Photoactive compounds

Abstract

A compound of formula (I): EAG—EDG—EAG (I) wherein EDG is an electron donating group comprising a polycyclic heteroaromatic group, and each EAG is an electron accepting group of formula (II): wherein R 10 is H or a substituent at each occurrence; ‑‑‑‑ is a bond to EDG; and each X 1 ‑X 4 Independently for CR 11 or N, where R 11 is H or a substituent at each occurrence, provided that X 1 ‑X 4 At least one occurrence of at least one of the above is N. The compound can be used as an acceptor in a bulk heterojunction layer of an organic photodetector.

Description

Technical Field

[0001] Embodiments of the present disclosure relate to photoactive compounds and their use in organic electronic devices, particularly organic photodetectors. Background Art

[0002] A range of organic electronic devices comprising organic semiconductor materials are known, including organic light emitting devices, organic field effect transistors, organic photovoltaic devices and organic photodetectors (OPDs).

[0003] WO 2018 / 065352 discloses an OPD having a photoactive layer, which contains a small molecule acceptor without a fullerene structure part and a conjugated copolymer electron donor having donor and acceptor units.

[0004] WO 2018 / 065356 discloses an OPD having a photoactive layer containing a small molecule acceptor without a fullerene structure part and a conjugated copolymer electron donor having randomly distributed donor and acceptor units.

[0005] Yao et al., “Design, Synthesis, and Photovoltaic Characterization of a Small Molecular Acceptor with an Ultra-Narrow Band Gap”, Angew Chem Int Ed Engl. 2017 Mar 6; 56(11): 3045-3049 discloses a non-fullerene acceptor with a band gap of 1.24 eV. Summary of the invention

[0006] The following is an overview of aspects of certain embodiments disclosed herein. It should be understood that these aspects are presented only to provide the reader with a brief overview of these embodiments, and these aspects are not intended to limit the scope of the present disclosure. In fact, the present disclosure may encompass a combination of multiple aspects and / or aspects that may not be described.

[0007] Embodiments of the present disclosure provide compounds of formula (I):

[0008] EAG—EDG—EAG

[0009] (I)

[0010] wherein EDG is an electron donating group comprising a polycyclic heteroaromatic group, and each EAG is an electron accepting group of formula (II):

[0011]

[0012] Where R 10 At each occurrence, H or a substituent;

[0013] ---- is the bond with EDG; and

[0014] Each X 1 -X 4 Independently for CR 11 or N, where R 11 is H or a substituent at each occurrence, provided that X 1 -X 4 At least one occurrence of at least one of is N.

[0015] The present inventors have discovered that compounds of formula (I) may be able to absorb long wavelength light, for example greater than 750 nm, optionally greater than 900 nm, optionally up to about 1500 nm, thereby allowing these compounds to be used in organic photodetectors, in particular in photosensors comprising such OPDs and near-infrared light sources.

[0016] Thus, in some embodiments, a composition is provided that includes an electron accepting (n-type) compound and an electron donor (p-type) compound as described herein.

[0017] In some embodiments, formulations are provided that include a composition described herein dissolved or dispersed in one or more solvents.

[0018] In some embodiments, an organic photodetector is provided, having: an anode; a cathode; and a photosensitive organic layer disposed between the anode and the cathode, wherein the photosensitive organic layer comprises a donor compound of formula (I) and an acceptor compound.

[0019] In some embodiments, a method of forming an organic photodetector as described herein is provided, the method comprising forming a photosensitive organic layer over one of an anode and a cathode, and forming the other of the anode and the cathode over the photosensitive organic layer.

[0020] In some embodiments, a circuit is provided that includes an organic photodetector as described herein, and at least one of: a voltage source for applying a reverse bias to the organic photodetector and a device configured to measure a photocurrent generated by the photodetector.

[0021] In some embodiments, a photosensor is provided that includes a light source and an organic light detector as described herein configured to detect light emitted from the light source.

[0022] In some embodiments, a method of determining the presence and / or concentration of a target material in a sample is provided, the method comprising illuminating the sample and measuring a response of an organic photodetector as described herein, the organic photodetector being configured to receive light emitted from the sample when illuminated. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] The disclosed technology and accompanying drawings describe some implementations of the disclosed technology.

[0024] Figure 1 shows an organic photodetector according to some embodiments; and

[0025] Figure 2 Absorption spectra of compounds according to some embodiments of the present disclosure and comparative compounds are shown.

