Top-contacts-interface Engineering for High-performance Perovskite Solar Cell with Reducing Lead Leakage

Abstract

Though great achievements have been realized in perovskite solar cells (PSCs), there are still some thorny challenges that exist such as 1) How to minimize the interfacial nonradiative recombination losses; 2) How to balance the power conversion efficiency (PCE) and environmental friendliness of the PSCs1-4. Here, effective top-contacts-interface engineering is developed via using a new multi-active site Lewis base molecule named emtricitabine (FTC)5. Both experimental and theoretical results confirm that a strong chemical interaction exists between FTC and Pb2+. After FTC treatment, the perovskite thin film has fewer defects density than the control film, meanwhile, the interfacial hole extraction becomes better due to the more matched energy level. Upon the FTC passivation, the PCE of the PSCs is improved from 20.83% to 22.24%. Simultaneously, the humidity stability of the PSCs is improved after the FTC modification. Last but not least, the unpackaged target film showed less lead leakage than the control film.