Department of Materials Science and Engineering, University of California , Los Angeles, California 90095, United States.
California NanoSystems Institute, University of California , Los Angeles, California 90095, United States.
J Am Chem Soc. 2016 Dec 7;138(48):15710-15716. doi: 10.1021/jacs.6b09656. Epub 2016 Nov 29.
Morphology is critical component to achieve high device performance hybrid perovskite solar cells. Here, we develop a vapor induced intermediate phase (VIP) strategy to manipulate the morphology of perovskite films. By exposing the perovskite precursor films to different saturated solvent vapor atmospheres, e.g., dimethylformamide and dimethylsufoxide, dramatic film morphological evolution occurs, associated with the formation of different intermediate phases. We observe that the crystallization kinetics is significantly altered due to the formation of these intermediate phases, yielding highly crystalline perovskite films with less defect states and high carrier lifetimes. The perovskite solar cells with the reconstructed films exhibits the highest power conversion efficiency (PCE) up to 19.2% under 1 sun AM 1.5G irradiance, which is among the highest planar heterojunction perovskite solar cells. Also, the perovskite solar cells with VIP processing shows less hysteresis behavior and a stabilized power output over 18%. Our work opens up a new direction for morphology control through intermediate phase formation, and paves the way toward further enhancing the device performances of perovskite solar cells.
形态学是实现高性能混合钙钛矿太阳能电池的关键组成部分。在这里，我们开发了一种蒸气诱导中间相（VIP）策略来控制钙钛矿薄膜的形态。通过将钙钛矿前驱体薄膜暴露于不同饱和溶剂蒸气气氛中，例如二甲基甲酰胺和二甲基亚砜，会发生剧烈的薄膜形态演变，伴随着不同中间相的形成。我们观察到由于这些中间相的形成，结晶动力学发生了显著变化，从而产生了具有更少缺陷态和高载流子寿命的高结晶钙钛矿薄膜。经过重构的薄膜的钙钛矿太阳能电池在 1 个太阳 AM1.5G 辐照下的最高功率转换效率（PCE）高达 19.2%，这是最高的平面异质结钙钛矿太阳能电池之一。此外，经过 VIP 处理的钙钛矿太阳能电池表现出较小的滞后行为和超过 18%的稳定功率输出。我们的工作为通过中间相形成来控制形态学开辟了新的方向，并为进一步提高钙钛矿太阳能电池的器件性能铺平了道路。