[0026] The accompanying drawings are not drawn to scale and have various viewing angles and angles. The accompanying drawings are some embodiments and examples. In addition, for the purpose of discussing some embodiments of the disclosed technology, some components and / or operations may be divided into different blocks or combined into a single block. In addition, although the technology can be subjected to various modifications and alternative forms, specific embodiments are shown by way of example in the accompanying drawings, and the specific embodiments are described in detail below. However, the present invention is not intended to limit the technology to the specific embodiments described. On the contrary, the technology is intended to cover all modifications, equivalents and alternative forms that fall within the technical scope defined by the appended claims. DETAILED DESCRIPTION

[0027] Unless the context clearly requires otherwise, throughout the specification and claims, the words "include", "comprising", etc. should be interpreted as inclusive, rather than exclusive or exhaustive; that is, in the sense of "including but not limited to". As used herein, the terms "connected", "coupled", or any variation thereof, refer to any connection or coupling between two or more elements, whether direct or indirect; the coupling or connection between elements may be physical, logical, electromagnetic, or a combination thereof. In addition, when used in this application, the words "herein", "above", "below", and words of similar meaning refer to the application as a whole, not to any particular part of the application. Where the context permits, words in the detailed description that use the singular or plural may also include the plural or singular, respectively. The word "or" in a list involving two or more items covers all of the following interpretations of the word: any item in the list, all items in the list, and any combination of items in the list.

[0028] The teaching of the technology provided herein can be applied to other systems, not necessarily the system described below. The elements and actions of the various embodiments described below can be combined to provide other implementations of the technology. Some alternative implementations of the technology can include not only the additional elements of those embodiments mentioned below, but also fewer elements.

[0029] These and other changes can be made to the technology according to the following detailed description. Although the specification describes certain embodiments of the technology and describes the best mode considered, no matter how detailed the description is, the technology can be practiced in many ways. The details of the system may vary significantly in its specific implementation, and still be covered by the technology disclosed herein. As mentioned above, the specific terms used when describing certain features or aspects of the technology should not be considered to imply that the term is redefined herein as being limited to any specific characteristics, features or aspects of the technology associated with the term. Generally, the terms used in the following claims should not be interpreted as limiting the technology to the specific examples disclosed in the specification unless the detailed description section clearly defines these terms. Therefore, the actual scope of the technology not only covers the disclosed examples, but also includes all equivalent ways of practicing or implementing the technology under the claims.

[0030] In order to reduce the number of claims, certain aspects of the technology are presented below in certain claim forms, but applicants contemplate various aspects of the technology in any number of claim forms. For example, while some aspects of the technology may be stated as computer-readable medium claims, other aspects may be equally embodied as computer-readable medium claims, or in other forms, such as device-plus-function claims.

[0031] In the following description, for the purpose of explanation, numerous specific details are set forth in order to provide a thorough understanding of the embodiments of the disclosed technology. However, it will be apparent to one skilled in the art that the embodiments of the disclosed technology can be practiced without some of these specific details.

[0032] Figure 1 An OPD according to some embodiments of the present disclosure is shown. The OPD comprises a cathode 103, an anode 107, and a bulk heterojunction layer 105 disposed between the anode and the cathode. The OPD may be supported on a substrate 101, optionally a glass or plastic substrate.

[0033] Figure 1 One arrangement is shown in which the cathode is disposed between the substrate and the anode. In other embodiments, the anode may be disposed between the cathode and the substrate.

[0034] The bulk heterojunction layer comprises a mixture of electron acceptors and electron donors. Optionally, the bulk heterojunction layer consists of electron acceptors and electron donors.

[0035] Each of the anode and cathode may independently be a single conductive layer or may include multiple layers.

[0036] OPD can include Figure 1 In some embodiments, a hole transport layer is disposed between the anode and the bulk heterojunction layer. In some embodiments, an electron transport layer is disposed between the cathode and the bulk heterojunction layer. In some embodiments, a work function adjustment layer is disposed between the bulk heterojunction layer and the anode and / or between the bulk heterojunction layer and the cathode.

[0037] In use, a photodetector as described in the present disclosure may be connected to a voltage source that applies a reverse bias to the device and / or a device configured to measure photocurrent. The voltage applied to the photodetector may be variable. In some embodiments, the photodetector may be continuously biased when in use.

[0038] In some embodiments, a light detector system comprises a plurality of light detectors as described herein, such as an image sensor of a camera.

[0039] In some embodiments, a sensor may include a light source and an OPD as described herein, wherein the OPD is configured to receive light emitted from the light source.

[0040] In some embodiments, the light from the light source may or may not be altered before reaching the OPD. For example, the light may be filtered, down-converted, or up-converted before reaching the OPD.

[0041] In some embodiments, the peak wavelength of the light source is greater than 750 nm, optionally greater than 900 nm, optionally less than 1500 nm.

[0042] The bulk heterojunction layer may comprise an electron acceptor (n-type) compound of formula (I):

[0043] EAG—EDG—EAG

[0044] (I)

[0045] wherein EDG is an electron donating group comprising a polycyclic heteroaromatic group, and each EAG is an electron accepting group of formula (II):

[0046]

[0047] Where R 10 At each occurrence, H or a substituent;

[0048] ---- is the bond with EDG; and

[0049] Each X 1 -X 4 Independently for CR 11 or N, where R 11 is H or a substituent at each occurrence, provided that X 1 -X 4 At least one occurrence of at least one of is N.

