Optoelectronic device comprising porous scaffold material and perovskites
The invention provides an optoelectronic device comprising: (i) a porous dielectric scaffold material; and (ii) a semiconductor having a band gap of less than or equal to 3.0 eV, in contact with the scaffold material. Typically the semiconductor, which may be a perovskite, is disposed on the surface of the porous dielectric scaffold material, so that it is supported on the surfaces of pores within the scaffold. In one embodiment, the optoelectronic device is an optoelectronic device which comprises a photoactive layer, wherein the photo-active layer comprises: (a) said porous dielectric scaffold material; (b) said semiconductor; and (c) a charge transporting material. The invention further provides the use, as a photoactive material in an optoelectronic device, of: (i) a porous dielectric scaffold material; and (ii) a semi-conductor having a band gap of less than or equal to 3.0 eV, in contact with the scaffold material. Further provided is the use of a layer comprising: (i) a porous dielectric scaffold material; and (ii) a semiconductor having a band gap of less than or equal to 3.0 eV, in contact with the scaffold material; as a photoactive layer in an optoelectronic device. In another aspect, the invention provides a photoactive layer for an optoelectronic device comprising (a) a porous dielectric scaffold material; (b) a semiconductor having a band gap of less than or equal to 3.0 eV, in contact with the scaffold material; and (c) a charge transporting material.
1. A light-emitting diode comprising:
a first electrode;
a second electrode;
and disposed between the first and second electrodes a photoactive layer comprising:
(i) a porous dielectric scaffold material having a band gap of equal to or greater than 4.0 eV; and
(ii) a perovskite semiconductor having a band gap of less than or equal to 3.0 eV, in contact with the porous dielectric scaffold material, wherein the perovskite semiconductor is disposed on a surface of said porous dielectric scaffold material and wherein
the perovskite semiconductor is coated as a substantially continuous layer on inside surfaces of pores within the porous dielectric scaffold material, and as a substantially continuous layer on an outer surface of the porous dielectric scaffold material
the perovskite semiconductor fills the pores of the porous dielectric scaffold.
2. A light-emitting diode according to claim 1 wherein the perovskite semiconductor has a band gap of less than or equal to 2.8 eV.
3. A light-emitting diode according to claim 1 wherein the perovskite semiconductor fills the pores of the porous dielectric scaffold material.
4. A light-emitting diode according to claim 1 wherein the porous dielectric scaffold material comprises an oxide of aluminium, germanium, zirconium, silicon, yttrium or ytterbium; or alumina silicate.
5. A light-emitting diode according to claim 4 wherein the porous dielectric scaffold material comprises mesoporous alumina.
6. A light-emitting diode according to claim 1 wherein the perovskite semiconductor comprises at least one halide anion.
7. A light-emitting diode according to claim 1 wherein the perovskite semiconductor is also a photosensitizing material.
8. A light-emitting diode according to claim 1 wherein the perovskite semiconductor is any one of an n-type semiconductor, a p-type semiconductor, or an intrinsic semiconductor.
9. A light-emitting diode according to claim 1 wherein the perovskite semiconductor comprises a first cation, a second cation, and at least one halide anion.
10. A light-emitting diode according to claim 9 wherein the second cation is a metal cation.
11. A light-emitting diode according to claim 10 wherein the metal cation is selected from Sn 2+ and Pb 2+ .
12. A light-emitting diode according to claim 9 wherein the first cation is an organic cation.
13. A light-emitting diode according to claim 12 wherein the organic cation has the formula (R 5 NH 3 ) + , wherein R 5 is hydrogen, or unsubstituted or substituted C 1 -C 20 alkyl.
14. A light-emitting diode according to claim 1 which further comprises a charge transporting material, wherein the charge transporting material is a hole transporting material or an electron transporting material.
15. A light-emitting diode according to claim 14 , wherein the photoactive layer comprises:
said porous dielectric scaffold material;
said perovskite semiconductor; and
said charge transporting material.
