Effect of PbI2 deposition rate on two step PVD/CVD all vacuum prepared perovskite
Abstract In this work we fabricate all vacuum processed methyl ammonium lead halide perovskite by a sequence of physical vapour deposition of PbI2 and chemical vapour deposition (CVD) of CH3NH3I under a static atmosphere. We demonstrate that for higher deposition rate the (001) planes of PbI2 film show a higher degree of alignment parallel to the sample's surface. From X ray diffraction data of the resulted perovskite film we derive that the intercalation rate of CH3NH3I is fostered for PbI2 films with higher degree of (001) planes alignment. The stoichiometry of the produced perovskite film is also studied by Hard X ray photoelectron spectroscopy measurements. Complete all vacuum perovskite solar cells were fabricated on glass/ITO substrates coated by an ultra thin (5 nm) Zn phthalocyanine film as hole selective layer. A dependence of residual PbI2 on the solar cells performance is displayed, while photovoltaic devices with efficiency up to e=11.6% were achieved.