WO2024115329A1

WO2024115329A1 - Compounds useful in the preparation of photoresponsive device

Info

Publication number: WO2024115329A1
Application number: PCT/EP2023/083051
Authority: WO
Inventors: Michal MACIEJCZYK; Florence BOURCET
Original assignee: Cambridge Display Technology Limited; Sumitomo Chemical Co., Ltd
Priority date: 2022-11-28
Filing date: 2023-11-24
Publication date: 2024-06-06
Also published as: GB2624716A; GB202217856D0

Abstract

A compound of formula (I) wherein: D is an electron-donating group; B¹ in each occurrence is independently a bridging group; n is at least 1; m is 0 or at least 1; p is 0 or 1; q is 0 or 1; A1 is a group represented by formula (II) wherein: R³ is independently H or a substituent; Y is C=O, C=S SO, SO₂, NR³³ or C(R³³)₂ wherein R³³ is CN or COOR⁴⁰; wherein R⁴⁰ in each occurrence is H or a substituent; and R⁴ in each occurrence is H or a substituent selected fromthe group consisting of C_1-20 hydrocarbyl and an electron withdrawing group, with the proviso that at least one R⁴ is CN.

Description

COMPOUNDS USEFUL IN THE PREPARATION OF PHOTORESPONSIVE DEVICE

BACKGROUND

Embodiments of the present disclosure relate to electron-accepting compounds and more specifically compounds suitable for use as an electron-accepting material in a photoresponsive device.

An organic photodetector may contain a photoactive layer of a blend of an electron-donating material and an electron- accepting material between an anode and a cathode. Known electronaccepting materials include fullerenes and non-fullerene acceptors (NFAs).

WO 2019/185580A1 describes organic semiconducting compounds.

WO 2015/044377A1 describes A-D-A compounds with a completely annelated midblock D and to the use thereof in optoelectronic components.

WO 2019/185578A1 describes organic semiconducting compounds.

US 2021/0336148A1 describes a semiconductor mixed material.

CN 110028488A describes an A-D-A type organic photovoltaic small molecule receptor.

CN111978335B describes a photovoltaic material.

Jia, Z et al, “High performance tandem organic solar cells via a strongly infrared-absorbing narrow bandgap acceptor”, Nat Commun, 2021, 12, 178 describes high performance tandem organic solar cells.

Qian Zhang et al, “Effect of 7t-bridges on the performance of indeno[l,2-b]fluorene- based non-fullerene small molecular acceptors”, Dyes and Pigments, 2019, 169, 22-28 describes two non-fullerene acceptors.

Jiefeng Hai et al, “Vinylene 7t-bridge: A simple building block for ultra-narrow bandgap nonfullerene acceptors enable 14.2% efficiency in binary organic solar cells” Dyes and Pigments, 2021, 188, 109171 describes designing ultra-NBG (ultra-narrow band gap) NFAs (nonfullerene acceptors). Xiaojun Li et al, “Synthesis and Photovoltaic Properties of a Series of Narrow Bandgap Organic Semiconductor Acceptors with Their Absorption Edge Reaching 900 nm” Chemistry of Materials, 2017, 29 (23), 10130- 10138 describes three n-OS (n-type organic semiconductor) acceptors.

Qunping Fan et al, “Vinylene-Inserted Asymmetric Polymer Acceptor with Absorption Approaching 1000 nm for Versatile Applications in All-Polymer Solar Cells and Photomultiplication-Type Polymeric Photodetectors” ACS Applied Materials & Interfaces, 2022, 14 (23), 26970-26977 describes an asymmetric PSMA (polymerized small-molecule acceptor).

SUMMARY

The present disclosure provides a compound of formula (I):

wherein: A² is a monovalent electron-accepting group; D is an electron-donating group; B¹ in each occurrence is independently a bridging group; n is at least 1; m is 0 or at least 1; p is 0 or 1; q is 0 or 1; A¹ is a group represented by formula (II):

wherein: R³ is independently H or a substituent; Y is C=O, C=S SO, SO2, NR³³ or C(R³³)2 wherein R³³ is CN or COOR⁴⁰; wherein R⁴⁰ in each occurrence is H or a substituent; and R⁴ in each occurrence is H or a substituent selected from the group consisting of Ci-20 hydrocarbyl and an electron withdrawing group, with the proviso that at least one R⁴ is CN.

The present disclosure provides a composition comprising an electron-donating material and an electron-accepting material wherein the electron accepting material is a compound as described herein.

The present disclosure provides an organic electronic device comprising an active layer comprising a compound or composition as described herein.

Optionally, the organic electronic device is an organic photoresponsive device comprising a photoactive layer disposed between an anode and a cathode and wherein the photoactive layer comprises a compound as described herein.

In some embodiments, the photoactive layer is a bulk heterojunction layer comprising a composition as described herein.

In some embodiments, the photoactive layer comprises two or more sub-layers including an electron-accepting sublayer comprising or consisting of a compound as described herein and an electron-donating sublayer comprising or consisting of an electron-donating material.

Optionally, the organic photoresponsive device is an organic photodetector.

The present disclosure provides a photosensor comprising a light source and an organic photodetector as described herein wherein the organic photodetector is configured to detect light emitted from the light source.

Optionally, the light source emits light having a peak wavelength of greater than 900 nm.

The present disclosure provides a formulation comprising a compound or composition as described herein dissolved or dispersed in one or more solvents.

The present disclosure provides a method of forming an organic electronic device as described herein wherein formation of the active layer comprises deposition of a formulation as described herein onto a surface and evaporation of the one or more solvents. DESCRIPTION OF DRAWINGS

The disclosed technology and accompanying figures describe some implementations of the disclosed technology.

Figure 1 illustrates an organic photoresponsive device according to some embodiments.

Figure 2 is the absorption spectra of a compound according to an embodiment of the disclosure and a comparative compound.

