Despite rapid advances in fluorescence detectors over the past decade,the development of a highly stable,sensitive,and selective fluorescence platform for molecular recognition remains a considerable challenge.Here we...Despite rapid advances in fluorescence detectors over the past decade,the development of a highly stable,sensitive,and selective fluorescence platform for molecular recognition remains a considerable challenge.Here we report a stable carbazole-based sp2 carbon fluorescence covalent organic framework(COF)nanosheet,termed a JUC-557 nanosheet.Owing to the synergistic effect of aggregation-induced emission-and aggregation-caused quenching-based chromophores,the architecture of the JUC-577 shows high absolute quantum yields(up to 23.0%)in the solid state and when dispersed in various solvents as well as excellent sensing performance toward specific analytes,such as iodine(Ka:2.10×10^(5)M−1 and LOD:302 ppb),2,4,6-trinitrotoluene(Ka:4.38×10^(5)M−1 and LOD:129 ppb),and especially nitrobenzene(Ka:6.18×10^(6)M−1 and LOD:5 ppb)that is superior to that of fluorescence detection materials reported so far.Furthermore,the JUC-557 nanosheet preserves strong luminescence and sensitive recognition,even under harsh conditions,and allows trace detection of various analytes via a handheld UV lamp.These findings pave the way for developing stable ultrathin COF nanomaterials for highly sensitive and selective molecular detection.展开更多
Organic-inorganic halide perovskites(OIHPs)are recognized as the promising next-generation X-ray detection materials.However,the device performance is largely limited by the ion migration issue of OIHPs.Here,we report...Organic-inorganic halide perovskites(OIHPs)are recognized as the promising next-generation X-ray detection materials.However,the device performance is largely limited by the ion migration issue of OIHPs.Here,we reported a simple atomistic surface passivation strategy with methylammonium iodide(MAI)to remarkably increase the ion migration activation energy of CH_(3)NH_(3)PbI_(3)single crystals.The amount of MAI deposited on the crystal surface is finely regulated by a self-assemble process to effectively suppress the metallic lead defects,while not introducing extra mobile ions,which results in significantly improved dark current stability of the coplanar-structure devices under a large electric field of 100Vmm^(-1).The X-ray detectors hence exhibit a record-high sensitivity above 700,000μC Gy^(-1)_(air) cm^(-2)under continuum X-ray irradiation with energy up to 50 keV,which enables an ultralow X-ray detection limit down to 1.5 nGy_(air)s^(-1).Our findings will allow for the dramatically reduced X-ray exposure of human bodies in medical imaging applications.展开更多
基金supported by the National Natural Science Foundation of China(grant nos.22025504,21621001,21390394,22105082,21772123,21761142011,51502173,and 21702095)the 111 Project(grant nos.BP0719036 and B17020)+3 种基金the China Postdoctoral Science Foundation(grant nos.2020TQ0118 and 2020M681034)the program for the JLU Science and Technology Innovative Research Team,Shanghai Engineering Research Center of Green Energy Chemical Engineering(grant no.18DZ2254200)the 111 Innovation and Talent Recruitment Base on Photochemical and Energy Materials(grant no.D18020),the Shanghai Government(grant nos.21010503400 and 18JC1412900)the International Joint Laboratory of Resource Chemistry(IJLRC).
文摘Despite rapid advances in fluorescence detectors over the past decade,the development of a highly stable,sensitive,and selective fluorescence platform for molecular recognition remains a considerable challenge.Here we report a stable carbazole-based sp2 carbon fluorescence covalent organic framework(COF)nanosheet,termed a JUC-557 nanosheet.Owing to the synergistic effect of aggregation-induced emission-and aggregation-caused quenching-based chromophores,the architecture of the JUC-577 shows high absolute quantum yields(up to 23.0%)in the solid state and when dispersed in various solvents as well as excellent sensing performance toward specific analytes,such as iodine(Ka:2.10×10^(5)M−1 and LOD:302 ppb),2,4,6-trinitrotoluene(Ka:4.38×10^(5)M−1 and LOD:129 ppb),and especially nitrobenzene(Ka:6.18×10^(6)M−1 and LOD:5 ppb)that is superior to that of fluorescence detection materials reported so far.Furthermore,the JUC-557 nanosheet preserves strong luminescence and sensitive recognition,even under harsh conditions,and allows trace detection of various analytes via a handheld UV lamp.These findings pave the way for developing stable ultrathin COF nanomaterials for highly sensitive and selective molecular detection.
基金The authors acknowledge funding support from the National Natural Science Foundation of China(No.21875089)the National Key Research and Development Program of China(No.2018YFB2200105)+1 种基金the Science Fund for Creative Research Groups of the National Natural Science Foundation of China(No.61721005)the Fundamental Research Funds for the Central Universities of China(No.2019QNA4009).
文摘Organic-inorganic halide perovskites(OIHPs)are recognized as the promising next-generation X-ray detection materials.However,the device performance is largely limited by the ion migration issue of OIHPs.Here,we reported a simple atomistic surface passivation strategy with methylammonium iodide(MAI)to remarkably increase the ion migration activation energy of CH_(3)NH_(3)PbI_(3)single crystals.The amount of MAI deposited on the crystal surface is finely regulated by a self-assemble process to effectively suppress the metallic lead defects,while not introducing extra mobile ions,which results in significantly improved dark current stability of the coplanar-structure devices under a large electric field of 100Vmm^(-1).The X-ray detectors hence exhibit a record-high sensitivity above 700,000μC Gy^(-1)_(air) cm^(-2)under continuum X-ray irradiation with energy up to 50 keV,which enables an ultralow X-ray detection limit down to 1.5 nGy_(air)s^(-1).Our findings will allow for the dramatically reduced X-ray exposure of human bodies in medical imaging applications.
