A Self‐Powered Photodetector Based on MAPbI3 Single‐Crystal Film/n‐Si Heterojunction with Broadband Response Enhanced by Pyro‐Phototronic and Piezo‐Phototronic Effects

Abstract Pyro‐phototronic and piezo‐phototronic effect have shown their important roles for high performance heterojunction‐based photodetectors (PDs). Here, a coupling effect of pyro‐phototronic and piezo‐phototronic effect is utilized to fabricate a self‐powered and broadband PD based on the MAPbI 3 single‐crystal film/n‐Si heterojunction. First, by using the pyro‐phototronic effect derived from MAPbI 3 , the maximum photoresponsivity of the self‐powered PD is 1.5 mA W −1 for 780 nm illumination, which is enhanced by more than 20 times in consideration of the relative peak‐to‐peak output current. Light‐induced temperature change in MAPbI 3 film will create pyro‐charges distributed at heterojunction interface, resulting in a downward bending of the energy band, facilitating the transport of photon‐generated electrons and holes, and generating spike‐like output currents. Second, piezo‐phototronic effect is further introduced by applying vertical pressures onto the PD. With a vertical pressure of 155 kPa, the responsivity can be improved by more than 120% compared to the condition with no pressure. The overall enhancement is due to the piezo‐phototronic and pyro‐phototronic coupling effects which utilize the polarization charges to modulate the band structure of heterojunction. These results provide a promising approach to develop high‐performance self‐powered and broadband perovskite‐based PDs by coupling pyro‐phototronic and piezo‐phototronic effect.