Edge assisted epitaxy of CsPbBr3 nanoplates on Bi2O2Se nanosheets for enhanced photoresponse

Bi2O2Se has been proved to be a promising candidate for electronic and optoelectronic devices due to their unique physical properties. However, it is still a great challenge to construct the heterostructures with direct epitaxy of hetero semiconductor materials on Bi2O2Se nanosheets. Here, a two-step chemical vapor deposition (CVD) route was used to directly grow the CsPbBr3 nanoplate-Bi2O2Se nanosheet heterostructures. The CsPbBr3 nanoplates were selectively grown on the Bi2O2Se nanosheet along the edges, where the dangling bonds provide the nucleation sites. The epitaxial relationships between CsPbBr3 and Bi2O2Se were determined as [200]Bi2O2Se||[110]CsPbBr3 and [110]Bi2O2Se||[200]CsPbBr3 by transmission electron microscopy characterization. The photoluminescence (PL) results reveal that the formation of heterostructures results in the remarkable PL quenching due to the type-I band arrangement at CsPbBr3/Bi2O2Se interface, which was confirmed by ultraviolet photoelectron spectroscopy (UPS) and Kelvin probe measurements, and makes the photogenerated carriers transfer from CsPbBr3 to Bi2O2Se. Importantly, the photodetectors based on the heterostructures exhibit a 4-time increase in the responsivity compared to those based on the pristine Bi2O2Se sheets, and the fast rise and decay time in microsecond. These results indicate that the direct epitaxy of the CsPbBr3 plates on the Bi2O2Se sheet may improve the optoelectronic performance of Bi2O2Se based devices.

Automated summary

This study demonstrates the direct growth of CsPbBr3 nanoplate-Bi2O2Se nanosheet heterostructures on Bi2O2Se nanosheets through a two-step chemical vapor deposition (CVD) route. The heterostructures exhibit significant photoluminescence quenching and fast photoresponse time, suggesting potential improvement of the optoelectronic performance of Bi2O2Se-based devices.