Ce4+ doping to modulate electrochemical and radiative-charge-transfer behaviors of CsPbBr3 perovskite nanocrystals

Tunable morphology and radiative charge transfer of perovskite nanocrystals (PNCs) were achieved by heterovalently doping CsPbBr3 PNCs with Ce(IV) cation in a hot-injection and doping-in-growth combined way. Ce(IV)-doping could bring out a new tetragonal CsPb2Br5 phase within the parent PNCs, and transformcubic CsPbBr3 PNCs to Ce4+-doped CsPbBr3 PNCs with a dot-shaped morphology of smaller size. Ce4+-doped CsPbBr3 PNCs exhibited enhanced absorption and electrochemical oxidative response as well as decreased photoluminescence and electrochemiluminescence than the parent CsPbBr3 PNCs. Processing Ce4+-doped CsPbBr3 PNCs with NH3 center dot H2O could eliminate the effects of ionic Ce(IV) dopants via forming CeO2, and enable CsPbBr3-CeO2 hybrids to directionally grow to columnar-morphology with partially restored photoluminescence and electrochemiluminescence.