Method of producing derivatives of 1,3,5-triarylbenzene

PHOTOACTIVE MATERIAL

A material comprising an electron-accepting unit of formula (I): Ar is an aromatic ring; Ar1 is a substituted or unsubstituted 5- or 6-membered heteroaromatic ring containing N and C ring atoms; when Ar1 is a substituted or unsubstituted 6-membered heteroaromatic ring, Ar2 is a substituted or unsubstituted 6-membered heteroaromatic ring wherein the ring atoms are selected from N and C; when Ar1 is a 5-membered heteroaromatic ring, Ar2 is a substituted or unsubstituted 5- or 6-membered heteroaromatic ring; Ar3 is a 5-membered ring or a substituted or unsubstituted 6-membered ring; Ar4 is a 5-membered ring or a substituted or unsubstituted 6-membered ring or is absent; Ar5 is a substituted or unsubstituted monocyclic or polycyclic group containing at least one aromatic or heteroaromatic ring; Ar6 is a substituted or unsubstituted monocyclic or polycyclic group containing at least one aromatic or heteroaromatic ring or is absent; and each X is independently a substituent bound to a C atom of Ar3, and where present Ar4, with the proviso that at least one X is an electron withdrawing group; and wherein the material further comprises an electron-donating unit.

COMPOUND

A compound formula (I): wherein: Ar 1 is a monocyclic or fused polycyclic group which, together with the rings it is fused to, forms a fused heteroaromatic group; Y is O, S or NR 55 , wherein R 55 is H or a C 1-30 hydrocarbyl group; X is O or S; R 1 in each occurrence is independently H or a substituent with the proviso that at least one R 1 is an electron-withdrawing group; R 2 in each occurrence is independently H or a substituent; L is a direct bond or, together with R 2 , forms an unsubstituted or substituted 5- or 6-membered aromatic or heteroaromatic ring; and A 1 in each occurrence is an electron-accepting group.

COMPOUND AND DEVICE

A compound of formula (I) or (II): A 1 -(B 1 )x 1 -(D 1 )y 1 -(B 1 )x 2 -A 1   (I) A 1 -(B 2 )x 5 -(D 2 )y 2 -(B 3 )x 3 -A 2 -(B 3 )x 4 -(D 3 )y 3 -(B 2 )x 6 -A 1   (II) wherein: A 1 in each occurrence is independently a monovalent electron-accepting group; A 2 is a divalent electron-accepting group; D 1 , D 2 and D 3 independently in each occurrence is an electron-donating group; y 1 , y 2 and y 3 are each independently at least 1; B 1 , B 2 , and B 3 independently in each occurrence is a bridging group; x 1 -x 6 are each independently 0, 1, 2 or 3 with the provisos that: in the case of the compound of formula (I) at least one of x 1 and x 2 is at least 1 and at least one B 1 is substituted with a fluorinated group; and in the case of the compound of formula (II) at least one of x 3 , x 4 , x 5 and x 6 is at least 1 and at least one occurrence of at least one of B 2 and B 3 is substituted with a fluorinated group. The compound of formula (I) or (II) may be used as an electron-accepting material in a photoresponsive device. (NO FIGURE)

COMPOUND

A compound of formula (I): wherein: each X is independently O or S; R 1 in each occurrence is independently H a substituent; R 2 in each occurrence is independently a substituent; B in each occurrence is independently a bridging unit; n in each occurrence is independently 0 or 1; A 1 in each occurrence is independently an electron-accepting group; Z is a direct bond or, together with R 1 , forms a monocyclic or fused ring; and the compound of formula (I) is substituted with at least one substituent of formula (II): -(L)p-[(OCH 2 CH 2 )r-R 3 ]q   (II) wherein: L is a linking group; p in each occurrence is independently is 0 or 1; r in each occurrence is independently an integer from 1 to 10; R 3 is H or a substituent; and q is 1 if p is 0 and q is at least 1 if p is 1.

Compound

A compound of formula (I): A1 is a divalent heteroaromatic electron-accepting group comprising at least 3 fused aromatic rings, or has a modelled LUMO of more than 2.70 eV from vacuum level; A2 and A3 are each independently a monovalent electron-accepting group; D1and D2 independently in each occurrence is an electron-donating group, wherein at least one occurrence of at least one of D1and D2 is a fused heteroaromatic group comprising at least 4 fused rings; B1 and B2 independently in each occurrence is a bridging group. x1, x2, z1 and z2 are each independently 0, 1, 2 or 3; y1 and y2 are each independently at least 1. The compound of formula (I) may be used as an electron-accepting material in an organic photodetector.