[0050] Optionally, each X 3 is N.

[0051] Optionally, each X 1 , X 2 and X 4 CR 11 .

[0052] Optionally, each R 11 Independently selected from H and C 1-12 alkyl.

[0053] Each EAG of formula (II) has a deeper LUMO energy level (i.e., further away from vacuum) than EDG, preferably at least 1 eV deeper. The LUMO energy levels of EAG and EDG can be determined by modeling the LUMO energy levels of EAG-H and H-EDG-H, i.e., by replacing the bond between EAG and EDG with a bond to a hydrogen atom. Modeling can be performed using Gaussian09 software available from Gaussian, using a software package with B3LYP (functional) and LACVP * (basis set) of Gaussian09.

[0054] Optionally, the EDG comprises a fused heteroaromatic group comprising at least one fused thiophene. Optionally, the fused heteroaromatic group comprises or consists of a fused thiophene and one or both of a benzene and a cyclopentadiene group, each of which may independently be unsubstituted or substituted with one or more substituents. Each thiophene is optionally unsubstituted or substituted with one or more groups R other than H. 4 Each benzene is optionally unsubstituted or substituted with one or more groups R other than H 3 Each cyclopentadiene is optionally unsubstituted or substituted with one or more R 1 Group. R 1 , R 3 and R 4 As described below with respect to formula (Ia).

[0055] Optionally, EDG is selected from:

[0056]

[0057] Where R 1 , R 2 , R 4 and R 7 is independently at each occurrence as described below for formula (Ia).

[0058] Optionally, the compound of formula (I) has formula (Ia):

[0059]

[0060] in:

[0061] Ar is furan, thiophene or benzene, said furan, thiophene or benzene being unsubstituted or substituted with one or more substituents;

[0062] Each Y is independently O or S;

[0063] Each A is independently O, S or CR 1 R 2 , where R 1 and R 2 is independently at each occurrence a substituent;

[0064] Each R 4 -R 9 are independently H or a substituent;

[0065] p is 0, 1, 2 or 3;

[0066] q is 0, 1, 2, or 3;

[0067] Z 1 is a direct key or with R 4 or R 5 Together they form an aromatic or heteroaromatic group Ar 1 ;

[0068] Z 2 is a direct key or with R 7 or R 8 Together they form an aromatic or heteroaromatic group Ar 2 ;

[0069] Z 3 is a direct key or with R 6 Together they form an aromatic or heteroaromatic group Ar 3 ;and

[0070] Z 4 is a direct key or with R 9 Together they form an aromatic or heteroaromatic group Ar 4 .

[0071] In some embodiments, each Z 1 -Z4 It is a direct key.

[0072] In Z 1 -Z 4 One or more of them form an aromatic or heteroaromatic group Ar 1 -Ar 4 In one embodiment of the present invention, each Ar 1 -Ar 4 (When present) preferably it is thiophene.

[0073] Ar 1 -Ar 4 Each is independently unsubstituted or substituted with one or more substituents. 1 -Ar 4 The substituents are selected from C 1-12 Alkyl groups in which one or more non-adjacent non-terminal C atoms may be replaced by O, S, COO or CO.

[0074] Optionally, the compound of formula (I) has formula (Ib):

[0075]

[0076] Each R 3 is independently at each occurrence H or a substituent.

[0077] Optionally, the compound of formula (I) has formula (Ic):

[0078]

[0079] Where R 13 is independently at each occurrence H or a substituent, optionally H or C 1-12 Alkyl groups in which one or more non-adjacent non-terminal C atoms may be replaced by O, S, COO or CO.

[0080] Optionally, R of formula (Ia), (Ib) or (Ic) 1 and R 2 Independently selected at each occurrence from:

[0081] Straight chain, branched or cyclic C 1-20 Alkyl, in which one or more non-adjacent non-terminal C atoms may be replaced by O, S, NR 12 , CO or COO, where R 12 C 1-12 hydrocarbon group, and the C 1-20 One or more H atoms of the alkyl group may be replaced by F; and

[0082] Formula (Ak)u—(Ar 6)v, wherein Ak is C 1-12 an alkylene chain in which one or more C atoms may be replaced by O, S, CO or COO; u is 0 or 1; Ar 6 is independently at each occurrence an aromatic or heteroaromatic group, the aromatic or heteroaromatic group being unsubstituted or substituted with one or more substituents; and v is at least 1, optionally 1, 2 or 3.

[0083] Ar 6 Preferred is phenyl.

[0084] When present, Ar 6 The substituent may be a substituent R 14 , where R 14 In each occurrence, independently selected from C 1-20 Alkyl, in which one or more non-adjacent non-terminal C atoms may be replaced by O, S, NR 12 , CO or COO, and the C 1-20 One or more H atoms of the alkyl group may be replaced by F.

