The Experts below are selected from a list of 15291 Experts worldwide ranked by ideXlab platform
Ben Zhong Tang - One of the best experts on this subject based on the ideXlab platform.
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tuning molecular emission of organic emitters from fluorescence to Phosphorescence through push pull electronic effects
Nature Communications, 2020Co-Authors: Ben Zhong Tang, Haitao Feng, Jiajie Zeng, Pingan Yin, Xuedong Wang, Qian Peng, Zujin Zhao, Jacky Wing Yip LamAbstract:Organic emitters with persistent Phosphorescence have shown potential application in optoelectronic devices. However, rational design and Phosphorescence tuning are still challenging. Here, a series of metal-free luminophores without heavy atoms and carbonyl groups from commercial/lab-synthesized carbazole and benzene were synthesized to realize tunable molecular emission from fluorescence to Phosphorescence by simply substituent variation. All the molecules emit blue fluorescence in both solution and solid state. Upon removal of excitation source, the fluorinated luminophores show obvious Phosphorescence. The lab-synthesized carbazole based molecules exhibit a huge lifetime difference to the commercially purchased ones due to the existence of isomer in the latter samples. The small energy gap between singlet and triplet state and low reorganization energy help enhance intersystem crossing to contribute to a more competitive radiative process from triplet to ground state. Blue and white organic light-emitting devices are fabricated by using fluorinated luminophore as emitting layer. Though organic emitters with room temperature Phosphorescence (RTP) are attractive for various applications, realizing highly efficient and long lifetime emission remains a challenge. Here, the authors report the role of push-pull electronic effects on emission for organic RTP emitters.
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boosting the efficiency of organic persistent room temperature Phosphorescence by intramolecular triplet triplet energy transfer
Nature Communications, 2019Co-Authors: Weijun Zhao, Ben Zhong Tang, Jacky Wing Yip Lam, Tsz Shing Cheung, Nan Jiang, Wenbin Huang, Xuepeng ZhangAbstract:Persistent luminescence is a fascinating phenomenon with exceptional applications. However, the development of organic materials capable of persistent luminescence, such as organic persistent room-temperature Phosphorescence, lags behind for their normally low efficiency. Moreover, enhancing the Phosphorescence efficiency of organic luminophores often results in short lifetime, which sets an irreconcilable obstacle. Here we report a strategy to boost the efficiency of Phosphorescence by intramolecular triplet-triplet energy transfer. Incorpotation of (bromo)dibenzofuran or (bromo)dibenzothiophene to carbazole has boosted the intersystem crossing and provided an intramolecular triplet-state bridge to offer a near quantitative exothermic triplet-triplet energy transfer to repopulate the lowest triplet-state of carbazole. All these factors work together to contribute the efficient Phosphorescence. The generation and transfer of triplet excitons within a single molecule is revealed by low-temperature spectra, energy level and lifetime investigations. The strategy developed here will enable the development of efficient phosphorescent materials for potential high-tech applications.
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achieving persistent room temperature Phosphorescence and remarkable mechanochromism from pure organic luminogens
Advanced Materials, 2015Co-Authors: Yongyang Gong, Wang Zhang Yuan, Yongming Zhang, Qian Peng, Gan Chen, Yujun Xie, Ben Zhong TangAbstract:Persistent room temperature Phosphorescence (RTP) from pure organic luminogens can be rationally realized based on the crystallization-induced Phosphorescence phenomenon and severe crystallization. A perfect crystal with dense molecular packing and effective inter-molecular interactions isolates the triplet excitons from quenching sites and significantly blocks the high-energy vibrational dissipation, thus yielding long-lasting RTP.
