Excess polymer-assisted crystal growth method for high-performance perovskite photodetectors

Abstract

Defects in grain boundaries and at the surface of perovskite polycrystalline film lead to nonradiative recombination losses and ion migration, which seriously affects the performance and stability of optoelectronic devices. However, the process of passivation by using functional groups in polymers is expected to solve the problem. In this work, a tandem-like perovskite photodetector (PD) is developed, and an improved solution process is proposed to promote perovskite crystal growth and reduce the horizontal grain boundaries by using excess poly(methyl methacrylate) (PMMA) as anti-solvent. In addition, PMMA retained in perovskite grains acts as an interlayer for storing photocarriers, reducing the dark current and enhancing the PD gain. As a result, optimal perovskite PD exhibits a peak specific detectivity of 3.38 × 1012 Jones, a high responsivity of 5.65 A/W, a linear dynamic range of 80 dB, and an external quantum efficiency of 1321% under 532 nm illumination at the small bias of − 1 V. In addition, the PD has a fast response (5.90 μs rise time, 6.75 μs decay time). These results combine to provide a low-cost method for designing high-performance, ultrafast-response perovskite optoelectronic devices with low power consumption.