A four-coordinate mononuclear cuprous complex oCBP-Cu-Pym(1, oCBP =1,2-bis(diphenylphosphine)-nido-carborane, Pym = 2-methyl-6-(1 H-pyrazol-1-yl)pyridine) was synthe-sized and characterized by elemental analysis, NMR,...A four-coordinate mononuclear cuprous complex oCBP-Cu-Pym(1, oCBP =1,2-bis(diphenylphosphine)-nido-carborane, Pym = 2-methyl-6-(1 H-pyrazol-1-yl)pyridine) was synthe-sized and characterized by elemental analysis, NMR, UV-Vis and X-ray single-crystal structure analysis. It crystallizes in monoclinic space group C2/c with a = 28.4182(8), b =16.2994(4), c = 22.2708(5) ?, β = 127.219(2)°, V = 8214.8(3) ?3, Z = 8, Mr = 766.92, ρcalc = 1.24 g/cm3, F(000) = 3160, μ = 2.30 mm–1, GOOF = 1.063, the final R = 0.0700 and wR = 0.1903 for7158 observed reflections with I > 2σ(I). The Cu(I) ion adopts a highly distorted tetrahedral geometry defined by two nitrogen and two phosphorous atoms. Under UV 365 nm at room temperature, this complex exhibits green emission with maximum emission peak at 516 nm,lifetime 32.4 μs and quantum yield(ф = 0.461) in the solid state. Photophysical investigation suggests that the emission of complex 1 at room temperature was attributed to TADF, which is strongly supported by theoretic calculation.展开更多
A four-coordinate mononuclear cuprous complex [Cu（ac1m）POP]BF4·0.5（C6H14）· 0.5（C2H5OH）（1, ac1 m = 2-（2-ethoxyphenyl）-1-phenyl-1H-imidazo[4,5-f][1,10]phenanthroline, POP = bis[2-（dipenylphosphino）p...A four-coordinate mononuclear cuprous complex [Cu（ac1m）POP]BF4·0.5（C6H14）· 0.5（C2H5OH）（1, ac1 m = 2-（2-ethoxyphenyl）-1-phenyl-1H-imidazo[4,5-f][1,10]phenanthroline, POP = bis[2-（dipenylphosphino）phenyl]ether） was synthesized and characterized by elemental analysis, NMR, UV-vis, cyclic voltammetry and X-ray single-crystal structure analysis. It crystallizes in monoclinic space group P21/c with a = 17.0546（19）, b = 15.4650（17）, c = 23.685（2） A, β = 104.007（11）°, V = 6061.1（12）A^3, Z = 4, Mr = 1171.46, Dc = 1.284 g/cm^3, F（000） = 2432, μ = 1.50 mm^–1, GOOF = 1.070, the final R = 0.059 and wR = 0.1640 for 8952 observed reflections with I 〉 2σ（Ⅰ）. Compound 1 is composed of a BF4-anion and a [Cu（ac1m）POP]^＋ cation. The Cu（Ⅰ） ion adopts a tetrahedral coordination geometry defined by two nitrogen and two phosphorous atoms. The complex exhibits yellow luminescence with maximum emission peaks at 546 nm, lifetimes 15.1 μs and quantum yields（ф = 0.130） at room temperature. The complex displays thermally activated delayed fluorescence（TADF） at room temperature, which is proved experimentally and theoretically. And the organic light-emitting diode（OLED） with 1 as the light emitting material has the maximum current efficiency of 5.86 cd/A and the highest brightness of 3215 cd/m^2.展开更多
Understanding the host-guest interactions for thermally activated delayed fluorescence(TADF)emitters is critical because the interactions between the host matrices and TADF emitters enable precise control on the optoe...Understanding the host-guest interactions for thermally activated delayed fluorescence(TADF)emitters is critical because the interactions between the host matrices and TADF emitters enable precise control on the optoelectronic performance,whereas technologically manipulating the singlet and triplet excitons by using different kinds of host-guest interactions remains elusive.Here,we report a comprehensive picture that rationalizes host-guest interaction-modulated exciton recombination by using time-resolved spectroscopy.We found that the early-time relaxation is accelerated in polar polymer because dipole-dipole interaction facilitates the stabilization of the 1CT state.However,an opposite trend is observed in longer delay time,and faster decay in the less polar polymer is ascribed to theπ-πinteraction that plays the dominant role in the later stage of the excited state.Our findings highlight the technological engineering singlet and triplet excitons using different kinds of host-guest interactions based on their electronic characteristics.展开更多
Thermally activated delayed fluorescence(TADF)organic light-emitting diodes(OLEDs)have been demonstrated in applications such as displays and solid-state lightings.However,weak stability and ineffi-cient emission of b...Thermally activated delayed fluorescence(TADF)organic light-emitting diodes(OLEDs)have been demonstrated in applications such as displays and solid-state lightings.However,weak stability and ineffi-cient emission of blue TADF OLEDs are two key bottlenecks limiting the development of solution processable displays and white light sources.This work presents a solution-processed OLED using a blue-emitting TADF small molecule bis[4-(9,9-dimethyl-9,10-dihydroacridine)phenyl]sulfone(DMAC-DPS)as an emitter.We comparatively investigated the effects of single host poly(Nvinylcarbazole)(PVK)and a co-host of 60%PVK and 30%2,2′-(1,3-phenylene)-bis[5-(4-tert-butylphenyl)-1,3,4-oxadiazole](OXD-7)on the device performance(the last 10%is emitter DMAC-DPS).The co-host device shows lower turn-on voltage,similar maximum luminance,and much slower external quantum efficiency(EQE)rolloff.In other words,device stability improved by doping OXD-7 into PVK,and the device impedance simultaneously and significantly reduced from 8.6103 to 4.2103 W at 1000 Hz.Finally,the electroluminescent stability of the co-host device was significantly enhanced by adjusting the annealing temperature.展开更多