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room temperature Phosphorescence from natural products crystallization matters
Science China-chemistry, 2013Co-Authors: Yongyang Gong, Wang Zhang Yuan, Yeqiang Tan, Ju Mei, Yiren Zhang, Yongming Zhang, Jing Zhi Sun, Ben Zhong TangAbstract:Efficient room temperature Phosphorescence is observed in natural compounds and polymers such as starch, cellulose, bovine serum albumin (BSA), and some other carbohydrates. Whereas being practically nonluminescent in solutions and TLC plates, they emit bright Phosphorescence in the crystalline states with lifetime up to microseconds, exhibiting crystallization-induced Phosphorescence (CIP) characteristics. The CIP of these natural products without any conventional chromophores offers a new platform for the exploration of conceptually novel luminogens.
Wei Huang - One of the best experts on this subject based on the ideXlab platform.
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organic room temperature Phosphorescence materials for biomedical applications
Chemistry-an Asian Journal, 2020Co-Authors: Jiahuan Zhi, Huifang Shi, Wei Huang, Qian ZhouAbstract:Organic room temperature Phosphorescence (RTP) materials have drawn increasing attention due to their unique features, especially the long emission lifetime for applications in biomedicine. In this review, we provide an overview of the recent developments of organic RTP materials applied in the biomedicine field. First, we introduce the basic mechanism of Phosphorescence and subsequently we present various strategies of modulating the lifetime and efficiency of room temperature organic Phosphorescence. Next, we summarize the progress of organic RTP materials in biological applications, including bioimaging, anti-cancer and antibacterial therapies. Finally, we provide an outlook with regard to the challenges and future perspectives in the field.
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utilizing d pπ bonds for ultralong organic Phosphorescence
Angewandte Chemie, 2019Co-Authors: Shuai Tian, Xuan Wang, Huifang Shi, Yun Geng, Fushun Liang, Wei HuangAbstract:Developing pure organic materials with ultralong lifetimes is attractive but challenging. Here we report a concise chemical approach to regulate the electronic configuration for Phosphorescence enhancement. After the introduction of d-pπ bonds into a phenothiazine model system, a Phosphorescence lifetime enhancement of up to 19 times was observed for DOPPMO, compared to the reference PPMO. A record Phosphorescence lifetime of up to 876 ms was obtained in phosphorescent phenothiazine. Theoretical calculations and single-crystal analysis reveal that the d-pπ bond not only reduces the (n, π*) proportion of the T1 state, but also endows the rigid molecular environment with multiple intermolecular interactions, thus enabling long-lived Phosphorescence. This finding makes a valuable contribution to the prolongation of Phosphorescence lifetimes and the extension of the scope of phosphorescent materials.
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prolonging the lifetime of ultralong organic Phosphorescence through dihydrogen bonding
Journal of Materials Chemistry C, 2018Co-Authors: Long Gu, Wei Huang, Chunyang Miao, Qi Wu, Zhichao Cheng, Mingxing Gu, Zhongfu AnAbstract:Developing metal-free organic Phosphorescence materials with ultralong lifetimes is a long-standing concern in optoelectronics. Herein, for the first time, we report a concise chemical strategy to prolong the lifetime of ultralong organic Phosphorescence (UOP) via dihydrogen bonding. On slighlty tailoring alkyl chain in their molecular structure, the Phosphorescence lifetime of the as-prepared triazine derivatives increased by 25% (to 788 ms) under ambient conditions. Moreover, tunable ultralong luminescence was realized with various excitation wavelengths. Significantly, a white persistent luminescence was obtained, for the first time, when the excitation at 300 nm was switched off. Combining theoretical simulations and single crystal analysis, we conclude that the polar dihydrogen bonds of C–H⋯H–N in the DCzNT crystal play a critical role in increasing the lifetime of the UOP. In addition, the ultralong phosphors were successfully applied to anti-counterfeiting of a currency bill. These results can offer a new platform towards tuning the lifetime of UOP and expanding the scope of organic Phosphorescence materials and their optoelectronic applications.