[0085] The hydrocarbon group as described anywhere herein is optionally selected from: 1-20 Alkyl; unsubstituted phenyl; and substituted with one or more C 1-12 Alkyl phenyl.

[0086] If v is 3 or greater, then –(Ar 6 )v can be Ar 6 The straight or branched chain of the group. 6 The linear chain of the group has only one monovalent terminal Ar 6 group, and Ar 6 The branched chain of the group has at least two monovalent terminal Ar 6 Group.

[0087] Optionally, R 1 and R 2 At least one of each occurrence is phenyl, optionally each R 1 and R 2 is phenyl, which is unsubstituted or substituted with one or more substituents selected from the R 14 .

[0088] Optionally, each R of formula (Ia) or (Ib) 4 -R 9 Independently selected from:

[0089] H;

[0090] C 1-12Alkyl groups in which one or more non-adjacent non-terminal C atoms may be replaced by O, S, COO or CO; and

[0091] Aromatic or heteroaromatic group Ar 5 , which is unsubstituted or substituted with one or more substituents.

[0092] Optionally, each R of formula (Ib) 3 is independently selected at each occurrence from:

[0093] H;

[0094] C 1-12 Alkyl groups in which one or more non-adjacent non-terminal C atoms may be replaced by O, S, COO or CO; and

[0095] Aromatic or heteroaromatic group Ar 5 , which is unsubstituted or substituted with one or more substituents.

[0096] Ar 5 Preferred is an aromatic group, more preferred is a phenyl group.

[0097] Ar 5 The one or more substituents, if present, may be selected from C 1-12 Alkyl groups in which one or more non-adjacent non-terminal C atoms may be replaced by O, S, COO or CO.

[0098] In some embodiments, each R 3 -R 10 H; C 1-20 Alkyl; or C 1-20 Alkoxy.

[0099] In some embodiments, R 5 and R 8 At least one of them is not H, optionally R 5 and R 8 Neither is H, and each R 3 , R 4 and R 6 -R 10 It's H.

[0100] As used herein, a "non-terminal" C atom of an alkyl group refers to a C atom of the alkyl group other than a methyl C atom of a straight (n-alkyl) chain or a methyl C atom of a branched alkyl chain.

[0101] Exemplary compounds of formula (I) are:

[0102]

[0103]

[0104]

[0105]

[0106] The compound of formula (I) may be used in combination with a fullerene acceptor.

[0107] The weight ratio of the compound of formula (I):fullerene acceptor may be in the range of about 1:0.1-1:1, preferably in the range of about 1:0.1-1:0.5.

[0108] Fullerenes can be C 60 , C 70 , C 76 , C 78 and C 84 Fullerene or its derivatives, including but not limited to: PCBM type fullerene derivatives (including phenyl-C61-butyric acid methyl ester (C 60 PCBM) and phenyl-C71-butyric acid methyl ester (C 70 PCBM)), TCBM type fullerene derivatives (e.g. tolyl-C61-butyric acid methyl ester (C 60 TCBM)) and ThCBM-type fullerene derivatives (e.g. thienyl-C61-butyric acid methyl ester (C 60 ThCBM).

[0109] When present, the fullerene acceptor may have the formula (III):

[0110]

[0111] wherein A together with the CC group of the fullerene forms a monocyclic or condensed ring group, which may be unsubstituted or substituted with one or more substituents.

[0112] Exemplary fullerene derivatives include formula (IIIa), (IIIb) and (IIIc):

[0113]

[0114] Where R 20 -R 32 Each is independently H or a substituent.

[0115] Substituent R 20 -R 32 is optionally and independently selected at each occurrence from: aryl or heteroaryl, optionally phenyl, which may be unsubstituted or substituted with one or more substituents; and C 1-20Alkyl groups in which one or more non-adjacent non-terminal C atoms may be replaced by O, S, CO or COO and one or more H atoms may be replaced by F.

[0116] The substituent R of the aryl or heteroaryl group 20 -R 32 (when present) optionally selected from C 1-12 Alkyl, wherein one or more non-adjacent non-terminal C atoms may be replaced by O, S, CO or COO, and one or more H atoms may be replaced by F.

[0117] The donor (p-type) compound is not particularly limited and can be appropriately selected from electron-donating materials known to those skilled in the art, including organic polymers and non-polymeric organic molecules. The HOMO of the p-type compound is deeper (farther away from vacuum) than the LUMO of the compound of formula (I). Optionally, the gap between the HOMO energy level of the p-type donor and the LUMO energy level of the n-type acceptor compound of formula (I) is less than 1.4 eV.

[0118] In a preferred embodiment, the p-type donor compound is an organic conjugated polymer, which may be a homopolymer or a copolymer, including alternating, random or block copolymers. Preferred are non-crystalline or semi-crystalline conjugated organic polymers. Further preferably, the p-type organic semiconductor is a conjugated organic polymer with a low band gap, typically between 2.5 eV and 1.5 eV, preferably between 2.3 eV and 1.8 eV.

