NSRRC Activity Report 2022

Chemical Science 031 Fig. 1 : HEP NCs. (a) Visual diagram under excited ultraviolet light, (b) PL spectra with clear emission blueshift, (c) increase in the PL quantum yield with the involvement of secondary elements, and (d) reduction in the PL lifetime upon high-entropy alloying. [Reproduced from Ref. 2] and they are regarded as promising candidates for application in display technology. Colloidal MHPs can generate numerous excitons after photoexcitation or electrical excitation, and these excitons tend to attain a stable state and recombine to generate visible light with a specific wavelength, thereby realizing a color display function. In particular, colloidal MHPs can achieve light color changes by altering the lengths of the different alkyl chains of ligands to produce quantum confinement effects. With this advantage, only a single emission material, which serves as a host material, is required to achieve full- wavelength visible light display capability. However, heavy metal hazards and environmental stability continue to be the key challenges for the commercial development of MHPs. Chih-Jen Shih (ETH Zürich, Switzerland) and Yu-Cheng Chiu (National Taiwan University of Science and Technology) Fig. 2 : (a) Synchrotron X-ray scattering analysis of HEP NCs. Magnified (100) plane peaks extracted from the GIWAXS patterns of bare MAPbBr 3 , single- doped perovskite NCs, and HEP NCs. (b) GIWAXS patterns of undoped MAPbBr 3 NCs (left) and MA(PbMgZnCd)Br 3 NCs. (c) Reduced lead content in HEP NCs. Characterized Br/Pb (black dots) and Br/(Pb + M) (M = Mg 2+ , Zn 2+ , and Cd 2+ ) ratios (red dots) obtained through energy-dispersive X-ray spectroscopy analysis. [Reproduced from Ref. 2]