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Triplet-triplet annihilation upconversion materials as electrophoretic inks
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作者 Qiaoyu Zhang Guiwen Luo +5 位作者 Jinping Chen Tianjun Yu Rui Hu Guoqiang Yang Yi Zeng Yi Li 《Chinese Chemical Letters》 SCIE CAS CSCD 2024年第3期439-442,共4页
Luminescent materials that can be reversibly switched by electric field stimulation are attractive since the potential application for optoelectronic devices.Here we report a triplet-triplet annihilation upconversion(... Luminescent materials that can be reversibly switched by electric field stimulation are attractive since the potential application for optoelectronic devices.Here we report a triplet-triplet annihilation upconversion(TTA-UC)system with electrophoretic response which is developed as the electrophoretic ink.The TTA-UC system consists of an ionic derivative of 9,10-diphenyl anthracene(DPA)as the annihilator and Pt(II)octaethylporphyrin(PtOEP)as the sensitizer.Upon applying an electric field,migration and enrichment of positively charged DPA derivatives towards the cathode results in a 20%enhancement of TTA-UC.A quasi-solid film for electrically writing is made using the electrophoretic TTA system as the ink and a platinum electrode as a pen.The prototype of TTA-UC ink demonstrates unique luminescence functions upon electrically writing and erasing,providing a promising strategy to develop electronic devices for display,information storage and encryption. 展开更多
关键词 triplet-triplet annihilation Photon upconversion ELECTROPHORESIS Electrophoretic ink Luminescence display
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Study on the energy level limitations of triplet-triplet annihilation upconversion with anthracene-isomerized dimers as annihilators
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作者 Shanshan Liu Tingting Gou +4 位作者 Xiaojuan Song Riming Hu Heyuan Liu Xiyou Li Xuchuan Jiang 《ChemPhysMater》 2024年第2期187-193,共7页
The enhancement in the efficiency of triplet-triplet annihilation upconversion(TTA-UC)is mainly determined by the triplet energy transfer(TET)and triplet-triplet annihilation(TTA)between the sensitizers and annihilato... The enhancement in the efficiency of triplet-triplet annihilation upconversion(TTA-UC)is mainly determined by the triplet energy transfer(TET)and triplet-triplet annihilation(TTA)between the sensitizers and annihilators.The TET process works efficiently by adjusting the concentration ratio of the sensitizers and annihilators.The efficiency of TTA is determined by the properties of the annihilator.Because TTA is a Dexter-type energy transfer and is affected by the diffusion rate,the energy levels of the excited states and the molecular size are both crucial in TTA.In this study,four isomerized dimers of 9,10-diphenlanthracene(DPA)and anthracene(An)were designed and prepared as annihilators for TTA-UC.The singlet and triplet energy levels could be adjusted by altering the connection position while maintaining the molecular weight and size.When PtOEP was used as the sensitizer,the maximum upconversion efficiency of 9-[4-(9-anthracenyl)phenyl]-10-phenylanthracene(9DPA-9An)was~11.18%.This is four times higher than that of 9,10-diphenyl-2,9-bianthracene(2DPA-9An,2.63%).The calculation of the energies of T_(1)and the higher triplet state(T_(3),because E(T_(2))is similar to the E(T)of these dimers)for these dimers has provided insights into the underlying reasons.These indicated that the energy gap value of 2×E(T_(1))-E(T_(3))is the determining factor for TTA efficiency.This work may provide a better understanding of the excited-state energy levels,which is crucial for designing novel annihilators to enhance the TTA-UCefficiency. 展开更多
关键词 UPCONVERSION ANNIHILATOR triplet-triplet annihilation Energy levels
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基于高激子利用率的第三代有机电致发光材料的研究进展 被引量:1
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作者 高桂才 任铁钢 《化学研究》 CAS 2017年第2期150-156,共7页
荧光OLED材料由于受到激子统计规律的限制,其能量利用效率小于25%.为了开发高效而价廉的OLED材料,突破激子统计规律的研究受到了广泛关注,目前的研究主要集中在三个方向:突破激子统计限制的共轭聚合物材料、三线态反系间窜越(RISC)的延... 荧光OLED材料由于受到激子统计规律的限制,其能量利用效率小于25%.为了开发高效而价廉的OLED材料,突破激子统计规律的研究受到了广泛关注,目前的研究主要集中在三个方向:突破激子统计限制的共轭聚合物材料、三线态反系间窜越(RISC)的延迟荧光材料以及"热激子"(hot exciton)与杂化局域-电荷转移(HLCT)激发态材料.对近年来在基于高激子利用率的第三代有机电致发光材料的研究方面的进展情况进行综述,同时对其未来的研究前景进行了展望. 展开更多
