PCBM/Ag interface dipole management in inverted perovskite solar cells
Dandan Qu, Tonghui Guo, Jing Zhang, Zhiqiang Deng, Zequn Zhang, Rui Zhao, Xiaohui Liu, Ziyang Hu, Like Huang, Yuejin Zhu
Abstract
In inverted perovskite solar cells, the [6,6]-phenyl-C61-butyric acid methyl ester (PCBM)/Ag back interface is quite important because serious recombination occurs and H2O/O2 directly attacks this interface to induce device instability. Here, bi-functional dipole layers are applied at the interface aiming at improving the charge transport and device stability simultaneously. Silane with -CF3 end group anchored on the PCBM surface induces more effective dipole effect than that with (CH2)7-CH3 end functional silane, bending the interface energy level to promote electron transport and reduce recombination. The hydrophobic nature of -CF3 also enhances the durability of the device. This work highlights the back surface dipole management method to achieve efficient and stable perovskite solar cells.