Modulating optical properties and interfacial electron transfer of CsPbBr perovskite nanocrystals via indium ion and chlorine ion co-doping.

In this work, we demonstrated an in situ approach for doping CsPbBr nanocrystals (NCs) with In and Cl with a ligand-assisted precipitation method at room temperature. The In and Cl co-doped NCs are characterized by the powder x-ray diffraction patterns, ultraviolet-visible, photoluminescence (PL) spectroscopy, time-resolved PL (TRPL), ultraviolet photoelectron spectroscopy, x-ray photoelectron spectroscopy, and transmission electron microscopy. Based on PL and TRPL results, the non-radiative nature of In-doping induced localized impurity states is revealed. Furthermore, the impact of In and Cl doping on charge transfer (CT) from the NCs to molecular acceptors was investigated and the results indicate that the CT at the interface of NCs can be tuned and promoted by In and Cl co-doping. This enhanced CT is attributed to the enlarged energy difference between relevant states of the molecular acceptor and the NCs by In and Cl upon co-doping. This work provides insight into how to control interfacial CT in perovskite NCs, which is important for optoelectronic applications.