Abstract: Provided herein are all-inorganic perovskite-based films, devices including all-inorganic perovskite-based films, and methods of forming all-inorganic perovskite-based films. The methods may include casting a precursor formulation that includes an all-inorganic perovskite, a liquid, and a polymer. The amount of polymer in the precursor formulation may be less than the amount of all-inorganic perovskite in the precursor formulation.

Abstract: Bandgap-tunable perovskite compositions are provided having the formula CsPb(A)xBy)3, wherein A and B are each a halogen. The mixed halide perovskite composition has a morphology which suppresses phase segregation to stabilize a tuned bandgap of the mixed halide perovskite composition. For example, the perovskite may be in the form of nanocrystals embedded in a non-perovskite matrix, which, for example, may have the formula Cs4Pb(A)xBy)6, wherein A and B are each a halogen. Solar cells and light-emitting diodes comprising the mixed perovskite compositions are also provided.

Abstract: A new type of charge transport layer based on organometal halide perovskite for highly efficient organic light emitting diodes (OLEDs) is demonstrated. By solution processing of halide perovskite precursors, smooth essentially pure perovskite thin films may be prepared with high transparency and conductivity. Solution processed multilayer OLED with this perovskite-based hole transport layer outperforms a device with a PEDOT:PSS layer.

Abstract: Provided herein are all-inorganic perovskite-based films, devices including all-inorganic perovskite-based films, and methods of forming all-inorganic perovskite-based films. The methods may include casting a precursor formulation that includes an all-inorganic perovskite, a liquid, and a polymer. The amount of polymer in the precursor formulation may be less than the amount of all-inorganic perovskite in the precursor formulation.

Abstract: Provided herein are all-inorganic perovskite-based films, devices including all-inorganic perovskite-based films, and methods of forming all-inorganic perovskite-based films. The methods may include casting a precursor formulation that includes an all-inorganic perovskite, a liquid, and a polymer. The amount of polymer in the precursor formulation may be less than the amount of all-inorganic perovskite in the precursor formulation.

Abstract: Provided herein are perovskite-polymer films, methods of forming polymer-perovskite films, and devices including polymer-perovskite films. The polymer-perovskite films may include a plurality of methylammonium lead chloride (CH3NH3PbCl3) nanopillar crystals embedded in a polymer matrix. The devices can be optoelectronic devices, such as light emitting diodes, which include polymer-perovskite films. The polymer-perovskite films of the devices can be hole transport layers in the devices. The methods of making films may include spin casting a precursor solution followed by thermal annealing.

Abstract: Nanoscale metal halide perovskites are provided. The nanoscale metal halide perovskites may have a 2D structure, a quasi-2D structure, or a 3D structure. Methods also are provided for making the nanoscale metal halide perovskites. The color emitted by the nanoscale metal halide perovskites may be tuned.

Abstract: Provided herein are methods of making metal halide perovskites, including methods of making bulk crystals or micro crystals. The metal halide perovskites may be a light emitting material.

Abstract: Nanoscale metal halide perovskites are provided. The nanoscale metal halide perovskites may have a 2D structure, a quasi-2D structure, or a 3D structure. Methods also are provided for making the nanoscale metal halide perovskites. The color emitted by the nanoscale metal halide perovskites may be tuned.

Abstract: Provided herein are perovskite-polymer films, methods of forming polymer-perovskite films, and devices including polymer-perovskite films. The polymer-perovskite films may include a plurality of methylammonium lead chloride (CH3NH3PbCl3) nanopillar crystals embedded in a polymer matrix. The devices can be optoelectronic devices, such as light emitting diodes, which include polymer-perovskite films. The polymer-perovskite films of the devices can be hole transport layers in the devices. The methods of making films may include spin casting a precursor solution followed by thermal annealing.

Abstract: Provided herein are metal halide perovskites that may have a 0D crystal structure, and may be lead free. Also provided are methods for making the metal halide perovskites, including methods for making bulk crystals or micro crystals. Devices, such as optoelectronic devices, also are provided that include one or more of the metal halide perovskites. A metal halide perovskite may be a light emitting material in the devices.

Abstract: Provided herein are all-inorganic perovskite-based films, devices including all-inorganic perovskite-based films, and methods of forming all-inorganic perovskite-based films. The methods may include casting a precursor formulation that includes an all-inorganic perovskite, a liquid, and a polymer. The amount of polymer in the precursor formulation may be less than the amount of all-inorganic perovskite in the precursor formulation.

Abstract: Provided herein are organic-inorganic hybrid-perovskites, including metal halide perovskites having a 1D crystal structure. The metal halide perovskites may be luminescent. The metal halide perovskites may include a dopant, including an emitter dopant. Methods of forming metal halide perovskites, and devices including the metal halide perovskites also are provided.

Abstract: Provided herein are metal halide perovskites, which may have a layered structure. The metal halide perovskites may emit white light. Also provided herein are neat films of the metal halide perovskites, films comprising a polymer matrix and the metal halide perovskites, and devices that include the metal halide perovskites. Methods of making metal halide perovskites also are provided.

Abstract: Nanoscale metal halide perovskites are provided. The nanoscale metal halide perovskites may have a 2D structure, a quasi-2D structure, or a 3D structure. Methods also are provided for making the nanoscale metal halide perovskites. The color emitted by the nanoscale metal halide perovskites may be tuned.

Abstract: Provided herein are metal halide perovskite nanoplatelets, methods for making metal halide perovskite nanoplatelets, and devices and composite materials that include metal halide nanoperovskite nanoplatelets. The metal halide perovskite nanoplatelets may be stable at ambient temperature and pressure, thereby easing device fabrication.

Abstract: Provided herein are perovskite-polymer films, methods of forming polymer-perovskite films, and devices including polymer-perovskite films. The polymer-perovskite films may include a plurality of methylammonium lead chloride (CH3NH3PbCl3) nanopillar crystals embedded in a polymer matrix. The devices can be optoelectronic devices, such as light emitting diodes, which include polymer-perovskite films. The polymer-perovskite films of the devices can be hole transport layers in the devices. The methods of making films may include spin casting a precursor solution followed by thermal annealing.

Abstract: An organic light emitting device is provided. The device has an anode, a cathode, and an emissive layer disposed between and electrically connected to the anode and the cathode. The emissive layer further comprises a compound having two metal centers, in which each metal has an atomic weight greater than 40. A bridging ligand, small molecule, or polymer is coordinated to both metal centers, and at least one photoactive ligand is bound to each metal. In one embodiment, the transition dipole moment of the photoactive ligand bound to the first metal is orthogonal to the photoactive ligand bound to the second metal. In another embodiment, the first metal center and the atoms of the bridging ligand that are coordinated to the first metal center form a plane and the atoms of the bridging ligand that are coordinated to the second metal center form another plane, and the planes form an angle that is between about 80 degrees and 100 degrees. In another embodiment, the bridging ligand is diacetylacetonate.