Figure 3 shows the EQE of a device comprising a compound according to an embodiment of the disclosure and a device comprising a comparative compound.

Figure 4 shows the current density of a device comprising a compound according to an embodiment of the disclosure.

Figure 5 shows the EQE of devices comprising a compound according to an embodiment of the disclosure.

Figure 6 shows the current density of devices comprising a compound according to an embodiment of the disclosure.

The drawings are not drawn to scale and have various viewpoints and perspectives. The drawings are some implementations and examples. Additionally, some components and/or operations may be separated into different blocks or combined into a single block for the purposes of discussion of some of the embodiments of the disclosed technology. Moreover, while the technology is amenable to various modifications and alternative forms, specific embodiments have been shown by way of example in the drawings and are described in detail below. The intention, however, is not to limit the technology to the particular implementations described. On the contrary, the technology is intended to cover all modifications, equivalents, and alternatives falling within the scope of the technology as defined by the appended claims.

DETAILED DESCRIPTION

Unless the context clearly requires otherwise, throughout the description and the claims, the words "comprise," "comprising," and the like are to be construed in an inclusive sense, as opposed to an exclusive or exhaustive sense; that is to say, in the sense of "including, but not limited to." Additionally, the words "herein," "above," "below," and words of similar import, when used in this application, refer to this application as a whole and not to any particular portions of this application. Where the context permits, words in the Detailed Description using the singular or plural number may also include the plural or singular number respectively. The word "or," in reference to a list of two or more items, covers all of the following interpretations of the word: any of the items in the list, all of the items in the list, and any combination of the items in the list. References to a layer “over” another layer when used in this application means that the layers may be in direct contact or one or more intervening layers may be present. References to a layer “on” another layer when used in this application means that the layers are in direct contact. References to a specific atom include any isotope of that atom unless specifically stated otherwise.

The teachings of the technology provided herein can be applied to other systems, not necessarily the system described below. The elements and acts of the various examples described below can be combined to provide further implementations of the technology. Some alternative implementations of the technology may include not only additional elements to those implementations noted below, but also may include fewer elements.

These and other changes can be made to the technology in light of the following detailed description. While the description describes certain examples of the technology, and describes the best mode contemplated, no matter how detailed the description appears, the technology can be practiced in many ways. As noted above, particular terminology used when describing certain features or aspects of the technology should not be taken to imply that the terminology is being redefined herein to be restricted to any specific characteristics, features, or aspects of the technology with which that terminology is associated. In general, the terms used in the following claims should not be construed to limit the technology to the specific examples disclosed in the specification, unless the Detailed Description section explicitly defines such terms. Accordingly, the actual scope of the technology encompasses not only the disclosed examples, but also all equivalent ways of practicing or implementing the technology under the claims.

To reduce the number of claims, certain aspects of the technology are presented below in certain claim forms, but the applicant contemplates the various aspects of the technology in any number of claim forms. In the following description, for the purposes of explanation, numerous specific details are set forth in order to provide a thorough understanding of implementations of the disclosed technology. It will be apparent, however, to one skilled in the art that embodiments of the disclosed technology may be practiced without some of these specific details.

It has been found that compounds according to formula (I) which comprise a vinylene group bonded to an A¹ group according to formula (II) have a surprisingly high peak wavelength in their absorption spectra relative to compounds that do not comprise a vinylene group bonded to an A¹ group according to formula (II).

Each of the electron-accepting groups A¹ and A² has a lowest unoccupied molecular orbital (LUMO) level that is deeper (i.e., further from vacuum) than the LUMO of any of the electrondonating groups D, preferably at least 1 eV deeper. The LUMO levels of electron- accepting groups and electron-donating groups may be as determined by modelling the LUMO level of these groups, in which each bond to adjacent group is replaced with a bond to a hydrogen atom. Modelling may be performed using Gaussian09 software available from Gaussian using Gaussian09 with B3LYP (functional) and LACVP* (Basis set).

The present disclosure provides a compound of formula (I):

wherein: A² is a monovalent electron-accepting group; D is an electron-donating group; B¹ in each occurrence is independently a bridging group; n is at least 1; m is 0 or at least 1; p is 0 or 1; q is 0 or 1; A¹ is a group represented by formula (II)

In some embodiments, R⁴ in each occurrence is H or an electron withdrawing group, with the proviso that at least one R⁴ is CN. Optionally, R⁴ in each occurrence is an electron withdrawing group selected from the group consisting of Ci-12 esters (such as C1-6 esters), Ci-12 ketones (such as C1-6 ketones), CF3, halogen, NO2, and CN, with the proviso that at least one R⁴ is CN. For example, two R⁴s are a substituent, optionally wherein the two R⁴s are CN.

In some embodiments, when one or more R⁴ is a substituent, each R⁴ is an electron withdrawing group selected from the group consisting of Ci-12 esters (such as C1-6 esters), Ci-12 ketones (such as C1-6 ketones), CF3, halogen, NO2, and CN, with the proviso that at least one R⁴ is CN.

Preferably, when one or more R⁴ is a substituent, each R⁴ is a halogen or CN, with the proviso that at least one R⁴ is CN. More preferably, when one or more R⁴ is a substituent, each R⁴ is CN.

In some embodiments, n is 1, 2, 3, 4, or 5. Optionally, n is at least 1, 2, 3 or 4. Optionally, n is 1, 2, or 3. Preferably, n is 1 or 2.

In some embodiments m is independently 0, 1, 2, 3, 4, or 5. Optionally, m is at least 0, 1, 2, 3 or 4. Optionally, m is 1, 2, or 3. Preferably, m is 1 or 2.

In some embodiments, n and m are the same. Alternatively, n and m are different. In some embodiments, p and q are the same. Alternatively, p and q are different.

