HaHc (Hydroxylamine Hydrochloride) Assisted Dual Surface Passivation via Charge Neutralization and Coordination Bond Formation of Cs₂AgBiBr₆ Double Perovskite for Solar Cell Application

The growth of lead-free perovskite-based solar cells is the key to achieve sustainable and green energy. Cs2AgBiBr6 (CABB) is one of the lead-free perovskites that is showing appreciable improvement in terms of performance of solar cells. The performance is still limited due to the presence of surface defects on the perovskite surface. In this work, by the use of hydroxylamine hydrochloride (HaHc) additive, the power conversion efficiency (PCE) of the device is able to get a boost of 167% to reach almost 2% PCE because of successful defect passivation of the perovskite surface. Also, the density functional theory (DFT) analysis reveals the successful lowering of energy at the perovskite surface via charge neutralization and the formation of coordination bonds. The device is capable of being fabricated in wet conditions (70% RH) and has excellent storing stability while retaining 80% of its initial PCE for more than 25 days.