Efficient Perovskite Solar Cells with Titanium Cathode Interlayer (Solar RRL 11∕2018)

In article no. 1800167, Xinhua Li, Jianming Dai, Zhengguo Xiao, and co-workers use an ultra-thin Ti as a cathode interlayer, without using any organic or inorganic electron transport layers, to improve the efficiency of perovskite solar cells. Ti forms a bonding layer with nitrogen atoms in metylammonium anions at the perovskite/Ti interface, which passivates surface defects and suppresses surface decomposition of the perovskite film. A power conversion efficiency of 18.1% is achieved. Furthermore, Ti has low diffusivity and prevents the diffusion of the cathode metal atoms into the perovskite layer, resulting in improved device stability.