Abstract: The present disclosure provides a quantum dot and its preparation method, composition and optoelectronic device, the quantum dot includes an inner core and a ZnSe shell located on a surface of the inner core, wherein the ZnSe shell includes at least 4 ZnSe monolayers, surface ligands of the quantum dot include long chain linear zinc carboxylate ligands, branched-chain zinc carboxylate ligands, and short chain linear zinc carboxylate ligands, and the quantum dot is a spherical quantum dot. The quantum dot has a controllable shape and size and uniform morphology. The tensile strain generated inside the ZnSe shell due to lattice mismatch can be significantly alleviated, and the inner core experiences weaker compression strain. Under the synergistic effect of surface ligands of the quantum dot, the quantum dot has a PL quantum yield of close to 100%, and the photophysical stability and photochemical stability are improved.

Abstract: The present disclosure provides a population of alloy nanocrystals, a population of core-shell nanocrystals, and a synthesis method therefor, a composition comprising same, and an electronic device. The population of alloy nanocrystals comprises a plurality of alloy nanocrystals, wherein each of the alloy nanocrystals comprises a first group II element, a second group II element, and a first group VI element, the population of alloy nanocrystals has a Raman peak with a full-width-at-half-maximum of less than or equal to 15 cm?1, and the alloy nanocrystals have an average size greater than a diameter of an exciton of a corresponding bulk alloy compound. The population of alloy nanocrystals has an excellent narrow full-width-at-half-maximum.

Abstract: The present disclosure provides a weakly-confined semiconductor nanocrystal, a preparation method therefor and use thereof. A size of the nanocrystals is larger than an exciton diameter thereof; excitons in the nanocrystal are dynamic excitons, electron-hole Coulomb interaction of the dynamic excitons is insufficient to bind electrons and holes into stable bound excitons at operating temperatures, and the electrons and the holes of the dynamic excitons are constrained by boundaries of the nanocrystal. Since the excitons in the weakly-confined nanocrystals herein possess the characteristics of dynamic excitons, the nanocrystals herein possess unique optical and photoelectric properties distinct from conventional semiconductor nanomaterials. It holds unique value for applications requiring broad-spectrum emission (such as lighting) and significant importance for photovoltaic solar devices, photoelectric detectors, and photocatalysis.