AUTHOR=Zhang Dan-Dan , Yu Rong-Mei 

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

JOURNAL=Frontiers in Chemistry

VOLUME=7

YEAR=2019

URL=https://www.frontiersin.org/journals/chemistry/articles/10.3389/fchem.2019.00257

DOI=10.3389/fchem.2019.00257

ISSN=2296-2646

ABSTRACT=<p>High-responsivity phototransistors with a structure of perovskite-WS<sub>2</sub> nanosheet composite optical absorber and a reduced graphene oxide (rGO) channel layer is demonstrated via a facile and low-cost solution-processing method. The WS<sub>2</sub> nanosheets are dispersed within the perovskite matrix, forming the perovskite-WS<sub>2</sub> 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 × 10<sup>11</sup> Jones, high EQE value of 2.04 × 10<sup>5</sup>% and rapid response to photoswitching. The high photoresponsivity could be attributed to the WS<sub>2</sub> nanosheets induced photo-generated electron-hole separation promotion effects due to the selective electron trapping effects in the WS<sub>2</sub> nanosheets, together with the high carrier mobility of the rGO channel. This work provides a promising platform for constructing high-responsivity photodetectors.</p>