In this work,a sky-blue luminescent down-shifting(LDS)layer bis[(4,6-difluorophenyl)-pyridinato-N,C^(2')]c(picolinate)iridium(II)(FIrpic)was inserted between tetraphenyl dibenzoperiflanthene(DBP)and Mo0_(3)as UV-s...In this work,a sky-blue luminescent down-shifting(LDS)layer bis[(4,6-difluorophenyl)-pyridinato-N,C^(2')]c(picolinate)iridium(II)(FIrpic)was inserted between tetraphenyl dibenzoperiflanthene(DBP)and Mo0_(3)as UV-screen and sensitizer for smallmolecule DBP/C_(60)based planar heterojunction(PHJ)solar cells.With 8-nm Flrpic theshort circuit current(J_(sc))and power conversion efficiency(PCE)of the device areenhanced by 28%and 15%,respectively,probably originating from the re-absorption ofthe photons emitted from Flrpic.The V_(oc)linearly increases over 1-nm Flrpic,ascribed tothe deeper HOMO level of Flrpic than DBP,while the fill factor continuously declines from 3-to 10-nm Flrpic.The EQE spectra prove that the J_(sc)is mainly contributed by thephotocurrent generated in DBP and C_(60)layers.When the FIrpic thickness is 8 nm,the filmsurface is very uniform with the smallest water contact angle.The impedance spectro-scopy demonstrates that the device resistance gradually increases from 4.1×10^(4)Ω(without Flrpic)to 4.6×10^(4)Ω(with 10-nm Flrpic)with the FIrpic thickness rise,simultaneously the device transits from the insulating state into the conductive statefaster for the thin Flrpic layer than the thick layer.展开更多
基金supported by the NationalNatural Science Foundation of China(Grant Nos.6167410l and 61504077)the Open Fund of State Key Laboratory of Luminescent Materials and Devices(South China University of Technology),China.
文摘In this work,a sky-blue luminescent down-shifting(LDS)layer bis[(4,6-difluorophenyl)-pyridinato-N,C^(2')]c(picolinate)iridium(II)(FIrpic)was inserted between tetraphenyl dibenzoperiflanthene(DBP)and Mo0_(3)as UV-screen and sensitizer for smallmolecule DBP/C_(60)based planar heterojunction(PHJ)solar cells.With 8-nm Flrpic theshort circuit current(J_(sc))and power conversion efficiency(PCE)of the device areenhanced by 28%and 15%,respectively,probably originating from the re-absorption ofthe photons emitted from Flrpic.The V_(oc)linearly increases over 1-nm Flrpic,ascribed tothe deeper HOMO level of Flrpic than DBP,while the fill factor continuously declines from 3-to 10-nm Flrpic.The EQE spectra prove that the J_(sc)is mainly contributed by thephotocurrent generated in DBP and C_(60)layers.When the FIrpic thickness is 8 nm,the filmsurface is very uniform with the smallest water contact angle.The impedance spectro-scopy demonstrates that the device resistance gradually increases from 4.1×10^(4)Ω(without Flrpic)to 4.6×10^(4)Ω(with 10-nm Flrpic)with the FIrpic thickness rise,simultaneously the device transits from the insulating state into the conductive statefaster for the thin Flrpic layer than the thick layer.
