Bi Dongqin, Luo Jingshan, Zhang Fei, Magrez Arnaud, Athanasopoulou Evangelia Nefeli, Hagfeldt Anders, Grätzel Michael
Laboratory of Photonics and Interfaces, Institute of Chemical Sciences and Engineering, École Polytechnique Fédérale de Lausanne (EPFL), Station 6, CH-1015, Lausanne, Switzerland.
School of Chemical Engineering and Technology, Tianjin University, 300072, Tianjin, P. R. China.
ChemSusChem. 2017 Apr 10;10(7):1624-1630. doi: 10.1002/cssc.201601387. Epub 2017 Feb 28.
Despite the rapid increase in the performance of perovskite solar cells (PSC), they still suffer from low lab-to-lab or people-to-people reproducibility. Aiming for a universal condition to high-performance devices, we investigated the morphology evolution of a composite perovskite by tuning annealing temperature and precursor concentration of the perovskite film. Here, we introduce thermal annealing as a powerful tool to generate a well-controlled excess of PbI in the perovskite formulation and show that this benefits the photovoltaic performance. We demonstrated the correlation between the film microstructure and electronic property and device performance. An optimized average grain size/thickness aspect ratio of the perovskite crystallite is identified, which brings about a highly reproducible power conversion efficiency (PCE) of 19.5 %, with a certified value of 19.08 %. Negligible hysteresis and outstanding morphology stability are observed with these devices. These findings lay the foundation for further boosting the PCE of PSC and can be very instructive for fabrication of high-quality perovskite films for a variety of applications, such as light-emitting diodes, field-effect transistors, and photodetectors.
尽管钙钛矿太阳能电池（PSC）的性能迅速提高，但它们在实验室之间或人员之间的重现性仍然较低。为了实现高性能器件的通用条件，我们通过调整钙钛矿薄膜的退火温度和前驱体浓度，研究了复合钙钛矿的形貌演变。在此，我们引入热退火作为一种强大的工具，以在钙钛矿配方中产生可控的过量PbI，并表明这有利于光伏性能。我们展示了薄膜微观结构与电子性能及器件性能之间的相关性。确定了钙钛矿微晶的优化平均晶粒尺寸/厚度比，这带来了19.5%的高度可重现功率转换效率（PCE），认证值为19.08%。这些器件表现出可忽略不计的滞后现象和出色的形貌稳定性。这些发现为进一步提高PSC的PCE奠定了基础，并且对于制造用于各种应用（如发光二极管、场效应晶体管和光电探测器）的高质量钙钛矿薄膜具有很大的指导意义。
