Silicon　(Si)-based　dopant-free　heterojunction　solar　cells　(SCs)　featuring　carrier-selective　contacts　(CSCs)　have　attracted　considerable　interest　due　to　the　extreme　simplifications　in　their　device　structure　and　manufacturing　procedure.　However,　these　SCs　are　limited　by　the　unsatisfactory　contact　properties　on　both　sides　of　the　junction,　and　their　efficiencies　are　not　comparable　with　those　of　commercially　available　Si　SCs.　In　this　report,　a　high-performance　silicon-oxide/magnesium　(SiOx/Mg)　electron-selective　contact　(ESC)　design　is　described.　Combining　an　ultrathin　SiOx　and　a　low　work　function　Mg　layer,　the　novel　ESC　simultaneously　yields　low　recombinative　and　resistive　losses.　In　addition,　deposition　of　Mg　on　SiOx　relaxes　the　restriction　on　the　threshold　thickness　of　the　SiOx　for　electron　tunneling　and　therefore　broadens　the　optimization　space　for　rear-sided　passivation.　Meanwhile,　hole-selective　contact　with　boosted　light　harvesting　and　suppressed　interfacial　recombination　is　achieved　by　forming　a　fully　conformal　contact　between　the　conducting　poly(3,4-ethylene　dioxythiophene):　poly(styrenesulfonate)　(PEDOT:　PSS)　and　periodic　Si　pyramid　arrays.　With　the　double-sided　carrier-selective　contact　designs,　PEDOT:　PSS/Si/SiOx/MgSCs　with　efficiency　of　15%　are　finally　obtained　via　a　totally　dopant-free　processing.　Subsequent　calculations　further　indicate　a　pathway　for　the　improvement　of　these　contacts　toward　an　efficiency　that　is　competitive　with　conventionally　diffused　pn　junction　SCs.