Electron- Accepting Group A²

The monovalent acceptor group A² may independently be selected from any such units known to the skilled person. A² may be the same or different to A¹, preferably the same. Exemplary monovalent acceptor groups A² include, without limitation, groups of formulae (IXa)-(IXq)

Rio , (IXq)

U is a 5- or 6-membered ring which is unsubstituted or substituted with one or more substituents and which may be fused to one or more further rings.

G is C=O, C=S SO, SO₂, NR³³ or C(R³³)₂ wherein R³³ is CN or COOR⁴⁰. G is preferably C=O or SO2, more preferably C=O.

Optionally, each R⁶ of any NR⁶ or PR⁶ described anywhere herein is independently selected from H; Ci -20 alkyl wherein one or more non-adjacent C atoms other than the C atom bound to N or P may be replaced with O, S, NR¹¹, COO or CO and one or more H atoms of the alkyl may be replaced with F; and phenyl which is unsubstituted or substituted with one or more substituents, optionally one or more Ci-12 alkyl groups wherein one or more non-adjacent C atoms of the alkyl may be replaced with O, S, NR¹¹, COO or CO and one or more H atoms of the alkyl may be replaced with F wherein R¹¹ is H or a Ci-2ohydrocarbyl group.

A Ci -20 hydrocarbyl group as described anywhere is preferably selected from Ci-20 alkyl; unsubstituted phenyl; and phenyl substituted with one or more Ci-12 alkyl groups

The N atom of formula (IXe) may be unsubstituted or substituted.

R¹⁰ is H or a substituent, preferably a substituent selected from the group consisting of Ci-12 alkyl wherein one or more non-adjacent C atoms may be replaced with O, S, NR⁶, COO or CO and one or more H atoms of the alkyl may be replaced with F; and an aromatic group, optionally phenyl, which is unsubstituted or substituted with one or more substituents selected from F and C1-12 alkyl wherein one or more non-adjacent C atoms may be replaced with O, S, NR⁶, COO or CO.

Preferably, R¹⁰ is H.

J is O or S, preferably O. R¹³ in each occurrence is a substituent, optionally Ci-12 alkyl wherein one or more non-adjacent C atoms may be replaced with O, S, NR⁶, COO or CO and one or more H atoms of the alkyl may be replaced with F.

R¹⁵ in each occurrence is independently H; F; Ci-12 alkyl wherein one or more non-adjacent C atoms may be replaced with O, S, NR⁶, COO or CO and one or more H atoms of the alkyl may be replaced with F; aromatic group Ar², optionally phenyl, which is unsubstituted or substituted with one or more substituents selected from F and Ci-12 alkyl wherein one or more non-adjacent C atoms may be replaced with O, S, NR⁶, COO or CO; or a group selected from:

R¹⁶ is H or a substituent, preferably a substituent selected from:

-(Ar³)_w wherein Ar³ in each occurrence is independently an unsubstituted or substituted aryl or heteroaryl group, preferably thiophene, and w is 1, 2 or 3;

and

C1-12 alkyl wherein one or more non-adjacent C atoms may be replaced with O, S, NR⁶, COO or CO and one or more H atoms of the alkyl may be replaced with F.

Ar⁶ is a 5-membered heteroaromatic group, preferably thiophene or furan, which is unsubstituted or substituted with one or more substituents.

Substituents of Ar³ and Ar⁶, where present, are optionally selected from Ci-12 alkyl wherein one or more non-adjacent C atoms may be replaced with O, S, NR⁶, COO or CO and one or more H atoms of the alkyl may be replaced with F. T¹, T² and T³ each independently represent an aryl or a heteroaryl ring, optionally benzene, which may be fused to one or more further rings. Substituents of T¹, T² and T³, where present, are optionally selected from non-H groups of R²⁵. In a preferred embodiment, T³ is benzo thiadiazole . z¹ is N or P.

Ar⁸ is a fused heteroaromatic group which is unsubstituted or substituted with one or more substituents, optionally one or more non-H substituents R¹⁰, and which is bound to an aromatic C atom of B¹ and to a boron substituent of B¹.

Preferably A² is a group of formula

(IXa-1) wherein:

G is as described above and is preferably C=O or SO2, more preferably C=O;

R¹⁰ is as described above;

Ar⁹ is an unsubstituted or substituted monocyclic or fused aromatic or heteroaromatic group, preferably benzene or a monocyclic or bicyclic heteroaromatic group having C or N ring atoms only; and

X⁶⁰ are each independently CN, CF3 or COOR⁴⁰ wherein R⁴⁰ in each occurrence is H or a substituent, preferably H or a Ci-2ohydrocarbyl group. Preferably, each X⁶⁰ is CN.

Ar⁹ may be unsubstituted or substituted with one or more substituents. Substituents of Ar⁹ are preferably selected from groups R¹² as described below.

Optionally, the group of formula (IXa-1) has formula (IXa-2):

each X⁷-X¹⁰ is independently CR¹² or N wherein R¹² in each occurrence is H or a substituent selected from Ci-20 hydrocarbyl and an electron withdrawing group. Preferably, the electron withdrawing group is F, Cl, Br or CN, more preferably F, Cl or CN; and for example F or CN.

The Ci -20 hydrocarbyl group R¹² may be selected from Ci-20 alkyl; unsubstituted phenyl; and phenyl substituted with one or more Ci-12 alkyl groups.

In a particularly preferred embodiment, each of X⁷-X¹⁰ is CR¹² and each R¹² is independently selected from H or an electron-withdrawing group, preferably H, F or CN. According to his embodiment, R¹² of X⁸ and X⁹ is an electron-withdrawing group, preferably F or CN.

