The in.jection of charge carriers from the electron/hole injection or transport layers in polymer light-emitting diodes potentially increases the device efficiency not by changing of charge intensity but by lattice di...The in.jection of charge carriers from the electron/hole injection or transport layers in polymer light-emitting diodes potentially increases the device efficiency not by changing of charge intensity but by lattice distortion variation and quasi-particle interactions. From the low-dimensional condensed matter physics perspective, a valid mechanism is proposed to bring a type of novel channels that, under a proper external electric field, transition- forbidden triplet excitons are transformed and partially charged by charge carriers （polarons/bipolarons）, thus are able to emit light and to enhance fluorescence greatly.展开更多
Easy non-radiative decay property of long-lived triplet excitons in aqueous solution obstructs their applications in aquatic surroundings.Recently reported phosphorescence phenomena in aqueous solution have excited re...Easy non-radiative decay property of long-lived triplet excitons in aqueous solution obstructs their applications in aquatic surroundings.Recently reported phosphorescence phenomena in aqueous solution have excited researchers enormously but achieving full-color water-soluble phosphorescent carbon nanodots(CNDs)is still a challenging issue.Herein,full-color phosphorescence of water-soluble CNDs has been demonstrated by triggering their triplet excitons through nanospace domain confinement,and Förster energy resonance transfer is used for further tuning phosphorescence range.The phosphorescence spans across most of the visible spectrum,ranging from 400 to 700 nm.In an aqueous solution,the CNDs exhibits blue,green,and red phosphorescence,lasting for approximately 6,10,and 7 s,respectively.Correspondingly,the phosphorescence quantum yields are 11.85%,8.6%and 3.56%,making them readily discernible to the naked eyes and laying a solid foundation for practical application.Furthermore,phosphorescence flexible optical display and bioimaging have been demonstrated by using the multicolor CNDs-based nanomaterials,showing distinct superiority for accuracy and complete display and imaging in complex emission background.展开更多
Buckybowl structures as non-uniform electrostatic potential distributions of poly-cyclic aromatic materials show a unique photoelectric performance.In this work,OTC was utilized for dynamic modulation of triplet excit...Buckybowl structures as non-uniform electrostatic potential distributions of poly-cyclic aromatic materials show a unique photoelectric performance.In this work,OTC was utilized for dynamic modulation of triplet exciton transition processes.Five host molecules with different functional units were selected,thus providing dif-ferent intermolecular interactions in the host/guest systems.Therefore,the delayed emissions were regulated from 536 to 624 nm via the tuning of the triplet exciton transition processes of OTC in different hosts.Experimental data and theoretical calculations revealed that the varied triplet transition behaviors resulted from the competition between the intersystem crossing(ISC)process of OTC-monomer and the reverse intersystem crossing(RISC)process of OTC-aggregates.This work proves the superior structure of buckybowl-based luminophore for controlling triplet exciton transition processes and supplies a new perspective for persistent afterglow luminophore design.展开更多
多色有机室温磷光(Room Temperature Phosphorescent,RTP)材料因其发射寿命长、颜色可调、生物相容性好以及激发态性质可调控等独特的性质,在显示技术、防伪、数据加密以及传感等领域展现出巨大的应用潜力,近年来受到了研究者的广泛关...多色有机室温磷光(Room Temperature Phosphorescent,RTP)材料因其发射寿命长、颜色可调、生物相容性好以及激发态性质可调控等独特的性质,在显示技术、防伪、数据加密以及传感等领域展现出巨大的应用潜力,近年来受到了研究者的广泛关注。然而,受限于有机材料的三重态激子固有的敏感性,其三重态发光性质的调控成为了一个重大挑战。因此,在有机体系中实现多色且稳定的RTP发射仍然是一项亟待解决的问题。本文旨在综述近年来在多色有机RTP材料设计方面所取得的进展,重点介绍了卤素效应、晶体工程、聚集体效应以及主客体掺杂策略。通过精心选择和设计磷光分子,结合分子内/分子间相互作用和聚集态调控,成功实现了多种颜色的RTP发射。希望本文能为多色RTP材料的合理设计提供一定的思路,并为多色RTP材料的各种前沿应用提供一定的指导。展开更多
