Mitigating <i>V</i>_oc Loss in Tin Perovskite Solar Cells via Simultaneous Suppression of Bulk and Interface Nonradiative Recombination

Tin-based perovskite solar cells (PSCs) have recently attracted extensive attention as a promising alternative to lead-based counterparts due to their low toxicity and narrow band gap. However, the severe open-circuit voltage (Voc) loss remains one of the most significant obstacles to further improving photovoltaic performance. Herein, we report an effective approach to reducing the Voc loss of tin-based PSCs. We find that introducing ethylammonium bromide (EABr) as an additive into the tin perovskite film can effectively reduce defect density both in the tin perovskite film and at the surface as well as optimize the energy level alignment between the perovskite layer and [6,6]-phenyl-C61-butyric acid methyl ester (PCBM) transport material, thereby suppressing nonradiative recombination both in the bulk film and at the interface. Furthermore, it is demonstrated that the Voc loss is gradually mitigated along with increasing storage duration due to the slow passivation effect. As a result, a remarkable Voc of 0.83 V is achieved in the devices optimized with the EABr additive, which shows a significantly improved power conversion efficiency (PCE) of 10.80% and good stability

Fabrication of Highly Luminescent Quasi Two-Dimensional CsPbBr₃ Perovskite Films in High Humidity Air for Light-Emitting Diodes

Perovskite light-emitting diodes (LEDs) have attracted extensive attention in recent years due to their outstanding performance and promise in lighting and display applications. However, the fabrication of perovskite LEDs usually requires a low-humidity atmosphere, which is unfavorable for industrial production. Herein, we report an effective strategy to fabricate highly luminescent quasi two-dimensional CsPbBr3 perovskite films in an ambient atmosphere with a humidity up to 60%. We reveal that the hole transport layer (HTL) plays a significant role in the morphology and optical properties of the perovskite films. Using hydrophobic self-assembled monolayer materials as HTLs can remarkably improve the quality of the perovskite films processed in high humidity air. The resultant perovskite LEDs show reduced leakage current and significantly enhanced performance. Furthermore, surface treatment is conducted to prevent water invasion and promote radiative recombination in perovskite films and LEDs. Eventually, the perovskite LEDs exhibit bright green emission with an external quantum efficiency of 4.87%. The present work provides a feasible pathway to overcome the humidity limitation for obtaining bright perovskite films and LEDs, which would contribute to further reducing the fabrication cost of perovskite LEDs and promoting their applications