A highly rigid tetradentate ligand is combined with a gold(III) ion as a thermally stable tetradentate gold(III) complex. The tetradentate gold(III) complex is a tetradentate gold(III) compound that can be used as a light-emitting material which can be used for fabricated of light-emitting devices such as an organic light-emitting diode (OLED). The tetradentate gold(III) compound can be deposited as a layer or a component of a layer using a solution-process or a vacuum deposition process. The luminescent tetradentate gold(III) compounds are robust and can provide electroluminescence (EL) with a high efficiency and brightness.

Various embodiments may provide a device for providing a first optical light of a first wavelength and a second optical light of a second wavelength. The device may include a halide perovskite structure including a first pattern and a second pattern different from the first pattern, so that the first pattern is configured to provide the first optical light of the first wavelength and the second pattern is configured to provide the second optical light of a second wavelength different from the first wavelength, upon a light incident on the first pattern and the second pattern. The halide perovskite structure may include a halide perovskite material.

Devices comprising an organic light emitting device are provided. The devices can include an anode; a cathode; and an organic layer, disposed between the anode and the cathode. The organic layer comprising at least one host material comprising a phosphorescent complex comprising novel phosphorescent trigonal copper carbene complexes. The complex comprise a carbene ligand coordinated to a three coordinate copper atom. The complex may be used in organic light emitting devices. In particular, the complexes may be especially useful in OLEDs used for lighting applications.

A light emitting device includes a first electrode, a hole transporting layer in contact with the first electrode, a second electrode, an electron transporting layer in contact with the second electrode; and an emissive layer between the hole transporting layer and the electron transporting layer. The emissive layer includes a metal-assisted delayed fluorescent (MADF) emitter, a fluorescent emitter, and a host, and the MADF emitter harvests electrogenerated excitons and transfers energy to the fluorescent emitter.

Colloidal perovskite nanoplatelets can provide a material platform, with tunability extending from the deep UV, across the visible, into the near-IR. The high degree of spectral tunability can be achieved through variation of the cation, metal, and halide composition as well as nanoplatelet thickness.

A dual host system for OLEDs that contains hole-transporting indolocarbazole and electron-transporting indolocarbazole exhibiting superior performance in the OLEDs is disclosed.

A two-dimensional (2D) hybrid perovskite based opto-electric device includes first and second 2D perovskite layers extending along a given plane; an organic layer sandwiched between the first and second 2D perovskite layers, and extending along the given plane; an external organic layer formed on the first 2D perovskite layer and configured to directly face an ambient of the opto-electric device and to extend along the given plane; and electrical pads directly formed over the external organic layer. A roughness of the external organic layer is smaller than 10 nm.

An organometallic compound represented by Formula 1: ##STR00001## wherein, in Formula 1, groups and variables are the same as described in the specification.

There is provided a method of preparing formamidinium lead halide perovskite quantum dots having a photoluminescence quantum yield higher than before. The disclosed method comprises steps of: preparing a lead halide solution by dissolving lead halide (II), oleic acid and oleylamine in a nonpolar solvent; preparing a formamidinium solution by dissolving formamidine acetate salt and oleic acid in a nonpolar solvent; mixing the formamidinium solution and the lead halide solution to form quantum dots; and centrifuging the mixed solution to obtain sediment; dispersing the sediment in a nonpolar solvent to prepare a crude quantum dot solution; mixing the crude quantum dot solution with methyl acetate; and centrifuging the crude quantum dot solution mixed with the methyl acetate to obtain sediment as purified quantum dots. The durable quantum dots are stably formed by injecting the lead halide solution into the formamidinium solution heated at 60° C.-90° C.

Self-assembled structures formed of a plurality of cyclic peptides which are in association with metal ions is provided. The cyclic peptides are each of from 2 to 6 amino acid residues, and two or more of the amino acid residues are each independently an aromatic amino acid residue. The self-assembled structures exhibit photoluminescence and can be used or incorporated in light emitting systems.