl,or- R1, R2, R5and R8are independently selected from: a bond, H, or optionally substituted C1.35 hydrocarbons; or- when an oligomer of Formula (I), is present the oligomer is optionally a compound of Formula (IV) or Formula (V), wherein:- when a compound of Formula (IV) is present:o R1Formula (IV)- R1, R2, R3are independently selected from: a bond, H, Ci_35alkyl, Ci_35heteroalkyl, C2.35alkenyl, C2.35alkynyl, C3.20carbocyclyl, C3.20heterocyclyl, C3.i8aryl, and C5.i8heteroaryl, each of which is optionally substituted with one or more substituents selected C1-10alkyl, C2-10alkenyl, C2-10alkynyl, halogen, -CN, -OR9, -SR9, -S(O)2R9, -NR9R10, -NO2, =(O), =(S), =(N)R9, =(N)R10, -C(O)R9, -C(O)NR9R10, -C(O)SR9or -C(O)OR9; or with one or more groups selected from C3-6carbocyclyl, C3-6heterocyclyl, C3-6aryl, and C5-12heteroaryl, each of which is optionally substituted with one or more substituents selected from C1-6alkyl, halogen, -CN, -OR9, -SR9, -S(O)2R9, -NR9R10, -NO2, =(O), =(S), =(N)R9, =(N)R10, -C(O)R9, -C(O)NR9R10, -C(O)SR9or-C(O)OR9; or - R1and R2are independently selected from: H, or optionally substituted Ci_35hydrocarbons,- wherein each R9is selected from H, optionally substituted C1-10alkyl, optionally substituted C2-io alkenyl, optionally substituted C2-io alkynyl, and optionally substituted C5.6aryl;- wherein each R10is selected from H, optionally substituted CI O alkyl, optionally substituted C2.io alkenyl, optionally substituted C2.io alkynyl, and optionally substituted C5.6aryl;- wherein — indicates a bond between repeat units; and- wherein n is between about 4 and about 100;orwhen a compound of Formula (V) is present,Formula (V)- R1and R2are independently selected from: a bond, H, Ci_35alkyl, Ci_35heteroalkyl, C2.35alkenyl, C2.35alkynyl, C3.20carbocyclyl, C3.20heterocyclyl, C3.18aryl, and C5.18heteroaryl, each of which is optionally substituted with one or more substituents selected C1-10alkyl, C2-10alkenyl, C2-10alkynyl, halogen, -CN, -OR9, -SR9, -S(O)2R9, -NR9R10, -NO2, =(O), =(S), =(N)R9, =(N)R10, -C(O)R9, -C(O)NR9R10, -C(O)SR9or -C(O)OR9; or with one or more groups selected from C3-6carbocyclyl, C3-6heterocyclyl, C3-6aryl, and C5-12heteroaryl, each of which is optionally substituted with one or more substituents selected from C1-6alkyl, halogen, -CN, -OR9, -SR9, -S(O)2R9, -NR9R10, -NO2, =(O), =(S), =(N)R9, =(N)R10, -C(O)R9, -C(O)NR9R10, -C(O)SR9or-C(O)OR9; or - R1and R2are independently selected from: H, or optionally substituted Ci_35hydrocarbons- wherein each R9is selected from H, optionally substituted C1-10alkyl, optionally substituted C2-io alkenyl, optionally substituted C2-io alkynyl, and optionally substituted C5.6aryl;- wherein each R10is selected from H, optionally substituted CI O alkyl, optionally substituted C2.io alkenyl, optionally substituted C2.io alkynyl, and optionally substituted C5.6aryl;- wherein — indicates a bond between repeat units; and- wherein n is between about 4 and about 100.51. The method of example embodiment 50, wherein the method further comprises depositing a metal oxide layer on the substrate prior to deposition of the singlet fission compound, such that the metal oxide layer is disposed between the light absorbing semiconductor layer and the singlet fission compound.52. The method of example embodiment 50, wherein the method further comprises depositing a passivating layer, such that the singlet fission layer is disposed between the substrate and the passivation layer.53. The method of example embodiment 50, wherein the depositing a singlet fission compound is by thermal evaporating.54. The method of example embodiment 50, wherein the absolute pressure (mbar) at which the thermal evaporating is performed is between about 0.0000001 to about 0.00001.55. The method of example embodiment 50, wherein the temperature (°C) at which the thermal evaporating is performed is between about 100 to about 150.56. The method of example embodiment 50, wherein the depositing a singlet fission compound is by spin coating, wherein the spin coating comprises:dissolving the singlet fission compound in a solvent to form a mixture depositing the mixture on the substrate;rotating the substrate to spread the mixture over at least a portion of the substrate.57. The method of example embodiment 50, wherein the method further comprises baking the substrate after the spin coating.58. The method of example embodiment 50, wherein the rotating the substrate is performed at a rotation speed (rpm) of between about 2000 to about 10000.59. The method of example embodiment 50, wherein the rotating the substrate is performed at a rotation speed (rpm) of between about 5000 to about 7000.60. The method of example embodiment 50, wherein the concentration (mg / ml) of the singlet fission compound in the mixture is between about 0.1 to about 10.61. The method of example embodiment 50, wherein the concentration (mg / ml) of the singlet fission compound in the mixture is between about 0.5 to about 2.62. The method of example embodiment 50, wherein the solvent is selected from 1,4-di oxane, 2-methyltetrahydrofuran, diethyl ether, dimethoxy ethane, acetonitrile, dimethylformamide, dimethyl sulfoxide, toluene, hexane, tetrahydrofuran, and mixtures thereof.63. The method of example embodiment 50, wherein the solvent is tetrahydrofuran.64. The method of example embodiment 50, wherein the time (min) for which baking is performed after the spin coating is between about 10 to about 30.65. The method of example embodiment 50, wherein the temperature (°C) at which baking is performed after the spin coating is between about 60 to about 100.66. The method of example embodiment 50, wherein the depositing a metal oxide layer is by atomic layer deposition.67. The method of example embodiment 50, wherein the depositing a passivating layer is by spin coating.68. The method of example embodiment 50, wherein the method further comprises depositing a second passivating layer of the substrate on the opposite side of the substrate to the singlet fission layer.69. The method according to any one of example embodiments 50 to 68, wherein the article is a device according to any one of example embodiments 1 to 49.70. An article produced according to the method of any one of example embodiments 50 to 69.71. A photovoltaic device comprising the device of any one of example embodiments 1 to 49.72. A use of the device of any one of example embodiments 1 to 49 in a photovoltaic device.73. A use of the device of any one of example embodiments 1 to 49 in the manufacture of a photovoltaic device.74. The photovoltaic precursor device or the photovoltaic device according to any one of example embodiments 1 to 49, wherein for a compound of Formula (I), R1and R2are joined to form a compound of Formula (VI):PNFormula (VI)wherein p is an integer of 5 to 100.75. The method according to any one of example embodiments 50 to 69, wherein for a compound of Formula (I), R1and R2are joined to form a compound of FormulaoFormula (VI)wherein p is an integer of 5 to 100; or at least one CH2group in (CH2)Pis exchanged for O or NR9, wherein each R9is selected from H, optionally substituted CMO alkyl, optionally substituted C2.10alkenyl, optionally substituted C2.10alkynyl, and optionally substituted C5.6aryl; or wherein (CH2)pis replaced with -(CH2)x-O-(CH2)y-, wherein each of x and y is an integer, and x +y is an integer between 4 and 100; or wherein (CH2)Pis be replaced with -(CH2)x-NR9-(CH2)y-, wherein each of x and y is an integer, and x +y is an integer between 4 and 100, and R9is selected from H, optionally substituted Ci. io alkyl, optionally substituted C2-io alkenyl, optionally substituted C2-io alkynyl, and optionally substituted C5.6aryl.76. The photovoltaic precursor device or the photovoltaic device according to any one of example embodiments 1 to 49, wherein at least one of R2, R3, R5and / or R6is independently selected from:- (-CH2^ *-fc=cj-*wherein:* denotes a point of attachmentq is an integer of from 1 to 100; andeach of Ra, Rb, Rc, and Rd is independently selected from: H, Ci.35alkyl, Ci.35heteroalkyl, C2.35alkenyl, C2.35alkynyl, C3.20carbocyclyl, C3.20heterocyclyl, C3.i8 aryl, and C5.i8heteroaryl, each of which is optionally substituted with one or more substituents selected Cuo alkyl, C2.i0alkenyl, C2.i0alkynyl, halogen, -CN, -OR9, -SR9, -S(O)2R9, -NR9R10, -NO2, =(O), =(S), =(N)R9, =(N)R10, -C(O)R9, -C(O)NR9R10, -C(O)SR9or -C(O)OR9; or with one or more groups selected from C3.6carbocyclyl, C3.6heterocyclyl, C3.6aryl, andC5.i2 heteroaryl, each of which is optionally substituted with one or more substituents selected from Ci.6alkyl, halogen, -CN, -OR9, -SR9, -S(O)2R9, - NR9R10, -NO2, =(O), =(S), =(N)R9, =(N)R10, -C(O)R9, -C(O)NR9R10, - C(O)SR9or-C(O)OR9.77. The method according to any one of example embodiments 50 to 69, wherein at least one of R2, R3, R5and / or R6is independently selected from:-(-CH2^ *-fc=cj-** denotes a point of attachmentq is an integer of from 1 to 100; andeach of Ra, Rb, Rc, and Rd is independently selected from: H, Ci.35alkyl, Ci.35heteroalkyl, C2.35alkenyl, C2.35alkynyl, C3.20carbocyclyl, C3.20heterocyclyl, C3.i8 aryl, and C5.18heteroaryl, each of which is optionally substituted with one or more substituents selected C1-10alkyl, C2-10alkenyl, C2-10alkynyl, halogen, -CN, -OR9, -SR9, -S(O)2R9, -NR9R10, -NO2, =(O), =(S), =(N)R9, =(N)R10, -C(O)R9, -C(O)NR9R10, -C(O)SR9or -C(O)OR9; or with one or more groups selected from C3.6carbocyclyl, C3.6heterocyclyl, C3.6aryl, and C5.12heteroaryl, each of which is optionally substituted with one or more substituents selected from Ci_6alkyl, halogen, -CN, -OR9, -SR9, -S(O)2R9, - NR9R10, -NO2, =(O), =(S), =(N)R9, =(N)R10, -C(O)R9, -C(O)NR9R10, - C(O)SR9or-C(O)OR9.EXAMPLES DPND chromophore synthesisMonomers

