Organic–inorganic perovskites have been shown to have excellent optoelectronic properties. Further, layered perovskites have been demonstrated, utilizing quantum confinement to achieve emission blue-shifted from the bulk band gap. Here, we tune this blue-shift to build LEDs that span the visible spectrum. We demonstrate that electroluminescence from red-shifted layers dominates emission from mixed-thickness devices and that the addition of excess ligand is necessary to drive emission toward blue-shifted layers. By tuning the thickness of the layers, we build LEDs with blue emission utilizing the lead bromide system and orange emission utilizing the lead iodide system. Finally, we demonstrate that these materials suffer reversible degradation under an applied electric field. The spectrally narrow emission, combined with the favorable electronic properties of perovskite materials and access to shorter emission wavelengths through quantum confinement, demonstrates the promise of these materials as a new plat...

Tunable Light-Emitting Diodes Utilizing Quantum-Confined Layered Perovskite Emitters

PROBLEM TO BE SOLVED: To provide a quantum dot composite material and a manufacturing method and an application thereofSOLUTION: The quantum dot composite material includes an all-inorganic perovskite quantum dot and a modification protection film on a surface of the all-inorganic perovskite quantum dot The all-inorganic perovskite quantum dot has the chemical formula CsPb(ClBrI), where 0≤a≤1 and 0≤b≤1SELECTED DRAWING: None

Quantum dot composite material and manufacturing method and application thereof

Disclosed is a plurality of metal chalcogenide nanocrystals coated with multiple organic and inorganic ligands; wherein the metal is selected from Hg, Pb, Sn, Cd, Bi, Sb or a mixture thereof; and the chalcogen is selected from S, Se, Te or a mixture thereof; wherein the multiple inorganic ligands includes at least one inorganic ligands are selected from S2−, HS−, Se2−, Te2−, OH−, BF4−, PF6−, Cl−, Br−, I−, As2Se3, Sb2S3, Sb2Te3, Sb2Se3, As2S3 or a mixture thereof; and wherein the absorption of the C—H bonds of the organic ligands relative to the absorption of metal chalcogenide nanocrystals is lower than 50%, preferably lower than 20%.

Mid and far-infrared nanocrystals based photodetectors with enhanced performances

Lead halide perovskite nanocrystals (PNCs) are emerging as promising light emitters to be actively explored for high color purity and efficient light-emitting diodes. However, the most reported lead halide perovskite nanocrystal light-emitting diodes (PNCLEDs) encountered issues of emission line width broadening and operation voltage elevating caused by the quantum confinement effect. Here, we report a new type of PNCLED using large-size CsPbBr3 PNCs overly exceeding the Bohr exciton diameter, achieving ultranarrow emission line width and rapid brightness rise around the turn-on voltage. We adopt calcium-tributylphosphine oxide hybrid ligand passivation to produce highly dispersed large-size colloidal CsPbBr3 PNCs with a weak size confinement effect and also high photoluminescence quantum yield (∼85%). Utilizing these large-size PNCs as emitters, we manifest that the detrimental effects caused by the quantum confinement effect can be avoided in the device, thereby realizing the highest color purity in green PNCLED, with a narrow full width at half-maximum of 16.4 nm and a high corrected maximum external quantum efficiency of 17.85%. Moreover, the operation half-life time of the large-size PNCLED is 5-fold of that based on smaller-size PNCs. Our work provides a new avenue for improving the performance of PNCLEDs based on unconventional large-size effects.

High Color Purity and Efficient Green Light-Emitting Diode Using Perovskite Nanocrystals with the Size Overly Exceeding Bohr Exciton Diameter.

Embodiments of the present disclosure provide for passivated quantum dots, methods of making passivated quantum dots, methods of using passivated quantum dots, and the like.

Air-stable surface-passivated perovskite quantum dots (qds), methods of making these qds, and methods of using these qds

Provided are perovskite nanocrystalline particle and an optoelectronic device using the same. The perovskite nanocrystalline particle may include a perovskite nanocrystalline structure while being dispersible in an organic solvent. Accordingly, the perovskite nanocrystalline particle in accordance with the present invention has therein a perovskite nanocrystal having a crystalline structure in which FCC and BCC are combined; forms a lamellar structure in which an organic plane and an inorganic plane are alternately stacked; and can show high color purity since excitons are confined to the inorganic plane. In addition, the perovskite nanocrystalline particle have a particle size greater than or equal to a Bohr diameter beyond a quantum confinement effect, and simultaneously can implement high emission efficiency and emission wavelength which is almost not dependent on particle size. Furthermore, the perovskite nanocrystalline particle in accordance with the present invention, as a nanoparticle which is dispersible in an organic solvent, is applicable in various electronic devices such as light emitting devices, lasers, solar cells, etc.

Perovskite nanocrystalline particles and optoelectronic device using same

A perovskite nanocrystal particle light emitting body with a core-shell structure, a method for fabricating the same, and a light emitting element using the same are provided. An organic/inorganic hybrid perovskite nanocrystal particle light emitting body with a core-shell structure or a metal halide perovskite nanocrystal particle light emitting body is dispersible in an organic solvent, comprises a perovskite nanocrystal structure and has a nanocrystal particle structure with a core-shell structure. Accordingly, the perovskite nanocrystal particle light emitting body according to the present invention allows exciton to be better restricted in a core by forming a shell with a material having a larger bandgap than the core, and can improve the durability of nanocrystals by preventing core perovskite from being exposed to air using perovskite which is stable in air, or an inorganic semiconductor or an organic polymer,.

Perovskite nanocrystal particle light emitting body with core-shell structure, method for fabricating same, and light emitting element using same

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 an organic-inorganic hybrid perovskite light emitting body; and a second electrode disposed on the light-emitting layer. Accordingly, an organic-inorganic hybrid perovskite is formed with a combined FCC and BSS crystal structure in a nanoparticle light-emitting body; the present invention forms a lamellar structure in which an organic plane and an inorganic plane are alternatively deposited; and an exciton is bound by the inorganic plane, thereby being capable of expressing high color purity.

Perovskite light emitting device containing exciton buffer layer and method for manufacturing same

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.

Light-emitting layer for perovskite light-emitting device, method for manufacturing same, and perovskite light-emitting device using same

Provided are an organic-inorganic hybrid perovskite nanocrystal particle light emitting body 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 emitting body 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 emitting body 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 a charge carrier, such that the nanocrystal particle light emitting body can have light emitting efficiency at high room temperature.

Organic-inorganic hybrid perovskite nanocrystal particle light emitting body having two-dimensional structure, method for producing same, and light emitting device using same

Sanghyuk Im

Papers

Perovskite nanocrystalline particles and optoelectronic device using same

Perovskite nanocrystal particle light emitting body with core-shell structure, method for fabricating same, and light emitting element using same

Perovskite light emitting device containing exciton buffer layer and method for manufacturing same

Light-emitting layer for perovskite light-emitting device, method for manufacturing same, and perovskite light-emitting device using same

Organic-inorganic hybrid perovskite nanocrystal particle light emitting body having two-dimensional structure, method for producing same, and light emitting device using same