Heavy atom effects and n-π*transitions have been frequently reported to enhance room-temperature organic phosphorescence efficiency but lead to shortage of phosphorescence lifetimes.Unlike these reported studies,we c...Heavy atom effects and n-π*transitions have been frequently reported to enhance room-temperature organic phosphorescence efficiency but lead to shortage of phosphorescence lifetimes.Unlike these reported studies,we conceive the incorporation of advanced charge transfer(CT)technology to boost room-temperature organic afterglow efficiency and simultaneously maintain afterglow lifetimes.Here we design difluoroboronβ-diketonate(BF2bdk)CT compounds with moderate singlet-triplet splitting energy(ΔEST)of around 0.4 e V,and relatively large spin-orbit coupling matrix elements(SOCME(S_(1)-T_(1)),1–10 cm^(-1))to achieve efficient intersystem crossing(ISC)and moderate rates of reverse intersystem crossing(kRISC,1–10 s^(-1)).The advanced CT technology,which includes multiple electron-donating groups and orthogonal donor-acceptor arrangement,have been found to narrowΔESTand enhance both ISC and RISC.Meanwhile,the organic matrices suppress nonradiative decay of BF2bdk’s T1states by their rigid microenvironment.Consequently,thermally activated delayed fluorescence(TADF)-type organic afterglow materials can be achieved with afterglow efficiency up to 83.0%,long lifetimes of 433 ms,excellent processablility,as well as advanced anti-counterfeiting and information encryption.Furthermore,with the aid of up-conversion materials and through radiative energy transfer,TADF-type afterglow materials with aqueous dispersity and near-infrared light-excitable property have been achieved,which paves the way for biomedical applications.展开更多
基金supported by the National Natural Science Foundation of China(21373221,21521061,51672271,21671190,21403236)the Natural Science Foundation of Fujian Province(2006L2005)
文摘A four-coordinate mononuclear cuprous complex oCBP-Cu-Pym(1, oCBP =1,2-bis(diphenylphosphine)-nido-carborane, Pym = 2-methyl-6-(1 H-pyrazol-1-yl)pyridine) was synthe-sized and characterized by elemental analysis, NMR, UV-Vis and X-ray single-crystal structure analysis. It crystallizes in monoclinic space group C2/c with a = 28.4182(8), b =16.2994(4), c = 22.2708(5) ?, β = 127.219(2)°, V = 8214.8(3) ?3, Z = 8, Mr = 766.92, ρcalc = 1.24 g/cm3, F(000) = 3160, μ = 2.30 mm–1, GOOF = 1.063, the final R = 0.0700 and wR = 0.1903 for7158 observed reflections with I > 2σ(I). The Cu(I) ion adopts a highly distorted tetrahedral geometry defined by two nitrogen and two phosphorous atoms. Under UV 365 nm at room temperature, this complex exhibits green emission with maximum emission peak at 516 nm,lifetime 32.4 μs and quantum yield(ф = 0.461) in the solid state. Photophysical investigation suggests that the emission of complex 1 at room temperature was attributed to TADF, which is strongly supported by theoretic calculation.
基金supported by the National Natural Science Foundation of China(21373221,21521061,51672271,21671190,21403236)the Natural Science Foundation of Fujian Province(2006L2005)
文摘A four-coordinate mononuclear cuprous complex [Cu（ac1m）POP]BF4·0.5（C6H14）· 0.5（C2H5OH）（1, ac1 m = 2-（2-ethoxyphenyl）-1-phenyl-1H-imidazo[4,5-f][1,10]phenanthroline, POP = bis[2-（dipenylphosphino）phenyl]ether） was synthesized and characterized by elemental analysis, NMR, UV-vis, cyclic voltammetry and X-ray single-crystal structure analysis. It crystallizes in monoclinic space group P21/c with a = 17.0546（19）, b = 15.4650（17）, c = 23.685（2） A, β = 104.007（11）°, V = 6061.1（12）A^3, Z = 4, Mr = 1171.46, Dc = 1.284 g/cm^3, F（000） = 2432, μ = 1.50 mm^–1, GOOF = 1.070, the final R = 0.059 and wR = 0.1640 for 8952 observed reflections with I 〉 2σ（Ⅰ）. Compound 1 is composed of a BF4-anion and a [Cu（ac1m）POP]^＋ cation. The Cu（Ⅰ） ion adopts a tetrahedral coordination geometry defined by two nitrogen and two phosphorous atoms. The complex exhibits yellow luminescence with maximum emission peaks at 546 nm, lifetimes 15.1 μs and quantum yields（ф = 0.130） at room temperature. The complex displays thermally activated delayed fluorescence（TADF） at room temperature, which is proved experimentally and theoretically. And the organic light-emitting diode（OLED） with 1 as the light emitting material has the maximum current efficiency of 5.86 cd/A and the highest brightness of 3215 cd/m^2.