The electroluminescence (EL) produced by a highly luminescent phosphorescent dye Cu-4(CdropCPh)(4)L-2 (L = 1.8-bis(di-phenylphosphino)-3,6-dioxaoctane, Cu-4) doped polymer as emitting layer is reported. The effects of...The electroluminescence (EL) produced by a highly luminescent phosphorescent dye Cu-4(CdropCPh)(4)L-2 (L = 1.8-bis(di-phenylphosphino)-3,6-dioxaoctane, Cu-4) doped polymer as emitting layer is reported. The effects of the charge injection balance on the polymers, in particular, poly(N-vinylcarbazole) (PVK) have been studied by using photoluminescence and electroluminescence spectroscopy. Changes in the emission spectra demonstrate the influence of the charge injection balance on the formation ratio of triplet and singlet excitons. This provides a new technical approach to realize the color patterning in polymer LEDs.展开更多
In organic solar cells,the singlet and triplet excitons dissociate into free charge carriers with different mechanisms due to their opposite spin state.Therefore,the ratio of the singlet and triplet excitons directly ...In organic solar cells,the singlet and triplet excitons dissociate into free charge carriers with different mechanisms due to their opposite spin state.Therefore,the ratio of the singlet and triplet excitons directly affects the photocurrent.Many methods were used to optimize the performance of the low-efficiency solar cell by improving the ratio of triplet excitons,which shows a long diffusion length.Here we observed that in high-efficiency systems,the proportion of singlet excitons under linearly polarized light excitation is higher than that of circularly polarized light.Since the singlet charge transfer state has lower binding energy than the triplet state,it makes a significant contribution to the charge carrier generation and enhancement of the photocurrent.Further,the positive magnetic field effect reflects that singlet excitons dissociation plays a major role in the photocurrent,which is opposite to the case of low-efficiency devices where triplet excitons dominate the photocurrent.展开更多
An efficient color-tunable hybrid white organic light-emitting diode is demonstrated with double interlayers of 2,7-bis(carbazol-9-yl)-9,9-ditoylfluo- rene/2-(diphenylphosphoryl) spiroflu-orene (DMFL-CBP/SPPO1) insert...An efficient color-tunable hybrid white organic light-emitting diode is demonstrated with double interlayers of 2,7-bis(carbazol-9-yl)-9,9-ditoylfluo- rene/2-(diphenylphosphoryl) spiroflu-orene (DMFL-CBP/SPPO1) inserted between blue fluorescent and yellow phosphorescent-emitting layers, and exhibits Commission Internationale de l’Eclairage (CIE1931) ranging from warm white (0.4368, 0.4497) to cool white (0.2781, 0.2896) with driving current density from 0.2 to 40 mA/cm2. The recombination of singlet and the triplet excitons in blue fluores-cent-emitting layer and yellow phosphorescent-emitting layer, respectively, can be modulated by both the thickness of these double interlayers and the applied current densities.展开更多
The development of fluorescent materials capable of harvesting triplet excitons efficiently is of great importance in achieving high-performance low-cost organic light-emitting diodes（OLEDs）.Among the three mechanis...The development of fluorescent materials capable of harvesting triplet excitons efficiently is of great importance in achieving high-performance low-cost organic light-emitting diodes（OLEDs）.Among the three mechanisms converting triplet to singlet excitons,triplet fusion delayed fluorescence（TFDF） plays a key role in the demonstration of highly efficient and reliable OLEDs,especially blue devices,for practice applications.This review focuses on the recent development of TFDF materials and their applications in OLEDs.Fundamental TFDF mechanism,molecular design principles,and the structure-property relationship of TFDF materials with a particular emphasis on their different excited state characters,are presented and discussed.Moreover,the future perspectives and ongoing challenges of TFDF materials are also highlighted.展开更多
文摘The in.jection of charge carriers from the electron/hole injection or transport layers in polymer light-emitting diodes potentially increases the device efficiency not by changing of charge intensity but by lattice distortion variation and quasi-particle interactions. From the low-dimensional condensed matter physics perspective, a valid mechanism is proposed to bring a type of novel channels that, under a proper external electric field, transition- forbidden triplet excitons are transformed and partially charged by charge carriers （polarons/bipolarons）, thus are able to emit light and to enhance fluorescence greatly.