[0183] The general reaction scheme to form monomers of the singlet fission compounds of the present disclosure is shown below in Scheme 1:R-COOH O R TFAA, TFA CH2CI20°C -> rt, 3 - 5 h.Scheme 1: Exemplified method of forming a singlet fission compound

[0184] l,4-Di(pyrrol-l-yl)butane- 1,4-dione (1 eq.) was dissolved in dry di chloromethane (6 mL / mmol) under an argon atmosphere at 0°C. To this was dropwise added the carboxylic acid (6 eq.), trifluoroacetic anhydride (TFAA, 12 eq.) and finally the trifluoroacetic acid (TFA, 6 eq.). The reaction was allowed to warm to room temperature in the dark and stirred for 3 to 5 hours, until consumption of the starting material (as confirmed by thin layer chromatography). The reaction mixture was then poured into a solution of saturated aqueous sodium bicarbonate and stirred for 30 minutes. The organic layer was separated, and the aqueous layer extracted three times with dichloromethane. The combined organic layers were washed with water, dried with magnesium sulfate, filtered and concentrated in vacuo. The crude product was washed through a silica gel plug with hexane / dichloromethane. The product was finally recrystallised from dichloromethane / methanol to afford purified DPND. Further purification can be performed using a Kugelrohr to fractionally sublimate the product.

[0185] Carboxylic acids used: acetic acid (DPND-1), propionic acid (DPND-2), hexanoic acid (DPND-5), octanoic acid (DPND-7), stearic acid (DPND- 17), oleic acid (DPND-Z-17), elaidic acid (DPND-E-17), fS')-2-methylbutanoic acid (DPND-5-3,1).

[0186] Synthesis was also performed by substituting out the carboxylic acid for its corresponding acyl chloride. DPND-3 was synthesised using butyric chloride in place of the carboxylic acid in the general procedure.Dimers / T rimers:

[0187] The general reaction scheme to form trimers and / or dimers of the singlet fission compounds of the present disclosure is shown below in Scheme 2:TMS TMS— = NBS Pd(dppf)CI2, Cui CHCI3, 16 h„ DIPA, C6H5CH30°C -> rt MW., 150°C, 15 min.K2CO3NBS CHCI3, 16 h„ 0°C -> rt CH3OH / CH2CI23 h„ rtScheme 2: Exemplified method of forming a functionalised singlet fission compound for potential dimerization or trimerization.