关键词 激子统计 延迟荧光 杂化局域-电荷转移 T-T态激子湮灭 热激子
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Recent Advances in Triplet-Triplet Annihilation Upconversion for Bioimaging and Biosensing 被引量:1
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作者 Wenyue Lin Jiayao Li +2 位作者 Hongjuan Feng Fang Qi Ling Huang 《Journal of Analysis and Testing》 EI CSCD 2023年第4期327-344,共18页
Photon upconversion is an anti-Stokes process that converts low-energy photons into high-energy photons.The use of upconversion luminescence can avoid the autofluorescence of biological tissue and realize background-f... Photon upconversion is an anti-Stokes process that converts low-energy photons into high-energy photons.The use of upconversion luminescence can avoid the autofluorescence of biological tissue and realize background-free bioimaging with a high signal-to-noise ratio at a low power density.In addition,the excitation of red or near-infrared light facilitates the reduction of photodamage in biological tissues and subsequent bioimaging of deep tissue features in vivo.Meanwhile,upconversion emission-mediated bio sensing offers both high sensitivity and low detection limits for quantitative analysis of the target substances in complicated biological samples.Due to its high upconversion quantum yield,low excitation power density,and tunable absorption and emission wavelengths,triplet-triplet annihilation upconversion(TTA-UC)has garnered considerable interest for bioimaging and biosensing.This review will introduce the fundamental concepts of TTA-UC,the factors that influence TTA-UC materials,and the methodologies for preparing TTA-UC materials.The important progress of TTA-UC in bioimaging and bio sensing in recent years will also be discussed in detail in vitro and in vivo.Furthermore,the current challenges of TTA-UC in bioimaging and biosensing will be discussed,along with potential solutions. 展开更多
关键词 triplet-triplet annihilation upconversion BIOIMAGING BIOSENSING
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Influence of Molecular Stacking Pattern on Excited State Dynamics of Copper Phthalocyanine Films
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作者 Meng Li Wen-hui Li +8 位作者 Yu-jie Hu Jing Leng Wen-ming Tian Chun-yi Zhao Jun-xue Liu Rong-rong Cui Sheng-ye Jin Chuan-hui Cheng Shu-lin Cong 《Chinese Journal of Chemical Physics》 SCIE EI CAS CSCD 2022年第6期900-906,I0073,共8页
Photophysical processes occurring within organic semiconductors is important for designing and fabricating organic solar cells.Copper phthalocyanine(CuPc)is a typical electron acceptor.In this work,the triplet exciton... Photophysical processes occurring within organic semiconductors is important for designing and fabricating organic solar cells.Copper phthalocyanine(CuPc)is a typical electron acceptor.In this work,the triplet exciton lifetime is prolonged by altering the molecular stacking pattern of the CuPc film.For CuPc thin films,the excited state decays are mainly determined by the triplet-triplet annihilation process.The ultrafast transient absorption measurements indicate that the primary annihilation mechanism is one-dimensional exciton diffusion collision destruction.The decay kinetics show a clearly time-dependent annihilation rate constant withγ∝t^(-1/2).Annihilation rate constants are determined to beγ0=(2.87±0.02)×10^(-20)cm^(3)·s^(-1/2)and(1.42±0.02)×10^(-20)cm^(3)·s^(-1/2)for upright and lyingdown configurations,respectively.Compared to the CuPc thin film with an upright configuration,the thin film with a lying-down configuration shows longer exciton lifetime and higher absorbance,which are beneficial to organic solar cells.The results in this work have important implications on the design and mechanistic understanding of organic optoelectronic devices. 展开更多
关键词 CUPC PHOTOPHYSICS Excited state triplet-triplet annihilation Organic solar cell
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A Fluorescein Derivative Chemosensor Combined with Triplet-Triplet Annihilation Upconversion System for Ratiometric Sensing of Cysteine
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作者 Shuoran Chen Fuming Chen +3 位作者 Yanling Li Yuyang Wang Xiaomei Wang Changqing Ye 《Journal of Analysis and Testing》 EI CSCD 2023年第4期369-376,共8页
