Optoelectronic device

Abstract

The invention provides an optoelectronic device comprising a photoactive region, which photoactive region comprises: an n-type region comprising at least one n-type layer; a p-type region comprising at least one p-type layer; and, disposed between the n-type region and the p-type region: a layer of a perovskite semiconductor without open porosity. The perovskite semiconductor is generally light-absorbing. In some embodiments, disposed between the n-type region and the p-type region is: (i) a first layer which comprises a scaffold material, which is typically porous, and a perovskite semiconductor, which is typically disposed in pores of the scaffold material; and (ii) a capping layer disposed on said first layer, which capping layer is said layer of a perovskite semiconductor without open porosity, wherein the perovskite semiconductor in the capping layer is in contact with the perovskite semiconductor in the first layer. The layer of the perovskite semiconductor without open porosity (which may be said capping layer) typically forms a planar heterojunction with the n-type region or the p-type region. The invention also provides processes for producing such optoelectronic devices which typically involve solution deposition or vapour deposition of the perovskite. In one embodiment, the process is a low temperature process; for instance, the entire process may be performed at a temperature or temperatures not exceeding 150° C.

1 - 105 . (canceled) 
     
     
         106 . An optoelectronic device comprising a photoactive region, which photoactive region comprises:
 an n-type region comprising at least one n-type layer;   a p-type region comprising at least one p-type layer; and, disposed between the n-type region and the p-type region:   a layer of a perovskite semiconductor without open porosity,   wherein said perovskite comprises a three-dimensional crystal structure.   
     
     
         107 . An optoelectronic device according to  claim 106  wherein said device is a light emitting device. 
     
     
         108 . An optoelectronic device according to  claim 106  wherein said device is a light emitting diode, a laser or a diode injection laser. 
     
     
         109 . An optoelectronic device according to  claim 106  wherein said perovskite comprises a three-dimensional network of perovskite unit cells without any separation between layers. 
     
     
         110 . An optoelectronic device according to  claim 106  wherein the layer of the perovskite semiconductor forms a planar heterojunction with the n-type region or the p-type region, or forms a first planar heterojunction with the n-type region and a second planar heterojunction with the p-type region. 
     
     
         111 . An optoelectronic device according to  claim 106  wherein the thickness of the layer of the perovskite semiconductor is from 10 nm to 100 μm. 
     
     
         112 . An optoelectronic device according to  claim 106  wherein the photoactive region comprises:
 said n-type region; 
 said p-type region; and, disposed between the n-type region and the p-type region: 
 (i) a first layer which comprises a scaffold material and a perovskite semiconductor; and 
 (ii) a capping layer disposed on said first layer, which capping layer is said layer of a perovskite semiconductor without open porosity, 
 wherein the perovskite semiconductor in the capping layer is in contact with the perovskite semiconductor in the first layer, and 
 wherein the scaffold material is porous and the perovskite semiconductor in the first layer is disposed in pores of the scaffold material. 
 
     
     
         113 . An optoelectronic device according to  claim 112  wherein:
 the scaffold material is a dielectric scaffold material or a charge-transporting scaffold material; and 
 the perovskite semiconductor in the capping layer forms a planar heterojunction with the p-type region or the n-type region. 
 
     
     
         114 . An optoelectronic device according to  claim 112  wherein the thickness of the capping layer is greater than the thickness of the first layer, optionally wherein the thickness of the capping layer is from 10 nm to 100 μm and the thickness of the first layer is from 5 nm to 1000 nm. 
     
     
         115 . An optoelectronic device according to  claim 106  wherein the perovskite is a light-emitting perovskite and/or the perovskite semiconductor has a band gap of equal to or less than 3.0 eV. 
     
     
         116 . An optoelectronic device according to  claim 106  wherein the perovskite comprises at least one anion selected from halide anions. 
     