[0188] These brominated / acetylated monomers can then be combined in various ways to afford the dimers / trimer, as exemplified in Scheme 3.Pd(dppf)CI2K2CO3, Dioxane / H20MW., 130°C, 20 min.Scheme 3: Exemplified method of forming dimer or a trimer of a singlet fission compound.

[0189] The DPND derivative (1 eq.) was dissolved in chloroform (10 mL / mmol) at 0 °C under argon. 7V-bromosuccinimide was added in portions (1.02 eq. for monobromination, 2.04 eq. for di-bromination). The reaction mixture was allowed to gradually warm to room temperature over an hour and stirred in the dark for 16 hours. The reaction mixture was washed with water three times, and the organic layer dried with magnesium sulfate, filtered and concentrated in vacuo. The brominated DPND derivative was purified by a silica gel plug, eluting with dichloromethane / hexane. Finally, recrystallisation using dichloromethane / methanol afforded the brominated derivatives.General procedure for the Sonogashira cross-coupling of DPND derivatives

[0190] In a microwave vial, the brominated DPND (1 eq.), acetylene (DPND acetylene, 0.75 eq. for the dimer, 2.5 eq. for the trimer; or TMS-acetylene, 3 eq.) was dissolved in toluene (4 mL / mmol) and diisopropylamine (7 mL / mmol). The solution was degassed with argon for 15 minutes, Pd(dppf)Cl2(0.1 - 0.2 eq.) and Cui (0.1 - 0.2 eq.) were added, and the reaction degassed for a further 5 minutes. The vial was then placed in the microwave reactor and heated to 150°C for 15 minutes. The product was purified using silica gel column chromatography, eluting with CH2Cl2 / hexane.Suzuki cross-coupling of DPND-7 and durene

[0191] In a microwave vial, 2,3,5,6-tetramethyl-l,4-benzenediboronic acid bis(pinacol) ester (1 eq.), Br-DPND-7 (3 eq.) and potassium carbonate (5 eq.) were suspended in dioxane (10 mL / mmol) and water (3 mL / mmol). The mixture was degassed for 15 minutes with argon, Pd(dppf)Cl2(0.2 eq.) was added and the reaction degassed for a further 5 minutes. The vial was then placed in the microwave reactor and heated to 130°C for 20 minutes. The product was purified using silica gel column chromatography, eluting with dichloromethane / hexane.General procedure for the cleavage of TMS from the TMS-acetylene DPND

[0192] TMS-acetylene-DPND (1 eq.) was dissolved in a solution of dichloromethane / methanol under argon. To this was added potassium carbonate (3 eq.) and the reaction stirred at room temperature under argon for 3 hours. The reaction mixture was concentrated in vacuo, and the resulting solid redissolved in di chloromethane. The organic solution was washed three times with water, then dried with magnesium sulfate, filtered and concentrated in vacuo to afford the product.Device assemblySilicon wafer preparation

[0193] Silicon wafers (base n doping) with rear SiNxpassivation are cleaned with RCA1 and RCA2 then etched using HF.Metal oxide addition (optional)

[0194] Following this, atomic layer deposition (ALD) of SnOx(or another metal oxide) is carried out, with thicknesses of this layer varying from 0.5nm - 1.5nm.Singlet fission layer

[0195] Next, DPND-2 / DPND-7 is deposited using either thermal evaporation under vacuum or spin-coating, with the thickness of this layer aimed at 30nm.Thermal evaporation

[0196] For thermal evaporation, a vacuum pressure of 1 x 10'6mbar is used, with temperatures in the range of 108 - 140 °C for DPND-7 or 80 - 120 °C for DPND-2. The evaporation is stopped once a 30nm layer has been deposited.Spin coating

[0197] Spin-coating of the DPNDs has been done using a range of solvents, concentrations and spin speeds. The best results so far have been from Img / mL of the DPND derivative in tetrahydrofuran (THF) spun at 6000rpm.Passivation layer (optional)

[0198] To further improve passivation, an additional passivation layer was included on top of the DPND layer. Poly(3,4-ethylenedi oxythiophene) polystyrene sulfonate (PEDOT: PSS) was used and deposited by spin-coating on top. The PEDOT: PSS was an aqueous solution of 1:6 wt / wt (purchased from Heraeus Epurio). After spin-coating, the substrate is annealed at 120 °C for 20 minutes. The PEDOT: PSS layer thickness was estimated to be between 10 nm to 200 nm. This PEDOT: PSS layer has been used both with and without the SnOxinterlayer present.Device characterisationAtomic force microscopy and Grazing-incident wide-angle x-ray scattering

[0199] AFM and GIWAXS were done on the films using standard techniques for AFM and GIWAXS. Initial atomic force microscopy (AFM) analysis has shown that the DPND forms small crystalline islands, rather than as a uniform film, see Figure 1.

[0200] Grazing-incident wide-angle x-ray scattering (GIWAXS) results have indicated that DPND-7 prefers to pack face on with the substrate it is being deposited on, while DPND-2 has more freedom for other orientations. Despite minimal differences in steady state absorption and PL in solution, the significant differences in the first microsecond of the transient absorption of the two evaporated films indicates chain length is playing a role in the singlet fission process. Without wishing to be bound by theory, the inventors postulate that this is due to a change in molecular packing on the substrate surface. Cyclic voltammetry

[0201] The DPND (2mM) was dissolved in a 0.1M tetrabutylammonium perchlorate solution in CH2Cl2. The working electrode used was glassy carbon, the counter electrode was platinum and the reference electrode was Ag / AgNO3. The DPNDs in CH2Cl2has been used to determine the H0M0 / LUM0 levels of the molecules. These H0M0 / LUM0 levels are favourable for stepwise charge transfer of the triplet exciton into silicon. Absorption and photoluminescence of DPND-2 and DPND-7, these showminimal change between the two DPNDs in CH2Cl2, indicating that the optical properties are unaffected by chain length, see Figure 2.Transient absorption of films

[0202] Transient absorption measurements of DPND on a quartz substrate were done on either a femtosecond (fs) or nanosecond (ns) timescale. fsTA on the DPND films was carried out using a 480nm pump wavelength followed by a white light probe after some time delay. nsTa was done the same way, instead using a 532nm pump. Transient absorption measurements of DPND on a quartz substrate show the presence of a long-lived state - indicative of triplet excitons present in the sample, see Figure 3.Magnetic photoluminescence of films

[0203] Magnetic photoluminescence measurements of the DPND / SnOx / Si system were carried out. It was observed that the photoluminescence of the silicon is reduced under the application of magnetic fields > ~100mT, indicative of triplets generated by singlet fission in the DPND layer transferring to silicon, see Figure 4.

