Stability improvement of CH3NH3PbI3 hybrid perovskite through tin and chlorine doping

Abstract

In recent years, the hybrid perovskite CH3NH3PbI3 has been widely studied because of its potential application in the fabrication of high efficiency solar cells. The main challenge is to avoid destabilization of this compound under working conditions. Indeed, the MAPbI3 begins to decompose into the precursor phases, a few hours or days after being formed. We reported a stability monitoring of doped compounds CH3NH3Pb0.9Sn0.1I2.8Cl0.2 and CH3NH3Pb0.75Sn0.25I2.5Cl0.5 obtained as films from solutions of the precursors in N-N dimethylformamide on chemically treated glass substrates. The monitoring was carried out using X-Ray diffraction and absorbance measurements in the UV-Vis region. The tetragonal symmetry initially determined for the three compounds, remains almost unaltered for CH3NH3Pb0.75Sn0.25I2.5Cl0.5 even after 600 days, under environmental conditions. The bandgap value for this doped perovskite is 1.44 eV.