Highly reproducible perovskite solar cells based on solution coating from mixed solvents

Highly reproducible and enhanced-efficiency perovskite solar cells based on oriented 1D TiO2 have been successfully fabricated from DMF/DMSO mixed solvents by a simple one-step deposition method, and the whole experimental section was proceeded in the air with temperature of 25–35 °C and humidity of 40–60% without a glove box. We have specifically studied the proportion of the DMF/DMSO mixed solvents influenced on the preparation of perovskite films and the efficiency of perovskite solar cells. Another main emphasis of our work was focus on the reproducibility of the perovskite solar cells, 40 fully independent devices for each kind of solar cells have been statistically analyzed, and the main photovoltaic parameters with small standard deviation (less than 0.6 of J sc and PCE, less than 0.03 of V oc and FF) indicating that the devices have excellent reproducibility. The best-performing device fabricated from 50 wt% DMF/DMSO mixed solvents showed the average efficiency as high as 10.56% with negligible hysteresis phenomenon, which was over 95% higher than those from pure solvents. These results may provide helpful progress toward the understanding of the function of the solvents for preparing extremely high-quality perovskite films and high-reproducible perovskite solar cells in ambient air.