Provided are an organic-inorganic-hybrid perovskite nanocrystal particle light-emitter having a two-dimensional structure, a method for producing the same, and a light emitting device using the same. The organic-inorganic-hybrid perovskite nanocrystal particle light-emitter having a two-dimensional structure comprises an organic-inorganic-hybrid perovskite nanocrystal structure having a two-dimensional structure which can be dispersed in an organic solvent. Accordingly, the nanocrystal particle light-emitter comprises an organic-inorganic-hybrid perovskite nanocrystal having a crystal structure combining FCC and BCC; forms a lamellar structure where organic planes and inorganic planes are accumulated in an alternating manner; and can exhibit high color purity by confining excitons in the inorganic planes. In addition, since the exciton diffusion distance decreases and exciton binding energy increases, it is possible to prevent exciton annihilation caused by thermal ionization and delocalization of charge carriers, such that the nanocrystal particle light-emitter can have high luminescence efficiency at room temperature.

Provided are: a light-emitting layer for a perovskite light-emitting device; a method for manufacturing the same; and a perovskite light-emitting device using the same. The method of the present invention for manufacturing a light-emitting layer for an organic and inorganic hybrid perovskite light-emitting device comprises a step of forming a first nanoparticle thin film by coating, on a member for coating a light-emitting layer, a solution comprising organic and inorganic perovskite nanoparticles including an organic and inorganic perovskite nanocrystalline structure. Thereby, a nanoparticle light emitter has therein an organic and inorganic hybrid perovskite having a crystalline structure in which FCC and BCC are combined; forms a lamella structure in which an organic plane and an inorganic plane are alternatively stacked; and can show high color purity since excitons are confined to the inorganic plane. In addition, it is possible to improve the luminescence efficiency and luminance of a device by making perovskite as nanoparticles and then introducing the same into a light-emitting layer.

A lighting device includes a light source and a photoconversion layer including a perovskite compound represented by Formula 1. The perovskite compound absorbs at least part of light emitted from the light source and emits light having a different wavelength range from the absorbed light:

[A][B][X].sub.3  <Formula 1>

In Formula 1, A is at least one monovalent organic cation, at least one a monovalent inorganic cation, or any combination thereof, B is at least one divalent inorganic cation, and X is at least one monovalent anion.

New organic materials having polyaromatic structure containing boron and high triplet energy are disclosed. The high triplet energy materials are useful as host materials in PHOLEDs and improve device quantum efficiency and stability.

Provided are a core-shell structured perovskite nanocrystalline particle light-emitting body, a method of preparing the same, and a light emitting device using the same. The core-shell structured organic-inorganic hybrid perovskite nanocrystalline particle light-emitting body or metal halide perovskite nanocrystalline particle light-emitting body is able to be dispersed in an organic solvent, and has a perovskite nanocrystal structure and a core-shell structured nanocrystalline particle structure. Therefore, in the perovskite nanocrystalline particle light-emitting body of the present invention, as a shell is formed of a substance having a wider band gap than that of a core, excitons may be more dominantly confined in the core, and durability of the nanocrystal may be improved to prevent exposure of the core perovskite to the air using a perovskite or inorganic semiconductor, which is stable in the air, or an organic polymer.

The present disclosure relates to a composition that includes a first phase that includes a perovskite and a second phase that includes a salt, a polymer, and a switching molecule, where the first phase and the second phase are in physical contact, and the composition is capable of reversibly switching between a substantially opaque state and a substantially transparent state.

Photovoltaic cells incorporating the compounds A/M/X compounds as hole transport materials are provide. The A/M/X compounds comprise one or more A moieties, one or more M atoms and one or more X atoms. The A moieties are selected from organic cations and elements from Group 1 of the periodic table, the M atoms are selected from elements from at least one of Groups 3, 4, 5, 13, 14 or 15 of the periodic table, and the X atoms are selected from elements from Group 17 of the periodic table.

Provided is an electrochemical luminescent cell 10 having a luminescent layer 12 and electrodes 13, 14 provided on each surface of the luminescent layer 12. The luminescent layer 12 comprises an organic polymeric luminescent material and a combination of at least two organic salts. In particular, the luminescent layer preferably comprises a combination of at least two types of ionic liquids represented by formula (1) (wherein R.sub.1, R.sub.2, R.sub.3 and R.sub.4 each represent an optionally-substituted alkyl group, alkoxy alkyl group, trialkylsilylalkyl group, alkenyl group, alkynyl group, aryl group or heterocylic group. R.sub.1, R.sub.2, R.sub.3 and R.sub.4 may be the same or different. M represents N or P. X.sup.− represents an anion.)

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.

A synchronized piezoelectric and luminescence (SPL) material includes a core layer including light-emitting particles and a shell layer which is attached onto a surface of the core layer and includes ligands having a piezoelectric property. Therefore, a piezoelectric property and a luminescent property can be simultaneously implemented using a single SPL material in which piezoelectric ligands and light-emitting particles are chemically coupled.