Perovskite-WS2 Nanosheet Composite Optical Absorbers on Graphene as High-Performance Phototransistors.

Dan-Dan Zhang,Rong-Mei Yu

doi:10.3389/fchem.2019.00257

Dan-Dan Zhang, Rong-Mei Yu

Open Access

https://doi.org/10.3389/fchem.2019.00257

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Abstract

High-responsivity phototransistors with a structure of perovskite-WS2 nanosheet composite optical absorber and a reduced graphene oxide (rGO) channel layer is demonstrated via a facile and low-cost solution-processing method. The WS2 nanosheets are dispersed within the perovskite matrix, forming the perovskite-WS2 bulk heterojunction (BHJ). The hybrid phototransistor exhibits excellent figures of merit including high photoresponsivity of 678.8 A/W, high specific detectivity of 4.99 × 1011 Jones, high EQE value of 2.04 × 105% and rapid response to photoswitching. The high photoresponsivity could be attributed to the WS2 nanosheets induced photo-generated electron-hole separation promotion effects due to the selective electron trapping effects in the WS2 nanosheets, together with the high carrier mobility of the rGO channel. This work provides a promising platform for constructing high-responsivity photodetectors.

Highlights

Graphene has attracted extensive interests for photodetection owing to its ultrahigh carrier mobility and wavelength independent broadband light absorption (Novoselov et al, 2005; Qiao et al, 2015; Han et al, 2019)
We demonstrate a solution-processed phototransistor with a hybrid channel consisting of perovskite/WS2 nanosheet composite optical absorbers and reduced graphene oxide, which exhibits excellent photodetection behaviors
WS2 nanosheets are well-dispersed within the perovskite matrix by a mixed perovskite-WS2 precursor, forming the perovskite-WS2 bulk heterojunction

Summary

Introduction

Graphene has attracted extensive interests for photodetection owing to its ultrahigh carrier mobility and wavelength independent broadband light absorption (Novoselov et al, 2005; Qiao et al, 2015; Han et al, 2019). We demonstrate a solution-processed phototransistor with a hybrid channel consisting of perovskite/WS2 nanosheet composite optical absorbers and reduced graphene oxide (rGO), which exhibits excellent photodetection behaviors.

Results

Conclusion