Exemplary groups of formula (IXd) include:

Exemplary groups of formula (IXe) include:

An exemplary group of formula (IXq) is:

An exemplary group of formula (IXg) is:

An exemplary group of formula (IXj) is:

wherein Ak is a Ci-12 alkylene chain in which one or more C atoms may be replaced with O, S, NR⁶, CO or COO; An is an anion, optionally -SO3’; and each benzene ring is independently unsubstituted or substituted with one or more substituents selected from substituents described with reference to R¹⁰. Exemplary groups of formula (IXm) are:

An exemplary group of formula (IXn) is:

Groups of formula (IXo) are bound directly to a bridging group B¹ substituted with a group of formula -B(R¹⁴)2 wherein R¹⁴ in each occurrence is a substituent, optionally a Ci-2ohydrocarbyl group; — is a bond to the boron atom -B(R¹⁴)2; and — is a C-C bond between formula (IXo) and the bridging group.

Optionally, R¹⁴ is selected from Ci-12 alkyl; unsubstituted phenyl; and phenyl substituted with one or more Ci-12 alkyl groups.

The group of formula (IXo), the B¹ group and the B(R¹⁴)2 substituent of B¹ may be linked together to form a 5- or 6-membered ring. Optionally groups of formula (IXo) are selected from:

In some embodiments A² is a group represented by formula (II)

wherein: R³, Y and R⁴ are each independently the same as defined in relation to formula (II) of A¹. A¹ and A² may be the same or different.

For example, when A² is a group represented by formula (II), in formula (II) of A², R³ is H or a substituent; Y is independently C=O, C=S SO, SO2, NR³³ or C(R³³)2 wherein R³³ is CN or COOR⁴⁰; wherein R⁴⁰ in each occurrence is H or a substituent; R⁴ in each occurrence is H or a substituent selected from the group consisting of Ci-20 hydrocarbyl and an electron withdrawing group, with the proviso that at least one R⁴ is CN.

In some embodiments, R⁴ in each occurrence is H or an electron withdrawing group, with the proviso that at least one R⁴ is CN. Optionally, R⁴ in each occurrence is an electron withdrawing group selected from the group consisting of halogen, NO2, and CN, with the proviso that at least one R⁴ is CN. For example, two R⁴s are a substituent, optionally wherein the two R⁴s are CN.

In some embodiments, when one or more R⁴ is a substituent, each R⁴ is an electron withdrawing group selected from the group consisting of halogen, NO2, and CN, with the proviso that at least one R⁴ is CN.

Preferably, when one or more R⁴ is a substituent, each R⁴ is a halogen or CN, with the proviso that at least one R⁴ is CN. More preferably, when one or more R⁴ is a substituent, each R⁴ is CN. Unless otherwise specified, any substituent described herein may be independently selected from the group consisting of Ci-12 alkyl wherein one or more non-adjacent C atoms may be replaced with O, S, NR⁶, COO or CO and one or more H atoms of the alkyl may be replaced with F; and an aromatic group, optionally phenyl, which is unsubstituted or substituted with one or more substituents selected from F and Ci-12 alkyl wherein one or more non-adjacent C atoms may be replaced with O, S, NR⁶, COO or CO; and wherein NR⁶ is as described herein. For example, R⁴⁰ as described herein may be a substituent as described herein.

If a C atom of an alkyl group as described anywhere herein is replaced with another atom or group, the replaced C atom may be a terminal C atom of the alkyl group or a non-terminal C- atom.

By “non-terminal C atom” of an alkyl group as used anywhere herein means a C atom other than the C atom of the methyl group at the end of an n-alkyl chain or the C atoms of the methyl groups at the ends of a branched alkyl chain.

If a terminal C atom of a group as described anywhere herein is replaced then the resulting group may be an anionic group comprising a countercation, e.g., an ammonium or metal countercation, preferably an ammonium or alkali metal cation.

A C atom of an alkyl substituent group which is replaced with another atom or group as described anywhere herein is preferably a non-terminal C atom, and the resultant substituent group is preferably non-ionic.

Bridging units

Bridging units B¹ are preferably each selected from arylene or heteroarylene wherein the arylene and heteroarylene groups are monocyclic or bicyclic groups, each of which may be unsubstituted or substituted with one or more substituents.

Optionally, B¹ is selected from units of formulae (Via) - (VIo):

(Via) (VIb) (Vic)

wherein R⁵⁵ is H or a substituent, optionally H or a Ci-20 hydrocarbyl group; and R⁸ in each occurrence is independently H or a substituent, preferably H or a substituent selected from F; CN; NO₂; Ci -20 alkyl wherein one or more non-adjacent C atoms may be replaced with O, S, NR⁶, COO or CO and one or more H atoms of the alkyl may be replaced with F; phenyl which is unsubstituted or substituted with one or more substituents; and -B(R¹⁴)2 wherein R¹⁴ in each occurrence is a substituent, optionally a C 1-20 hydrocarbyl group.

R⁸ groups of formulae (Via), (VIb) and (Vic) may be linked to form a bicyclic ring which may be substituted with one or more substituents, optionally one or more substituents selected from F; CN; NO₂; Ci -20 alkyl wherein one or more non-adjacent C atoms may be replaced with O, S, NR⁶, COO or CO and one or more H atoms of the alkyl may be replaced with F.

R⁸ is preferably H, Ci-20 alkyl or Ci-19 alkoxy. R⁸ groups of formulae (Via), (VIb) and (Vic) may be linked to form an optionally substituted bicyclic ring.