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Enhancing Organic Phosphorescence by Manipulating Heavy-Atom Interaction
2016Co-Authors: Huifang Shi, Jun Yin, Guichuan Xing, Hongzhong Chen, Jingui Wang, Handong Sun, Wei HuangAbstract:Achieving highly efficient Phosphorescence in metal-free materials under ambient conditions remains a major challenge in organic optoelectronics. Herein, we report a concise approach to obtaining pure organic Phosphorescence with high quantum efficiency of up to 21.9% and millisecond-scale lifetime by manipulating heavy-atom interaction based on a class of dibromobenzene derivatives in the solid state under ambient conditions. By comparing two pairs of the organic compounds designed, the one with two more bromine atoms on the alky terminals (PhBr2C6Br2/PhBr2C8Br2) showed higher luminescence efficiency than the other one (PhBr2C6/PhBr2C8). From the single-crystal analysis, it was proposed that the enhancement of Phosphorescence resulted from increased intermolecular heavy-atom interaction in the organic crystals. Furthermore, a temperature sensor was demonstrated by using a model probe of this kind of organic phosphorescent crystals. This work not only provides a concise alternative to enhance Phosphorescence in metal-free materials but also extends the scope of pure organic phosphorescent materials with high luminescent efficiency in a single component
Cassandra L Fraser - One of the best experts on this subject based on the ideXlab platform.
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a dual emissive materials design concept enables tumour hypoxia imaging
Nature Materials, 2009Co-Authors: Guoqing Zhang, Gregory M Palmer, Mark W Dewhirst, Cassandra L FraserAbstract:Luminescent materials are widely used for imaging and sensing because of their high sensitivity and rapid response. A strategy for modulating dual emission for radiometric sensing in a single component is now shown to enable tumour hypoxia imaging. Luminescent materials are widely used for imaging and sensing owing to their high sensitivity, rapid response and facile detection by many optical technologies1. Typically materials must be chemically tailored to achieve intense, photostable fluorescence, oxygen-sensitive Phosphorescence or dual emission for ratiometric sensing, often by blending two dyes in a matrix. Dual-emissive materials combining all of these features in one easily tunable molecular platform are desirable, but when fluorescence and Phosphorescence originate from the same dye, it can be challenging to vary relative fluorescence/Phosphorescence intensities for practical sensing applications. Heavy-atom substitution2 alone increases Phosphorescence by a given, not variable amount. Here, we report a strategy for modulating fluorescence/Phosphorescence for a single-component, dual-emissive, iodide-substituted difluoroboron dibenzoylmethane-poly(lactic acid) (BF2dbm(I)PLA) solid-state sensor material. This is accomplished through systematic variation of the PLA chain length in controlled solvent-free lactide polymerization3 combined with heavy-atom substitution2. We demonstrate the versatility of this approach by showing that films made from low-molecular-weight BF2dbm(I)PLA with weak fluorescence and strong Phosphorescence are promising as ‘turn on’ sensors for aerodynamics applications4, and that nanoparticles fabricated from a higher-molecular-weight polymer with balanced fluorescence and Phosphorescence intensities serve as ratiometric tumour hypoxia imaging agents.
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a dual emissive materials design concept enables tumour hypoxia imaging
Nature Materials, 2009Co-Authors: Guoqing Zhang, Gregory M Palmer, Mark W Dewhirst, Cassandra L FraserAbstract:Luminescent materials are widely used for imaging and sensing owing to their high sensitivity, rapid response and facile detection by many optical technologies. Typically materials must be chemically tailored to achieve intense, photostable fluorescence, oxygen-sensitive Phosphorescence or dual emission for ratiometric sensing, often by blending two dyes in a matrix. Dual-emissive materials combining all of these features in one easily tunable molecular platform are desirable, but when fluorescence and Phosphorescence originate from the same dye, it can be challenging to vary relative fluorescence/Phosphorescence intensities for practical sensing applications. Heavy-atom substitution alone increases Phosphorescence by a given, not variable amount. Here, we report a strategy for modulating fluorescence/Phosphorescence for a single-component, dual-emissive, iodide-substituted difluoroboron dibenzoylmethane-poly(lactic acid) (BF(2)dbm(I)PLA) solid-state sensor material. This is accomplished through systematic variation of the PLA chain length in controlled solvent-free lactide polymerization combined with heavy-atom substitution. We demonstrate the versatility of this approach by showing that films made from low-molecular-weight BF(2)dbm(I)PLA with weak fluorescence and strong Phosphorescence are promising as 'turn on' sensors for aerodynamics applications, and that nanoparticles fabricated from a higher-molecular-weight polymer with balanced fluorescence and Phosphorescence intensities serve as ratiometric tumour hypoxia imaging agents.
