Fig. 3From: Fabrication of Efficient Organic-Inorganic Perovskite Solar Cells in Ambient AirSEM images of PbI2 films on FTO/c-TiO2/mp-TiO2 substrates without (a) and with (b) BTA additive; and corresponding MAPbI3 films without (c) and with (d) BTA additive prepared under 25% RHBack to article page