Gas Quenching under Ambient Conditions for Efficient and Stable Wide-Bandgap Perovskite Solar Cells with Surface Passivation.

Wide-bandgap perovskite solar cells play a key role in tandem solar cells, which aim to overcome the Shockley-Queisser limit for single-junction solar cells. In this work, we develop and optimize a gas quenching method under ambient conditions for the fabrication of wide-bandgap (1.77 eV) perovskite films. To improve the performance of PSCs, three different organic spacer cations, including aromatic amino molecules (PEAI), aliphatic amino with long alkyl chain molecules (OAI), and short alkyl chain molecules (BAI), are applied and investigated as surface passivation materials. As a result, the 2D perovskite layers form on top of the 3D perovskite films. The n-i-p devices with PEAI passivation exhibit the highest photovoltaic performance with a champion power conversion efficiency (PCE) of 16.26% along with a high Voc of 1.21 V, exceeding the control device (PCE = 13.42%, Voc = 1.15 V), and maintaining 88% of its initial PCE after 120 min of continuous illumination under a nitrogen atmosphere at room temperature. This work offers a guide for the fabrication of wide-bandgap PSCs under ambient conditions and the choice of organic spacer cations for passivation.