A series of novel hyperbranched polymers （HBPs） consisting ofa 2,7-subsituted 9-（heptadecan-9-yl）-9H-carbazole unit （A2＋A2＇） and a tetra-substituted green thermally activated delayed fluorescence （TADF） dye ...A series of novel hyperbranched polymers （HBPs） consisting ofa 2,7-subsituted 9-（heptadecan-9-yl）-9H-carbazole unit （A2＋A2＇） and a tetra-substituted green thermally activated delayed fluorescence （TADF） dye of 2,3,5,6-tetra（9H- carbazol-9-yl）-4-pyridinecarbonitrile （4CzCNPy, B4） have been synthesized via Suzuki cross-coupling reaction following an ＂Az＋A2＇＋B4＂ method. The polymers are named according to the polymerization ratio of 4CzCNPy monomer （5 mol%, 10 mol% and 15 mol% for HBPs of P2-P4 respectively, and 0 mol% for the control linear polymer P1）. Their thermal, optoelectronic and electrochemical properties have been characterized by a combination of techniques. All the polymers exhibit high thermal stability with the decomposition temperatures （Ta） above 400 ℃ and glass transition temperatures （Tg） up to 98℃. Unfortunately, the incorporation of TADF moiety into these HBP materials induced non-TADF characteristics. However, when the HBPs functionalized as the host for our previously developed 4CzCNPy TADF dopant in solution processed devices, maximum external quantum efficiency of 5.7% and current efficiency of 17.9 cd/A have been achieved in P3-based device, which is significantly higher than those of 1.5% and 4.2 cd/A for the linear polymer P1.展开更多
Organic scintillators have recently gained considerable attentions in X-ray detection for their potential applications in biomedical radiograph and security inspection.However,the weak X-ray absorption and/or ineffici...Organic scintillators have recently gained considerable attentions in X-ray detection for their potential applications in biomedical radiograph and security inspection.However,the weak X-ray absorption and/or inefficient exciton utilization have limited the development and commercialization of organic scintillators.Currently,high-performance X-ray organic scintillators are scarce and organic scintillators with dual triplet-harvesting channels have not been explored before.Here,we develop several proof-of-concept sulfone-based organic molecules,C1–C7,using different alkoxy chains to manipulate molecular packing mode.These materials exhibit dual triplet-harvesting channels of thermally activated delayedfluorescence(TADF)and room-temperature phosphorescence(RTP)in aggregated state.Inspiringly,these molecules display distinct radioluminescence under the X-ray stimulation.Among them,C6 behaves the highest light yield of 16,558 photons MeV-1.Moreover,clear X-ray images are demonstrated in both aggregated state and single-molecule level.High spatial resolutions of 15.0 and 10.6 line pairs per millimeter(lp mm-1)are achieved for rigid andflexible scintillator screens,exceeding most reported organic and conventional inorganic scintillators.These results highlight the great potential of organic molecules with TADF and RTP nature for efficient X-ray scintillation and imaging.展开更多
基金financially supported by the National Natural Science Foundation of China(No.21304047)Natural Science Foundation of Jiangsu Province(No.BK2016042)Research Fund for the Doctoral Program of Higher Education(No.20133221120015)
文摘A series of novel hyperbranched polymers （HBPs） consisting ofa 2,7-subsituted 9-（heptadecan-9-yl）-9H-carbazole unit （A2＋A2＇） and a tetra-substituted green thermally activated delayed fluorescence （TADF） dye of 2,3,5,6-tetra（9H- carbazol-9-yl）-4-pyridinecarbonitrile （4CzCNPy, B4） have been synthesized via Suzuki cross-coupling reaction following an ＂Az＋A2＇＋B4＂ method. The polymers are named according to the polymerization ratio of 4CzCNPy monomer （5 mol%, 10 mol% and 15 mol% for HBPs of P2-P4 respectively, and 0 mol% for the control linear polymer P1）. Their thermal, optoelectronic and electrochemical properties have been characterized by a combination of techniques. All the polymers exhibit high thermal stability with the decomposition temperatures （Ta） above 400 ℃ and glass transition temperatures （Tg） up to 98℃. Unfortunately, the incorporation of TADF moiety into these HBP materials induced non-TADF characteristics. However, when the HBPs functionalized as the host for our previously developed 4CzCNPy TADF dopant in solution processed devices, maximum external quantum efficiency of 5.7% and current efficiency of 17.9 cd/A have been achieved in P3-based device, which is significantly higher than those of 1.5% and 4.2 cd/A for the linear polymer P1.
基金National Natural Science Foundation of China,Grant/Award Number:52022071Shenzhen Science and Technology Program,Grant/Award Number:ZDSYS20210623091813040。
文摘Organic scintillators have recently gained considerable attentions in X-ray detection for their potential applications in biomedical radiograph and security inspection.However,the weak X-ray absorption and/or inefficient exciton utilization have limited the development and commercialization of organic scintillators.Currently,high-performance X-ray organic scintillators are scarce and organic scintillators with dual triplet-harvesting channels have not been explored before.Here,we develop several proof-of-concept sulfone-based organic molecules,C1–C7,using different alkoxy chains to manipulate molecular packing mode.These materials exhibit dual triplet-harvesting channels of thermally activated delayedfluorescence(TADF)and room-temperature phosphorescence(RTP)in aggregated state.Inspiringly,these molecules display distinct radioluminescence under the X-ray stimulation.Among them,C6 behaves the highest light yield of 16,558 photons MeV-1.Moreover,clear X-ray images are demonstrated in both aggregated state and single-molecule level.High spatial resolutions of 15.0 and 10.6 line pairs per millimeter(lp mm-1)are achieved for rigid andflexible scintillator screens,exceeding most reported organic and conventional inorganic scintillators.These results highlight the great potential of organic molecules with TADF and RTP nature for efficient X-ray scintillation and imaging.