16. A light-emitting diode according to claim 1 wherein the perovskite semiconductor is a mixed-anion perovskite comprising a first cation, a second cation, and two or more different anions selected from halide anions and chalcogenide anions.
17. A light-emitting diode according to claim 16 wherein said two or more different anions are two or more different halide anions.
18. A light-emitting diode according to claim 16 wherein the mixed-anion perovskite is a compound of formula (I):
[A][B][X] 3 (I)
wherein:
[A] is at least one organic cation;
[B] is at least one metal cation; and
[X] is said two or more different anions selected from halide anions and chalcogenide anions.
19. A light-emitting diode according to claim 18 wherein [X] is two or more different halide anions.
20. A light-emitting diode according to claim 19 wherein the mixed-anion perovskite is selected from CH 3 NH 3 PbBrI 2 , CH 3 NH 3 PbBrCl 2 , CH 3 NH 3 PbIBr 2 , CH 3 NH 3 PbICl 2 , CH 3 NH 3 PbClBr 2 , CH 3 NH 3 PbI 2 Cl, CH 3 NH 3 SnBrI 2 , CH 3 NH 3 SnBrCl 2 , CH 3 NH 3 SnF 2 Br, CH 3 NH 3 SnIBr 2 , CH 3 NH 3 SnICl 2 , CH 3 NH 3 SnF 2 I, CH 3 NH 3 SnClBr 2 , CH 3 NH 3 SnI 2 Cl and CH 3 NH 3 SnF 2 Cl.
21. A photoactive layer for a light-emitting diode comprising (a) a porous dielectric scaffold material having a band gap of equal to or greater than 4.0 eV; (b) a perovskite semiconductor having a band gap of less than or equal to 3.0 eV, in contact with the porous dielectric scaffold material; and (c) a charge transporting material, wherein the perovskite semiconductor is disposed on a surface of said porous dielectric scaffold material and wherein
the perovskite semiconductor is coated as a substantially continuous layer on inside surfaces of pores within the porous dielectric scaffold material, and as a substantially continuous layer on an outer surface of the porous dielectric scaffold material.
22. A light-emitting diode comprising:
a first electrode;
a second electrode; and
a photoactive layer disposed between the first and second electrodes;
wherein the photoactive layer comprises:
(i) a porous dielectric scaffold material having a band gap of equal to or greater than 4.0 eV;
(ii) a perovskite semiconductor having a band gap of less than or equal to 3.0 eV, in contact with the porous dielectric scaffold material; and
(iii) a charge transporting material which is a solid state hole transporting material, wherein the perovskite semiconductor comprises at least one halide anion, wherein the perovskite semiconductor is disposed on a surface of said porous dielectric scaffold material and wherein
the perovskite semiconductor is coated as a substantially continuous layer on inside surfaces of pores within the porous dielectric scaffold material, and as a substantially continuous layer on an outer surface of the porous dielectric scaffold material.
23. A light-emitting diode according to claim 22 wherein the light-emitting diode further comprises a compact layer, wherein the compact layer comprises a metal oxide or a metal chalcogenide, and wherein the compact layer and said photoactive layer are disposed between the first and second electrodes.
24. A light-emitting diode according to claim 22 wherein the photoactive layer comprises a layer comprising said porous dielectric scaffold material and said perovskite semiconductor, wherein the perovskite semiconductor is disposed on the inside surfaces of pores within said porous dielectric scaffold material, and wherein said charge transporting material is disposed within the pores of said porous dielectric scaffold material.
25. A light-emitting diode according to claim 22 wherein the photoactive layer comprises a layer comprising said charge transporting material disposed on a layer comprising said porous dielectric scaffold material and said perovskite semiconductor, wherein the perovskite semiconductor is disposed on the inside surfaces of pores within said porous dielectric scaffold material, and wherein the optoelectronic device further comprises said charge transporting material disposed within the pores of said porous dielectric scaffold material.