Highly Sensitive, Fast Response Perovskite Photodetectors Demonstrated in Weak Light Detection Circuit and Visible Light Communication System

Abstract

Organic-inorganic hybrid perovskite (OIHP) photodetectors have presented unprecedented device performance mainly owing to outstanding material properties. However, the solution-processed OIHP polycrystalline thin films with defective surface and grain boundaries always impair the key parameter of photodetectors. Herein, a nonfullerene passivation layer exhibits more efficient passivation for OIHP materials to dramatically reduce the trap density of state, yielding a dark current as low as 2.6 × 10-8 A cm-2 under -0.1 V. In addition, the strong absorption in near-infrared (NIR) region of nonfullerene/C60 heterojunction broadens the detectable range to over 900 nm by effective charge transport, ultimately leading to a specific detectivity of 1.45 × 1012 and 7.37 × 1011 cm Hz1/2 W-1 at 650 and 820 nm, respectively. Encouragingly, the response speed of 27 ns is obtained at 0.6 mm2 of device area by removing constrain from the resistance-capacitance constant. Moreover, the prominent practical application of the photodetector is demonstrated in a weak light detection circuit and a visible light communication system. It is believed that the OIHP photodetectors with high sensitivity, NIR photoresponse, and ultrafast speed would pave the way to commercial applications.