Understanding　the　factors　controlling　radiative　and　non-radiative　transition　rates　for　charge　transfer　states　in　organic　systems　is　important　for　applications　ranging　from　organic　photovoltaics　(OPV)　to　lasers　and　LEDs.　We　explore　the　role　of　charge-transfer　(CT)　energetics,　lifetimes,　and　photovoltaic　properties　in　the　limit　of　very　slow　non-radiative　rates　by　using　a　model　donor/acceptor　system　with　photoluminescence　dominated　by　thermally　activated　delayed　fluorescence　(TADF).　This　blend　exhibits　an　extremely　high　photoluminescence　quantum　efficiency　(PLQY　=　similar　to　22%)　and　comparatively　long　PL　lifetime,　while　simultaneously　yielding　appreciable　amounts　of　free　charge　generation　(photocurrent　external　quantum　efficiency　EQE　of　24%).　In　solar　cells,　this　blend　exhibits　non-radiative　voltage　losses　of　only　similar　to　0.1　V,　among　the　lowest　reported　for　an　organic　system.　Notably,　we　find　that　the　non-radiative　decay　rate,　k(nr),　is　on　the　order　of　10(5)　s(-1),　approximately　4-5　orders　of　magnitude　slower　than　typical　OPV　blends,　thereby　confirming　that　high　radiative　efficiency　and　low　non-radiative　voltage　losses　are　achievable　by　reducing　k(nr).　Furthermore,　despite　the　high　radiative　efficiency　and　already　comparatively　slow　k(nr),　we　find　that　k(nr)　is　nevertheless　much　faster　than　predicted　by　Marcus-Levich-Jortner　two-state　theory　and　we　conclude　that　CT-local　exciton　(LE)　hybridization　is　present.　Our　findings　highlight　that　it　is　crucial　to　evaluate　how　radiative　and　non-radiative　rates　of　the　LE　states　individually　influence　the　PLQY　of　charge-transfer　states,　rather　than　solely　focusing　on　the　PLQY　of　the　LE.　This　conclusion　will　guide　material　selection　in　achieving　low　non-radiative　voltage　loss　in　organic　solar　cells　and　high　luminescence　efficiency　in　organic　LEDs.