CH3NH3PbI3/Au/Mg0.2Zn0.8O Heterojunction Self-Powered Photodetectors with Suppressed Dark Current and Enhanced Detectivity

Meijiao Wang; Man Zhao; Dayong Jiang

doi:10.3390/ma16124330

CH₃NH₃PbI₃/Au/Mg_0.2Zn_0.8O Heterojunction Self-Powered Photodetectors with Suppressed Dark Current and Enhanced Detectivity

Materials (Basel). 2023 Jun 12;16(12):4330. doi: 10.3390/ma16124330.

Authors

Meijiao Wang^{1

2}, Man Zhao¹, Dayong Jiang^{1

3}

Affiliations

¹ School of Materials Science and Engineering, Changchun University of Science and Technology, Changchun 130022, China.
² School of Optoelectronic Engineering, Changchun College of Electronic Technology, Changchun 130022, China.
³ Engineering Research Center of Optoelectronic Functional Materials, Ministry of Education, Changchun 130022, China.

Abstract

Interface engineering of the hole transport layer in CH₃NH₃PbI₃ photodetectors has resulted in significantly increased carrier accumulation and dark current as well as energy band mismatch, thus achieving the goal of high-power conversion efficiency. However, the reported heterojunction perovskite photodetectors exhibit high dark currents and low responsivities. Herein, heterojunction self-powered photodetectors, composed of p-type CH₃NH₃PbI₃ and n-type Mg_0.2Zn_0.8O, are prepared through the spin coating and magnetron sputtering. The obtained heterojunctions exhibit a high responsivity of 0.58 A/W, and the EQE of the CH₃NH₃PbI₃/Au/Mg_0.2Zn_0.8O heterojunction self-powered photodetectors is 10.23 times that of the CH₃NH₃PbI₃/Au photodetectors and 84.51 times that of the Mg_0.2ZnO_0.8/Au photodetectors. The built-in electric field of the p-n heterojunction significantly suppresses the dark current and improves the responsivity. Remarkably, in the self-supply voltage detection mode, the heterojunction achieves a high responsivity of up to 1.1 mA/W. The dark current of the CH₃NH₃PbI₃/Au/Mg_0.2Zn_0.8O heterojunction self-powered photodetectors is less than 1.4 × 10^-1 pA at 0 V, which is more than 10 times lower than that of the CH₃NH₃PbI₃ photodetectors. The best value of the detectivity is as high as 4.7 × 10¹² Jones. Furthermore, the heterojunction self-powered photodetectors exhibit a uniform photodetection response over a wide spectral range from 200 to 850 nm. This work provides guidance for achieving a low dark current and high detectivity for perovskite photodetectors.

Keywords: CH3NH3PbI3 photodetectors; Mg0.2Zn0.8O; heterojunction; self-powered photodetectors.

Abstract

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