Addressing ambient stability challenges in pure FASnI3 perovskite solar cells through organic additive engineering

Abstract

Tin halide perovskite solar cells (Sn-PSCs) have emerged as promising alternatives to their lead-based counterparts. However, their potential for commercialization is threatened by their inherent stability issues and lower efficiencies that have not yet matched those of established technologies. Therefore, in this work we strategically designed and synthesized two novel organic compounds, referred to as OM4 and OM6, which have been successfully incorporated as additives into pure FASnI₃ PSCs enhancing the crystal properties and simultaneously acting as protective and passivating agents. Through a systematic exploration of chemical interactions, OM4 and OM6 demonstrated a remarkable ability to improve film morphology and optical properties. Consequently, both additives significantly contributed to the enhancement of the overall device performances and exhibited impressive stabilities in the ambient atmosphere, which is attributed to their hydrophobic nature. Notably, the unencapsulated devices incorporating OM4 and OM6 retained over 80% and 90% of their initial power conversion efficiency (PCE) after 250 hours in the ambient atmosphere at RH = 30%, respectively; in contrast, the devices without any of the organic additives suffered complete degradation after 72 hours under the same conditions. As a result, this work opens new possibilities in the rational design and development of organic additives capable of mitigating the instability and low-performance issues commonly associated with Sn-PSCs.