Laboratory of Photonics and Interfaces, Institute of Chemical Sciences and Engineering, School of Basic Sciences, Ecole Polytechnique Fédérale de Lausanne (EPFL) , CH-1015 Lausanne, Switzerland.
Institute of Physical Chemistry, Polish Academy of Sciences , Kasprzaka 44/52, 01-224 Warsaw, Poland.
ACS Appl Mater Interfaces. 2017 Aug 30;9(34):28418-28425. doi: 10.1021/acsami.7b06788. Epub 2017 Aug 16.
Organo-lead halide perovskites have emerged as promising light harvesting materials for solar cells. The ability to prepare high quality films with a low concentration of defects is essential for obtaining high device performance. Here, we advance the procedure for the fabrication of efficient perovskite solar cells (PSCs) based on mechanochemically synthesized MAPbI. The use of mechano-perovskite for the thin film formation provides a high degree of control of the stoichiometry and allows for the growth of relatively large crystalline grains. The best device achieved a maximum PCE of 17.5% from a current-voltage scan (J-V), which stabilized at 16.8% after 60 s of maximum power point tracking. Strikingly, PSCs based on MAPbI mechanoperovskite exhibit lower "hysteretic" behavior in comparison to that comprising MAPbI obtained from the conventional solvothermal reaction between PbI and MAI. To gain a better understanding of the difference in J-V hysteresis, we analyze the charge/ion accumulation mechanism and identify the defect energy distribution in the resulting MAPbI based devices. These results indicate that the use of mechanochemically synthesized perovskites provides a promising strategy for the formation of crystalline films demonstrating slow charge recombination and low trap density.
有机-铅卤钙钛矿作为太阳能电池有前途的光捕获材料已经出现。制备具有低缺陷浓度的高质量薄膜的能力对于获得高器件性能至关重要。在这里，我们改进了基于机械化学合成的 MAPbI 的高效钙钛矿太阳能电池 (PSC) 的制备工艺。机械钙钛矿用于薄膜形成提供了高度控制化学计量的能力，并允许相对较大的晶粒生长。从电流-电压扫描 (J-V) 获得的最佳器件达到了 17.5%的最大 PCE，在最大功率点跟踪 60 秒后稳定在 16.8%。值得注意的是，与由 PbI 和 MAI 之间的传统溶剂热反应获得的 MAPbI 制成的器件相比，基于 MAPbI 机械钙钛矿的 PSC 表现出较低的“滞后”行为。为了更好地理解 J-V 滞后的差异，我们分析了电荷/离子积累机制，并确定了所得基于 MAPbI 的器件中的缺陷能分布。这些结果表明，使用机械化学合成的钙钛矿提供了一种有前途的策略，用于形成具有缓慢电荷复合和低陷阱密度的结晶薄膜。