基金Strategic Priority Research Program of the Chinese Academy of Sciences,Grant/Award Number:XDB0450202Chinese Academy of Sciences,Grant/Award Number:YSBR-007National Natural Science Foundation of China,Grant/Award Numbers:22203085,22273095。
文摘Understanding the host-guest interactions for thermally activated delayed fluorescence(TADF)emitters is critical because the interactions between the host matrices and TADF emitters enable precise control on the optoelectronic performance,whereas technologically manipulating the singlet and triplet excitons by using different kinds of host-guest interactions remains elusive.Here,we report a comprehensive picture that rationalizes host-guest interaction-modulated exciton recombination by using time-resolved spectroscopy.We found that the early-time relaxation is accelerated in polar polymer because dipole-dipole interaction facilitates the stabilization of the 1CT state.However,an opposite trend is observed in longer delay time,and faster decay in the less polar polymer is ascribed to theπ-πinteraction that plays the dominant role in the later stage of the excited state.Our findings highlight the technological engineering singlet and triplet excitons using different kinds of host-guest interactions based on their electronic characteristics.
基金the National Key Research and Development Program of China(No.2017YFB0404404)the Open Fund of State Key Laboratory of Luminescent Materials and Devices(South China University of Technology),China。
文摘Thermally activated delayed fluorescence(TADF)organic light-emitting diodes(OLEDs)have been demonstrated in applications such as displays and solid-state lightings.However,weak stability and ineffi-cient emission of blue TADF OLEDs are two key bottlenecks limiting the development of solution processable displays and white light sources.This work presents a solution-processed OLED using a blue-emitting TADF small molecule bis[4-(9,9-dimethyl-9,10-dihydroacridine)phenyl]sulfone(DMAC-DPS)as an emitter.We comparatively investigated the effects of single host poly(Nvinylcarbazole)(PVK)and a co-host of 60%PVK and 30%2,2′-(1,3-phenylene)-bis[5-(4-tert-butylphenyl)-1,3,4-oxadiazole](OXD-7)on the device performance(the last 10%is emitter DMAC-DPS).The co-host device shows lower turn-on voltage,similar maximum luminance,and much slower external quantum efficiency(EQE)rolloff.In other words,device stability improved by doping OXD-7 into PVK,and the device impedance simultaneously and significantly reduced from 8.6103 to 4.2103 W at 1000 Hz.Finally,the electroluminescent stability of the co-host device was significantly enhanced by adjusting the annealing temperature.
基金supported by the National Natural Science Foundation of China(22175194)Shanghai Scientific and Technological Innovation Project(20QA1411600,20ZR1469200)Hundred Talents Program from Shanghai Institute of Organic Chemistry(Y121078)。
文摘Heavy atom effects and n-π*transitions have been frequently reported to enhance room-temperature organic phosphorescence efficiency but lead to shortage of phosphorescence lifetimes.Unlike these reported studies,we conceive the incorporation of advanced charge transfer(CT)technology to boost room-temperature organic afterglow efficiency and simultaneously maintain afterglow lifetimes.Here we design difluoroboronβ-diketonate(BF2bdk)CT compounds with moderate singlet-triplet splitting energy(ΔEST)of around 0.4 e V,and relatively large spin-orbit coupling matrix elements(SOCME(S_(1)-T_(1)),1–10 cm^(-1))to achieve efficient intersystem crossing(ISC)and moderate rates of reverse intersystem crossing(kRISC,1–10 s^(-1)).The advanced CT technology,which includes multiple electron-donating groups and orthogonal donor-acceptor arrangement,have been found to narrowΔESTand enhance both ISC and RISC.Meanwhile,the organic matrices suppress nonradiative decay of BF2bdk’s T1states by their rigid microenvironment.Consequently,thermally activated delayed fluorescence(TADF)-type organic afterglow materials can be achieved with afterglow efficiency up to 83.0%,long lifetimes of 433 ms,excellent processablility,as well as advanced anti-counterfeiting and information encryption.Furthermore,with the aid of up-conversion materials and through radiative energy transfer,TADF-type afterglow materials with aqueous dispersity and near-infrared light-excitable property have been achieved,which paves the way for biomedical applications.
