High-performance nondoped organic light-emitting diodes(OLEDs)are promising technologies for future commercial applications.Herein,we synthesized two new thermally activated delayed fluorescence(TADF)emitters that ena...High-performance nondoped organic light-emitting diodes(OLEDs)are promising technologies for future commercial applications.Herein,we synthesized two new thermally activated delayed fluorescence(TADF)emitters that enable us,for the first time,to combine three effective approaches for enhancing the efficiency of nondoped OLEDs.First,the two emitters are designed to have high steric hindrances such that their emitting cores will be suitably isolated from those of their neighbors to minimize concentration quenching.On the other hand,each of the two emitters has two stable conformations in solid films.In their neat films,molecules with the minority conformation behave effectively as dopants in the matrix composing of the majority conformation.One hundred percent exciton harvesting is thus theoretically feasible in this unique architecture of“self-doped”neat films.Furthermore,both emitters have relatively high aspect ratios in terms of their molecular shapes.This leads to films with preferred molecular orientations enabling high populations of horizontal dipoles beneficial for optical outcoupling.With these three factors,OLEDs with nondoped emitting layers of the respective emitters both achieve nearly 100%exciton utilization and deliver over 30%external quantum efficiencies and ultralow efficiency roll-off at high brightness,which have not been observed in reported nondoped OLEDs.展开更多
Developing dynamic color-tunable ultra-long room temperature phosphorescence(URTP)polymers with afterglow of over 1 s,photo-chromism,and multi-stimuli response for practical anti-counterfeiting and information securit...Developing dynamic color-tunable ultra-long room temperature phosphorescence(URTP)polymers with afterglow of over 1 s,photo-chromism,and multi-stimuli response for practical anti-counterfeiting and information security applications is attractive but very challenging.Herein,by doping multicolor phosphorescence pyri-dinium bromide L block or viologen-based photo-chromic V block into polyvinyl alcohol matrixes,the water-stimuli-responsive color-tunable URTP polymerfilms with afterglow of up to 8 s and the reversible viologen-based photochromic polymerfilms have been developed.More significantly,a series of dynamic color-tunable URTP polymerfilms with ultra-long afterglow of over 6 s,photo-chromism,and water-stimuli response have been successfully exploited by integrating L and V blocks into one polymer system.Mechanistic investigations have revealed that their photo-chromism mainly comes from the photo-generated viologen free radicals.Furthermore,their dynamic multilevel anti-counterfeiting applications have been demonstrated.These results pave the way to develop smarter multifunctional URTP materials for anti-counterfeiting and optical sensing.展开更多
Covalent organic frameworks(COFs)are one class of porous materials with permanent porosity and regular channels,and have a covalent bond structure.Due to their interesting characteristics,COFs have exhibited diverse p...Covalent organic frameworks(COFs)are one class of porous materials with permanent porosity and regular channels,and have a covalent bond structure.Due to their interesting characteristics,COFs have exhibited diverse potential applications in many felds.However,some applications require the frameworks to possess high structural stability,excellent crystallinity,and suitable pore size.COFs based onβ-ketoenamine and imines are prepared through the irreversible enol-to-keto tautomerization.These materials have high crystallinity and exhibit high stability in boiling water,with strong resistance to acids and bases,resulting in various possible applications.In this review,we frst summarize the preparation methods for COFs based onβ-ketoenamine,in the form of powders,flms and foams.Then,the efects of diferent synthetic methods on the crystallinity and pore structure of COFs based onβ-ketoenamine are analyzed and compared.The relationship between structures and diferent applications including fuorescence sensors,energy storage,photocatalysis,electrocatalysis,batteries and proton conduction are carefully summarized.Finally,the potential applications,large-scale industrial preparation and challenges in the future are presented.展开更多
Climate warming is projected to drive the extinction of approximately one-fifth of the world’s lizard species within the next 60 years(by 2080).However,it remains unclear to what extent and how the global lizard popu...Climate warming is projected to drive the extinction of approximately one-fifth of the world’s lizard species within the next 60 years(by 2080).However,it remains unclear to what extent and how the global lizard population will be affected by this phenomenon on a geographical scale.Furthermore,there is a need to establish a connection between extinction risk and the prioritization of conservation efforts.In this context,we aim to address concerns related to geographically isolated and critically small lizard populations,highlighting why they face an exceptionally high risk of extinction.We also explore the potential for entire populations to vanish without notice.A comprehensive understanding of these factors is essential to inform the prioritization of conservation initiatives aimed at safeguarding lizard populations in tropical countries under future climate change scenarios.展开更多
基金National Natural Science Foundation of China,Grant/Award Numbers:51821002,52003185,52003186,52130304National Key Research&Development Program of China,Grant/Award Numbers:2020YFA0714601,2020YFA0714604+2 种基金Suzhou Key Laboratory of Functional Nano&Soft MaterialsCollaborative Innovation Center of Suzhou Nano Science&Technologythe 111 Project。
文摘High-performance nondoped organic light-emitting diodes(OLEDs)are promising technologies for future commercial applications.Herein,we synthesized two new thermally activated delayed fluorescence(TADF)emitters that enable us,for the first time,to combine three effective approaches for enhancing the efficiency of nondoped OLEDs.First,the two emitters are designed to have high steric hindrances such that their emitting cores will be suitably isolated from those of their neighbors to minimize concentration quenching.On the other hand,each of the two emitters has two stable conformations in solid films.In their neat films,molecules with the minority conformation behave effectively as dopants in the matrix composing of the majority conformation.One hundred percent exciton harvesting is thus theoretically feasible in this unique architecture of“self-doped”neat films.Furthermore,both emitters have relatively high aspect ratios in terms of their molecular shapes.This leads to films with preferred molecular orientations enabling high populations of horizontal dipoles beneficial for optical outcoupling.With these three factors,OLEDs with nondoped emitting layers of the respective emitters both achieve nearly 100%exciton utilization and deliver over 30%external quantum efficiencies and ultralow efficiency roll-off at high brightness,which have not been observed in reported nondoped OLEDs.
