Heterostructure of CsPbBr3-CdS perovskite quantum dots for enhanced stability and charge transfer

Abstract CsPbBr3 quantum dot (PQD) was interfaced with CdS quantum dot (QD), via modified hot injection method to form a heterostructure, across whose interface a significantly enhanced charge transfer is demonstrated. Formation of heterostructure (with retention of individual characteristics) was evidenced by various spectroscopy, microscopy and DFT tools. The heterostructure is observed to be much stable (one acting as pseudo protecting layer for the other) with enhanced electron lifetime and favorable band energy offset. CdS QDs reduce the strain within PQDs by holding them in a matrix kind of a structure, thus passivating the uncoordinated sites. It thus holds potential to be exploited for faster charge transfer in solar cell and other optoelectronic applications. Nature of PL quenching with growth of CdS QDs on PQDs, suggest energy transfer. The optimized formulation was also applied to liquid junction solar cells as sensitizers just to evidence the better electron transport, and charge separation properties.