Investigation of the effect of MAI and PbI$$_{\mathrm {2}}$$ concentrations on the properties of perovskite solar cells

Here, the effect of perovskites layer quality on the performance of compact-TiO(_{mathrm {2}})/mesoporous-TiO(_{mathrm {2}})/CH(_{mathrm {3}})NH(_{mathrm {3}})PbI(_{mathrm {3}})/carbon solar cells was investigated. Different perovskite layers were prepared by varying concentrations of PbI(_{mathrm {2}}) and CH(_{mathrm {3}})NH(_{mathrm {3}})I, while reaction temperature and dipping time were fixed. The range of concentrations for PbI(_{mathrm {2}}) and methylammonium iodide (MAI) were 1–1.4 M and 6–10 mg ml(^{mathrm {-1}}), respectively. Fabricated perovskite layers were first coated by carbon electrodes (5-layer) and then, the champion one was coated by Spiro-OMeTAD (as a hole transport material) and Au-evaporated layer as a cathode (6-layer). Fabricated films were fully characterized by field emission scanning electron microscopy, X-ray diffraction analysis, UV–Vis spectroscopy and photoluminescence spectrum. Photovoltaic properties were measured under AM 1.5. Output currents of 5-layer cells were in the range of 228–476 (upmu )A, of which the highest one was obtained by using 1.2 M PbI(_{mathrm {2}}) and 8 mg ml(^{mathrm {-1}}) MAI. Ultimately, the maximum power conversion efficiency of 9.1% was obtained with 6-layer cell.