Although　SnO2　has　been　reported　to　give　high　efficiencies　of　over　20%　for　organic-inorganic　perovskite　solar　cells　and　has　been　frequently　used　in　perovskite　tandem　solar　cells,　very　few　contributions　have　explored　its　feasibility　in　inorganic　perovskite　solar　cells　(IPSCs).　Inorganic　perovskites　with　a　wide　bandgap　tunable　from　1.7　to　2.0　eV　are　promising　candidates　for　top　cells　in　tandem　structures;　development　of　IPSCs　based　on　SnO2　will　greatly　benefit　their　integration　into　tandem　solar　cells.　We　examined　SnO2　in　comparison　to　the　prevalent　TiO2.　We　found　that　although　SnO2　had　a　good　energy　alignment　with　the　inorganic　perovskite　and　exhibited　slower　nonradiative　recombination,　the　relatively　low　conduction　band　minimum　energy　offset　restricted　efficient　charge　extraction.　In　contrast,　TiO2　that　had　a　large　energy　offset　of　∼400　meV　led　to　a　high　fill　factor　of　78.7%　and　a　state-of-the-art　efficiency　of　14.2%　for　IPSCs　with　a　bandgap　of　1.93　eV.　Copyright　©　2020　American　Chemical　Society.