Methods are disclosed to restore the halide ions lost in the purification (ligand removal) of photoluminescent cesium lead halide or FA lead halide perovskite quantum dots. Quantum dots thus prepared can be used to deposit solid films with high packing density featuring dots with <0.4 nm gaps therebetween, low trap density 1/40 of previously reported, high mobility 100× previously reported, high photoluminescent quantum yield exceeding 90%, high external quantum yield exceeding 20%, and increased stability under electrical current. The quantum dots are used to formulate inks suitable for ink jet printing, drop casting, spin coating, and other solution-based methods for forming emissive layers used in light producing semiconductor devices.

A compound has a perovskite type crystal structure containing A which is a monovalent cation, B which is a metal ion, and X which is a halide ion as components. The perovskite type crystal structure has a unit cell volume of 0.2000 nm.sup.3 or more and 0.2150 nm.sup.3 or less, an ionic radius of B of 0.7 Å or more and 1.4 Å or less, and an ionic radius of X of 0.5 Å or more and 2.5 Å or less.

An A/M/X crystalline material, a photovoltaic device, and preparation methods thereof are provided. The photovoltaic device includes a photoactive crystalline material layer. The photoactive crystalline material layer includes a penetrating crystal, where the penetrating crystal is a crystal penetrating through the photoactive crystalline material layer, and a percentage p of a quantity of penetrating crystals in a total quantity of crystals of the photoactive crystalline material layer is ≥80%. The photoactive crystalline material layer includes a backlight side and a backlight crystal, where the backlight crystal is a crystal exposed to the backlight side and has a backlight crystal face exposed to the backlight side. At least one region of the backlight side has an average flatness index R.sub.avg being ≤75.

Provided herein is a method of preparing carbon-graphene-lead composite particles, comprising the steps of forming a dispersion of lead particles, graphene particles and cellulose in an aqueous solution, spray drying the dispersion to aggregate the lead particles, graphene particles and cellulose to form cellulose-graphene-lead composite particles, and heating the cellulose-graphene-lead composite particles, to carbonize the cellulose to result in the formation of the carbon-graphene-lead composite particles.

The present disclosure relates to a method that includes treating a liquid that includes a first precursor at a concentration C.sub.1, a second precursor at a concentration C.sub.2, a third precursor at a concentration C.sub.3, and an additive at a concentration C.sub.4, where the treating results in a perovskite, each of C.sub.1, C.sub.2, and C.sub.3 are between 0.001 M and 100 M, inclusively, and at least one of C.sub.4/C.sub.1 or C.sub.4/C.sub.2 equals a ratio greater than or equal to zero

A method for forming CsPbBr.sub.3 perovskite nanocrystals into a two-dimensional (2D) nanosheet includes providing CsPbBr.sub.3 perovskite nanocrystals; mixing the CsPbBr.sub.3 perovskite nanocrystals into a mixture of a first solvent and a second solvent, to form a solution of the CsPbBr.sub.3 perovskite nanocrystals, the first solvent, and the second solvent; and forming an optoelectronic device by patterning the CsPbBr.sub.3 perovskite nanocrystals into a nanosheet, between first and second electrodes. The first solvent is selected to evaporate before the second solvent.

A flexible photovoltaic device is provided. The flexible photovoltaic device includes a flexible inorganic halide perovskite. The flexible inorganic halide perovskite is free of organic components, has a thickness of greater than or equal to about 1 μm to less than or equal to about 1 nm, and has an average grain size of less than or equal to about 500 nm.

Embodiments of the present disclosure generally describe scintillation materials, including colloidal scintillation materials and solid scintillation materials, methods of preparing the scintillation materials, applications of the scintillation materials, methods of using the scintillation materials, and the like.

Methods are disclosed to restore the halide ions lost in the purification (ligand removal) of photoluminescent cesium lead halide or FA lead halide perovskite quantum dots. Quantum dots thus prepared can be used to deposit solid films with high packing density featuring dots with <0.4 nm gaps therebetween, low trap density 1/40 of previously reported, high mobility 100× previously reported, high photoluminescent quantum yield exceeding 90%, high external quantum yield exceeding 20%, and increased stability under electrical current. The quantum dots are used to formulate inks suitable for ink jet printing, drop casting, spin coating, and other solution-based methods for forming emissive layers used in light producing semiconductor devices.

The present invention relates to the field of luminescent crystals (LCs), and more specifically to Quantum Dots (QDs) of formula M.sup.1.sub.aM.sup.2.sub.bX.sub.c, wherein the substituents are as defined in the specification. The invention provides methods of manufacturing such luminescent crystals, particularly by dispersing suitable starting materials in the presence of a liquid and by the aid of milling balls; to compositions comprising luminescent crystals and to electronic devices, decorative coatings; and to intermediates comprising luminescent crystals.