基金Priority Academic Program Development of Jiangsu Higher Education InstitutionsApplied Basic Research Programs of Science and Technology Commission Foundation of Jiangsu Province,Grant/Award Number:BK20231340+4 种基金Changzhou Introduction Program of Innovative Leading Talents,Grant/Award Number:CQ20220111Natural Science Foundation of Jiangsu Province,Grant/Award Number:BK20170290Natural Science Foundation of the Higher Education Institutions of Jiangsu Province,Grant/Award Number:17KJB150002Opening Project of Zhejiang Engineering Research Center of Fat-soluble Vitamin,Grant/Award Number:202107National Natural Science Foundation of China,Grant/Award Numbers:51803143,。
文摘Developing dynamic color-tunable ultra-long room temperature phosphorescence(URTP)polymers with afterglow of over 1 s,photo-chromism,and multi-stimuli response for practical anti-counterfeiting and information security applications is attractive but very challenging.Herein,by doping multicolor phosphorescence pyri-dinium bromide L block or viologen-based photo-chromic V block into polyvinyl alcohol matrixes,the water-stimuli-responsive color-tunable URTP polymerfilms with afterglow of up to 8 s and the reversible viologen-based photochromic polymerfilms have been developed.More significantly,a series of dynamic color-tunable URTP polymerfilms with ultra-long afterglow of over 6 s,photo-chromism,and water-stimuli response have been successfully exploited by integrating L and V blocks into one polymer system.Mechanistic investigations have revealed that their photo-chromism mainly comes from the photo-generated viologen free radicals.Furthermore,their dynamic multilevel anti-counterfeiting applications have been demonstrated.These results pave the way to develop smarter multifunctional URTP materials for anti-counterfeiting and optical sensing.
基金supported by the Open Fund of Beijing National Laboratory for Molecular Sciences(No.BNLMS201842)The Open Fund of the State Key Laboratory of Advanced Technology for Materials Synthesis and Processing(Wuhan University of Technology)(No.2020-KF-17)+1 种基金Postgraduate Innovation Foundation from Wuhan Institute of Technologysupport from starting funds from City University of Hongkong and 111 Project(No.D20015).
文摘Covalent organic frameworks(COFs)are one class of porous materials with permanent porosity and regular channels,and have a covalent bond structure.Due to their interesting characteristics,COFs have exhibited diverse potential applications in many felds.However,some applications require the frameworks to possess high structural stability,excellent crystallinity,and suitable pore size.COFs based onβ-ketoenamine and imines are prepared through the irreversible enol-to-keto tautomerization.These materials have high crystallinity and exhibit high stability in boiling water,with strong resistance to acids and bases,resulting in various possible applications.In this review,we frst summarize the preparation methods for COFs based onβ-ketoenamine,in the form of powders,flms and foams.Then,the efects of diferent synthetic methods on the crystallinity and pore structure of COFs based onβ-ketoenamine are analyzed and compared.The relationship between structures and diferent applications including fuorescence sensors,energy storage,photocatalysis,electrocatalysis,batteries and proton conduction are carefully summarized.Finally,the potential applications,large-scale industrial preparation and challenges in the future are presented.
文摘Climate warming is projected to drive the extinction of approximately one-fifth of the world’s lizard species within the next 60 years(by 2080).However,it remains unclear to what extent and how the global lizard population will be affected by this phenomenon on a geographical scale.Furthermore,there is a need to establish a connection between extinction risk and the prioritization of conservation efforts.In this context,we aim to address concerns related to geographically isolated and critically small lizard populations,highlighting why they face an exceptionally high risk of extinction.We also explore the potential for entire populations to vanish without notice.A comprehensive understanding of these factors is essential to inform the prioritization of conservation initiatives aimed at safeguarding lizard populations in tropical countries under future climate change scenarios.
