Tuning the phase separation of PEDOT:PSS affords efficient lead-free perovskite solar cells

Poly(3,4-ethylenedioxythiphene):poly(styrenesulfonate) (PEDOT:PSS) shows great potential for applications in tin halide perovskite solar cells (TPSCs). Nevertheless, the physicochemical, electrical properties and surface characteristics of pristine PEDOT:PSS are poorly suitable for high-quality tin halide perovskite films, as well as for efficient carrier transport. In this work, we tuned the phase separation of PEDOT and PSS chains by ammonium carbamate (AC). The modified film showed a lower trap density and more facile carrier transport than did the pristine film. Consequently, the target TPSCs achieved a substantially improved short-circuit photocurrent (Jsc) and open-circuit voltage (Voc), together with a markedly improved power conversion efficiency (PCE) from 9.48% to 11.24%.