Electron-Donating Groups D

Electron-donating groups preferably are fused aromatic or heteroaromatic groups, more preferably fused heteroaromatic groups containing three or more rings. Particularly preferred electron-donating groups comprise fused thiophene or furan rings, optionally fused rings containing thiophene or furan rings and one or more rings selected from benzene, cyclopentadiene, tetrahydropyran, tetrahydrothiopyran and piperidine rings, each of said rings being unsubstituted or substituted with one or more substituents. Exemplary electron-donating groups D include groups of formulae (Vlla)-(VIIm):

wherein Y^A in each occurrence is independently O, S or NR⁵⁵, Y^A1 in each occurrence is independently O or S; Z^A in each occurrence is O, CO, S, NR⁵⁵ or C(R⁵⁴ ; R⁵¹, R⁵² R⁵⁴ and R⁵⁵ independently in each occurrence is H or a substituent; R⁵³ independently in each occurrence is a substituent; and Ar⁴ is an optionally substituted monocyclic or fused heteroaromatic group. Optionally, R⁵¹ and R⁵² independently in each occurrence are selected from H; F; Ci-20 alkyl wherein one or more non-adjacent C atoms may be replaced with O, S, NR⁶, COO or CO and one or more H atoms of the alkyl may be replaced with F; and an aromatic or heteroaromatic group Ar³ which is unsubstituted or substituted with one or more substituents.

In some embodiments, Ar³ may be an aromatic group, e.g., phenyl.

Ar⁴ is preferably selected from optionally substituted oxadiazole, thiadiazole, triazole, and 1,4- diazine. In the case where Ar⁴ is 1,4-diazine, the 1,4-diazine may be fused to a further heterocyclic group, optionally a group selected from optionally substituted oxadiazole, thiadiazole, triazole, 1,4-diazine and succinimide.

The one or more substituents of Ar³, if present, may be selected from Ci-12 alkyl wherein one or more non-adjacent C atoms may be replaced with O, S, NR⁶, COO or CO and one or more H atoms of the alkyl may be replaced with F.

Preferably, each R⁵⁴ is selected from the group consisting of:

H;

F; linear, branched or cyclic Ci-20 alkyl wherein one or more non-adjacent C atoms may be replaced by O, S, NR¹⁷, CO or COO wherein R¹⁷ is a C1-12 hydrocarbyl and one or more H atoms of the Ci-20 alkyl may be replaced with F; and a group of formula (Ak)u-(Ar⁷)v wherein Ak is a Ci-20 alkylene chain in which one or more non-adjacent C atoms may be replaced with O, S, NR⁶, CO or COO; u is 0 or 1; Ar⁷ in each occurrence is independently an aromatic or heteroaromatic group which is unsubstituted or substituted with one or more substituents; and v is at least 1, optionally 1, 2 or 3.

Substituents of Ar⁷, if present, are preferably selected from F; Cl; NO2; CN; and Ci-20 alkyl wherein one or more non-adjacent C atoms may be replaced with O, S, NR⁶, CO or COO and one or more H atoms may be replaced with F. Preferably, Ar⁷ is phenyl.

Preferably, each R⁵¹ is H.

Optionally, R⁵³ independently in each occurrence is selected from Ci-20 alkyl wherein one or more non-adjacent C atoms may be replaced with O, S, NR⁶, COO or CO and one or more H atoms of the alkyl may be replaced with F; and phenyl which is unsubstituted or substituted with one or more substituents, optionally one or more Ci-12 alkyl groups wherein one or more non-adjacent C atoms may be replaced with O, S, NR⁶, COO or CO and one or more H atoms of the alkyl may be replaced with F.

Preferably, R⁵⁵ as described anywhere herein is H or Ci-3ohydrocarbyl group. In a preferred embodiment, D¹ of the compound of formula (I) is a group of formula (Vile).

Exemplary compounds of formula (I) include, without limitation:

wherein R in each occurrence is independently a Ci-12 alkyl group or Ci-12 alkoxy group.

5 Electron-donating material A photoactive layer as described herein comprises an electron-donating material. The photoactive layer may be a bulk heterojunction layer comprising an electron-donating material and a compound of formula (I) as described herein. The photoactive layer may comprise two or more sub-layers including an electron-donating sub-layer comprising or consisting of an electron-donating material.

Exemplary donor materials are disclosed in, for example, WO2013/051676, the contents of which are incorporated herein by reference.

The electron-donating material may be a non-poly meric or polymeric material.

In a preferred embodiment the electron-donating material is an organic conjugated polymer, which can be a homopolymer or copolymer including alternating, random or block copolymers. The conjugated polymer is preferably a donor- acceptor polymer comprising alternating electron-donating repeat units and electron- accepting repeat units.

Preferred are non-crystalline or semi- crystalline conjugated organic polymers.

Further preferably the electron-donating polymer is a conjugated organic polymer with a low bandgap, typically between 2.5 eV and 1.5 eV, preferably between 2.3 eV and 1.8 eV.

Optionally, the electron-donating polymer has a HOMO level no more than 5.5 eV from vacuum level. Optionally, the electron-donating polymer has a HOMO level at least 4.1 eV from vacuum level. As exemplary electron-donating polymers, polymers selected from conjugated hydrocarbon or heterocyclic polymers including polyacene, polyaniline, polyazulene, polybenzofuran, polyfluorene, polyfuran, polyindenofluorene, polyindole, polyphenylene, polypyrazoline, polypyrene, polypyridazine, polypyridine, polytriarylamine, poly(phenylene vinylene), poly(3-substituted thiophene), poly(3,4-bisubstituted thiophene), polyselenophene, poly(3-substituted selenophene), poly(3,4- bisubstituted selenophene), poly(bisthiophene), poly(terthiophene), poly(bisselenophene), poly(terselenophene), polythieno[2,3-b]thiophene, poly thieno [3, 2-b] thiophene, polybenzothiophene, polybenzo [1,2- b:4,5-b']dithiophene, polyisothianaphthene, poly(monosubstituted pyrrole), poly(3,4- bisubstituted pyrrole), poly-1, 3, 4-oxadiazoles, polyisothianaphthene, derivatives and copolymers thereof may be mentioned. Preferred examples of donor polymers are copolymers of polyfluorenes and poly thiophenes, each of which may be substituted, and polymers comprising benzothiadiazole-based and thiophene-based repeating units, each of which may be substituted.