基金supported by the National Natural Science Foundation of China(Nos.11904326,62075198,12274378,and 12304474)the Natural Science Foundation of Henan province(No.222300420087)+1 种基金the Henan Center for Outstanding Overseas Scientists(No.GZS201903)the Key Research and Promotion Projects in Henan Province(No.232102231033).
文摘Easy non-radiative decay property of long-lived triplet excitons in aqueous solution obstructs their applications in aquatic surroundings.Recently reported phosphorescence phenomena in aqueous solution have excited researchers enormously but achieving full-color water-soluble phosphorescent carbon nanodots(CNDs)is still a challenging issue.Herein,full-color phosphorescence of water-soluble CNDs has been demonstrated by triggering their triplet excitons through nanospace domain confinement,and Förster energy resonance transfer is used for further tuning phosphorescence range.The phosphorescence spans across most of the visible spectrum,ranging from 400 to 700 nm.In an aqueous solution,the CNDs exhibits blue,green,and red phosphorescence,lasting for approximately 6,10,and 7 s,respectively.Correspondingly,the phosphorescence quantum yields are 11.85%,8.6%and 3.56%,making them readily discernible to the naked eyes and laying a solid foundation for practical application.Furthermore,phosphorescence flexible optical display and bioimaging have been demonstrated by using the multicolor CNDs-based nanomaterials,showing distinct superiority for accuracy and complete display and imaging in complex emission background.
基金National Natural Scientific Foundation of China,Grant/Award Numbers:21975021,21975020,21875019,21871119,22105019,22175023Beijing National Laboratory for Molecular Sciences,Grant/Award Number:BNLMS192007BIT Research and Innovation Promoting Project,Grant/Award Number:2022YCXZ035。
文摘Buckybowl structures as non-uniform electrostatic potential distributions of poly-cyclic aromatic materials show a unique photoelectric performance.In this work,OTC was utilized for dynamic modulation of triplet exciton transition processes.Five host molecules with different functional units were selected,thus providing dif-ferent intermolecular interactions in the host/guest systems.Therefore,the delayed emissions were regulated from 536 to 624 nm via the tuning of the triplet exciton transition processes of OTC in different hosts.Experimental data and theoretical calculations revealed that the varied triplet transition behaviors resulted from the competition between the intersystem crossing(ISC)process of OTC-monomer and the reverse intersystem crossing(RISC)process of OTC-aggregates.This work proves the superior structure of buckybowl-based luminophore for controlling triplet exciton transition processes and supplies a new perspective for persistent afterglow luminophore design.
文摘多色有机室温磷光(Room Temperature Phosphorescent,RTP)材料因其发射寿命长、颜色可调、生物相容性好以及激发态性质可调控等独特的性质,在显示技术、防伪、数据加密以及传感等领域展现出巨大的应用潜力,近年来受到了研究者的广泛关注。然而,受限于有机材料的三重态激子固有的敏感性,其三重态发光性质的调控成为了一个重大挑战。因此,在有机体系中实现多色且稳定的RTP发射仍然是一项亟待解决的问题。本文旨在综述近年来在多色有机RTP材料设计方面所取得的进展,重点介绍了卤素效应、晶体工程、聚集体效应以及主客体掺杂策略。通过精心选择和设计磷光分子,结合分子内/分子间相互作用和聚集态调控,成功实现了多种颜色的RTP发射。希望本文能为多色RTP材料的合理设计提供一定的思路,并为多色RTP材料的各种前沿应用提供一定的指导。
基金This work was supported by the National Nature Foundation of China (No. 597905006).