Jinsang Kim - One of the best experts on this subject based on the ideXlab platform.
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tailoring intermolecular interactions for efficient room temperature Phosphorescence from purely organic materials in amorphous polymer matrices
Angewandte Chemie, 2014Co-Authors: Min Sang Kwon, Dongwook Lee, Sungbaek Seo, Jaehun Jung, Jinsang KimAbstract:Herein we report a rational design strategy for tailoring intermolecular interactions to enhance room-temperature Phosphorescence from purely organic materials in amorphous matrices at ambient conditions. The built-in strong halogen and hydrogen bonding between the newly developed phosphor G1 and the poly(vinyl alcohol) (PVA) matrix efficiently suppresses vibrational dissipation and thus enables bright room-temperature Phosphorescence (RTP) with quantum yields reaching 24 %. Furthermore, we found that modulation of the strength of halogen and hydrogen bonding in the G1–PVA system by water molecules produced unique reversible Phosphorescence-to-fluorescence switching behavior. This unique system can be utilized as a ratiometric water sensor.
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room temperature Phosphorescence of metal free organic materials in amorphous polymer matrices
Journal of the American Chemical Society, 2013Co-Authors: Dongwook Lee, Onas Bolton, Byoung Choul Kim, Ji Ho Youk, Shuichi Takayama, Jinsang KimAbstract:Developing metal-free organic phosphorescent materials is promising but challenging because achieving emissive triplet relaxation that outcompetes the vibrational loss of triplets, a key process to achieving Phosphorescence, is difficult without heavy metal atoms. While recent studies reveal that bright room temperature Phosphorescence can be realized in purely organic crystalline materials through directed halogen bonding, these organic phosphors still have limitations to practical applications due to the stringent requirement of high quality crystal formation. Here we report bright room temperature Phosphorescence by embedding a purely organic phosphor into an amorphous glassy polymer matrix. Our study implies that the reduced beta (β)-relaxation of isotactic PMMA most efficiently suppresses vibrational triplet decay and allows the embedded organic phosphors to achieve a bright 7.5% Phosphorescence quantum yield. We also demonstrate a microfluidic device integrated with a novel temperature sensor based ...
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room temperature Phosphorescence of metal free organic materials in amorphous polymer matrices
Journal of the American Chemical Society, 2013Co-Authors: Dongwook Lee, Onas Bolton, Byoung Choul Kim, Ji Ho Youk, Shuichi Takayama, Jinsang KimAbstract:Developing metal-free organic phosphorescent materials is promising but challenging because achieving emissive triplet relaxation that outcompetes the vibrational loss of triplets, a key process to achieving Phosphorescence, is difficult without heavy metal atoms. While recent studies reveal that bright room temperature Phosphorescence can be realized in purely organic crystalline materials through directed halogen bonding, these organic phosphors still have limitations to practical applications due to the stringent requirement of high quality crystal formation. Here we report bright room temperature Phosphorescence by embedding a purely organic phosphor into an amorphous glassy polymer matrix. Our study implies that the reduced beta (β)-relaxation of isotactic PMMA most efficiently suppresses vibrational triplet decay and allows the embedded organic phosphors to achieve a bright 7.5% Phosphorescence quantum yield. We also demonstrate a microfluidic device integrated with a novel temperature sensor based on the metal-free purely organic phosphors in the temperature-sensitive polymer matrix. This unique system has many advantages: (i) simple device structures without feeding additional temperature sensing agents, (ii) bright Phosphorescence emission, (iii) a reversible thermal response, and (iv) tunable temperature sensing ranges by using different polymers.