[0204] It will be appreciated by persons skilled in the art that numerous variations and / or modifications may be made to the above-described embodiments, without departing from the broad general scope of the present disclosure. The present embodiments are, therefore, to be considered in all respects as illustrative and not restrictive.

Claims

CLAIMS:

1. A photovoltaic precursor device, the photovoltaic precursor device comprising: a)a light absorbing semiconductor layer;a singlet fission layer; andat least one of a metal oxide layer and a passivation layer,wherein:if present, at least one metal oxide layer is disposed between the light absorbing semiconductor layer and the singlet fission layer; and if at least one passivation layer is present, the singlet fission layer is disposed between the light absorbing semiconductor layer and the at least one passivation layer; orb)a light absorbing semiconductor layer;a singlet fission layer; andat least one of a metal oxide layer and a passivation layer,wherein:- if present, at least one metal oxide layer is disposed between the light absorbing semiconductor layer and the singlet fission layer; and - if at least one passivation layer is present, the at least one passivation layer is disposed between the semiconductor layer and the singlet fission layer; andthe singlet fission layer comprises at least one singlet fission compound of Formula (I), or a dimer or trimer thereof, or an oligomer thereof, or a compound of Formula (IV), or a compound of Formula (V),wherein:when a compound of Formula (I) is present:Formula (I)- R1and R2are independently selected from: H, C1-35alkyl, C1-35heteroalkyl, C2-35alkenyl, C2-35alkynyl, C3-20carbocyclyl, C3-20heterocyclyl, C3-18aryl, and C5-18heteroaryl, each of which is optionally substituted with one or more substituents selected C1-10alkyl, C2-10alkenyl, C2-10alkynyl, halogen, -CN, -OR9, -SR9, -S(O)2R9, -NR9R10, - NO2, =(O), =(S), =(N)R9, =(N)R10, -C(O)R9, -C(O)NR9R10, -C(O)SR9or -C(O)OR9; or with one or more groups selected from C3.6carbocyclyl, C3.6heterocyclyl, C3.6aryl, and C5-12heteroaryl, each of which is optionally substituted with one or more substituents selected from C1-6alkyl, halogen, -CN, -OR9, -SR9, -S(O)2R9, -NR9R10, -NO2, =(O), =(S), =(N)R9, =(N)R10, -C(O)R9, -C(O)NR9R10, -C(O)SR9or -C(O)OR9; - wherein each R9is selected from H, optionally substituted C1-10alkyl, optionally substituted C2-10alkenyl, optionally substituted C2-10alkynyl, and optionally substituted C5.6aryl;- wherein each R10is selected from H, optionally substituted C1-10alkyl, optionally substituted C2-10alkenyl, optionally substituted C2-10alkynyl, and optionally substituted C5.6aryl;or- R1and R2are independently selected from: H or optionally substituted Ci.35hydrocarbons; orwhen a compound of Formula (IV) is present:Formula (IV)- R1, R2, R3are independently selected from: a bond, H, Ci_35alkyl, Ci_35heteroalkyl, C2.35alkenyl, C2.35alkynyl, C3.20carbocyclyl, C3.20heterocyclyl, C3.i8aryl, and C5.i8heteroaryl, each of which is optionally substituted with one or more substituents selected C1-10alkyl, C2-10alkenyl, C2-10alkynyl, halogen, -CN, -OR9, -SR9, -S(O)2R9, -NR9R10, -NO2, =(O), =(S), =(N)R9, =(N)R10, -C(O)R9, -C(O)NR9R10, -C(O)SR9or -C(O)OR9; or with one or more groups selected from C3-6carbocyclyl, C3-6heterocyclyl, C3-6aryl, and C5-12heteroaryl, each of which is optionally substituted with one or more substituents selected from C1-6alkyl, halogen, -CN, -OR9, -SR9, -S(O)2R9, -NR9R10, -NO2, =(O), =(S), =(N)R9, =(N)R10, -C(O)R9, -C(O)NR9R10, -C(O)SR9or-C(O)OR9; or - R1and R2are independently selected from: H, or optionally substituted Ci.35hydrocarbons,- wherein each R9is selected from H, optionally substituted C1-10alkyl, optionally substituted C2.10alkenyl, optionally substituted C2.10alkynyl, and optionally substituted C5.6aryl;- wherein each R10is selected from H, optionally substituted CI O alkyl, optionally substituted C2-io alkenyl, optionally substituted C2-io alkynyl, and optionally substituted C5.6aryl;- wherein — indicates a bond between repeat units; and- wherein n is between about 4 and about 100;orwhen a compound of Formula (V) is present,Formula (V)- R1and R2are independently selected from: a bond, H, Ci.35alkyl, Ci.35heteroalkyl, C2.35alkenyl, C2.35alkynyl, C3.20carbocyclyl, C3.20heterocyclyl, C3.18aryl, and C5.18heteroaryl, each of which is optionally substituted with one or more substituents selected C1-10alkyl, C2-io alkenyl, C2-io alkynyl, halogen, -CN, -OR9, -SR9, -S(O)2R9, -NR9R10, - NO2, =(O), =(S), =(N)R9, =(N)R10, -C(O)R9, -C(O)NR9R10, -C(O)SR9or -C(O)OR9; or with one or more groups selected from C3.6carbocyclyl, C3.6heterocyclyl, C3.6aryl, and C5.12heteroaryl, each of which is optionally substituted with one or more substituents selected from Ci.6alkyl, halogen, -CN, -OR9, -SR9, -S(O)2R9, -NR9R10, -NO2, =(O), =(S), =(N)R9, =(N)R10, -C(O)R9, -C(O)NR9R10, -C(O)SR9or-C(O)OR9; or - R1and R2are independently selected from: H, or optionally substituted Ci_35hydrocarbons- wherein each R9is selected from H, optionally substituted C1-10alkyl, optionally substituted C2.io alkenyl, optionally substituted C2.io alkynyl, and optionally substituted C5.6aryl;- wherein each R10is selected from H, optionally substituted C1-10alkyl, optionally substituted C2-10alkenyl, optionally substituted C2-10alkynyl, and optionally substituted C5.6aryl;- wherein — indicates a bond between repeat units; and- wherein n is between about 4 and about 100.

