Abstract
Lead halide perovskite (LHP) heterojunctions have proven to be promising for achieving low-cost and efficient photodetection. However, the remarkable interfacial non-radiative recombination severely deteriorated the performance of the resulting devices. Herein, surface engineering of SnO(2) with ammonium tetrathiotungstate ((NH(4))(2)WS(4)) has been proposed to effectively passivate the interfacial defects at the LHP CH(3)NH(3)PbI(3)/SnO(2) interface to fabricate high-performance photodetectors (PDs). Experimental and theoretical studies showed that the surface engineering with (NH(4))(2)WS(4) resulted in S substituting for oxygen lattice of SnO(2), which passivated the surface oxygen vacancies of SnO(2). Further studies have shown that the S atoms at the surface of SnO(2) further suppressed the I vacancies and Pb vacancies at the bottom surface of CH(3)NH(3)PbI(3). Finally, improved CH(3)NH(3)PbI(3)/SnO(2) PDs with the responsivity and detectivity of 0.41 A W(-1) and 5 × 10(12) Jones, respectively, at zero bias, have been demonstrated. The results presented in this work provide promising pathways to effectively passivate the interfacial defects of LHP/SnO(2) heterojunctions for achieving efficient photodetection in the future.