Photoelectron-Extractive and Ambient-Stable CsPbBr3@SnO2 Nanocrystals for High-Performance Photodetection

The severe recombination of carriers and poor stability against moisture environment have limited the application of CsPbX3 (X = Cl, Br, I) nanocrystals in photodetection. Herein, a large-scale synthesis of SnO2-coated CsPbBr3 NCs (abbreviated to CsPbBr3@SnO2 NCs) has been reported for the first time by combining the water-triggered transformation of Cs4PbBr6 NCs and the hydrolysis of tin 2-ethylhexanoate. Owing to the construction of the CsPbBr3/SnO2 heterojunction, the recombination rate of carriers in the CsPbBr3@SnO2 NCs is greatly reduced compared to that of the pristine CsPbBr3 NCs. The stability against water degradation is also improved due to the protection of the SnO2 coating. Accordingly, a CsPbBr3@SnO2-graphene hybrid device for high-performance photodetection is demonstrated. Results show that the responsivity of the device reaches 6.2 x$\ \ensuremath{\times{}}$10(4) A W-1 at 1 V, which is over 496-fold of the pristine CsPbBr3 device. This work not only provides a robust approach for the surface modification of CsPbX3 NCs but also offers useful guidance on the optoelectronic applications with CsPbX3 NCs.

Automated summary

This study reports a large-scale synthesis of SnO2-coated CsPbBr3 nanocrystals, which greatly reduces the carrier recombination rate and improves the stability against water degradation by constructing heterojunction and applying SnO2 coating. A high-performance CsPbBr3@SnO2-graphene hybrid device for photodetection is demonstrated.