Sb2S3　has　emerged　as　a　promising　light-absorbing　material　due　to　its　nontoxicity,　low　cost,　high　stability,　and　absorption　coefficient.　However,　the　absorption　spectrum　ranges　and　back-contact　barrier　between　Sb2S3　and　Au　strongly　limit　the　device　performance.　p-type　Sb2Se3　has　a　similar　lattice　structure　and　properties　as　Sb2S3,　obtaining　absorption　expansion　and　ohmic　back　contact.　Herein,　efficient　all-inorganic　planar　Sb2S3　solar　cells　with　the　addition　of　Sb2Se3　layers　are　fabricated.　The　functions　of　Sb2Se3　as　cooperative　absorber　(400　nm)　and　hole　transport　layers　(HTL,　80　nm)　are　further　explored.　Systematic　characterizations　indicate　that　the　junction　quality　and　depletion　widths　of　the　device　with　the　addition　of　Sb2Se3　are　improved　by　forming　a　p–i–n　structure.　As　a　result,　the　all-inorganic　Sb2S3　solar　cell　with　a　Sb2Se3　HTL　greatly　increases　the　power　conversion　efficiency　from　2.7%　to　5.8%　and　the　fill　factor　from　40%　to　55.4%.　The　additional　Sb2Se3/Au　interface　with　matched　energy-level　alignments　reduces　the　back-contact　barrier　and　facilitates　hole　transport　and　collection.　The　present　design　and　methods　promote　the　development　of　Sb2S3　solar　cells.　©　2021　Wiley-VCH　GmbH.