Perovskite Solar Cells (PSCs) have experienced an incredible rise in power conversion efficiencies (PCEs) starting from 3.8% in 2009 to 22.1% in 2016. Due to their electron transporting properties and low cost deposition techniques, fullerene derivatives are the most attractive semiconductors used as electron transporting materials (ETMs) in PSCs. The most widely used fullerene in inverted planar perovskite solar cells is [6,6]-phenyl-C₆₁-butyric acid methyl ester (PC₆₁BM), which exhibits high performance. Devices based on that compound have achieved a maximum PCE of 20.15%, reduced hysteresis, and improved stability. In our laboratories, PC₆₁BM like fullerene derivatives were synthesized via Bingel reaction at room temperature in high yields and incorporated into PSCs as ETMs. It was demonstrated that the branched alkyl chain of the fullerene derivative can highly influence the solubility, film morphology, passivation ability, ETL-perovskite contact, and electron extraction ability of the fullerene derivative. Overall device performance and stability were improved compared to those devices based on PC₆₁BM.