A particularly preferred donor polymer comprises a repeat unit of formula (X):

wherein Y^A, Z^A, R⁵¹ and R⁵⁴ are as described above.

Another particularly preferred donor polymer comprises repeat units of formula (XI):

wherein R¹⁸ and R¹⁹ are each independently selected from H; F; Ci-12 alkyl wherein one or more non-adjacent, non-terminal C atoms may be replaced with O, S, COO or CO and one or more H atoms of the alkyl may be replaced with F; or an aromatic or heteroaromatic group Ar⁶ which is unsubstituted or substituted with one or more substituents selected from F and Ci-12 alkyl wherein one or more non-adjacent, non-terminal C atoms may be replaced with O, S, COO or CO.

The donor polymer is preferably a donor-acceptor (DA) copolymer comprising a donor repeat unit, for example a repeat unit of formula (X) or (XI), and an acceptor repeat unit, for example divalent electron- accepting units A² as described herein provided as polymeric repeat units.

Organic Electronic Device A compound of formula (I) may be provided as an active layer of an organic electronic device. In a preferred embodiment, a photoactive layer of an organic photoresponsive device, more preferably an organic photodetector, comprises a compound of formula (I).

In some embodiments, the photoactive layer is a bulk heterojunction layer comprising or consisting of an electron-donating material and an electron-accepting compound of formula (I) as described herein.

In some embodiments, the bulk heterojunction layer contains two or more electron-donating materials and / or two or more electron- accepting materials.

In some embodiments, the weight of the electron-donating material(s) to the electron- accepting material(s) is from about 1:0.5 to about 1:2, preferably about 1:1.1 to about 1:2.

Preferably, the electron-donating material has a type II interface with the electron-accepting material, i.e. the electron-donating material has a shallower HOMO and LUMO that the corresponding HOMO and LUMO levels of the electron- accepting material. Preferably, the compound of formula (I) has a HOMO level that is at least 0.05 eV deeper, optionally at least 0.10 eV deeper, than the HOMO of the electron-donating material.

Optionally, the gap between the HOMO level of the electron-donating material and the LUMO level of the electron- accepting compound of formula (I) is less than 1.4 eV.

Unless stated otherwise, HOMO and LUMO levels of materials as described herein are as measured by square wave voltammetry (SWV).

In SWV, the current at a working electrode is measured while the potential between the working electrode and a reference electrode is swept linearly in time. The difference current between a forward and reverse pulse is plotted as a function of potential to yield a voltammogram. Measurement may be with a CHI 660D Potentiostat.

The apparatus to measure HOMO or LUMO energy levels by SWV may comprise a cell containing 0.1 M tertiary butyl ammonium hexafluorophosphate in acetonitrile; a 3 mm diameter glassy carbon working electrode; a platinum counter electrode and a leak free Ag/AgCl reference electrode. Ferrocene is added directly to the existing cell at the end of the experiment for calculation purposes where the potentials are determined for the oxidation and reduction of ferrocene versus Ag/AgCl using cyclic voltammetry (CV).

The sample is dissolved in toluene (3 mg / ml) and spun at 3000 rpm directly on to the glassy carbon working electrode.

LUMO = 4.8-E ferrocene (peak to peak average) - E reduction of sample (peak maximum).

HOMO = 4.8-E ferrocene (peak to peak average) + E oxidation of sample (peak maximum).

A typical SWV experiment runs at 15 Hz frequency; 25 mV amplitude and 0.004 V increment steps. Results are calculated from 3 freshly spun film samples for both the HOMO and LUMO data.

Figure 1 illustrates an organic photoresponsive device according to some embodiments of the present disclosure. The organic photoresponsive device comprises a cathode 103, an anode 107 and a bulk heterojunction layer 105 disposed between the anode and the cathode. The organic photoresponsive device may be supported on a substrate 101, optionally a glass or plastic substrate.

Each of the anode and cathode may independently be a single conductive layer or may comprise a plurality of layers.

At least one of the anode and cathode is transparent so that light incident on the device may reach the bulk heterojunction layer. In some embodiments, both of the anode and cathode are transparent. The transmittance of a transparent electrode may be selected according to an emission wavelength of a light source for use with the organic photodetector.

Figure 1 illustrates an arrangement 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.

The organic photoresponsive device may comprise layers other than the anode, cathode and bulk heterojunction layer shown in Figure 1. In some embodiments, a hole-transporting layer is disposed between the anode and the bulk heterojunction layer. In some embodiments, an electron-transporting layer is disposed between the cathode and the bulk heterojunction layer. In some embodiments, a work function modification layer is disposed between the bulk heterojunction layer and the anode, and/or between the bulk heterojunction layer and the cathode.

Photoactive layer 105 of Figure 1 is a bulk heterojunction layer. In other embodiments, the photoactive layer comprises or consists of an electron-accepting sub-layer comprising or consisting of a compound of formula (I) and an electron-donating sub-layer comprising an electron-donating material.

The area of the OPD may be less than about 3 cm², less than about 2 cm², less than about 1 cm², less than about 0.75 cm², less than about 0.5 cm² or less than about 0.25 cm². Optionally, each OPD may be part of an OPD array wherein each OPD is a pixel of the array having an area as described herein, optionally an area of less than 1 mm², optionally in the range of 0.5 micron² - 900 micron².

The substrate may be, without limitation, a glass or plastic substrate. The substrate can be an inorganic semiconductor. In some embodiments, the substrate may be silicon. For example, the substrate can be a wafer of silicon. The substrate is transparent if, in use, incident light is to be transmitted through the substrate and the electrode supported by the substrate.

Fullerene

In some embodiments, a compound of formula (I) is the only electron- accepting material of a bulk heterojunction layer as described herein.

In some embodiments, a bulk heterojuction layer contains a compound of formula (I) and one or more further electron-accepting materials. Preferred further electron-accepting materials are fullerenes. The compound of formula (I) : fullerene acceptor weight ratio may be in the range of about 1 : 0.1 - 1 : 1, preferably in the range of about 1 : 0.1 - 1 : 0.5.

