Tin-based perovskite solar cells (Sn-PSCs) have been attracting researchers’ attention as a promising material for fabrication of eco-friendly perovskite solar cells. However, the power conversion efficiency (PCE) and the stability of Sn-PSCs are still inferior compared to those of lead-based PSCs. This is due to some basic problems in Sn perovskite materials, such as the easier oxidation of Sn²⁺ to Sn⁴⁺ leading to faster recombination, which increases electron loss in Sn-PSCs. In this work, we focused on minimizing the electron loss during transportation from the FASnI₃ perovskite layer to the adjacent electron-transport layer (ETL) by introducing diaminomaleonitrile (DAMN) in the perovskite precursor. DAMN with two cyano groups in its skeleton can work as an electron-withdrawing group to extract electrons effectively from the perovskite layer and transfer them to the adjacent ETL. Our finding highlights that the FASnI₃-DAMN-based PSCs possess a 42% higher electron mobility compared to pristine FASnI₃ and the transient photocurrent decay lifetimes are accelerated by 2.3 times, revealing an enhancement in electron transportation after incorporation of DAMN. Apart from the successful electron transportation enhancement, the FASnI₃-DAMN perovskite absorbers showed a reduced charge carrier recombination rate, thanks to the simultaneous reduction of lattice strain of the FASnI₃-DAMN film. Consequently, the fabricated Sn-PSCs with FASnI₃-DAMN perovskites showed enhanced PCE of 8.11% and a highly light soaking stable performance of over 300 h when measured under maximum power point tracking conditions.