[0119] Optionally, the HOMO energy level of the p-type donor is no more than 5.5 eV from the vacuum level. Optionally, the HOMO energy level of the p-type donor is at least 4.1 eV from the vacuum level.

[0120] As exemplary p-type donor polymers, there may be mentioned polymers selected from conjugated hydrocarbon or heterocyclic polymers, including polyacenes, polyanilines, polyazulenes, polybenzofurans, polyfluorenes, polyfurans, polyindenofluorenes, polyindoles, polyphenylenes, polypyrazolines, polypyrenes, polypyridazines, polypyridines, polytriarylamines, poly(phenylene vinylenes), poly(3-substituted thiophenes), poly(3,4-disubstituted thiophenes), polyselenophenes, poly(3-substituted selenophenes), poly(3,4-disubstituted thiophenes), polyselenophenes, poly(3-substituted selenophenes), poly(3,4-disubstituted thiophenes), polyselenophenes, poly(3-substituted selenophenes), poly(3,4-disubstituted thiophenes), polyselenophenes, poly(3,4-disubstituted thiophenes), polyselenophenes, poly(3,4-disubstituted thiophenes), polyselenophenes, poly(3,4-disubstituted thiophenes), polyselenophenes, poly(3,4-disubstituted thiophenes), polyselenophenes, polyselenophenes ... ,4-disubstituted selenophene), poly(dithiophene), poly(terthiophene), poly(diselenophene), poly(triselenophene), polythieno[2,3-b]thiophene, polythieno[3,2-b]thiophene, polybenzothiophene, polybenzo[1,2-b:4,5-b']dithiophene, polyisothionaphthene, poly(monosubstituted pyrrole), poly(3,4-disubstituted pyrrole), poly-1,3,4-oxadiazole, polyisothionaphthene, derivatives and copolymers thereof. Preferred examples of p-type donors are copolymers of polyfluorene and polythiophene (each of which may be substituted), and polymers comprising repeating units based on benzothiadiazole and repeating units based on thiophene (each of which may be substituted). It should be understood that the p-type donor may also be composed of a mixture of multiple electron-donating materials.

[0121] Optionally, the donor polymer comprises repeating units of formula (IV):

[0122]

[0123] Where R 50 and R 51 is independently at each occurrence H or a substituent.

[0124] Substituent R 50 and R 51 Can be selected from about R 4 and R 7 The groups other than H mentioned above.

[0125] Preferably, each R 50 In a preferred embodiment, R 50 The groups are connected to form the formula -Z 1 -C(R 52 )2-, wherein Z 1 O, NR 53 or C(R 52 )2; R 52 At each occurrence, H or a substituent, preferably with respect to R 1 The substituent is most preferably C 1-30 A hydrocarbon group; and R 53 is a substituent, preferably C 1-30 Hydrocarbon.

[0126] Preferably, each R51 For H.

[0127] Optionally, the donor polymer comprises repeating units of formula (V):

[0128]

[0129] Where R 54 is independently H or a substituent at each occurrence. Optionally, the substituent R 54 Selected from F, CN, NO2 and C 1-20 Alkyl, wherein one or more non-adjacent non-terminal C atoms may be replaced by O, S, CO or COO, and one or more H atoms may be replaced by F.

[0130] In some embodiments, the weight ratio of the donor compound to the acceptor compound is from about 1:0.5 to about 1:2.

[0131] Preferably, the weight ratio of the donor compound to the acceptor compound is about 1:1 or about 1:1.5.

[0132] At least one of the first electrode and the second electrode is transparent so that light incident on the device can reach the bulk heterojunction layer. In some embodiments, both the first electrode and the second electrode are transparent.

[0133] Each transparent electrode preferably has a transmittance of at least 70%, optionally at least 80%, for wavelengths in the range of 300-900 nm.

[0134] In some embodiments, one electrode is transparent and the other electrode is reflective.

[0135] Optionally, the transparent electrode comprises or consists of a layer of a transparent conductive oxide, preferably indium tin oxide or indium zinc oxide. In a preferred embodiment, the electrode may comprise poly 3,4-ethylenedioxythiophene (PEDOT). In other preferred embodiments, the electrode may comprise a mixture of PEDOT and polystyrene sulfonate (PSS). The electrode may consist of a layer of PEDOT:PSS.

[0136] Optionally, the reflective electrode may include a reflective metal layer. The reflective material may be aluminum or silver or gold. In some embodiments, a double layer electrode may be used. For example, the electrode may be an indium tin oxide (ITO) / silver double layer, an ITO / aluminum double layer, or an ITO / gold double layer.

[0137] The device may be formed by forming a bulk heterojunction layer over one of the anode and the cathode supported by a substrate, and depositing the other of the anode or the cathode over the bulk heterojunction layer.

