Doping effects of transition metal elements to titanium dioxide for perovskite solar cells.

Organic-inorganic hybrid heterojunction solar cells containing perovskite CH3NH3PbI3 using Nb, Ta, or V-doped TiO2 as electron-transporting layers were fabricated and characterized. By Nb doping, the conductivity and carrier density of the TiO2 increased, and its flat-band potential showed a positive shift. The short-circuit current density and power conversion efficiency of perovskite solar cells were improved by using Ti0.95Nb0.05O2 compared to undoped TiO2. [ABSTRACT FROM AUTHOR]