压强对钙钛矿薄膜形貌和结晶性影响的研究

摘要

A novel and simple method to control the crystallization process during the formation of perovskite thin films is critical for optimizing the device fabrication process and constructing high efficiency perovskite solar cells.In this article,a method of adjusting the vacuum was used to effectively control the crystallization process.Furthermore,the role of pressure and its influence upon perovskite crystal growth,film formation and device performance were systematically investigated.The crystallinity and morphology of the perovskite thin film were characterized by scanning electron microscope (SEM),ultraviolet-visible absorption spectra (UV-Vis) and X-ray diffraction (XRD).Based on the structure of Glass/ITO/PEDOT:PSS/CH3NH3PbI3/PCBM/ A1,the performance of the device corresponding to the different pressure was studied.The results indicate that the decreased pressure can enhance the crystallinity of the perovskite film obviously,and improve the surface coverage by reducing the amount of holes.At the same time,the short circuit current,filling factor and photoelectric conversion efficiency of the device are all improved with the pressure decreasing.A 19％ higher power conversion efficiency of 12.36％ was achieved in comparison to the device fabricated by traditional method,which exhibited just 10.38％ efficiency.%采用新型简便的方法控制钙钛矿层薄膜的结晶过程,对优化制备工艺、获得高性能器件至关重要.本文采用调节真空度的方法有效控制钙钛矿层结晶,系统地研究了压强的作用及其对晶体生长、薄膜形成及器件性能的影响.采用扫描电子显微镜(SEM)、紫外-可见吸收光谱、X射线衍射光谱(XRD)谱图等手段对钙钛矿层的形貌及结晶程度进行了分析表征.在此基础上,制备出器件结构为Glass/ITO/PEDOT:PSS/CH3NH3PbI3/PCBM/Al的钙钛矿太阳能电池,考察了不同压强下的器件性能.结果表明:随压强降低,钙钛矿层结晶程度明显提高,孔洞减少,表面覆盖率提高.同时,器件的短路电流、填充因子以及光电转化效率均随压强降低而提高,器件效率由原来的10.38％提高到12.36％,提高了19％.