2. A photovoltaic device, the photovoltaic device comprising:a)a light absorbing semiconductor layer;a singlet fission layer; andat least one of a metal oxide layer and a passivation layer,wherein:if present, at least one metal oxide layer is disposed between the light absorbing semiconductor layer and the singlet fission layer; and if at least one passivation layer is present, the singlet fission layer is disposed between the light absorbing semiconductor layer and the at least one passivation layer; orb)a light absorbing semiconductor layer;a singlet fission layer; andat least one of a metal oxide layer and a passivation layer,wherein:- if present, at least one metal oxide layer is disposed between the light absorbing semiconductor layer and the singlet fission layer; and - if at least one passivation layer is present, the at least one passivation layer is disposed between the semiconductor layer and the singlet fission layer; andthe singlet fission layer comprises at least one singlet fission compound of Formula (I), or a dimer or trimer thereof, or an oligomer thereof, or a compound of Formula (IV), or a compound of Formula (V),wherein:when a compound of Formula (I) is present:Formula (I)- R1and R2are independently selected from: H, C1.35 alkyl, C1.35 heteroalkyl, C2.35 alkenyl, C2.35 alkynyl, C3.20carbocyclyl, C3.20heterocyclyl, C3.18aryl, and C5.18heteroaryl, each of which is optionally substituted with one or more substituents selected C1-10alkyl, C2-io alkenyl, C2-io alkynyl, halogen, -CN, -OR9, -SR9, -S(O)2R9, -NR9R10, - NO2, =(O), =(S), =(N)R9, =(N)R10, -C(O)R9, -C(O)NR9R10, -C(O)SR9or -C(O)OR9; or with one or more groups selected from C3.6carbocyclyl, C3.6heterocyclyl, C3.6aryl, and C5.12heteroaryl, each of which is optionally substituted with one or more substituents selected from Ci.6alkyl, halogen, -CN, -OR9, -SR9, -S(O)2R9, -NR9R10, -NO2, =(O), =(S), =(N)R9, =(N)R10, -C(O)R9, -C(O)NR9R10, -C(O)SR9or -C(O)OR9;- wherein each R9is selected from H, optionally substituted C1-10alkyl, optionally substituted C2-io alkenyl, optionally substituted C2-io alkynyl, and optionally substituted C5.6aryl;- wherein each R10is selected from H, optionally substituted CM0alkyl, optionally substituted C2.10alkenyl, optionally substituted C2.10alkynyl, and optionally substituted C5.6aryl;- R1and R2are independently selected from: H or optionally substituted Ci.35 hydrocarbons;- R1and R2are independently selected from: H or optionally substituted Ci.35 hydrocarbons; orwhen a compound of Formula (IV) is present:Formula (IV)- R1, R2, R3are independently selected from: a bond, H, C1.35 alkyl, C1.35 heteroalkyl, C2.35alkenyl, C2.35alkynyl, C3.20carbocyclyl, C3.20heterocyclyl, C3.18aryl, and C5.18heteroaryl, each of which is optionally substituted with one or more substituents selected CM0alkyl, C2.10alkenyl, C2.10alkynyl, halogen, -CN, -OR9, -SR9, -S(O)2R9, -NR9R10, - NO2, =(O), =(S), =(N)R9, =(N)R10, -C(O)R9, -C(O)NR9R10, -C(O)SR9or -C(O)OR9; or with one or more groups selected from C3.6carbocyclyl, C3.6heterocyclyl, C3.6aryl, and C5.12heteroaryl, each of which is optionally substituted with one or more substituents selected from Ci_6alkyl, halogen, -CN, -OR9, -SR9, -S(O)2R9, -NR9R10, -NO2, =(O), =(S), =(N)R9, =(N)R10, -C(O)R9, -C(O)NR9R10, -C(O)SR9or-C(O)OR9; or - R1and R2are independently selected from: H, or optionally substituted C1.35 hydrocarbons,- wherein each R9is selected from H, optionally substituted C1-10alkyl, optionally substituted C2-io alkenyl, optionally substituted C2-io alkynyl, and optionally substituted C5.6aryl;- wherein each R10is selected from H, optionally substituted CM0alkyl, optionally substituted C2.10alkenyl, optionally substituted C2.10alkynyl, and optionally substituted C5.6aryl;- wherein — indicates a bond between repeat units; and- wherein n is between about 4 and about 100;orwhen a compound of Formula (V) is present,Formula (V)- R1and R2are independently selected from: a bond, H, Ci_35alkyl, Ci_35heteroalkyl, C2.35alkenyl, C2.35alkynyl, C3.20carbocyclyl, C3.20heterocyclyl, C3.i8aryl, and C5.i8heteroaryl, each of which is optionally substituted with one or more substituents selected C1-10alkyl, C2.i0alkenyl, C2.10alkynyl, halogen, -CN, -OR9, -SR9, -S(O)2R9, -NR9R10, - NO2, =(O), =(S), =(N)R9, =(N)R10, -C(O)R9, -C(O)NR9R10, -C(O)SR9or -C(O)OR9; or with one or more groups selected from C3.6carbocyclyl, C3.6heterocyclyl, C3.6aryl, and C5-12heteroaryl, each of which is optionally substituted with one or more substituents selected from C1-6alkyl, halogen, -CN, -OR9, -SR9, -S(O)2R9, -NR9R10, -NO2, =(O), =(S), =(N)R9, =(N)R10, -C(O)R9, -C(O)NR9R10, -C(O)SR9or-C(O)OR9; or - R1and R2are independently selected from: H, or optionally substituted Ci_35hydrocarbons- wherein each R9is selected from H, optionally substituted C1-10alkyl, optionally substituted C2-io alkenyl, optionally substituted C2-io alkynyl, and optionally substituted C5.6aryl;- wherein each R10is selected from H, optionally substituted CM0alkyl, optionally substituted C2.10alkenyl, optionally substituted C2.10alkynyl, and optionally substituted C5.6aryl;- wherein — indicates a bond between repeat units; and- wherein n is between about 4 and about 100.

