浴铜灵有机分子材料对钙钛矿薄膜表面的钝化作用

Surface Passivation of Perovskite Films by Bathocuproine Molecule

摘要:

采用2,9-二甲基-4,7-二苯基-1,10-邻二氮杂菲(浴铜灵,缩写:BCP)有机小分子作为钙钛矿薄膜与电子传输层之间的界面修饰层,从而使得反型结构的钙钛矿太阳电池性能得到显著改善。通过扫描电子显微镜研究发现:BCP分子可在钙钛矿薄膜样品表面的晶界间充分填充,推测其抑制了界面缺陷态的产生。进一步研究器件内部界面电荷的累积,并结合交流阻抗谱的分析,证实经BCP钝化的钙钛矿太阳电池中界面电荷的累积减少,光生载流子的复合被抑制,电池的光电转换效率由原来的15.7%提升到了17.4%。

Abstract:

In this work, organic small molecule 2,9-Dimethyl-4,7-diphenyl-1,10-phenanthroline (bathocuproine, abbr. BCP) was selected as a buffer layer for interface engineering between active and electron-transporting layers (ETL) in a reversed perovskite solar cells. It was found that the device performance was significantly improved after THE deposition of a BCP layer between the ETL and the perovskite layer. It reveals that the spacing between the grains was effectively filled by the BCP by scanning electron microscope, which can be responsible to prevent the generation of defect state at perovskite interface. Further analysis of the charge accumulation in the device in combination with AC impedance measurement proved that the migration of ions and the photon-generated carrier recombination in the perovskite solar device were reduced after the deposition of BCP layer. As a result, the optoelectronic power-conversion-efficiency is improved from 15.7% to 17.4%.