Disclosed is a long-afterglow luminescent material, comprising A) at least one light-absorbing agent, B) at least one luminescent agent, and C) at least one photochemical cache agent. The light-absorbing agent and the luminescent agent are compounds having different structures, and the cache agent is selected from one or more compounds of formula (I), (II) and/or (III).

##STR00001##

The material has luminescent intensity reaching the level of commercialized inorganic long-afterglow powder SrAl.sub.2O.sub.4:Eu.sup.2+, Dy.sup.3+, and can emit light when the exciting light is turned off with a light emitting time up to 100 ms to 3600 s.

Provided are a perovskite optoelectronic device containing an exciton buffer layer, and a method for manufacturing the same. The optoelectronic device of the present invention comprises: an exciton buffer layer in which a first electrode, a conductive layer disposed on the first electrode and comprising a conductive material, and a surface buffer layer containing fluorine-based material having lower surface energy than the conductive material are sequentially deposited; a photoactive layer disposed on the exciton buffer layer and containing a perovskite photoactive layer; and a second electrode disposed on the photoactive layer. Accordingly, a perovskite is formed with a combined FCC and BSS crystal structure in a nanoparticle photoactive layer. The present invention can also form a lamellar or layered structure in which an organic plane and an inorganic plane are alternatively deposited; and an exciton can be bound by the inorganic plane, thereby being capable of expressing high color purity.

A light emitting device includes a first electrode, a second electrode, and an emissive layer between the first and second electrodes. The emissive layer comprises quantum dots that are capable of producing circularly polarized luminescence. The quantum dots are chiral structured perovskite quantum dots, each comprising a core having a chiral crystal structure.

The present invention provides an organic material composition and applications thereof. By the combination of the compounds comprised in the organic material composition, the organic material composition makes the element have a lower driving voltage, a higher current efficiency and a longer service life.

Provided are a perovskite light emitting device containing an exciton buffer layer, and a method for manufacturing the same. A light emitting device of the present invention comprises: an exciton buffer layer in which a first electrode, a conductive layer disposed on the first electrode and comprising a conductive material, and a surface buffer layer containing fluorine-based material having lower surface energy than the conductive material are sequentially deposited; a light-emitting layer disposed on the exciton buffer layer and containing a perovskite light-emitter; and a second electrode disposed on the light-emitting layer. Accordingly, a perovskite is formed with a combined FCC and BSS crystal structure in a nanoparticle light-emitter. The present invention can also form a lamellar or layered structure in which an organic plane and an inorganic plane are alternatively deposited; and an exciton can be bound by the inorganic plane, thereby being capable of expressing high color purity.

A photon multiplying material containing a luminescent material having organic semiconductor molecules capable of singlet fission attached thereto, wherein the organic semiconductor molecules are chemically attached to the luminescent material by a linking group and wherein the linking group and the band gap of the luminescent material are selected so that exciton triplet states formed by singlet fission in the attached organic semiconductor molecules can be energy transferred into the luminescent material.

Described herein are gold (III) compounds according to formula (I) for use as emitters in organic light-emitting devices (OLEDs) and methods of making and using said compounds. The gold (III) compound includes a group 15 element containing tridentate ligand and one aryl auxiliary ligand that are both coordinated to the gold (III) metal center to form a series of thermally stable and highly luminescent gold (III) complexes. The gold (III) compounds disclosed herein can be used as light-emitting material for fabrication of OLEDs. The gold (III) compounds can be deposited as a layer or a component of a layer using a solution processing technique or a vacuum deposition process. The gold (III) compounds are robust and can provide electroluminescence with high efficiency and brightness. ##STR00001##

An object of the present invention is to provide a novel electrochromic device (ECD). Disclosed is an electrochromic device (ECD) comprising two metal-complex-based electrochromic thin films individually acting as a working electrode and a counter electrode; (i) one of the two metal-complex-based electrochromic thin films being a film of a cathodically coloring metallo-supramolecular polymer comprising at least one organic ligand having a plurality of metal coordination positions and a metal ion of at least one transition metal and/or lanthanoid metal with the at least one organic ligand and the metal ion being arranged alternately, and the other of the two metal-complex-based electrochromic thin films being a film of an anodically coloring metal hexacyanoferrate (MHCF) represented by the formula: M(II).sub.3[Fe(III)CN.sub.6].sub.2 (where M=Fe, Ni or Zn), and (ii) the electrochromic device having a first conducting substrate; the film of the cathodically coloring metallo-supramolecular polymer; an electrolyte; the film of the anodically coloring metal hexacyanoferrate (MHCF); and a second conducting substrate being arranged in this order.

Herein are described two-dimensional metal organic frameworks (2D MOFs). The 2D MOFs includes a plurality of multivalent metals or metal ions and a plurality of multidentate ligands arranged to form a crystalline structure having a lateral size of at least about 2.5 μm and a thickness of less than about 5 nm. Herein are also described methods for preparing the 2D MOFs. The 2D MOFs can be used, for example, in electrochromic devices such as smart windows and flexible displays.

Complexes and devices, such as organic light emitting devices and full color displays, including a compound of the formula:

##STR00001## wherein: M is Pd.sup.2+, Ir.sup.+, Rh.sup.+, or Au.sup.3+; each of V.sup.1, V.sup.2, V.sup.3, and V.sup.4 is coordinated to M and is independently N, C, P, B, or Si; each of L.sup.1, L.sup.2, L.sup.3, and L.sup.4 is independently a substituted or unsubstituted aryl, cycloalkyl, cycloalkenyl, heterocyclyl, heteroaryl, carbene, or N-heterocyclic carbene; and Z is O, S, NR, CR.sub.2, SiR.sub.2, BR, PR,

##STR00002## where each R is independently substituted or unsubstituted C.sub.1-C.sub.4 alkyl or substituted or unsubstituted aryl.