3. The photovoltaic precursor device according to claim 1, or the photovoltaic device according to claim 2, wherein the dimer of a compound of Formula (I) is a compound of Formula (II):\R\'O IR2R5Formula (II)wherein for a compound of Formula (II):- R1, R2, R3, R4, and R5are independently selected from: a bond, H, Ci.35alkyl, Ci.35 heteroalkyl, C2.35alkenyl, C2.35alkynyl, C3.20carbocyclyl, C3.20heterocyclyl, C3.i8aryl, and C5.i8heteroaryl, each of which is optionally substituted with one or more substituents selected CM0alkyl, C2.i0alkenyl, C2.10alkynyl, halogen, -CN, -OR9, -SR9, -S(O)2R9, -NR9R10, - NO2, =(O), =(S), =(N)R9, =(N)R10, -C(O)R9, -C(O)NR9R10, -C(O)SR9or -C(O)OR9; or with one or more groups selected from C3.6carbocyclyl, C3.6heterocyclyl, C3.6aryl, and C5.i2heteroaryl, each of which is optionally substituted with one or more substituents selected from Ci_6alkyl, halogen, -CN, -OR9, -SR9, -S(O)2R9, -NR9R10, -NO2, =(O), =(S), =(N)R9, =(N)R10, -C(O)R9, -C(O)NR9R10, -C(O)SR9or-C(O)OR9; - wherein each R9is selected from H, optionally substituted C1-10alkyl, optionally substituted C2.10alkenyl, optionally substituted C2.10alkynyl, and optionally substituted C5.6aryl;- wherein each R10is selected from H, optionally substituted CM0alkyl, optionally substituted C2-io alkenyl, optionally substituted C2-io alkynyl, and optionally substituted C5.6aryl,or- R1, R2, R3, R4, and R5are independently selected from: a bond, H, or optionally substituted Ci_35hydrocarbons.

4. The photovoltaic precursor device according to claim 1, or the photovoltaic device according to claim 2, wherein the dimer of a compound of Formula (I), is a compound of Formula (Ila):Formula (Ila)wherein for a compound of Formula (Ila):- R1, R2, R3, R4, and R5are independently selected from: a bond, H, Ci_35alkyl, Ci_35heteroalkyl, C2.35alkenyl, C2.35alkynyl, C3.20carbocyclyl, C3.20heterocyclyl, C3.18aryl, and C5.18heteroaryl, each of which is optionally substituted with one or more substituents selected C1-10alkyl, C2.i0alkenyl, C2.10alkynyl, halogen, -CN, -OR9, -SR9, -S(O)2R9, -NR9R10, - NO2, =(O), =(S), =(N)R9, =(N)R10, -C(O)R9, -C(O)NR9R10, -C(O)SR9or -C(O)OR9; or with one or more groups selected from C3.6carbocyclyl, C3.6heterocyclyl, C3.6aryl, and C5.12heteroaryl, each of which is optionally substituted with one or more substituents selected from Ci.6alkyl, halogen, -CN, -OR9, -SR9, -S(O)2R9, -NR9R10, -NO2, =(O), =(S), =(N)R9, =(N)R10, -C(O)R9, -C(O)NR9R10, -C(O)SR9or -C(O)OR9; - wherein each R9is selected from H, optionally substituted C1-10alkyl, optionally substituted C2.10alkenyl, optionally substituted C2.10alkynyl, and optionally substituted C5.6aryl;- wherein each R10is selected from H, optionally substituted CM0alkyl, optionally substituted C2-io alkenyl, optionally substituted C2-io alkynyl, and optionally substituted C5.6aryl,or- R1, R2, R3, R4, and R5are independently selected from: a bond, H, or optionally substituted Ci_35hydrocarbons.

5. The photovoltaic precursor device according to claim 1, or the photovoltaic device according to claim 2, wherein the dimer of a compound of Formula (I), is a compound of Formula (lib):Formula (lib)wherein for a compound of Formula (lib):- R1, R2and R5are independently selected from: a bond, H, Ci_35alkyl, C3.35heteroalkyl, C2.35alkenyl, C2.35alkynyl, C3.20carbocyclyl, C3.20heterocyclyl, C3.i8aryl, and C5.i8heteroaryl, each of which is optionally substituted with one or more substituents selected C1-10alkyl, C2.i0alkenyl, C2.10alkynyl, halogen, -CN, -OR9, -SR9, -S(O)2R9, -NR9R10, - NO2, =(O), =(S), =(N)R9, =(N)R10, -C(O)R9, -C(O)NR9R10, -C(O)SR9or -C(O)OR9; or with one or more groups selected from C3.6carbocyclyl, C3.6heterocyclyl, C3.6aryl, and C5-12heteroaryl, each of which is optionally substituted with one or more substituents selected from C1-6alkyl, halogen, -CN, -OR9, -SR9, -S(O)2R9, -NR9R10, -NO2, =(O), =(S), =(N)R9, =(N)R10, -C(O)R9, -C(O)NR9R10, -C(O)SR9or -C(O)OR9; - wherein each R9is selected from H, optionally substituted C1-10alkyl, optionally substituted C2.io alkenyl, optionally substituted C2.io alkynyl, and optionally substituted C5.6aryl;- wherein each R10is selected from H, optionally substituted CM0alkyl, optionally substituted C2-io alkenyl, optionally substituted C2-io alkynyl, and optionally substituted C5.6aryl,- R1, R2and R5are independently selected from: a bond, H, Ci-35hydrocarbons.

6. The photovoltaic precursor device according to claim 1, or the photovoltaic device according to claim 2, wherein the trimer of a compound of Formula (I) is a compound of Formula (III):' xfl O,N N x SRVN ' R6R2R5R8Formula (III)wherein for a compound of Formula (III):R1, R2, R3, R4, R5, R6, R7, and R8are independently selected from: a bond, H, Ci-35 alkyl, Ci_35heteroalkyl, C2.35alkenyl, C2.35alkynyl, C3.20carbocyclyl, C3.20heterocyclyl, C3.18aryl, and C5.18heteroaryl, each of which is optionally substituted with one or more substituents selected Ci. io alkyl, C2.io alkenyl, C2.io alkynyl, halogen, -CN, -OR9, -SR9, - S(O)2R9, -NR9R10, -NO2, =(O), =(S), =(N)R9, =(N)R10, -C(O)R9, - C(O)NR9R10, -C(O)SR9or -C(O)OR9; or with one or more groups selected from C3.6carbocyclyl, C3.6heterocyclyl, C3.6aryl, and C5-12heteroaryl, each of which is optionally substituted with one or more substituents selected from C1-6alkyl, halogen, -CN, -OR9, -SR9, - S(O)2R9, -NR9R10, -NO2, =(O), =(S), =(N)R9, =(N)R10, -C(O)R9, - C(O)NR9R10, -C(O)SR9or-C(O)OR9;- wherein each R9is selected from H, optionally substituted C1-10alkyl, optionally substituted C2.io alkenyl, optionally substituted C2.io alkynyl, and optionally substituted C5.6aryl;- wherein each R10is selected from H, optionally substituted CM0alkyl, optionally substituted C2-io alkenyl, optionally substituted C2-io alkynyl, and optionally substituted C5.6aryl,orR1, R2, R3, R4, R5, R6, R7, and R8are independently selected from: a bond, H, or optionally substituted Ci_35hydrocarbons.