Photoactive material

A material comprising an electron-accepting unit of formula (I). According to some embodiments, the present disclosure provides a material comprising an electron-accepting unit of formula (I) wherein Ar is a substituted or unsubstituted benzene or 6-membered heteroaromatic ring containing N and C ring atoms; Ar 1 is a substituted or unsubstituted 5- or 6-membered heteroaromatic ring containing N and C ring atoms; Ar 2 is a substituted or unsubstituted 5- or 6-membered heteroaromatic ring or is absent; Ar 3 is a 5-membered ring or a substituted or unsubstituted 6-membered ring; Ar 4 is a 5-membered ring or a substituted or unsubstituted 6-membered ring or is absent; Ar 5 is a substituted or unsubstituted monocyclic or polycyclic group containing at least one aromatic or heteroaromatic ring; Ar 6 is a substituted or unsubstituted monocyclic or polycyclic group containing at least one aromatic or heteroaromatic ring or is absent; and each X is independently a substituent bound to a carbon atom of Ar 3 and, where present, Ar 4 with the proviso that at least one X group is an electron-withdrawing group and wherein the material further comprises a conjugated electron-donating unit. The material may be a polymer comprising repeat units of formula (I). The material may be a non-polymeric compound. An organic photodetector may contain a bulk heterojunction layer containing an electron acceptor or an electron donor wherein at least one of the electron acceptor and electron donor contains a unit of formula (I).

Photoactive material

A material comprising an electron-accepting unit of formula (I): Ar is an aromatic ring; Ar 1 is a substituted or unsubstituted 5- or 6-membered heteroaromatic ring containing N and C ring atoms; when Ar 1 is a substituted or unsubstituted 6-membered heteroaromatic ring, Ar 2 is a substituted or unsubstituted 6-membered heteroaromatic ring wherein the ring atoms are selected from N and C; when Ar 1 is a 5-membered heteroaromatic ring, Ar 2 is a substituted or unsubstituted 5- or 6-membered heteroaromatic ring; Ar 3 is a 5-membered ring or a substituted or unsubstituted 6-membered ring; Ar 4 is a 5-membered ring or a substituted or unsubstituted 6-membered ring or is absent; Ar 5 is a substituted or unsubstituted monocyclic or polycyclic group containing at least one aromatic or heteroaromatic ring; Ar 6 is a substituted or unsubstituted monocyclic or polycyclic group containing at least one aromatic or heteroaromatic ring or is absent; and each X is independently a substituent bound to a C atom of Ar 3 , and where present Ar 4 , with the proviso that at least one X is an electron withdrawing group; and wherein the material further comprises an electron-donating unit.

Compound

A compound of formula (I) or (II): A1-(B1)x1-(D1)y1-(B1)x2-A1 (I) A1-(B2)x5-(D2)y2-(B3)x3-A2-(B3)x4-(D3)y3-(B3)x6-A1 (II) A2 is a divalent heteroaromatic electron-accepting group; D1, D2 and D3 is independently an electron-donating group; B1, B2, and B3 is independently a bridging group; x1 to x6 are each independently 0, 1, 2 or 3; y1 and y2 are each independently at least 1; and each A1 is independently a group of formula (III): wherein each R1 is independently a substituent; R2, R3 and R4 are independently H or a substituent; J is C=O, C=S, NR11 or CR12R13, each Z1 is N and each Z2 is CR4, or each Z1 is CR4 and each Z2 is N. In other aspects, a composition comprising an electron-donating material wherein the electron accepting material is a compound of formula (I) or (II) and/or an organic electronic device comprising an active layer comprising said compound or composition. The organic electronic device may be an organic photoresponsive device comprising a bulk heterojunction layer disposed between an anode and a cathode and wherein the bulk heterojunction layer comprises said composition. The organic photoresponsive device may be an organic photodetector, which may be to detect light emitted from a light source. 