A derivative of fluorescein,fluorescein O,O-diacrylate(FODA),was utilized in a triplet-triplet annihilation upconversion(TTA-UC)system to develop a composite ratiometric chemosensor capable of detecting cysteine(Cys).... A derivative of fluorescein,fluorescein O,O-diacrylate(FODA),was utilized in a triplet-triplet annihilation upconversion(TTA-UC)system to develop a composite ratiometric chemosensor capable of detecting cysteine(Cys).FODA acted as both the probe for Cys and the energy acceptor for upconversion(UC)emission,thereby making UC a responsive signal to Cys.In addition,the phosphorescence signal of the sensitizer in the TTA-UC system remained constant and did not respond to Cys,making it an ideal internal reference signal for constructing a ratiometric sensor.Through this simple strategy,traditional fluorescent probes can be combined with TTA-UC system to establish a ratiometric sensing platform,which can be applied in more scenarios due to the longer wavelength excitation. 展开更多
关键词 triplet-triplet annihilation UPCONVERSION Ratiometric sensor Fluorescein derivative CYSTEINE
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Efficient soluble deep blue electroluminescent dianthracenylphenylene emitters with CIE y(y≤0.08) based on triplet-triplet annihilation 被引量:3
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作者 Ling Peng Jing-Wen Yao +6 位作者 Mei Wang Lin-Ye Wang Xiao-Lan Huang Xin-Feng Wei Dong-Ge Ma Yong Cao Xu-Hui Zhu 《Science Bulletin》 SCIE EI CSCD 2019年第11期774-781,共8页
It has been challenging to develop deep blue organic molecular fluorescent emitters with CIE y(y≤0.08)based on triplet-triplet annihilation(TTA). Here, we report facilely available dianthracenylphenylenebased emitter... It has been challenging to develop deep blue organic molecular fluorescent emitters with CIE y(y≤0.08)based on triplet-triplet annihilation(TTA). Here, we report facilely available dianthracenylphenylenebased emitters, which have a 3,5-di(4-t-butylphenyl)phenyl moiety at the one end and 4-cyanophenyl or 3-pyridyl at the other end, respectively. Both fluorophores show a high glass transition temperature of over 220℃ with a thermal decomposition temperature of over 430℃ at an initial weight loss of1%. The preliminary characterizations of the organic light-emitting diodes(OLEDs) that utilized these nondoped emitters provided high EQEs of 4.6%à5.9% with CIE coordinates(0.15, 0.07–0.08). The analysis of the EL transient decay revealed that TTA contributed to the observed performance. The results show that the new emitters are attractive as a potential TTA-based host to afford stable deep blue fluorescent OLEDs. 展开更多
关键词 Anthracene DEEP BLUE emission Fluorescence Organic LIGHT-EMITTING diodes triplet-triplet annihilation
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Assembly-enhanced triplet-triplet annihilation upconversion in the aggregation formed by Schiff-base Pt(Ⅱ) complex grafting-permethyl-β-CD and 9,10-diphenylanthracence dimer 被引量:1
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作者 Hongxia Lai Ting Zhao +3 位作者 Yurong Deng Chunyin Fan Wanhua Wu Cheng Yang 《Chinese Chemical Letters》 SCIE CAS CSCD 2019年第11期1979-1983,共5页
Water-soluble triplet sensitizer with permethyl-β-cyclodextrin(PMCD)grafting on a Schiff-base Pt(II)complex(Pt-2),in which PMCD unit serves as a host for binding the acceptors and the Schiff-base Pt(II)complex serves... Water-soluble triplet sensitizer with permethyl-β-cyclodextrin(PMCD)grafting on a Schiff-base Pt(II)complex(Pt-2),in which PMCD unit serves as a host for binding the acceptors and the Schiff-base Pt(II)complex serves as a triplet sensitizer,was synthesized to investigate the effect of supramolecular complexation and assembly on the triplet-triplet annihilation upconversion emission in water.9,10-Diphenylanthracence(DPA)carboxylate(A-1)and its dimer(A-2)in which two DPA carboxylate were covalently linked with an alkyl chain were synthesized as triplet acceptors which also play a role of guest molecules for PMCD.A-1 and A-2 showed high affinity with PMCD,and A-2 can readily aggregate in water and form micron sized assemblies due to the hydrophobic effect andπ-πstacking of anthracene core in A-2.The efficiency of TTA-UC was demonstrated to be enhanced by a synergistic effect of host-guest complexation of Pt-2 with A-2 and the self-aggregation of the acceptor A-2,which facilitated the energy transfer and energy fusion among donor and acceptor. 展开更多
