As a key component of perovskite solar cells (PSCs), the electron transport layer (ETL) extracts charges efficiently. While TiO 2 is widely recognized as a superior electron transport material (ETM) for its numerous advantages, the morphological limitations of spherical TiO 2 nanoparticles (NPs) lead to significant electron losses. Therefore, as an alternative to nanospheres, TiO 2 nanocubes are synthesized through a solvothermal route and employed as ETM in the low-cost carbon electrode-based perovskite solar cells (CPSCs). The structural, morphological, and optical properties of the TiO 2 nanocubes (NCs) are studied and compared with TiO 2 nanospheres (NSs) in detail. The device possessing cubic TiO 2 achieved a power conversion efficiency (PCE) of 10.6% with a current density (J sc ) of 21.79 mA/cm 2 . Recognizing that the oxygen vacancies in cubic TiO 2 are lower than in spherical TiO 2 , it is inferred that further reduction of oxygen vacancies in cubic TiO 2 could enhance the current collection. Hence, to get rid of the oxygen vacancy (which acts as an electron trap) in the cubical TiO 2 , aluminum (Al 3+ ) is incorporated into its matrix. A comprehensive analysis of its impact on structural and optical behavior follows. In addition to its cost-effectiveness and conductive nature, it has been observed that the stable form of Al 3+ replaces the unstable Ti 3+ (which acts as a trap state), thereby reducing the recombination rate. With the highest current collection of 22.85 mA/cm 2 , a PCE of 11.3% has been recorded for the solar cell that possessed 1% Al-doped TNC. Furthermore, the ambient stability of the respective device shows ∼85% of its initial PCE. The effect of the TiO 2 nanostructure and Al 3+ doping in TiO 2 nanocubes is discussed elaborately in this work.