© 2021 Elsevier B.V.Carbon based perovskite solar cells are rapidly emerging as promising photovoltaic devices, combining low cost production and prolonged device operation, due to the exclusion of polymeric conductors and integration of highly durable metal oxide charge selective layers. Modification of metal oxide mesoporous layers via element additions and enhancement of electrical conductivity is a major strategy for reduced internal resistances inside the cell. This work investigates the effect of excessive Y and Li additions on the charge selective mesoporous layers. A novel flame synthesis method can be successfully employed for production of yttrium added TiO2 (Y:TiO2) and conductive lithium added NiO (Li:NiO) nanoparticles. This novel methanol combustion method is an effective strategy for incorporation of additives into host lattices, resulting in modified mesoporous layers. Ultraviolet photoelectron spectroscopy studies reveal a profound effect of Li and Y additions on the electronic band structure of the particles. Electrochemical impedance studies confirms that modification of TiO2 with excessive yttrium atoms results in suppressed charge injection, where excessive lithium addition enhances the charge transport properties of the NiO layer. Power conversion efficiency of the pristine NiO based cells are enhanced from 8.38% to 9.63% upon lithium addition, in a TiO2/MgO/Li:NiO/carbon configuration.