     
         117 . An optoelectronic device according to  claim 116  wherein the perovskite comprises a first cation, a second cation, and said at least one anion, optionally wherein:
 the second cation is a metal cation selected from Ca 2+ , Sr 2+ , Cd 2+ , Cu 2+ , Ni 2+ , Mn 2+ , Fe 2+ , Co 2+ , Pd 2+ , Ge 2+ , Sn 2+ , Pb 2+ , Yb 2+  and Eu 2+ , and/or 
 the first cation is an organic cation, optionally wherein: 
 the organic cation has the formula (R 1 R 2 R 3 R 4 N) + , wherein: 
 R 1  is hydrogen, unsubstituted or substituted C 1 -C 20  alkyl, or unsubstituted or substituted aryl; 
 R 2  is hydrogen, unsubstituted or substituted C 1 -C 20  alkyl, or unsubstituted or substituted aryl; 
 R 3  is hydrogen, unsubstituted or substituted C 1 -C 20  alkyl, or unsubstituted or substituted aryl; and 
 R 4  is hydrogen, unsubstituted or substituted C 1 -C 20  alkyl, or unsubstituted or substituted aryl; or 
 the organic cation has the formula (R 5 R 6 N═CH—NR 7 R 8 ) + , wherein: R 5  is hydrogen, unsubstituted or substituted C 1 -C 20  alkyl, or unsubstituted or substituted aryl; R 6  is hydrogen, unsubstituted or substituted C 1 -C 20  alkyl, or unsubstituted or substituted aryl; R 7  is hydrogen, unsubstituted or substituted C 1 -C 20  alkyl, or unsubstituted or substituted aryl; and R 8  is hydrogen, unsubstituted or substituted C 1 -C 20  alkyl, or unsubstituted or substituted aryl. 
 
     
     
         118 . An optoelectronic device according to  claim 106  wherein the perovskite is a mixed-halide perovskite, wherein said two or more different anions are two or more different halide anions. 
     
     
         119 . An optoelectronic device comprising a compact layer of a photoactive perovskite semiconductor, wherein the photoactive perovskite semiconductor has a three-dimensional crystal structure. 
     
     
         120 . An optoelectronic device according to  claim 119  wherein said device is a light emitting device. 
     
     
         121 . An optoelectronic device according to  claim 119  wherein the perovskite comprises a halide anion and the thickness of the compact layer of the photoactive perovskite semiconductor is from 10 nm to 100 μm. 
     
     
         122 . An optoelectronic device according to  claim 121  wherein the optoelectronic device does not comprise a perovskite semiconductor supported on a porous material. 
     
     
         123 . A process for producing an optoelectronic device comprising a photoactive region, which photoactive region comprises:
 an n-type region comprising at least one n-type layer;   a p-type region comprising at least one p-type layer; and, disposed between the n-type region and the p-type region:   a layer of a perovskite semiconductor without open porosity,   wherein said perovskite comprises a three-dimensional crystal structure, which process comprises:   (a) providing a first region;   (b) disposing a second region on the first region, which second region comprises a layer of a perovskite semiconductor without open porosity, wherein said perovskite comprises a three-dimensional crystal structure; and   (c) disposing a third region on the second region,   
       wherein:
 the first region is an n-type region comprising at least one n-type layer and the third region is a p-type region comprising at least one p-type layer; or 
 the first region is a p-type region comprising at least one p-type layer and the third region is an n-type region comprising at least one n-type layer. 
 
     
     
         124 . A process according to  claim 123  wherein said device is a light emitting device. 
     
     
         125 . A process according to  claim 124  wherein said photoactive region comprises:
 said n-type region; 
 said p-type region; and, disposed between the n-type region and the p-type region: 
 (i) a first layer which comprises a scaffold material and a perovskite semiconductor; and 
 (ii) a capping layer disposed on said first layer, which capping layer is said layer of a perovskite semiconductor without open porosity, 
 wherein the perovskite semiconductor in the capping layer is in contact with the perovskite semiconductor in the first layer, 
 wherein the scaffold material is porous and the perovskite semiconductor in the first layer is disposed in pores of the scaffold material, 
 wherein the process comprises: 
 (a) providing said first region; 
 (b) disposing said second region on the first region, wherein the second region comprises:
 (i) a first layer which comprises a scaffold material and a perovskite semiconductor; and 
 (ii) a capping layer on said first layer, which capping layer is said layer of a perovskite semiconductor without open porosity, wherein the perovskite semiconductor in the capping layer is in contact with the perovskite semiconductor in the first layer; and 
 
 (c) disposing said third region on the second region.