Xu Haitao, Wu Yanglin, Cui Jian, Ni Chaowei, Xu Fuzong, Cai Jiang, Hong Feng, Fang Zebo, Wang Wenzhen, Zhu Jiabin, Wang Linjun, Xu Run, Xu Fei
School of Materials Science and Engineering, Shanghai University, 99 Shangda Road, Shanghai 200444, China.
Phys Chem Chem Phys. 2016 Jul 21;18(27):18607-13. doi: 10.1039/c6cp02737g. Epub 2016 Jun 27.
The interface chemistry and evolution of the evaporated perovskite films on ITO, pedot/ITO, Si and glass substrates are studied. As evidenced by X-ray diffraction and X-ray photoemission spectroscopy (XPS) results, the PbI2 phase is found to be inevitably formed at the very initial growth stage, even under the conditions of a MAI-rich environment. The extremely low binding energy of adsorbed MAI particles on all the above substrates, as compared to that of PbI2 particles, is responsible for the presence of the PbI2 phase at the interface. The formation of both hole and electron barriers at the interface of PbI2/MAPbI3, as evidenced by XPS measurements, could block carrier transport into the electrode and thus deteriorate solar cell performance. This result reveals the origin of the poor performance of perovskite solar cells (PSCs) by the vacuum evaporation method, and may help to improve the performance of PSCs made using the vacuum evaporation method.
研究了在氧化铟锡（ITO）、聚（3,4-乙撑二氧噻吩）/氧化铟锡（pedot/ITO）、硅和玻璃基板上蒸发的钙钛矿薄膜的界面化学和演变。X射线衍射和X射线光电子能谱（XPS）结果表明，即使在富甲脒碘化铵（MAI）环境条件下，在最初的生长阶段也不可避免地会形成碘化铅（PbI2）相。与PbI2颗粒相比，上述所有基板上吸附的MAI颗粒的结合能极低，这是界面处存在PbI2相的原因。XPS测量表明，在PbI2/MAPbI3界面处形成的空穴和电子势垒会阻碍载流子向电极的传输，从而降低太阳能电池的性能。这一结果揭示了采用真空蒸发法制备的钙钛矿太阳能电池（PSC）性能不佳的原因，并可能有助于提高采用真空蒸发法制备的PSC的性能。
