Fig. 12: Chiral upconversion nanoparticles based on chiral liquid-crystalline template.

a Schematic illustration of switchable CPL in chiral UCNPs under electric field. b Upconversion emission spectra of chiral UCNPs with different incident excitation intensities of 980 nm NIR light. c Upconversion CPL spectra of chiral UNCPs upon NIR irradiations. Reproduced with permission from ref. 304. Copyright 2020, WILEY-VCH