Figure 4
(a) The PCE of the devices as a function of immersing time. 12 solar cells were repeated and measured for each immersing time; (b) XRD patterns of PbI2 film with different immersing time in MAI solution; (c) SEM image of the PbI2 film deposited by thermal evaporation on Glass/FTO/cp-TiO2 substrate without immersing in MAI; (d) SEM image of the product obtained by immersing PbI2 film in CH3NH3I for 10 min; (e) SEM image of MAPbI3 layer prepared by immersing PbI2 film in MAI for 45 min; (f) SEM image of MAPbI3 layer fabricated with immersing PbI2 film in MAI for 240 min.
