The　advancement　of　electron　transport　layer　(ETL)-free　perovskite　solar　cells　(PSCs)　is　crucial　for　the　commercialization　of　PSCs.　At　present,　the　slow　electron　extraction　and　significant　carrier　recombination,　related　to　the　energy-level　alignment　at　the　FTO/perovskite　interface,　restrict　the　performance　of　ETL-free　PSCs.　The　facile　modification　of　bottom　electrodes　is　pivotal　for　tackling　these　issues　and　stimulating　the　photovoltaic　potential　of　perovskite.　Herein,　a　cost-competitive　and　neoteric　1-hydroxyethyl-3-methylimidazolium　chloride,　[HOEtMIM]Cl,　ionic　liquid　is　employed　to　modify　the　surface　of　rigid　and　flexible　electrodes,　and　thus　enable　an　energetically　well-aligned　interface　with　perovskite　layer　via　the　electric　dipole　effects.　The　resulting　barrier-free　FTO/perovskite　contact　can　tremendously　ameliorate　the　electron　extraction　and　collection,　with　mitigated　nonradiative　interfacial　carrier　recombination　loss.　Additionally,　the　lone　pair　on　the　nitrogen　of　the　imidazole　group　passivates　the　surface　defects　of　perovskite　layers,　and　the　chloride　anion　plays　a　role　in　the　crystallinity　improvement　of　perovskite.　Leveraged　by　the　[HOEtMIM]Cl　modification,　the　resulting　ETL-free　rigid　and　flexible　devices　deliver　an　outstanding　power　conversion　efficiency　of　19.60　%　and　15.57　%,　along　with　the　ameliorated　hysteresis　and　long-term　tenability.　This　finding　highlights　the　drastic　potential　of　the　engineered　[HOEtMIM]Cl　in　manufacturing　stable　and　high-performance　ETL-free　PSCs　for　their　scaled-up　production.　Ionic　liquids　can　do　more!　A　facile　and　efficient　self-assembled　[HOEtMIM]Cl　layer　is　introduced　for　the　first　time　in　the　rigid　and　flexible　electron　transport　layer-free　perovskite　solar　cells,　giving　rise　an　improved　power　conversion　efficiency　of　19.60　%　and　15.57　%,　along　with　an　improved　hysteresis　and　stability.image