Carbazole-triazine dendrimers with a bulky terminal substituent were synthesized,and the thermally activated delayed fluorescence(TADF)property was investigated.Compared to unsubstituted carbazole dendrimers,dendrimer...Carbazole-triazine dendrimers with a bulky terminal substituent were synthesized,and the thermally activated delayed fluorescence(TADF)property was investigated.Compared to unsubstituted carbazole dendrimers,dendrimers with bulky terminal substituents showed comparable to better photoluminescence quantum yields(PLQY)in neat films.Phenylfluorene(PF)-substituted dendrimers showed the highest PLQY of 81%,a smallΔEst of 0.06 eV,and the fastest reverse intersystem crossing(RISC)rate of∼1×10^(5 )s^(−1) compared to other dendrimers.Phosphorescence measurements of dendrimers and dendrons(fragments)indicate that the close proximity of the triplet energy of phenylfluorene-substituted carbazole dendrons(^(3)LE)to that of phenylfluorene-substituted dendrimers(^(1)CT,^(3)CT)contributes to RISC promotion and improves TADF efficiency.Terminal modification fine-tunes the energy level and suppresses intermolecular interactions,and this study provides a guideline for designing efficient solution-processable and non-doped TADF materials.展开更多
Achieving high heat-resisting room temperature phosphorescence(RTP)performance and robust white emission from pure small molecules is a meaningful but challenging work.Herein,a simple donor-acceptor(D-A)molecule,9-(1H...Achieving high heat-resisting room temperature phosphorescence(RTP)performance and robust white emission from pure small molecules is a meaningful but challenging work.Herein,a simple donor-acceptor(D-A)molecule,9-(1H-benzotriazol-1-ylmethyl)-9H-carbazole(CzBtrz),was investigated.This simple molecule not only exhibits multiple emissions including white light,thermally activated delayed fluorescence(TADF)and ultralong RTP with a lifetime of 988.54 ms at 545 nm,but also shows superhigh heat-resisting phosphorescence property which can maintain stability in a large temperature region from 77 to 350 K(ΔT=273 K),exceeding those of other RTP systems.Meanwhile,this molecule shows the time-evolved dynamic RTP.The experimental and theoretical an-alyses from CzBtrz crystal demonstrate that the intramolecular charge transfer(ICT)interaction and molecular stacking play an important role in the generation of RTP.Therefore,this work provides an efficient strategy to design ultrahigh heat-resistant RTP,ultralong RTP and single-phased white-light emitting materials.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
Albeit their high efficiencies, the operational stability of the organic light emitting diodes(OLEDs) based on thermally activated delayed fluorescence(TADF) emitters is still far from satisfaction, and few strategies...Albeit their high efficiencies, the operational stability of the organic light emitting diodes(OLEDs) based on thermally activated delayed fluorescence(TADF) emitters is still far from satisfaction, and few strategies have been proposed to improve their stability. Here, we show that by modifying the carbazole unit, one of the most commonly used donors in TADF emitters, with peripheral groups, both the device efficiency and operational stability can be greatly improved. Awell-known TADF molecule—4,5-di(9H-carbazol-9-yl)phthalonitrile(2CzPN) was chosen as the prototype and modified by introducing peripheral tert-butyl and phenyl groups to the 3,6-positions of the carbazole(named 2tBuCzPN and 2PhCzPN, respectively). The introduced groups not only improve the compounds' electrochemical stabilities referred to the cyclic voltammetry multi-sweep results, but also promote their photoluminescence quantum yields. Furthermore, reduced singlet-triplet energy gaps are observed, leading to the shortened exciton lifetimes which are benefit to suppress the exciton annihilations. Besides, the steric hindrance of introduced phenyl groups can partly restrain the concentration quenching of the TADF emitter. Consequently, OLEDs based on 2tBuCzPN and 2PhCzPN achieved improved maximum external quantum efficiencies(EQEs) of 17.0% and 14.0%, respectively(compared to 8.5% for 2CzPN). Meanwhile, 2PhCzPN based OLED showed reduced roll-off characteristics and a longer lifetime of 7.8 times higher than that of 2CzPN, testifying the effectiveness of subtle modification of the unstable moieties in simultaneous enhancement of efficiency and stability of OLEDs based on TADF emitters.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
以咔唑和吩噻嗪为原料,合成了2种具有D-π-A结构的新型咔唑衍生物(4-(9H-咔唑-9-基)苯基)(9-苯基-9H-咔唑-3-基)甲酮(3a)和(4-(10H-吩噻嗪-10-基)苯基)(9-苯基-9H-咔唑-3-基)甲酮(3b).化合物3a和3b的结构分别经1 H NMR和IR进行了表征,...以咔唑和吩噻嗪为原料,合成了2种具有D-π-A结构的新型咔唑衍生物(4-(9H-咔唑-9-基)苯基)(9-苯基-9H-咔唑-3-基)甲酮(3a)和(4-(10H-吩噻嗪-10-基)苯基)(9-苯基-9H-咔唑-3-基)甲酮(3b).化合物3a和3b的结构分别经1 H NMR和IR进行了表征,同时通过紫外-可见吸收光谱和光致发光光谱研究了其光物理性质,并进一步采用含时密度泛函理论(TDDFT)对化合物3a和3b的最低能量电子跃迁和最低三线态进行了计算.结果表明:它们都具有分子内电荷转移ICT特征,而且理论计算的吸收光谱与实验测得的光谱数据基本符合.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
