A light-emitting element according to the present disclosure includes at least one pair of light-emitting layers formed between a cathode and an anode and the at least one pair of light-emitting layers includes, in a stated order from the cathode, a P-type light-emitting layer and an N-type light-emitting layer adjacent to each other.

To provide Cd-free chalcopyrite-based quantum dots with a narrow fluorescence FWHM and a high fluorescence quantum yield. The quantum dots of the present invention contain AgIn.sub.xGa.sub.1-xS.sub.ySe.sub.1-y or ZnAgIn.sub.xGa.sub.1-xS.sub.ySe.sub.1-y (where 0x<1 and 0y1) and exhibit fluorescence properties including a fluorescence FWHM of less than or equal to 45 nm and a fluorescence quantum yield of greater than or equal to 35% in the green wavelength range to the red wavelength range.

A method of producing semiconductor nanoparticles, semiconductor nanoparticles, and a light-emitting device are provided. The method includes heat-treating a mixture containing a salt of Ag, a salt containing at least one of In and Ga, an Se supply source, and an organic solvent at a temperature in the range of above 200 C. to 370 C. In the method, the ratio of the number of Ag atoms to the total number of In and Ga atoms in the mixture is above 0.43 to 2.5. The semiconductor nanoparticles contains Ag, at least one of In and Ga, and Se. The light-emitting device includes a light conversion member containing the semiconductor nanoparticles and a semiconductor light-emitting element.

The ability to upconvert two low energy photons into one high energy photon has potential applications in solar cells, photodetectors and data storage. In this disclosure, CdSe and PbSe semiconductor nanocrystals are combined with molecular emitters (diphenylanthracene and rubrene) to upconvert photons in both the visible and near infrared spectral regions. Absorption of low energy photons by the nanocrystals is followed by energy transfer to the molecular triplet states, which then undergo triplet-triplet annihilation to create high energy singlet states that emit upconverted light. By using conjugated organic ligands on the nanocrystals to form an energy cascade, the upconversion process can be enhanced by up to three orders of magnitude. The use of different combinations of nanocrystals and emitters shows that this platform has great flexibility in the choice of both excitation and emission wavelengths.

Semiconductor nanoparticles are provided. The semiconductor nanoparticles contains Ag, at least one of In and Ga, and Se. An Ag content is 10 mol % to 30 mol %, a total content of the at least one of In and Ga is 15 mol % to 35 mol %, and an Se content is 35 mol % to 55 mol % in the semiconductor nanoparticles. The semiconductor nanoparticles emit light having an emission spectrum with a peak emission wavelength in a range of 500 nm to 900 nm, and a half bandwidth of 250 meV or less upon irradiation with light in a wavelength range of 350 nm to less than 500 nm.

A method for synthesizing two-dimensional (2D) nanosheets comprises heating a bulk material in a solvent. The process is scalable and can be used to produce solution-processable 2D nanosheets with uniform properties in large volumes.

A method of producing nanoparticles comprises effecting conversion of a molecular cluster compound to the material of the nanoparticles. The molecular cluster compound comprises a first ion and a second ion to be incorporated into the growing nanoparticles. The conversion can be effected in the presence of a second molecular cluster compound comprising a third ion and a fourth ion to be incorporated into the growing nanoparticles, under conditions permitting seeding and growth of the nanoparticles via consumption of a first molecular cluster compound.

Quantum dots are proposed. Quantum dots include a multicomponent quantum dot core including four or more elements selected from a combination of Group 11-Group 13-Group 16. The quantum dots may emit band-edge peak wavelength from a red region (590 nm) to an infrared region (700 nm or more).

Methods of nanomanufacturing based on continuous additive nanomanufacturing at fluid interfaces (CANFI). This approach is a fabrication technique that involves, for example, photocuring or printing self-assembled layers. CANFI presents a fabrication capability with significant transformative potential improve (i) the spatial resolution, (ii) the speed, and (iii) the range of material compositions that can be printed. Various articles of manufacture can be made using the methods.

The invention discloses a method for the synthesis of monodispersed luminescent quantum dots of transition metal dichalcogenides (TMDC), single- or few-layered, using a single-step electrochemical exfoliation that involves dilute ionic liquid and water. The method disclosed helps to obtain nanoclusters of TMDC of desired size including small sizes ranging up to 6 nm, by varying the concentration of the electrolyte and the applied DC voltage. The invention further discloses a method by which mono- or few-layered luminescent transition metal dichalcogenides can be directly deposited onto conducting substrates in a uniform manner. The monodispersed single- or few-layered luminescent TMDC and electro-deposited substrates exhibit improved electronic conductivity and new active sites, making them suitable as high-performance electrocatalysts in hydrogen evolution reactions in solar water-splitting applications and also as electrodes for solar cell applications.