Synthesis and Characterization of CH 3 NH 3 Pb 1-x Sn x I 3 Crystal

The CH3NH3PbI3 light-absorbing layer shows preferably photovoltaic performance. However, comparing with CH3NH3PbI3 film, the CH3NH3SnI3 film show smaller band gap and wider light absorption range, meanwhile, it is non-toxic and environmental friendly solar cell material. In this paper, different proportions of tin (Sn) was doped into CH3NH3PbI3 film, the atomic ratio of lead-tin strictly controlled to form CH3NH3SnI3 from CH3NH3PbI3. The five different proportions of doping CH3NH3Pb1-xSnxI3 perovskite powders were studied. The morphology of powders was observed by scanning electron microscopy (SEM). X-ray diffraction (XRD) and energy dispersive spectrum (EDS) were used to analyze the crystallization and the proportion composition of powders, respectively. The experimental results show that the powder crystal orientation was very obvious at the ratio of lead-tin around 1:1.99 and the atomic ratio close to the ideal stoichiometric ratio of doped atoms.