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
Structural modifications are a successful and commonly used approach to tune the emission properties of diverse fluorophores,but extending this approach to heavy-atom-free persistent luminophores has so far been unsuc...Structural modifications are a successful and commonly used approach to tune the emission properties of diverse fluorophores,but extending this approach to heavy-atom-free persistent luminophores has so far been unsuccessful.Here we employed a novel strategy to demonstrate triplet–triplet energy transfer from an organic room-temperature phosphor(RTP)with persistent luminescence to an organic molecule with thermally activated delayed fluorescence(TADF).We illustrated this approach by preparing heavy-atom-free composite crystals of an RTP with a long-lifetime emission and a red emissive organic fluorophore with TADF to yield materials with emission above 650 nm.The emission arose from the triplet excited state of an acceptor undergoing thermally activated reverse intersystem crossing(RISC)to the emissive S1 state.Such composite crystal is the first organic material with persistent TADF,achieved by triplet–triplet energy transfer.展开更多
For the first time,a series of photochromic dyes SP1-3 with dual-responsive thermally activated delayed fluorescence(TADF)characteristics were reported in this research.Benefitting from the reversible light-responsive...For the first time,a series of photochromic dyes SP1-3 with dual-responsive thermally activated delayed fluorescence(TADF)characteristics were reported in this research.Benefitting from the reversible light-responsive property of SP1-3,the eigen TADF of these compounds could be regulated between 588 and 678 nm or turned on/off by different wavelengths of light irradiation in a polyvinylpyrrolidone(PVP)matrix.The emission lifetime of the spiropyran derivative was prolonged to millisecond level for the first time.Moreover,the delayed fluorescence of SP1 and SP3 could also be manipulated by mechanical force because of the mechanochromistic properties of SP1 and SP3.This research is a significant breakthrough for photochromic materials and may broaden its scope.展开更多
基金Ministry of Education,Culture,Sports,Science and Technology,Grant/Award Number:ARIM/JPMXP1222JI0040Japan Society for the Promotion of Science,Grant/Award Numbers:KAKENHI/JP20KK0316,KAKENHI/JP21H05405,KAKENHI/JP22H02055,KAKENHI/JP23H02026,KAKENHI/JP23H03966,KAKENHI/JP20H02801。
文摘Carbazole-triazine dendrimers with a bulky terminal substituent were synthesized,and the thermally activated delayed fluorescence(TADF)property was investigated.Compared to unsubstituted carbazole dendrimers,dendrimers with bulky terminal substituents showed comparable to better photoluminescence quantum yields(PLQY)in neat films.Phenylfluorene(PF)-substituted dendrimers showed the highest PLQY of 81%,a smallΔEst of 0.06 eV,and the fastest reverse intersystem crossing(RISC)rate of∼1×10^(5 )s^(−1) compared to other dendrimers.Phosphorescence measurements of dendrimers and dendrons(fragments)indicate that the close proximity of the triplet energy of phenylfluorene-substituted carbazole dendrons(^(3)LE)to that of phenylfluorene-substituted dendrimers(^(1)CT,^(3)CT)contributes to RISC promotion and improves TADF efficiency.Terminal modification fine-tunes the energy level and suppresses intermolecular interactions,and this study provides a guideline for designing efficient solution-processable and non-doped TADF materials.
基金supported by the National Natural Science Foundation of China(U1904183,22171123 and 22102068)the Natural Science Foundation for Excellent Young Scholars of Henan Province(232300421083,212300410061)+2 种基金the Program for Innovative Research Team from the University of Henan Province(24IRTSTHN005)the Science and Technology R&D program of the Joint Funds of Henan Province(225200810082)the Open Foundation of State Key Laboratory of Structural Chemistry(20230021).
文摘Achieving high heat-resisting room temperature phosphorescence(RTP)performance and robust white emission from pure small molecules is a meaningful but challenging work.Herein,a simple donor-acceptor(D-A)molecule,9-(1H-benzotriazol-1-ylmethyl)-9H-carbazole(CzBtrz),was investigated.This simple molecule not only exhibits multiple emissions including white light,thermally activated delayed fluorescence(TADF)and ultralong RTP with a lifetime of 988.54 ms at 545 nm,but also shows superhigh heat-resisting phosphorescence property which can maintain stability in a large temperature region from 77 to 350 K(ΔT=273 K),exceeding those of other RTP systems.Meanwhile,this molecule shows the time-evolved dynamic RTP.The experimental and theoretical an-alyses from CzBtrz crystal demonstrate that the intramolecular charge transfer(ICT)interaction and molecular stacking play an important role in the generation of RTP.Therefore,this work provides an efficient strategy to design ultrahigh heat-resistant RTP,ultralong RTP and single-phased white-light emitting materials.
