||Black TiO2 nanoparticles were synthesized by reducing mesoporous TiO2, which is widely used as an electron transport layer, and the effect of blending the electron transport layer of perovskite solar cell was verified. B-TiO2 blended in PC70BM increases the absorption of light and forms a narrow bandgap, which acts as a major factor in the change of optical excitation and relaxation. It also provides trapping sites for optoelectronic carriers and prevents fast recombination and is advantageously applied to the electron transport layer in the device. Also, the effect was observed in the electron transport layer by tuning at an energy level that is easy for electron transport. Optimization was performed by varying the amount of B-TiO2 applied to the electron transport layer, and the power conversion efficiency was increased by more than 11% compared to the reference cell. This was demonstrated by AFM, PL, Reflectance, SCLC, and Impedance.