Enhanced Performance for Planar Perovskite Solar Cells with Samarium-Doped TiO2 Compact Electron Transport Layers

The tactics of ion doping in metal oxide is normally used to improve the film quality, achieve an appropriate energy band, and enhance carrier mobility. Here, a rare earth element (samarium) was doped into TiO2 compact electron transport layers (ETLs) by adding samarium trinitrate into the titanium precursor solution. The results show that perovskite solar cells (PSCs) with Sm-doped TiO2 exhibit 10.3% enhancement with a power conversion efficiency (PCE) of 14.10%, compared to nondoped devices. It is found that Sm doping can upward shift the Fermi energy level of the ETLs, increase the carrier transport ability, and inhibit the carrier recombination. The results indicate that rare earth ion doping could be a promising method for producing effective ETLs and high performance PSCs.