The Investigation for Coating Method of Titanium Dioxide Layer in Perovskite Solar Cells

The effect of conventional Perovskite solar cells (PSCs) by using different concentration and spin-coating speeds of titanium dioxide (TiO2) as an electron transport layer (ETL) was studied. The influence of TiO2 based on device structure: fluorine-doped tin oxide substrate/TiO2/Perovskite (CH3NH3PbI3)/2,2′,7,7′-Tetrakis[N,N-di(4-methoxyp phenyl)amino]-9,9′-spirobifluorene/silver, is also studied. The spin-coating speed is varied in a range from 1000 to 3000 rpm to get optimal performance of device. The optimized power conversion efficiency (PCE) of PSCs with original concentration (OC) and double concentration (DC) TiO2 is 8.74 and 9.93%, respectively. The reason is attributed to excellent absorption in shorter wavelength, compact characteristic, and suitable thickness of TiO2, leading to perfect short-circuit current density (Jsc), lower series resistance (Rs), and higher fill factor (FF) of 0.75. Besides, recombination of electron and hole is also decreased due to the compact feature, leading to higher open-circuit voltage (VOC) of 0.91 V.