The multiple effects of polyaniline additive to improve the efficiency and stability of perovskite solar cells

Abstract

The introduction of polymer additives is a simple but effective method to achieve highly stable perovskite solar cells (PSCs). However, most polymer additives display the characteristic of being insulating, which will restrain the carrier transport in the perovskite light absorption layer and have a negative impact on the photoelectric performance of the devices. Hence, to address this issue, a new conductive polymer additive of polyaniline (PANI), which has special electrical and optical properties, was employed. Under the multiple effects of PANI, the quality of perovskite films was markedly enhanced, with outstanding crystalline structure, improved light absorption and uniform surface morphology, leading to faster PL quenching and charge transfer. As a result, the device with PANI exhibited a dramatically improved PCE from 16.96% (pristine) to 19.09% and reduced hysteresis behavior. The aging tests indicated that PANI perovskite devices show stronger humidity and heat stability, and they exhibited a larger water contact angle than the pristine perovskite. In particular, a PANI perovskite device maintained 86% of its initial PCE after aging under 50% RH for about 1600 h. Our results reveal that a suitable polymer additive displays a huge potential to improve the PCE and long-term stability of PSCs.