文摘The electroluminescence (EL) produced by a highly luminescent phosphorescent dye Cu-4(CdropCPh)(4)L-2 (L = 1.8-bis(di-phenylphosphino)-3,6-dioxaoctane, Cu-4) doped polymer as emitting layer is reported. The effects of the charge injection balance on the polymers, in particular, poly(N-vinylcarbazole) (PVK) have been studied by using photoluminescence and electroluminescence spectroscopy. Changes in the emission spectra demonstrate the influence of the charge injection balance on the formation ratio of triplet and singlet excitons. This provides a new technical approach to realize the color patterning in polymer LEDs.
基金the National Key Research and Development Program of China(No.2018YFE0204000)the National Natural Science Foundation of China(Nos.U20A20206,51972300,62274155,and 21975245)+3 种基金the Strategic Priority Research Program of the Chinese Academy of Sciences(No.XDB43000000)the Key Research Program of Frontier Science,Chinese Academy of Sciences(No.QYZDBSSWSLH006)K.L.appreciates the support from the Youth Innovation Promotion Association,the Chinese Academy of Sciences(No.2020114)the Beijing Nova Program(No.2020117).
文摘In organic solar cells,the singlet and triplet excitons dissociate into free charge carriers with different mechanisms due to their opposite spin state.Therefore,the ratio of the singlet and triplet excitons directly affects the photocurrent.Many methods were used to optimize the performance of the low-efficiency solar cell by improving the ratio of triplet excitons,which shows a long diffusion length.Here we observed that in high-efficiency systems,the proportion of singlet excitons under linearly polarized light excitation is higher than that of circularly polarized light.Since the singlet charge transfer state has lower binding energy than the triplet state,it makes a significant contribution to the charge carrier generation and enhancement of the photocurrent.Further,the positive magnetic field effect reflects that singlet excitons dissociation plays a major role in the photocurrent,which is opposite to the case of low-efficiency devices where triplet excitons dominate the photocurrent.
文摘An efficient color-tunable hybrid white organic light-emitting diode is demonstrated with double interlayers of 2,7-bis(carbazol-9-yl)-9,9-ditoylfluo- rene/2-(diphenylphosphoryl) spiroflu-orene (DMFL-CBP/SPPO1) inserted between blue fluorescent and yellow phosphorescent-emitting layers, and exhibits Commission Internationale de l’Eclairage (CIE1931) ranging from warm white (0.4368, 0.4497) to cool white (0.2781, 0.2896) with driving current density from 0.2 to 40 mA/cm2. The recombination of singlet and the triplet excitons in blue fluores-cent-emitting layer and yellow phosphorescent-emitting layer, respectively, can be modulated by both the thickness of these double interlayers and the applied current densities.
基金supported by the National Key R&D Program of China (Grant Nos. 2018YFA0209101 and 2017YFA0303700)the National Science Foundation of China (Grant NOs. 21922302, 21873047, 91833305, and 91850105)
基金supported by National Natural Science Foundation of China(No.21372168)
文摘The development of fluorescent materials capable of harvesting triplet excitons efficiently is of great importance in achieving high-performance low-cost organic light-emitting diodes（OLEDs）.Among the three mechanisms converting triplet to singlet excitons,triplet fusion delayed fluorescence（TFDF） plays a key role in the demonstration of highly efficient and reliable OLEDs,especially blue devices,for practice applications.This review focuses on the recent development of TFDF materials and their applications in OLEDs.Fundamental TFDF mechanism,molecular design principles,and the structure-property relationship of TFDF materials with a particular emphasis on their different excited state characters,are presented and discussed.Moreover,the future perspectives and ongoing challenges of TFDF materials are also highlighted.
