The effect of divalent europium doping on stability and electronic properties of CH3NH3PbI3: a theoretical investigation

In the present study, we have investigated the effect of Eu(2+)doping on the stability and electronic properties of MAPbI(3)based on first-principles calculations. Our calculated results indicate that Eu doping is a good strategy to improve the structural stability of MAPbI(3). The predicted band gaps for the Eu-doped MAPbI(3)are in the range of 1.5-2.8 eV. A direct-to-indirect band gap transition is observed for the Eu-doped perovskite systems. MAPb(0.75)Eu(0.25)I(3)and MAPb(0.50)Eu(0.50)I(3)are potential candidate materials for applications in single-junction solar cells, and the content of the toxic element Pb can be further reduced to a certain extent.