Compound

A compound of formula (I) or (II). A 2 is a divalent heteroaromatic electron-accepting group; D 1 , D 2 and D 3 independently in each occurrence is an electron-donating group; B 1 , B 2 , and B 3 independently in each occurrence is a bridging group; x 1 - x 6 are each independently 0, 1, 2 or 3; y 1 , y 2 and y 3 are each independently at least 1; and A 1 in each occurrence is independently a group of formula (III) wherein J is C=O, C=S, S=O, SO 2 , NR 11 or CR 12 R 13 , each Z 1 is N and each Z 2 is CR 4 , or each Z 1 is CR 4 and each Z 2 is N wherein each R 4 is independently H or a substituent.

Fullerene derivatives in a photoresponsive device

A compound of formula (I): [(Fu) r -L] s -(NFA) t , Fu is a fullerene; NFA is a non-fullerene acceptor; L is a linker group; r, s and t are each at least 1; and NFA is a non-fullerene acceptor. The NFA contains electron-accepting groups, electron-donating groups and, optionally, bridging groups therebetween. At least one bridging group or electron-donating group of the NFA is bound to at least one group of formula (Fu)r-L-.

Compounds useful in the preparation of photoresponsive device

A compound of formula (I) wherein: D is an electron-donating group; B 1 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: R 3 is independently H or a substituent; Y is C=O, C=S SO, SO 2 , NR 33 or C(R 33 ) 2 wherein R 33 is CN or COOR 40 ; wherein R 40 in each occurrence is H or a substituent; and R 4 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 R 4 is CN.

Method and compound

A method of forming an organic photoresponsive device comprising an anode (107), a cathode (103) and a photoactive layer (105) disposed between the anode and the cathode, the method comprising: forming a precursor layer over one of the anode and cathode, the precursor layer comprising a reactive non-fullerene acceptor substituted with at least two reactive groups; and forming the photoactive layer comprising reacting the reactive groups to form a chain or network comprising a plurality of molecules of the reacted non-fullerene acceptor; and forming the other of the anode and cathode before or after reaction of the reactive groups.

Compound

A compound of formula (I): (I) (II) 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 from the group consisting of C1-20 hydrocarbyl and an electron withdrawing group, with the proviso that at least one R4 is CN. B1 is preferably thiophene, and D is preferably a 6-membered thiophene chain ring. A photoresponsive device, preferably a photodetector, is further disclosed, comprising an anode, cathode, a bulk heterojunction photoactive layer comprising a compound of formula (I), wherein the compound is dissolved, deposited on the photoactive, layer, then the solvent is evaporated.

Compound

A compound of formula (I): A1-(B1)x1-(D1)y1-(B1)x2-A1; or a compound of formula (II): A1-(B2)x5-(D2)y2-(B3)x3-A2-(B3)x4-(D3)y3-(B2)x6-A1 is provided; wherein A2 is a divalent heteroaromatic electron-accepting group; D1, D2 and D3 are independently electron-donating groups; B1, B2, and B3 are independently bridging groups; x1-x6 are independently 0, 1, 2 or 3; y1, y2 and y3 are each independently at least 1; and A1 is independently a group of formula (III): wherein: R10 is H or a substituent; G is SO or SO2; ArA is optionally present; and each of RA, RB, RC, and RD are independently H or a substituent with the proviso that at least one of least one of RA, RB, RC, and RD is CN in the case where ArA is absent. A composition comprising an electron-donating material and the compound of Formula (I) or (II) as an electron-accepting material is provided. An organic electronic device comprising the compound or composition as an active layer is provided. The organic electronic device may be an organic photoresponsive device. The moiety formula (III) may be a 2(-2-methylene-1,1-dioxidothieno[2,3-b]quinoxalin-3(2H)-ylidene)malononitrile or 3-(dicyanomethylene)-2-methylene-2,3-dihydrobenzo[b]thiophene-5,6-dicarbonitrile 1,1-dioxide moiety.

Compound

A compound of formula (I): Wherein Fu is a fullerene; NFA is a non-fullerene acceptor of Formula (II) or (III); L is a linker group; r, s and t are each at least 1; wherein A1 is a divalent heteroaromatic electron accepting group; A2 and A3 are independently monovalent electron-accepting groups; D1, D2 and D3 are independently electron donating groups; B1, B2 and B3 are independently bridging groups; x1 and x2 are each 0-3; y1 and y2 are each at least 1; z1 and z2 are each 0-3; and wherein at least one of B1 or D1 is bound to a fullerene containing group; or at least one of B2, B3 D2 or D3 is bound to a fullerene containing group. Compositions, organic electronic devices and photosensors comprising the disclosed compounds are also described. Formulations comprising the disclosed compounds in one or more solvents, along with methods of preparing organic electronic devices using these formulations is also described.

