Overcoming Short-Circuit in Lead-Free CH 3 NH 3 SnI 3 Perovskite Solar Cells via Kinetically Controlled Gas–Solid Reaction Film Fabrication Process

作者：T. Yokoyama, Duyen H. Cao, Constantinos C. Stoumpos, Tze‐Bin Song, Yoshiharu Sato, Shinji Aramaki, Mercouri G. Kanatzidis · 发表于：The Journal of Physical Chemistry Letters · 年份：2016 · DOI：10.1021/acs.jpclett.6b00118 · 被引用次数：351 · 研究领域：Perovskite Materials and Applications、Chalcogenide Semiconductor Thin Films、Quantum Dots Synthesis And Properties

The development of Sn-based perovskite solar cells has been challenging because devices often show short-circuit behavior due to poor morphologies and undesired electrical properties of the thin films. A low-temperature vapor-assisted solution process (LT-VASP) has been employed as a novel kinetically controlled gas-solid reaction film fabrication method to prepare lead-free CH3NH3SnI3 thin films. We show that the solid SnI2 substrate temperature is the key parameter in achieving perovskite films with high surface coverage and excellent uniformity. The resulting high-quality CH3NH3SnI3 films allow the successful fabrication of solar cells with drastically improved reproducibility, reaching an efficiency of 1.86%. Furthermore, our Kelvin probe studies show the VASP films have a doping level lower than that of films prepared from the conventional one-step method, effectively lowering the film conductivity. Above all, with (LT)-VASP, the short-circuit behavior often obtained from the conventional one-step-fabricated Sn-based perovskite devices has been overcome. This study facilitates the path to more successful Sn-perovskite photovoltaic research.