7. The photovoltaic precursor device according to claim 1, or the photovoltaic device according to claim 2, wherein the trimer of a compound of Formula (I) is a compound of Formula (Illa):Formula (Illa)wherein for a compound of Formula (Illa):R1, R2, R3, R4, R5, R6, R7, and R8are independently selected from: a bond, H, Ci-35 alkyl, Ci_35heteroalkyl, C2.35alkenyl, C2.35alkynyl, C3.20carbocyclyl, C3.20heterocyclyl, C3.18aryl, and C5.18heteroaryl, each of which is optionally substituted with one or more substituents selected Ci. io alkyl, C2.io alkenyl, C2.io alkynyl, halogen, -CN, -OR9, -SR9, - S(O)2R9, -NR9R10, -NO2, =(O), =(S), =(N)R9, =(N)R10, -C(O)R9, - C(O)NR9R10, -C(O)SR9or -C(O)OR9; or with one or more groups selected from C3.6carbocyclyl, C3.6heterocyclyl, C3.6aryl, and C5-12heteroaryl, each of which is optionally substituted with one or more substituents selected from C1-6alkyl, halogen, -CN, -OR9, -SR9, - S(O)2R9, -NR9R10, -NO2, =(O), =(S), =(N)R9, =(N)R10, -C(O)R9, - C(O)NR9R10, -C(O)SR9or-C(O)OR9;- wherein each R9is selected from H, optionally substituted C1-10alkyl, optionally substituted C2.io alkenyl, optionally substituted C2.io alkynyl, and optionally substituted C5.6aryl;- wherein each R10is selected from H, optionally substituted CM0alkyl, optionally substituted C2-io alkenyl, optionally substituted C2-io alkynyl, and optionally substituted C5.6aryl,orR1, R2, R3, R4, R5, R6, R7, and R8are independently selected from: a bond, H, or optionally substituted Ci_35hydrocarbons.

8. The photovoltaic precursor device according to claim 1, or the photovoltaic device according to claim 2, wherein the trimer of a compound of Formula (I) is a compound of Formula (lib):Formula (Illb)wherein for a compound of Formula (Illb):- R1, R2, R5and R8are independently selected from: a bond, H, Ci_35alkyl, Ci_35heteroalkyl, C2.35alkenyl, C2.35alkynyl, C3.20carbocyclyl, C3.20heterocyclyl, C3.i8aryl, and C5.i8heteroaryl, each of which is optionally substituted with one or more substituents selected C1-10alkyl, C2.i0alkenyl, C2.10alkynyl, halogen, -CN, -OR9, -SR9, -S(O)2R9, -NR9R10, - NO2, =(O), =(S), =(N)R9, =(N)R10, -C(O)R9, -C(O)NR9R10, -C(O)SR9or -C(O)OR9; or with one or more groups selected from C3.6carbocyclyl, C3.6heterocyclyl, C3.6aryl, and C5-12heteroaryl, each of which is optionally substituted with one or more substituents selected from C1-6alkyl, halogen, -CN, -OR9, -SR9, -S(O)2R9, -NR9R10, -NO2, =(O), =(S), =(N)R9, =(N)R10, -C(O)R9, -C(O)NR9R10, -C(O)SR9or -C(O)OR9; - wherein each R9is selected from H, optionally substituted C1-10alkyl, optionally substituted C2.io alkenyl, optionally substituted C2.io alkynyl, and optionally substituted C5.6aryl;- wherein each R10is selected from H, optionally substituted CM0alkyl, optionally substituted C2-io alkenyl, optionally substituted C2-io alkynyl, and optionally substituted C5.6aryl,or- R1, R2, R5and R8are independently selected from: a bond, H, or optionally substituted Ci_35hydrocarbons; or9. The photovoltaic precursor device or the photovoltaic device according to any one of claims 1 to 8, wherein:- at least one of R1, R2, R4, R5, R7, and R8, is selected from H, C1 7 alkyl, C2.i7alkenyl, each of which is optionally substituted with one substituent selected from C1.5 alkyl; and / or- at least one of R3and R6, is selected from C2.5alkynyl, and C3.6aryl, each of which is optionally substituted with one or more substituents selected from Ci.2alkyl; and / or- at least one of R1, R2, R4, R5, R7, and R8is selected from H, methyl, n-propyl, n-pentyl, n-heptadecyl, 8 -heptadecenyl; and / or- R1, R2, and if present, R4, R5, R7, and R8are the same;- at least one of R3and R6is selected from C2.25alkynyl, and C3.6aryl, each of which is optionally substituted with one or more substituents selected from Ci.10alkyl; and / or- at least one of R3and R6is ethynyl, 2,3,5,6-tetramethylphenyl; and / or- R3and R6are the same.

10. The photovoltaic precursor device or the photovoltaic device according to any one of claims 1 to 9, wherein singlet fission compound is selected from:D-CjHy O n-CgH-j-i O / 1-C7H-15 Oand mixtures thereof.

11. The photovoltaic precursor device or the photovoltaic device according to any one of claims 1 to 9, wherein singlet fission compound is selected from:and mixtures thereof.

12. The photovoltaic precursor device or the photovoltaic device according to any one of claims 1 to 9, wherein singlet fission compound is selected from:

13. The photovoltaic precursor device or the photovoltaic device according to any one of claims 1 to 12, wherein:- the thickness (nm) of at least a portion of the singlet fission layer is between about 5 to about 100, or between about 10 to about 50; and / or- the singlet fission layer is a discontinuous layer; and / or- the singlet fission layer comprises one or more discrete islands.- the one or more discrete islands as substantially homogeneously dispersed across the cross sectional are in the region of the device comprising the singlet fission layer; and / or- at least a portion of the region of the device comprising the singlet fission layer, the percentage of the cross sectional area of the device comprising the singlet fission layer is between about 10 to about 95; and / or- at least a portion of the region of the device comprising the singlet fission layer, the percentage of the cross sectional area of the device comprising the singlet fission layer is at least about 20; and / or- the device comprises the metal oxide layer and optionally the singlet fission layer is contiguous with at least a portion of the metal oxide layer; and / or - the metal oxide comprises a material selected from aluminium oxide (A1OX), indium tin oxide (ITO), zinc oxide (ZnOx), tin oxide (SnOx), aluminum-doped zinc oxide (AZO), copper oxide (CuxO), gallium-doped zinc oxide (GZO), and mixtures thereof; and / or- the thickness (nm) of the metal oxide layer is between about 0.1 to about 5 or between about 0.5 to about 1.5; and / or- the device comprises the passivating layer; and / or- the passivating layer comprises a conductive polymer, and optionally the passivating layer comprises poly(3,4-ethylenedi oxythiophene) polystyrene sulfonate (PEDOT: PSS), wherein optionally the weight ratio of PEDOT to PSS in the passivating layer is between about 1:1 to about 1:20 or optionally the weight ratio of PEDOT to PSS in the passivating layer is between about 1:2 to about 1:10; and / or- the thickness (nm) of the passivating layer is between about 1 to about 500, or the thickness (nm) of the passivating layer is between about 10 to about 200; and / or- the passivating layer substantially covers the singlet fission layer; and / or - at least a portion of the passivating layer is contiguous with the singlet fission layer; and / or- at least a portion of the passivating layer is contiguous with at least a portion of the metal oxide layer; and / or- at least a portion of the passivating layer is contiguous with at least a portion of the light absorbing semiconductor layer; and / or- the singlet fission layer is contiguous with at least a portion of the light absorbing semiconductor layer; and / or- the singlet fission layer is contiguous with at least a portion of the metal oxide layer.

