Piezo-phototronic Effect Enhanced Photodetector Based on CH₃NH₃PbI₃ Single Crystals

TLDR

Piezoelectric organic–inorganic lead halide perovskites have attracted attention in optoelectronic devices, yet their piezoelectric properties for performance modulation are rarely reported. The study investigates a photodetector based on CH₃NH₃PbI₃ single crystals whose performance is modulated via the piezo‑phototronic effect. An experimental photodetector was fabricated from MAPbI₃ single crystals, employing piezoelectric polarization charges to tune optoelectronic processes at the interface. The MAPbI₃ crystal exhibited a piezoelectric coefficient of 10.81 pm/V, and under 680 nm illumination the photodetector’s current increased by ~120 % and response speed improved 3× (on) and 2× (off) when 43.48 kPa compressive pressure was applied, proving effective performance enhancement via the piezo‑phototronic effect.

Abstract

Piezoelectric organic–inorganic lead halide perovskites have recently attracted much attention in the field of optoelectronic devices. However, their piezoelectric properties as a possible way to modulate device performances have rarely been reported. Here, we study experimentally a photodetector based on CH3NH3PbI3(MAPbI3) single crystals, whose performance is effectively modulated via an emerging effect—the piezo-phototronic effect, which is to use the piezoelectric polarization charges to tune the optoelectronic processes at the interface. A piezoelectric coefficient of 10.81 pm/V of the CH3NH3PbI3 single crystal is obtained. Under 680 nm laser illumination with a power density of 3.641 mW/cm2 and at an external bias of 2 V, compared to the case without straining, the light current of the photodetector is enhanced by ∼120% when a 43.48 kPa compressive pressure is applied. The response speed of the photocurrent is 3 and 2 times faster than the cases without applying pressure for the light-on and light-off states, respectively. This work proves that the performance of the photodetector based on MAPbI3 single crystals can be effectively enhanced by the piezo-phototronic effect, providing a good method for optimizing the performance of future perovskite-based optoelectronic devices.