Mesoporous silica nanospheres-containing encapsulation layer for tin-based light-emitting perovskite thin-films towards prolonged ambient stability

Abstract

<p>Metal halide perovskites are an emerging class of semiconductors for a wide range of optoelectronic applications, with lead-based formulations exhibiting impressive device performance. However, the toxic nature of lead-based components in these materials pose a serious challenge, thereby limiting the scope of their applications. In this scenario, tin-based perovskites emerge as a more sustainable choice and are considered as a potential candidate particularly for lightemitting applications because of their broad emission in the yellow region. Nevertheless, poor stability of tin-based perovskites is a major bottleneck as Sn2+ cations tend to readily oxidize to Sn4+. In this work, a top-surface encapsulation layer, consisting of a conventional polymer and oxygen scavenging mesoporous silica nanospheres, is developed to prolong the stability of tin-based perovskites thin-films. The encapsulation layer is spin-coated on top of the yellowemitting HDASnBr4 perovskite thin-films as a composite barrier layer to mitigate Sn2+ oxidation. The solution-processed protective layer effectively prolonged the ambient stability of the oxygen-sensitive HDASnBr4 perovskite thin-films and maintained the light emission for several days while the counterpart without encapsulation lost light emission within a few hours of ambient exposure. This work provides a simple approach to maintain ambient stability of highly sensitive tin-based perovskite thin-films without compromising their light emission capability.<br></p>