Apparent Piezo-Photocurrent Modulation in Methylammonium Lead Iodide Perovskite Photodetectors

Methylammonium lead iodide perovskite (MAPbI(3)) have recently been found to have piezoelectricity which can enhance the performance of MAPbI(3)-based photodetectors in the form of piezo-phototronic effects or can be employed in fabricating hybrid photovoltaic devices. In this work, the effect of an external force in different directions on the photocurrent of a lateral structure of an indium tin oxide (ITO)-MAPbI(3)-ITO photodetector is investigated. The photodetector is fabricated by using the capillary motion of a solution containing the perovskite precursor on a microchannel. The structure is characterized by scanning electron microscopy, X-ray diffraction, and atomic force microscopy. The current-voltage characteristics and current transient responses are measured under different conditions of dark and light. Additionally, an apparent piezo-photocurrent modulation is observed under both normal and transverse forces on MAPbI(3) by testing the device under normal forces and bending conditions (inward and outward). In the highest state, the photocurrent is increased by 97% when 340 kPa normal force is applied to the device. At this state, the device shows a I-ph/I-dark of 3250 at 2.0 V bias with a photocurrent of approximate to 6.9 mu A and responsivity of 14.56 mA W-1. These results promise utilizing MAPbI(3) in piezotronic applications and hybrid energy harvesters.