Compound and device

A compound of formula (I) A1–(B1)x1–(D1)y1–(B1)x2–A1 or (II) A1–(B2)x5–(D2)y2–(B3)x3– A2–(B3)x4–(D3)y3–(B2)x6–A1 wherein: A1 and A2 are electron-accepting groups; D1, D2, and D3 are electron-donating groups; y1, y2, and y3 are each independently at least 1; B1, B2, and B3 are bridging groups; x1 – x6 are each independently 0, 1, 2, or 3, however one bridging group must be present, and at least one bridging group is substituted with a fluorinated group. Preferred bridging groups B1 include the fluorinated thieno[3,4-b]pyrazine exemplified in Model Compound 1. An organic photoresponsive device is disclosed, wherein a bulk heterojunction layer 105 using compounds of formula (I) or (II) as is disposed between an anode 107 and a cathode 103. The device is preferably a photodetector. The compound of formula (I) or (II) in the photodetector is preferably dissolved in a fluorinated solvent, and an electron-donating-sub-layer comprises an electron-donating compound and a non-halogenated solvent. Compounds of formula (I’) and (II’) are also disclosed, wherein the fluorinated group may be substituted anywhere on the compound.

Method and compound

A method of forming an organic photoresponsive device comprising an anode, a cathode and a photoactive layer disposed between the anode and the cathode, the method comprising: forming a precursor e layer over one of the anode and cathode, the precursor layer comprising a reactive non-fullerene acceptor substituted with at least two reactive groups; and forming the photoactive layer comprising reacting the reactive groups to form a chain or network comprising a plurality of molecules of the reacted non-fullerene acceptor; and forming the other of the anode and cathode before or after reaction of the reactive groups. Also shown is a reactive compound of formula (I) or (II): wherein the compounds of formula (I) or (II) is substituted with at least two first reactive groups.

Compounds for organic electronic devices

A compound of formula (I) or (II): A 1 − (B 1 )x 1 − (D 1 )y 1 − (B 1 )x 2 − A 1 (I), A 1 − (B 2 )x 5 − (D 2 )y 2 − (B 3 )x 3 − A 2 − (B 3 )x 4 − (D 3 )y 3 − (B 2 )x 6 − A 1 (II). A 2 is a divalent heteroaromatic electron-accepting group; D 1 , D 2 and D 3 independently in each occurrence is an electron-donating group; B 1 , B 2 , and B 3 independently in each occurrence is a bridging group; x 1 − x 6 are each independently 0, 1, 2 or 3; y 1 , y 2 and y 3 are each independently at least 1; and A 1 in each occurrence is independently a group of formula (III) wherein: R 10 is H or a substituent; G is SO or SO 2 ; Ar A is optionally present; and each of R A , R B , R C and R D is independently H or a substituent with the proviso that at least one of least one of R A , R B , R C and R D is CN in the case where Ar A is absent.

Compound

A compound of formula (I): A1-(B1)x1-(D1)y1-(B1)x1-A1; or a compound of formula (II):A1-(B2)x2-(D2)y2-(B3)x3-A2-(B3)x3-(D3)y3-(B2)x2-A1 is provided; wherein A1 is independently a monovalent electron-accepting group; A2 is a divalent heteroaromatic electron-accepting group; D1, D2, D3 are independently divalent electron-donating groups; each x1 is independently 0 or 1 with the proviso that at least one x1 is 1; each x2 and each x3 is independently 0 or 1 with the proviso that at least one occurrence of x2 and x3 is 1; y1, y2 and y3 are each independently at least 1; and B1, B2 and B3 are independently a bridging group and at least one B1 of formula (I) or at least one of B2 and B3 of formula (II) is a thieno[3,4-b]pyrazine group of formula (III): wherein each R1 is independently H or a substituent; or both R1 groups together form a monocyclic or polycyclic aromatic or heteroaromatic group Ary which is unsubstituted or substituted with one or more substituents. The compound of formula (I) or (II) may be used as an electron-accepting material in organic electronic devices such as organic photodetectors. Preferred groups of Formula (III) include 9H-indeno[1,2-b]thieno[3,4-e]pyrazin-9-one; benzo[4,5]thieno[2,3-b]thieno[3,4-e]pyrazine; and 5H-pyrrolo[3,4-b]thieno[3,4-e]pyrazine-5,7(6H)-dione motifs.

