The　development　of　excellent　ternary　metal　oxides　as　electron　transporting　layers　(ETLs)　is　highly　chal-lenging　for　perovskite　solar　cells　(PSCs).　In　this　study,　ZnTiO3　(ZTO)　nanoparticles　are　synthesized　via　a　facile　sol-gel　method,　and　used　as　an　ETL　in　PSCs.　Furthermore,　for　the　first　time,　iodine-doped　g-C3N4　(ICN)　is　introduced　into　ZnTiO3-based　ETL　as　additive　via　a　glass-assisted　annealing　route.　Characterizations　demonstrate　that　the　ZnTiO3-based　ETL　with　the　addition　of　ICN　will　enhance　the　PCE,　which　is　attributed　to　the　improved　crystalline　quality　and　more　favorable　energy　level　alignment.　Moreover,　the　existence　of　ICN　will　strengthen　the　interfacial　cohesion　between　perovskite　layer　and　ETL　as　well　as　retard　the　perovskite　crystals　from　decomposing,　leading　to　the　high　quality　capping　light　-harvesting　layer　upon　ICN-modified　ZnTiO3　(ZTO-ICN)　film.　Consequently,　a　champion　device　fabricated　with　ZTO-ICN　ETL　achieves　a　maximum　PCE　of　19.17　%　with　an　open　circuit　voltage　(Voc)　of　1.012　V,　a　short-circuit　current　density　(Jsc)　of　26.32　mA　cm-2　and　a　fill　factor　(FF)　of　0.720　under　AM　1.5　G　sunlight　(100　mW　cm-2).(c)　2022　Elsevier　Inc.　All　rights　reserved.