Issue 35, 2021

Understanding the interfacial charge transfer in the CVD grown Bi2O2Se/CsPbBr3 nanocrystal heterostructure and its exploitation in superior photodetection: experiment vs. theory

Abstract

Efficient charge transfer in a 2D semiconductor heterostructure plays a crucial role in high-performance photodetectors and energy harvesting devices. Non-van der Waals 2D Bi2O2Se has enormous potential for high-performance optoelectronics, though very little is known about the interfacial charge transport at the corresponding 2D heterojunction. Herein, we report a combined experimental and theoretical investigation of interfacial charge transfer in the Bi2O2Se/CsPbBr3 heterostructure through various microscopic and spectroscopic tools corroborated with density functional theory calculations. The CVD-grown few-layer Bi2O2Se nanosheet possesses high crystallinity and a high absorption coefficient in the visible-near IR region. We integrated the few-layer Bi2O2Se nanosheet possessing superior electron mobility and CsPbBr3 nanocrystals with high light-harvesting capability for efficient broadband photodetection. The band alignment reveals a type-I heterojunction, and the device under reverse bias reveals a fast response time of 12 μs/24 μs (rise time/fall time) and an improved responsivity in the 390 to 840 nm range due to the effective interfacial charge transfer and efficient interlayer coupling at the Bi2O2Se/CsPbBr3 interface. Notably, a photodetector with a better light on/off ratio and a peak responsivity of ∼103 A W−1 was achieved in the Bi2O2Se/CsPbBr3 heterostructure due to the synergistic effects in the heterostructure under ambient conditions. The DFT analysis of the density of states and charge density plots in the heterostructure revealed a net transfer of electrons/holes from perovskite nanocrystals to Bi2O2Se layers and additional density of states in Bi2O2Se. These results are significant for the development of non-van der Waals heterostructure based high-performance low-powered photodetectors.

Graphical abstract: Understanding the interfacial charge transfer in the CVD grown Bi2O2Se/CsPbBr3 nanocrystal heterostructure and its exploitation in superior photodetection: experiment vs. theory

Supplementary files

Article information

Article type
Paper
Submitted
09 7 2021
Accepted
12 8 2021
First published
13 8 2021

Nanoscale, 2021,13, 14945-14959

Understanding the interfacial charge transfer in the CVD grown Bi2O2Se/CsPbBr3 nanocrystal heterostructure and its exploitation in superior photodetection: experiment vs. theory

M. T. Hossain, M. Das, J. Ghosh, S. Ghosh and P. K. Giri, Nanoscale, 2021, 13, 14945 DOI: 10.1039/D1NR04470B

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