A widely used component of high-efficiency perovskite solar cells (PSCs) is the molecular hole-transport material (HTM) spiro-OMeTAD. This organic solid needs to be p-doped to acquire sufficient hole conductivity. However, the conventional doping method using LiTFSI in the air is slow, sensitive to the environment, and may lead to the deterioration of the PSCs by unintended oxidation or dopant migration. It is thus highly desirable to develop fast doping approaches that avoid exposing the PSC to ambient air and easy-to-move dopant ions. We report here that light absorption by spiro-OMeTAD itself triggers redox photochemistry that has so far been ignored. Strikingly, we found that Y(III) or La(III)-tBP complexes catalyze the symmetry-breaking charge separation of photo-excited spiro-OMeTAD, resulting in the efficient p-doping of the HTM. Using this photo-redox process, we realize PSCs with superior stability over cells using conventional doping that show no degradation under continuous illumination over 1,000 h.

高效钙钛矿太阳能电池（PSC）广泛使用的组件是分子空穴传输材料（HTM）spiro-OMeTAD。这种有机固体需要进行 p 掺杂以获得足够的空穴电导率。然而，在空气中使用LiTFSI的传统掺杂方法速度慢、对环境敏感，并且可能因意外氧化或掺杂剂迁移而导致PSC劣化。因此，非常需要开发快速掺杂方法，避免将 PSC 暴露于环境空气和易于移动的掺杂剂离子中。我们在这里报告，spiro-OMeTAD 本身的光吸收会触发迄今为止被忽视的氧化还原光化学。引人注目的是，我们发现 Y(III) 或 La(III)-tBP 配合物能够催化光激发 spiro-OMeTAD 的对称性破缺电荷分离，从而实现 HTM 的有效 p 掺杂。使用这种光氧化还原过程，我们实现的 PSC 比使用传统掺杂的电池具有更高的稳定性，在连续光照超过 1,000 小时的情况下不会出现降解。