[0138] The area of ​​the OPD can be less than about 3 cm2 , less than about 2cm 2 , less than about 1cm 2 , less than about 0.75cm 2 , less than about 0.5cm 2 or less than about 0.25 cm 2 The substrate may be, without limitation, a glass or plastic substrate. The substrate may be described as an inorganic semiconductor. In some embodiments, the substrate may be silicon. For example, the substrate may be a silicon wafer. If, in use, incident light is to be transmitted through the substrate and the electrode supported by the substrate, the substrate is transparent.

[0139] The substrate supporting one of the anode and cathode may or may not be transparent if incident light is to be transmitted through the other of the anode and cathode in use.

[0140] The bulk heterojunction layer may be formed by any process including, but not limited to, thermal evaporation and solution deposition methods.

[0141] Preferably, the bulk heterojunction layer is formed by depositing a formulation comprising an acceptor material and an electron donor material dissolved or dispersed in a solvent or a mixture of two or more solvents. The formulation may be deposited by any coating or printing method, including but not limited to spin coating, dip coating, roller coating, spray coating, blade coating, wire rod coating, slot coating, inkjet printing, screen printing, gravure printing, and flexographic printing.

[0142] The one or more solvents in the formulation may optionally comprise or consist of benzene substituted with a moiety selected from the group consisting of chlorine, C 1-10 Alkyl and C 1-10 One or more substituents of an alkoxy group, wherein two or more substituents may be linked to form a ring, which may be unsubstituted or substituted with one or more C 1-6 The alkyl group is optionally toluene, xylene, trimethylbenzene, tetramethylbenzene, anisole, indane and alkyl-substituted derivatives thereof, and tetralin and alkyl-substituted derivatives thereof.

[0143] The formulation may comprise a mixture of two or more solvents, preferably a mixture comprising at least one benzene substituted with one or more substituents as described above, and one or more other solvents. The one or more other solvents may be selected from esters, optionally alkyl or aryl esters of alkyl or aryl carboxylic acids, optionally C 1-10 Alkyl benzoate, benzyl benzoate or dimethoxybenzene. In a preferred embodiment, a mixture of trimethylbenzene and benzyl benzoate is used as the solvent. In other preferred embodiments, a mixture of trimethylbenzene and dimethoxybenzene is used as the solvent.

[0144] In addition to the electron acceptor, the electron donor and the one or more solvents, the formulation may also contain other components. As examples of such components, mention may be made of: binders, defoamers, deaerators, viscosity enhancers, diluents, adjuvants, flow improvers, colorants, dyes or pigments, sensitizers, stabilizers, nanoparticles, surface-active compounds, lubricants, wetting agents, dispersants and inhibitors.

[0145] The organic photodetectors described herein can be used in a wide range of applications, including but not limited to detecting the presence and / or brightness of ambient light, and in sensors comprising an organic photodetector and a light source. The photodetector can be configured so that light emitted from a light source is incident on the photodetector, and changes in the wavelength and / or brightness of the light can be detected, for example due to absorption and / or emission of light by a target material in a sample disposed in the light path between the light source and the organic photodetector. The sensor can be, but is not limited to: a gas sensor, a biosensor, an X-ray imaging device, an image sensor (e.g., a camera image sensor), a motion sensor (e.g., for security applications), a proximity sensor, or a fingerprint sensor. A 1D or 2D photoelectric sensor array can include a plurality of photodetectors as described herein in an image sensor. The photodetector can be configured to detect light emitted from a target analyte, which emits light when illuminated by a light source, or the target analyte is bound to a luminescent tag, which emits light when illuminated by a light source. The photodetector can be configured to detect the wavelength of light emitted by the target analyte or a luminescent tag bound thereto.

[0146] Example

[0147] synthesis

[0148] The electron acceptor group precursor (mixture of isomers) was prepared according to the following reaction scheme:

[0149]

[0150] Compound Example 1 is formed by reaction of an electron acceptor group precursor according to the following reaction scheme:

[0151]

[0152] Steps 1 and 2

[0153] Pyridine-3,4-dicarboxylic acid (10g, 59.8mmol) was refluxed for 30 minutes in acetic anhydride (70mL) under a nitrogen atmosphere. After cooling, trimethylamine (16.5mL, 119mmol) was added dropwise, and then tert-butyl 3-oxobutyrate (9.46g, 59.8mmol) was added dropwise, and the reaction mixture was stirred at room temperature for 18 hours. Volatiles were removed, leaving a crude material. The crude material was purified by silica gel column chromatography, eluted with 10% solution of methanol in DCM, and 12g of sticky solid was obtained. The material was dissolved in water and cooled in an ice bath. 1.5N HCl (100mL) and concentrated HCl (5mL) were added to acidify the mixture to pH 2-3. A brown precipitate was formed and separated by filtration. The solid was triturated twice with acetone, then filtered and dried. 5 g of this material was recrystallized from acetonitrile and placed in a freezer overnight to yield 2.9 g of crude bis-ketone.