Formulation

A formulation comprising a solvent comprising at least one nitrile group e.g. benzonitrile; and a non-fullerene acceptor substituted with a nitrile group dissolved in the formulation. The formulation may also have an electron-donating material dissolved in the formulation. The formulation may be used in formation of a photoactive layer of a photoresponsive device.

Composition

A composition comprises a first electron-accepting compound of formula (I) and a second electron-accepting compound of formula (II): A 1 – (B1 )x1 – (D1 )y1 – (B1 )x2 – A1 (I) A 1 – (B2 )x5 – (D2 )y2 – (B3 )x3 – A2 – (B3 )x4 – (D3 )y3 – (B2 )x6 – A1 (II) wherein: A 1 in each occurrence is independently a monovalent electron-accepting group; A2 is a divalent heteroaromatic electron-accepting group; D1 , D2 and D3 in each occurrence is a heteroaromatic electron-donating group which is unsubstituted or substituted with one or more substituents; B 1 , B2 , and B3 independently in each occurrence is a bridging group; x1 – x6 are each independently 0, 1, 2 or 3; y1 , y2 and y3 are each independently at least 1; and the heteroaromatic group of at least one occurrence of D1 is the same as the heteroaromatic group of at least one occurrence of D2 or at least one occurrence of D3 . The composition may be used in the photoactive layer of an organic photoresponsive device.

Compound

Wherein X1 is C(R1)2, Si(R1)2 or Ge(R1)2 wherein R1 in each occurrence is a substituent; Y1 is O, S or Se; Ar1 in each occurrence is independently an unsubstituted or substituted monocyclic or polycyclic aryl or heteroaryl group or is absent; B1 independently in each occurrence is a bridging group; f1 and f2 are each independently 1, 2 or 3; g is at least 1; and A in each occurrence is independently a monovalent electron-accepting group. Ar1 is preferably absent. The compound of formula (I) may be used as an electron-accepting material of an organic photo-responsive device. Compositions and formulations comprising the disclosed compounds and an electron-donating material are disclosed. A photosensor comprising an organic photodetector for detecting light emitted from a light source comprising a compound of Formula (I) is disclosed, particularly wherein the light source emits light having a peak wavelength of greater than 1000 nm.

Compounds for use in photosensors

A compound of formula (I) wherein: X1 is O, S, Se, NR2 or PR2 wherein R2 in each occurrence is H or a substituent; Y1 is O, S or Se; Ar1 in each occurrence is independently an unsubstituted or substituted monocyclic or polycyclic aryl or heteroaryl group or is absent; R1 in each occurrence is independently a substituent; B1 independently in each occurrence is a bridging group; f1 and f2 are each 1; g is at least 1; and A in each occurrence is independently a monovalent electron-accepting group.

Compounds for use in photosensors

A compound of formula (I) wherein: X1 is C(R1)2, Si(R1)2 or Ge(R1)2 wherein R1 in each occurrence is a substituent; Y1 is O, S or Se; Ar1 in each occurrence is independently an unsubstituted or substituted monocyclic or polycyclic aryl or heteroaryl group or is absent; B1 independently in each occurrence is a bridging group; f1 and f2 are each 1; g is at least 1; and A in each occurrence is independently a monovalent electron-accepting group. The compound of formula (I) may be used as an electron-accepting material of an organic photoresponsive device.

Polymer

A polymer comprising a donor repeat unit and an acceptor repeat unit wherein the acceptor repeat unit comprise a repeat unit of formula (I): A 1 is selected from formula (IIa): formula (lib); O; S; and NR 1 wherein R 1 is H or a substituent: (Ha) (lib) Ar 3 is a monocyclic or polycyclic aromatic group; X 1 and X 2 are each independently selected from N and CR 2 wherein R 2 in each occurrence is H or a substituent with the proviso that at least one of X 1 and X 2 is selected from N and CR 2 wherein R 2 is an electron withdrawing group; Ar 1 is selected from pyrrole, benzene, pyridine and 1,4-diazine; A 2 is O, S, SO 2 , NR 1 , PR 1 , C(R 3 ) 2 and Si(R 3 )2 wherein R 3 in each occurrence is independently H or a substituent; and Ar 2 is a monocyclic or polycyclic aromatic group.