14. The photovoltaic precursor device or the photovoltaic device according to any one of claims 1 to 13, wherein:- the device further comprises a second passivating layer on the opposite side of the light absorbing semiconductor layer to the singlet fission layer; and / or - the second passivation layer comprises silicon nitride (SiNx);15. The photovoltaic precursor device or the photovoltaic device according to any one of claims 1 to 14, wherein the light absorbing semiconductor layer is a n-type semiconductor layer, optionally comprising silicon and optionally substantially consisting of a n-type silicon.

16. The photovoltaic precursor device or the photovoltaic device according to any one of claims 1 to 14, wherein the light absorbing semiconductor layer is a p-type semiconductor layer, optionally the p-type semiconductor layer comprising silicon, and optionally wherein the n-type semiconductor layer substantially consists of a p-type silicon.

17. The photovoltaic precursor device or the photovoltaic device according to any one of claims 1 to 16, wherein for a compound of Formula (I), R1and R2are joined to form a compound of Formula (VI):OFormula (VI)wherein p is an integer of 5 to 100.

18. The photovoltaic precursor device or the photovoltaic device according to any one of claims 1 to 17, wherein at least one of R2, R3, R5and / or R6is independently selected from:4-CH2^ * -(-c=c-)-wherein:* denotes a point of attachmentq is an integer of from 1 to 100; andeach of Ra, Rb, Rc, and Rd is independently selected from: H, Ci_35alkyl, Ci_35heteroalkyl, C2.35alkenyl, C2.35alkynyl, C3.20carbocyclyl, C3.20heterocyclyl, C3.i8 aryl, and C5.i8heteroaryl, each of which is optionally substituted with one or more substituents selected C1-10alkyl, C2-10alkenyl, C2-10alkynyl, halogen, -CN, -OR9, -SR9, -S(O)2R9, -NR9R10, -NO2, =(O), =(S), =(N)R9, =(N)R10, -C(O)R9, -C(O)NR9R10, -C(O)SR9or -C(O)OR9; or with one or more groups selected from C3.6carbocyclyl, C3.6heterocyclyl, C3.6aryl, and C5-12heteroaryl, each of which is optionally substituted with one or more substituents selected from C1-6alkyl, halogen, -CN, -OR9, -SR9, -S(O)2R9, - NR9R10, -NO2, =(O), =(S), =(N)R9, =(N)R10, -C(O)R9, -C(O)NR9R10, - C(O)SR9or-C(O)OR9.

19. A method of forming an article, for use in a photovoltaic device, the method comprising:depositing a singlet fission layer compound on a substrate comprising a light absorbing semiconductor layer,wherein the singlet fission layer comprises at least one singlet fission compound of:- Formula (I) as defined in claim 1 or claim 2, or a dimer or trimer thereof, or an oligomer thereof;- a compound of Formula (IV) as defined in claim 1 or claim 2; and / or- a compound of Formula (V) as defined in claim 1 or claim 2.

20. The method of claim 19, wherein the dimer of a compound of Formula (I) is:- a compound of Formula (II) as defined by claim 3; or- a compound of Formula (Ila) as defined by claim 4; or- a compound of Formula (lib) as defined by claim 5.

21. The method of claim 19 or claim 20, wherein the trimer of a compound of Formula (I) is:- a compound of Formula (III) as defined by claim 6; or- a compound of Formula (Illa) as defined by claim 7; or- a compound of Formula (Illb) as defined by claim 8.

22. The method of any one of claims 19 to 21, wherein:- the method further comprises depositing a metal oxide layer, optionally by atomic layer deposition, on the substrate prior to deposition of the singlet fission compound, such that the metal oxide layer is disposed between the light absorbing semiconductor layer and the singlet fission compound; and / or - the method further comprises depositing a passivating layer, optionally by spin coating, such that the singlet fission layer is disposed between the substrate and the passivation layer; and / or- the depositing a singlet fission compound is by thermal evaporating; and / or - the absolute pressure (mbar) at which the thermal evaporating is performed is between about 0.0000001 to about 0.00001; and / or- the temperature (°C) at which the thermal evaporating is performed is between about 100 to about 150.

23. The method of any one of claims 19 to 22, wherein the depositing a singlet fission compound is by spin coating, wherein the spin coating comprises:- dissolving the singlet fission compound in a solvent to form a mixture- depositing the mixture on the substrate;-rotating the substrate to spread the mixture over at least a portion of the substrate, optionally the rotating the substrate is performed at a rotation speed (rpm) of between about 2000 to about 10000, or optionally the rotating the substrate is performed at a rotation speed (rpm) of between about 5000 to about 7000; andoptionally:- the method further comprises baking the substrate after the spin coating; and / or - the concentration (mg / ml) of the singlet fission compound in the mixture is between about 0.1 to about 10, or between about 0.5 to about 2; and / or- the solvent is selected from 1,4-di oxane, 2-methyltetrahydrofuran, diethyl ether, dimethoxyethane, acetonitrile, dimethylformamide, dimethyl sulfoxide, toluene, hexane, tetrahydrofuran, and mixtures thereof; and / or- the solvent is tetrahydrofuran; and / or- the time (min) for which baking is performed after the spin coating is between about 10 to about 30; and / or- the temperature (°C) at which baking is performed after the spin coating is between about 60 to about 100; and / or- the method further comprises depositing a second passivating layer of the substrate on the opposite side of the substrate to the singlet fission layer.

24. The method according to any one of claims 19 to 23, wherein the article is a device according to any one of claims 1 to 18.

25. An article produced according to the method of any one of claims 19 to 24.

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