[0154] Step 3

[0155] Malononitrile (7.79 g, 118 mmol) was dissolved in ethanol (300 mL) under a nitrogen atmosphere. Sodium acetate (8.07 g, 98.4 mmol) was added, and the mixture was stirred at room temperature for 1 hour. Crude stage 2 material (2.9 g) was added to the mixture in batches, and stirred for 16 hours. The reaction mixture was concentrated, and the crude product was placed in acetone (300 mL), and stirred for 4 hours. The solid was removed by filtration and the filtrate was concentrated to obtain 12 g of crude product. The crude product was purified by reverse phase column chromatography, eluted with 10% acetonitrile aqueous solution. The fraction containing the product was concentrated and placed in a freezer to obtain 600 mg. The product was suspended in 1.5 N HCl (25 mL), and placed in a freeze dryer. When completed, it was used in the next step without further purification.

[0156] Step 4

[0157] Under nitrogen atmosphere, thiophene core (400mg, 288μmol) and stage 3 material (562mg, 115μmol) were dissolved in chloroform. Pyridine (5mL) was added and the reaction was stirred at 65°C for 65 hours. After cooling, the solvent was removed and the crude residue was purified by silica gel column chromatography, eluting with a 2% solution of methanol in chloroform. The fraction containing the product was concentrated and triturated with acetonitrile for 3 hours. After filtration, the solid was precipitated twice from DCM / hexane (3 / 30mL), the solid was filtered out and dried to obtain 495mg of product. LCMS showed a purity of 98.31%.

[0158] Modeling Data

[0159] The LUMO energy level and HOMO-LUMO band gap of the compound of formula (Ib) were modeled, where R 1 , R 2 , R 5 and R 8 Each is a methyl group; R 3 , R 4 , R 6 , R 7 , R 9 and R 10 Each is H; and X 1 -X 4 As shown in Table 1.

[0160] For comparison, X in Formula (Ib) is also 1 -X 4 Compounds where the group is CH or CF replaced by F are modeled.

[0161] Quantum chemical modeling was performed using Gaussian09 software available from Gaussian using the B3LYP (functional) and LACVP * (basis set) of Gaussian09.

[0162] Table 1

[0163]

[0164]

[0165]

[0166] Referring to Table 1, model compound Examples 1 and 2 have deeper LUMOs (ie, farther from the vacuum level) and similar or smaller band gaps than model comparative compounds 1-3.

[0167] absorb

[0168] Figure 2 The absorption spectra of Compound Example 1 and Comparative Compound IEICO-4F are shown. The peak wavelength (786 nm) of Compound Example 1 is significantly longer than the peak wavelength (762 nm) of IEICO-4F.

[0169]

[0170] HOMO and LUMO energy levels

[0171] The HOMO and LUMO energy levels of the films of Compound Example 1 and Comparative Compound IEICO-4F were measured by square wave voltammetry (SWV). The results are listed in Table 2.

[0172] Having the structure of Compound Example 1 but each X 2 and X 3 Compared with the comparative compound IEICO-4F, which is also CF, the LUMO energy level of compound Example 1 is deeper and its HOMO-LUMO gap is smaller.

[0173] Table 2

[0174]

[0175] The HOMO and LUMO energy levels of the compounds reported herein were determined from films of the compounds using SWV at room temperature. In SWV, the current at the working electrode is measured while the potential between the working electrode and the reference electrode is swept linearly over time. The difference current between the forward pulse and the reverse pulse is plotted as a function of the potential to produce a voltammogram. An apparatus for measuring HOMO or LUMO energy levels by SWV may include a cell containing tert-butylammonium perchlorate or tert-butylammonium hexafluorophosphate in acetonitrile; a glassy carbon working electrode; a platinum counter electrode and a non-leaking Ag / AgCl reference electrode.

[0176] For calculation purposes, ferrocene was added directly to the existing cell at the end of the experiment, where the potentials for oxidation and reduction of ferrocene relative to Ag / AgCl were determined using cyclic voltammetry (CV).

[0177] equipment:

[0178] CHI 660D Potentiostat

[0179] 3mm diameter glassy carbon working electrode

[0180] Leak-free Ag / AgCl reference electrode

[0181] Pt wire auxiliary electrode or counter electrode

[0182] 0.1 M tetrabutylammonium hexafluorophosphate in acetonitrile.

[0183] method:

[0184] The sample was dissolved in toluene (3 mg / ml) and spin-coated directly onto the glassy carbon working electrode at 3000 rpm.

[0185] LUMO = 4.8 - E Ferrocene (peak to peak average) - E Sample reduction (peak maximum)

[0186] HOMO = 4.8-E ferrocene (peak-to-peak average) + E sample oxidation (peak maximum)

[0187] A typical SWV experiment was performed as follows: frequency of 15 Hz; amplitude of 25 mV and incremental step size of 0.004 V. Results of HOMO and LUMO data calculated from 3 freshly spin-coated film samples.