Photoactive material

A material comprising an electron-accepting unit of formula (I). According to some embodiments, the present disclosure provides a material comprising an electron-accepting unit of formula (I) wherein Ar is a substituted or unsubstituted benzene or 6-membered heteroaromatic ring containing N and C ring atoms; Ar 1 is a substituted or unsubstituted 5- or 6-membered heteroaromatic ring containing N and C ring atoms; Ar 2 is a substituted or unsubstituted 5- or 6-membered heteroaromatic ring or is absent; Ar 3 is a 5-membered ring or a substituted or unsubstituted 6-membered ring; Ar 4 is a 5-membered ring or a substituted or unsubstituted 6-membered ring or is absent; Ar 5 is a substituted or unsubstituted monocyclic or polycyclic group containing at least one aromatic or heteroaromatic ring; Ar 6 is a substituted or unsubstituted monocyclic or polycyclic group containing at least one aromatic or heteroaromatic ring or is absent; and each X is independently a substituent bound to a carbon atom of Ar 3 and, where present, Ar 4 with the proviso that at least one X group is an electron-withdrawing group and wherein the material further comprises a conjugated electron-donating unit. The material may be a polymer comprising repeat units of formula (I). The material may be a non-polymeric compound. An organic photodetector may contain a bulk heterojunction layer containing an electron acceptor or an electron donor wherein at least one of the electron acceptor and electron donor contains a unit of formula (I).

Photoresponsive nonfullerene acceptors of the a-d-a’-d-a type for use in optoelectronic devices

A compound of formula (I), A1 is a divalent heteroaromatic electron-accepting group comprising at least 3 fused aromatic rings, or has a modelled LUMO of more than 2.70 eV from vacuum level. A2 and A3 are each independently a monovalent electron-accepting group. D1 and D2 independently in each occurrence is an electron-donating group, wherein at least one occurrence of at least one of D1 and D2 is a fused heteroaromatic group comprising at least 4 fused rings. B1 and B2 independently in each occurrence is a bridging group. x1, x2, z1 and z2 are each independently 0, 1, 2 or 3. y1 and y2 are each independently at least 1. The compound of formula (I) may be used as an acceptor in an organic photodetector.

Photoresponsive nonfullerene acceptors of the a-d-a'-d-a type for use in optoelectronic devices

A compound of formula (I). A1 is a divalent heteroaromatic electron-accepting group; A2 and A3 are each independently a monovalent electron-accepting group; D1 and D2 independently in each occurrence is an electron-donating group; B1 and B2 independently in each occurrence is a bridging group; x1 and x2 are each independently 0, 1, 2 or 3; y1 and y2 are each independently at least 1; and z1 and z2 are each independently 0, 1, 2 or 3, with the proviso that at least one of z1 and z2 is at least 1. The compound of formula (I) may be used as an electron-accepting material in an organic photodetector.

Photoresponsive asymmetric nonfullerene acceptors of the a-d-a'-d-a type for use in optoelectronic devices

A compound of formula (I), A1 is an electron-accepting group; D1 and D2 independently in each occurrence is an N electron-donating group; A1, A2 and A3 are each independently an electron-accepting group; B1 and B2 in each occurrence are independently a bridging group; x1 and x2 are each independently 0, 1, 2 or 3; y1 and y2 are each independently at least 1; z1 and z2 are each independently 0, 1, 2 or 3; and at least one of (i)-(iv) applies: (i) (D1)y1 and (D2)y2 are different; (ii) A2 and A3 are different; (iii) (B1)x1 and (B1)x2 are different; and (iv) (B2)z1 and (B2)z2 are different. The compound of formula (I) may be used as an electron acceptor in an organic photodetector.

Photoactive nonfullerene acceptors of the a-d-a'-d-a type for use in optoelectronic devices

A compound of formula (I), D 1 and D 2 are electron-donating groups; A 2 and A 3 are electron-accepting groups; B 1 and B 2 are bridging groups; x1 and x2 are 0, 1, 2 or 3; y1 and y2 are at least 1; z1 and z2 are 0, 1, 2 or 3; and A 1 is a group of formula (II) wherein Ar 1 is an aromatic or heteroaromatic group; and Y is O, S, NR 4 or R1-C═C—R 1 wherein R 1 in each occurrence is independently H or a substituent wherein two substituents R 1 may be linked to form a monocyclic or polycyclic ring and R 4 is H or a substituent. The compound may be used as an electron-accepting material with an electron-donating material in an organic photodetector.