Guoqing Zhang - One of the best experts on this subject based on the ideXlab platform.
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a dual emissive materials design concept enables tumour hypoxia imaging
Nature Materials, 2009Co-Authors: Guoqing Zhang, Gregory M Palmer, Mark W Dewhirst, Cassandra L FraserAbstract:Luminescent materials are widely used for imaging and sensing because of their high sensitivity and rapid response. A strategy for modulating dual emission for radiometric sensing in a single component is now shown to enable tumour hypoxia imaging. Luminescent materials are widely used for imaging and sensing owing to their high sensitivity, rapid response and facile detection by many optical technologies1. Typically materials must be chemically tailored to achieve intense, photostable fluorescence, oxygen-sensitive Phosphorescence or dual emission for ratiometric sensing, often by blending two dyes in a matrix. Dual-emissive materials combining all of these features in one easily tunable molecular platform are desirable, but when fluorescence and Phosphorescence originate from the same dye, it can be challenging to vary relative fluorescence/Phosphorescence intensities for practical sensing applications. Heavy-atom substitution2 alone increases Phosphorescence by a given, not variable amount. Here, we report a strategy for modulating fluorescence/Phosphorescence for a single-component, dual-emissive, iodide-substituted difluoroboron dibenzoylmethane-poly(lactic acid) (BF2dbm(I)PLA) solid-state sensor material. This is accomplished through systematic variation of the PLA chain length in controlled solvent-free lactide polymerization3 combined with heavy-atom substitution2. We demonstrate the versatility of this approach by showing that films made from low-molecular-weight BF2dbm(I)PLA with weak fluorescence and strong Phosphorescence are promising as ‘turn on’ sensors for aerodynamics applications4, and that nanoparticles fabricated from a higher-molecular-weight polymer with balanced fluorescence and Phosphorescence intensities serve as ratiometric tumour hypoxia imaging agents.
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a dual emissive materials design concept enables tumour hypoxia imaging
Nature Materials, 2009Co-Authors: Guoqing Zhang, Gregory M Palmer, Mark W Dewhirst, Cassandra L FraserAbstract:Luminescent materials are widely used for imaging and sensing owing to their high sensitivity, rapid response and facile detection by many optical technologies. Typically materials must be chemically tailored to achieve intense, photostable fluorescence, oxygen-sensitive Phosphorescence or dual emission for ratiometric sensing, often by blending two dyes in a matrix. Dual-emissive materials combining all of these features in one easily tunable molecular platform are desirable, but when fluorescence and Phosphorescence originate from the same dye, it can be challenging to vary relative fluorescence/Phosphorescence intensities for practical sensing applications. Heavy-atom substitution alone increases Phosphorescence by a given, not variable amount. Here, we report a strategy for modulating fluorescence/Phosphorescence for a single-component, dual-emissive, iodide-substituted difluoroboron dibenzoylmethane-poly(lactic acid) (BF(2)dbm(I)PLA) solid-state sensor material. This is accomplished through systematic variation of the PLA chain length in controlled solvent-free lactide polymerization combined with heavy-atom substitution. We demonstrate the versatility of this approach by showing that films made from low-molecular-weight BF(2)dbm(I)PLA with weak fluorescence and strong Phosphorescence are promising as 'turn on' sensors for aerodynamics applications, and that nanoparticles fabricated from a higher-molecular-weight polymer with balanced fluorescence and Phosphorescence intensities serve as ratiometric tumour hypoxia imaging agents.