[0188] All experiments were performed under argon purge.

Claims

1. Compounds of formula (Ia): in: Ar is furan, thiophene, thienothiophene or benzene, said furan, thiophene, thienothiophene or benzene being unsubstituted or substituted with one or more substituents; Each Y is independently O or S; Each A is independently O, S or CR 1 R 2 , where R 1 and R 2 is independently at each occurrence a substituent; Each R 4 -R 9 are independently H or a substituent; p is 0, 1, 2 or 3; q is 0, 1, 2, or 3; Z 1 Is a direct key or with R 4 or R 5 Together they form an aromatic or heteroaromatic group Ar 1 ; Z 2 Is a direct key or with R 7 or R 8 Together they form an aromatic or heteroaromatic group Ar 2 ; Z 3 Is a direct key or with R 6 Together they form an aromatic or heteroaromatic group Ar 3 ;and Z 4 Is a direct key or with R 9 Together they form an aromatic or heteroaromatic group Ar 4 ; Where R 10 At each occurrence, H or a substituent; Each X 1 -X 4 Independently for CR 11 or N, where R 11 is H or a substituent at each occurrence, provided that X 1 -X 4 At least one occurrence of at least one of is N.

2. The compound according to claim 1, wherein each X 3 It is N.

3. The compound according to claim 2, wherein each X 1 , X 2 and X 4 CR 11 .

4. A compound according to any one of claims 1 to 3, wherein each R 11 Independently selected from H and C 1-12 alkyl.

5. The compound according to any one of claims 1 to 3, wherein the compound has formula (Ib): Each R 3 is independently at each occurrence H or a substituent.

6. The compound according to any one of claims 1 to 3, wherein R 1 and R 2 is independently selected at each occurrence from: Straight chain, branched or cyclic C 1-20 Alkyl, in which one or more non-adjacent non-terminal C atoms may be replaced by O, S, NR 12 , CO or COO, where R 12 C 1-12 hydrocarbon group, and the C 1-20 One or more H atoms of the alkyl group may be replaced by F; and Formula (Ak)u—(Ar 6 )v, wherein Ak is C 1-12 an alkylene chain in which one or more C atoms may be replaced by O, S, CO or COO; u is 0 or 1; Ar 6 is independently at each occurrence an aromatic or heteroaromatic group that is unsubstituted or substituted with one or more substituents; and v is at least 1.

7. The compound according to claim 6, wherein R 1 and R 2 At least one of them is a phenyl group, which is unsubstituted or substituted with one or more substituents selected from C 1-20 Alkyl, in which one or more non-adjacent non-terminal C atoms may be replaced by O, S, NR 12 , CO or COO, and the C 1-20 One or more H atoms of the alkyl group may be replaced by F.

8. The compound according to any one of claims 1 to 3, wherein each R 4 -R 9 Independently selected from: H； C 1-12 Alkyl groups in which one or more non-adjacent non-terminal C atoms may be replaced by O, S, COO or CO; and Aromatic or heteroaromatic group Ar 5 , which is unsubstituted or substituted with one or more substituents.

9. The compound according to claim 5, wherein each R 3 is independently selected at each occurrence from: H； C 1-12 Alkyl groups in which one or more non-adjacent non-terminal C atoms may be replaced by O, S, COO or CO; and Aromatic or heteroaromatic group Ar 5 , which is unsubstituted or substituted with one or more substituents.

10. A composition comprising a compound according to any one of claims 1 to 9 and an electron donating material capable of donating electrons to the compound.

11. A formulation comprising a compound according to any one of claims 1 to 9 or a composition according to claim 10 dissolved or dispersed in one or more solvents.

12. An organic light detector comprising: anode; cathode; and a photosensitive organic layer disposed between the anode and the cathode, wherein the photosensitive organic layer comprises the compound according to any one of claims 1 to 9.

13. A method of forming the organic photodetector of claim 12, comprising forming a photosensitive organic layer over one of the anode and cathode, and forming the other of the anode and cathode over the photosensitive organic layer.

14. The method of claim 13, wherein the formation of the photosensitive organic layer comprises deposition of a formulation according to claim 11 and evaporation of the one or more solvents. 15 . A photosensor comprising a light source and the organic light detector according to claim 12 , the organic light detector being configured to detect light emitted from the light source.

16. The photosensor of claim 15, wherein the light source emits light having a peak wavelength greater than 750 nm.

17. A photosensor according to claim 15 or 16, configured to receive a sample in an optical path between the organic light detector and the light source.

18. A method of determining the presence and / or concentration of a target material in a sample, the method comprising illuminating the sample and measuring a response of an organic light detector according to claim 12, the organic light detector being configured to receive light emitted from the sample when illuminated.

19. The method of claim 18, wherein the organic photodetector is an organic photodetector of a photosensor according to any one of claims 15-17.

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