Nowadays, there is a focus on perovskite solar cells (PSCs) as one of the most efficient photovoltaic systems. This research presents the effect of the fabrication method on the aluminum-doped titanium dioxide (Al-doped TiO2) as the electron transport layer for the improvement of photovoltaic performance of mesostructured PSCs. In the initial step, TiO2 sol with different concentrations of Al+3 was prepared using the sol-gel method in the presence of ultrasonic irradiation with low intensity. The compact TiO2 films (c-TiO2) were deposited using the spin-coating method, and after thermal treatment, were used to fabricate PSCs. Structural, optical, morphological, and electrical properties of layers were studied using different characterizations. The results obtained imply that increasing the conductivity of Al-doped TiO2 layers compared to undoped TiO2 requires an optimal amount of Al dopant. According to the applied optimization, the PSCs achieved the best performance when the Al dopant concentration was 1 wt%. Therefore, the best device containing 1 wt% Al-doped TiO2 film showed a short-circuit current density of 24.06 mA/cm2, open-circuit voltage (Voc) of 0.970 V, and fill factor of 0.67, yielding a power conversion efficiency of 15.34%.

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