Some electron transporting layers (ETLs) were designed for perovskite solar cells (PSCs) and contained NDIID (N,N′-bis(1-indanyl) naphthalene-1,4,5,8-tetracarboxylic diimide) core, in which R groups were attached to phenyl rings, where R = H (NDIID), SiF3, SiCl3, SiBr3, SiCN3, SiH3, SiMe3, SiOH3, SiOMe3, SiSH3, SiSMe3, Si(NH2)3, and Si(NMe2)3. Density functional theory (DFT) computations were conducted to investigate structural, electronic, and optical features of NDIID-based ETLs. The LUMO levels of all ETLs could be positioned lower compared to that of CH(NH2)2PbI3-xBrx perovskite after their coupling in the assembled PSCs to efficiently inject electrons from the CH(NH2)2PbI3-xBrx towards the Al electrode. Furthermore, the HOMO levels of all ETLs had much deeper energies (changing in the range of −5.54 to −6.94 eV) than that of CH(NH2)2PbI3-xBrx, validating stopped backward hole transfer toward the valence band of perovskite (−5.4 eV). The hole mobilities of all samples were very much smaller than their related electron mobility values. The NDIID-SiMe3 ETL revealed utmost calculated electron mobility of 229.459 cm2V−1s−1, displaying a larger value compared to 202.510 cm2V−1s−1 for NDIID reference ETL. All calculated power conversion efficiencies (PCEs) of PSCs were very comparable (PCEs were about 22.5–23.7 %) so that four NDIID-Si(NH2)3, NDIID-SiMe3, NDIID, and NDIID-Si(NMe2)3 ETLs displayed largest PCEs of 23.726, 23.710, 23.682, and 23.663 %, respectively, illustrating their exceptional efficacy.