Fullerenes may be selected from, without limitation, Ceo, C70, C76, C78 and Cs4 fullerenes or a derivative thereof, including, without limitation, PCBM-type fullerene derivatives including phenyl-Cei-butyric acid methyl ester (CeoPCBM), TCBM-type fullerene derivatives (e.g. tolyl- Cei-butyric acid methyl ester (CeoTCBM)), and ThCBM-type fullerene derivatives (e.g. thienyl-Cei -butyric acid methyl ester (CeoThCBM). Fullerene derivatives may have formula (V):

wherein A, together with the C-C group of the fullerene, forms a monocyclic or fused ring group which may be unsubstituted or substituted with one or more substituents.

Exemplary fullerene derivatives include formulae (Va), (Vb) and (Vc):

wherein R²⁰-R³² are each independently H or a substituent.

Substituents R²⁰-R³² are optionally and independently in each occurrence selected from the group consisting of aryl or heteroaryl, optionally phenyl, which may be unsubstituted or substituted with one or more substituents; and Ci-20 alkyl wherein one or more non-adjacent C atoms may be replaced with O, S, NR⁶, CO or COO and one or more H atoms may be replaced with F. Substituents of aryl or heteroaryl, where present, are optionally selected from Ci-12 alkyl wherein one or more non-adjacent C atoms may be replaced with O, S, NR⁶, CO or COO and one or more H atoms may be replaced with F.

Formulations

The photoactive layer may be formed by any process including, without limitation, thermal evaporation and solution deposition methods.

Preferably, the photoactive layer comprising the compound of formula (I) or (II) is formed by depositing a formulation comprising or consisting of the electron-accepting material(s) and, in the case of a the bulk heterojunction layer, the electron-donating materials 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, without limitation, spin-coating, dip-coating, rollcoating, spray coating, doctor blade coating, wire bar coating, slit coating, ink jet printing, screen printing, gravure printing and flexographic printing.

The one or more solvents of the formulation may optionally comprise or consist of benzene or naphthalene substituted with one or more substituents selected from fluorine, chlorine, Ci-10 alkyl and Ci-10 alkoxy wherein two or more substituents may be linked to form a ring which may be unsubstituted or substituted with one or more C1-6 alkyl groups, optionally toluene, xylenes, trimethylbenzenes, tetramethylbenzenes, anisole, indane and its alkyl-substituted derivatives, and tetralin and its alkyl-substituted derivatives.

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 further solvents. The one or more further solvents may be selected from esters, optionally alkyl or aryl esters of alkyl or aryl carboxylic acids, optionally a Ci-10 alkyl benzoate, benzyl benzoate or dimethoxybenzene. In preferred embodiments, 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.

The formulation may comprise further components in addition to the electron- accepting material, the electron-donating material (in the case of a bulk heterojunction layer) and the one or more solvents. As examples of such components, adhesive agents, defoaming agents, deaerators, viscosity enhancers, diluents, auxiliaries, flow improvers colourants, dyes or pigments, sensitizers, stabilizers, nanoparticles, surface-active compounds, lubricating agents, wetting agents, dispersing agents and inhibitors may be mentioned.

Applications

A circuit may comprise the OPD connected to one or more of a voltage source for applying a reverse bias to the device; a device configured to measure photocurrent; and an amplifier configured to amplify an output signal of the OPD. The voltage applied to the photodetector may be variable. In some embodiments, the photodetector may be continuously biased when in use.

In some embodiments, a photodetector system comprises a plurality of photodetectors as described herein, such as an image sensor of a camera.

In some embodiments, a sensor may comprise an OPD as described herein and a light source wherein the OPD is configured to receive light emitted from the light source. In some embodiments, the light source has a peak wavelength of at least 900 nm or at least 1000 nm, optionally in the range of 900-1500 nm.

In some embodiments, the light from the light source may or may not be changed before reaching the OPD. For example, the light may be reflected, filtered, down-converted or up- converted before it reaches the OPD.

The organic photoresponsive device as described herein may be an organic photovoltaic device or an organic photodetector. An organic photodetector as described herein may be used in a wide range of applications including, without limitation, detecting the presence and / or brightness of ambient light and in a sensor comprising the organic photodetector and a light source. The photodetector may be configured such that light emitted from the light source is incident on the photodetector and changes in wavelength and/or brightness of the light may be detected, e.g., due to absorption by, reflection by and/or emission of light from an object, e.g. a target material in a sample disposed in a light path between the light source and the organic photodetector. The sample may be a non-biological sample, e.g. a water sample, or a biological sample taken from a human or animal subject. The sensor may be, without limitation, a gas sensor, a biosensor, an X-ray imaging device, an image sensor such as a camera image sensor, a motion sensor (for example for use in security applications) a proximity sensor or a fingerprint sensor. A ID or 2D photosensor array may comprise a plurality of photodetectors as described herein in an image sensor. The photodetector may be configured to detect light emitted from a target analyte which emits light upon irradiation by the light source or which is bound to a luminescent tag which emits light upon irradiation by the light source. The photodetector may be configured to detect a wavelength of light emitted by the target analyte or a luminescent tag bound thereto.

Examples

Synthesis

Compound 1 was synthesised according to Scheme 1.

Scheme 1:

Step 1/2

Compound 1

Compound A was synthesised as described in WO 2022/129137, which is incorporated in its entirety herein. Comparative Compound 1 : Comparative Compound 1 was synthesised according to the method described in WO2022/129137, which is incorporated in its entirety herein.

Comparative Compound 1

Analysis

The solution absorption of spectra of Compound 1 and Comparative Compound 1 in o-DCB were analysed using a Cary 5000 UV-VIS-NIR Spectrometer. Measurements were taken from 175 nm to 3300 nm using a PbSmart NIR detector for extended photometric range with variable slit widths (down to 0.01 nm) for optimum control over data resolution.