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supported by the National Key Research and Development Program of China (2017YFA0204501)the National Science Fund of China (51525304, 61890942, U1601651)
文摘Albeit their high efficiencies, the operational stability of the organic light emitting diodes(OLEDs) based on thermally activated delayed fluorescence(TADF) emitters is still far from satisfaction, and few strategies have been proposed to improve their stability. Here, we show that by modifying the carbazole unit, one of the most commonly used donors in TADF emitters, with peripheral groups, both the device efficiency and operational stability can be greatly improved. Awell-known TADF molecule—4,5-di(9H-carbazol-9-yl)phthalonitrile(2CzPN) was chosen as the prototype and modified by introducing peripheral tert-butyl and phenyl groups to the 3,6-positions of the carbazole(named 2tBuCzPN and 2PhCzPN, respectively). The introduced groups not only improve the compounds' electrochemical stabilities referred to the cyclic voltammetry multi-sweep results, but also promote their photoluminescence quantum yields. Furthermore, reduced singlet-triplet energy gaps are observed, leading to the shortened exciton lifetimes which are benefit to suppress the exciton annihilations. Besides, the steric hindrance of introduced phenyl groups can partly restrain the concentration quenching of the TADF emitter. Consequently, OLEDs based on 2tBuCzPN and 2PhCzPN achieved improved maximum external quantum efficiencies(EQEs) of 17.0% and 14.0%, respectively(compared to 8.5% for 2CzPN). Meanwhile, 2PhCzPN based OLED showed reduced roll-off characteristics and a longer lifetime of 7.8 times higher than that of 2CzPN, testifying the effectiveness of subtle modification of the unstable moieties in simultaneous enhancement of efficiency and stability of OLEDs based on TADF emitters.
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.
文摘以咔唑和吩噻嗪为原料,合成了2种具有D-π-A结构的新型咔唑衍生物(4-(9H-咔唑-9-基)苯基)(9-苯基-9H-咔唑-3-基)甲酮(3a)和(4-(10H-吩噻嗪-10-基)苯基)(9-苯基-9H-咔唑-3-基)甲酮(3b).化合物3a和3b的结构分别经1 H NMR和IR进行了表征,同时通过紫外-可见吸收光谱和光致发光光谱研究了其光物理性质,并进一步采用含时密度泛函理论(TDDFT)对化合物3a和3b的最低能量电子跃迁和最低三线态进行了计算.结果表明:它们都具有分子内电荷转移ICT特征,而且理论计算的吸收光谱与实验测得的光谱数据基本符合.
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This study was financially supported by the National Natural Science Foundation of China(nos.21525206 and 21971023)Q.-Z.Y.and by the EPSRC Early Career Fellowship(no.EP/L000075/1)to R.B.
文摘Structural modifications are a successful and commonly used approach to tune the emission properties of diverse fluorophores,but extending this approach to heavy-atom-free persistent luminophores has so far been unsuccessful.Here we employed a novel strategy to demonstrate triplet–triplet energy transfer from an organic room-temperature phosphor(RTP)with persistent luminescence to an organic molecule with thermally activated delayed fluorescence(TADF).We illustrated this approach by preparing heavy-atom-free composite crystals of an RTP with a long-lifetime emission and a red emissive organic fluorophore with TADF to yield materials with emission above 650 nm.The emission arose from the triplet excited state of an acceptor undergoing thermally activated reverse intersystem crossing(RISC)to the emissive S1 state.Such composite crystal is the first organic material with persistent TADF,achieved by triplet–triplet energy transfer.
基金the financial support from the National Natural Science Foundation of China(nos.21788102,22020102006,21722603,and 21871083)project support by the Shanghai Municipal Science and Technology Major Project(grant no.2018SHZDZX03)+3 种基金Program of Shanghai Academic/Technology Research Leader(no.20XD1421300)“Shu Guang”project supported by Shanghai Municipal Education Commission and Shanghai Education Development Foundation(no.19SG26)the Innovation Program of Shanghai Municipal Education Commission(no.201701-07-00-02-E00010)the Fundamental Research Funds for the Central Universities.
文摘For the first time,a series of photochromic dyes SP1-3 with dual-responsive thermally activated delayed fluorescence(TADF)characteristics were reported in this research.Benefitting from the reversible light-responsive property of SP1-3,the eigen TADF of these compounds could be regulated between 588 and 678 nm or turned on/off by different wavelengths of light irradiation in a polyvinylpyrrolidone(PVP)matrix.The emission lifetime of the spiropyran derivative was prolonged to millisecond level for the first time.Moreover,the delayed fluorescence of SP1 and SP3 could also be manipulated by mechanical force because of the mechanochromistic properties of SP1 and SP3.This research is a significant breakthrough for photochromic materials and may broaden its scope.