Absorption data are obtained by measuring the intensity of transmitted radiation through a solution sample. Absorption intensity is plotted vs. incident wavelength to generate an absorption spectrum. A method for measuring absorption may comprise measuring a 15 mg / ml solution in a quartz cuvette and comparing to a cuvette containing the solvent only.

It was surprisingly found that the peak absorption wavelength of Compound 1 red shifted (increased in wavelength value) by over 100 nm relative to Comparative Compound 1 (see Figure 2).

Device Manufacture

Example Device 1

An organic electronic device was manufactured using the following method.

A glass substrate coated with a 150 nm thick layer of indium-tin oxide (ITO) was coated with a 0.2 % polyethyleneimine (PEIE) solution in water to form a ~5 nm film modifying the work function of the ITO. A ca. 200-330 nm thick bulk heterojunction layer of a mixture of Donor Polymer 2 : Compound 1 (1 : 1.5 by weight) was deposited over the modified ITO layer by bar coating from a 15 mg/ml 1,2,4 trimethylbenzene; dimethoxybenzene 95:5 v/v solvent mixture. An anode stack of MoOs (lOnm) and ITO (50nm) was formed over the bulk heterojunction by thermal evaporation (MoOs) and sputtering (ITO). Donor Polymer 2 may be prepared as described in W02013/051676, the contents of which are incorporated herein by reference.

Donor Polymer 2

Example Device 2

An organic electronic device was manufactured using the same method described for Eample Device 1, except that a ca. 200-330 nm thick bulk heterojunction layer of a mixture of Donor Polymer 2 : Compound 1 (1 : 1 by weight) was deposited over the modified ITO layer by bar coating from a 24 mg/ml chloroform; chloronapthalene 98:2 v/v solvent mixture.

As show in in Figures 3-6, devices comprising a compound according to the present disclosure exhibits surprisingly good characteristics. For example, absorption at long wavelengths, high external quantum efficiency (EQE) (in particular from 1470 nm to 1800 nm), and excellent dark current and current density.

Claims

CLAIMS A compound of formula (I):

wherein:

A² is a monovalent electron- accepting group;

D is an electron-donating group;

B¹ in each occurrence is independently a bridging group; n is at least 1 ; m is 0 or at least 1 ; p is 0 or 1 ; q is 0 or 1 ;

A¹ is a group represented by formula (II)

wherein:

R³ is independently H or a substituent;

Y is C=O, C=S SO, SO₂, NR³³ or C(R³³)₂ wherein R³³ is CN or COOR⁴⁰; wherein R⁴⁰ in each occurrence is H or a substituent; and R⁴ in each occurrence is H or a substituent selected from the group consisting of Ci-20 hydrocarbyl and an electron withdrawing group, with the proviso that at least one R⁴ is CN. A compound according to claim 1, wherein Y is C=O or C=S, optionally C=O. A compound according to claim 1 or 2, wherein R³ is H. A compound according to any one of claims 1 to 3, wherein R⁴ in each occurrence is H or an electron withdrawing group, with the proviso that at least one R⁴ is CN. A compound according to any one of claims 1 to 4, wherein R⁴ in each occurrence is an electron withdrawing group selected from the group consisting of Ci-12 esters, Ci-12 ketones, CF3, halogen, NO2, and CN, with the proviso that at least one R⁴ is CN. A compound according to any one of claims 1 to 5 wherein two R⁴s are a substituent, optionally wherein the two R⁴s are CN. A compound according to any one of claims 1 to 6, wherein A² is a group represented by formula (II) as defined in any of claims 1 to 6. A compound according to any one of claims 1 to 7, wherein each n is 1, 2, 3, 4, or 5. A compound according to any one of claims 1 to 8, wherein each m is independently 0,

1, 2, 3, 4, or 5. A compound according to any one of claims 1 to 9, wherein n and m are the same. A compound according to any one of claims 1 to 10, wherein D is a fused aromatic or heteroaromatic group. A compound according to any one of claims 1 to 11, wherein D is:

wherein:

R⁵³ independently in each occurrence is H or a substituent; and R⁵¹ independently in each occurrence is H or a substituent. A compound according to any one of claims 1 to 12, wherein B¹ in each occurrence is independently selected from the group consisting of vinylene, arylene, heteroarylene, arylenevinylene and heteroarylenevinylene wherein the arylene and heteroarylene groups are monocyclic or bicyclic groups, each of which may be unsubstituted or substituted with one or more substituents. A composition comprising an electron-donating material and an electron- accepting material wherein the electron accepting material is a compound according to any one of the claims 1 to 13. An organic electronic device comprising an active layer comprising a compound according to any one of the claims 1 to 13 or composition according to claim 14. An organic electronic device according to claim 15, wherein the organic electronic device is an organic photoresponsive device comprising a a photoactive layer comprising a compound or composition according to any one of claims 1-14 disposed between the anode and cathode. The organic electronic device according to claim 16 wherein the photoactive layer is bulk heterojunction layer disposed between an anode and a cathode and wherein the bulk heterojunction layer comprises a composition according to claim 14. An organic electronic device according to claim 16 or 17, wherein the organic photoresponsive device is an organic photodetector. A photosensor comprising a light source and an organic photodetector according to claim 18 wherein the organic photodetector is configured to detect light emitted from the light source. The photosensor according to claim 19, wherein the light source emits light having a peak wavelength of greater than 900 nm. A formulation comprising a compound any one of the claims 1 to 13 or composition according to claim 14, dissolved or dispersed in one or more solvents. A method of forming an organic electronic device according to any one of claims 15 to 18, wherein formation of the active layer comprises deposition of a formulation according to claim 21 onto a surface and evaporation of the one or more solvents.