关键词 triplet-triplet annihilation upconversion Host-guest interactions SELF-AGGREGATION Permethyl-β-CD
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Three-dimensional direct-writing via photopolymerization based on triplet-triplet annihilation
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作者 Zhiye Wang Yusheng Zhang +2 位作者 Yuming Su Cankun Zhang Cheng Wang 《Science China Chemistry》 SCIE EI CAS CSCD 2022年第11期2283-2289,共7页
3D direct-writing via photopolymerization based on two-photon absorption(TPA) can achieve excellent out-of-plane resolution.The key to this technology is a quadratic intensity dependence in photoexciting the TPA photo... 3D direct-writing via photopolymerization based on two-photon absorption(TPA) can achieve excellent out-of-plane resolution.The key to this technology is a quadratic intensity dependence in photoexciting the TPA photosensitizers. Triplet-triplet annihilation(TTA) also has similar nonlinear light-intensity dependence. As a result, TTA can also generate spatially confined excitation near the beam focus. Combining the photopolymerization reaction with the TTA system composed of palladium porphyrin and diphenylanthracene, 3D direct-writing micro-fabrication based on photopolymerization and the TTAwas realized.The out-of-plane resolution can reach 10 μm under continuous-wave laser excitation. TTA-based 3D direct-writing technology does not need an expensive femtosecond pulsed laser, showing the potential of a next-generation 3D printing technology. 展开更多
关键词 triplet-triplet annihilation PHOTOPOLYMERIZATION 3D printing energy transfer
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Dual Triplet Sensitization Strategy for Efficient and Stable Triplet–Triplet Annihilation Upconversion Perovskite Solar Cells 被引量:2
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作者 Wangping Sheng Jia Yang +7 位作者 Xiang Li Jiaqi Zhang Yang Su Yang Zhong Yanda Zhang Lingyun Gong Licheng Tan Yiwang Chen 《CCS Chemistry》 CAS CSCD 2023年第3期729-740,共12页
The novel triplet–triplet annihilation(TTA)upconversion(UC)field of rubrene(Rub)and dibenzotetraphenylperiflanthene(DBP)sensitized by bulk metal halide perovskite,integrated with copper-2,3,9,10,16,17,23,24-octafluor... The novel triplet–triplet annihilation(TTA)upconversion(UC)field of rubrene(Rub)and dibenzotetraphenylperiflanthene(DBP)sensitized by bulk metal halide perovskite,integrated with copper-2,3,9,10,16,17,23,24-octafluorophthalocyanine(F_(8)CuPc)as cosensitizer,have been investigated in perovskite solar cells(PVSCs)to minimize sub-bandgap photon transmission loss.The firm hydrogen bonding interaction(F…H–N between F_(8)CuPc and MA+),cation-πinteraction(MA+with Rub),and the hydrophobic characteristic of additives enable F_(8)CuPc:Rub:DBP dually-sensitized p-i-n PVSCs based on MAPbI_(3)and Cs_(0.05)(FA_(0.83)MA_(0.17))_(0.95)Pb(Br_(0.17)I_(0.83))_(3)absorbers to attain champion efficiencies of 20.83%and 21.51%,respectively.Furthermore,due to the excellent photochemical and thermal stability of F_(8)CuPc,the corresponding PVSCs can maintain nearly 80%of the original efficiencies exposed to air with 50∼70%relative humidity over 1100 h and N_(2)at 85℃for 300 h. 展开更多
关键词 perovskite solar cells UPCONVERSION triplet-triplet annihilation cosensitizer
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Amplified circularly polarized luminescence enabled by photon upconversion in spin-coating cellulose matrix
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作者 Lingxia Liu Jinping Chen +4 位作者 Tianjun Yu Rui Hu Guoqiang Yang Yi Zeng Yi Li 《Chinese Chemical Letters》 SCIE CAS CSCD 2023年第3期313-316,共4页
It is of great significance to construct organic circularly polarized luminescence systems(CPL) with large luminescence dissymmetry factors(g_(lum)) for practical applications. Here we report organic CPL systems const... It is of great significance to construct organic circularly polarized luminescence systems(CPL) with large luminescence dissymmetry factors(g_(lum)) for practical applications. Here we report organic CPL systems constructed by merging triplet-triplet annihilation upconversion chromophores in cellulose matrices. The chirality of the matrix is transferred to the achiral chromophores of photon upconversion and then the multistep energy transfer processes of upconversion amplify g_(lum). The g_(lum)value of upconversion CPL in the left-handed ethyl cellulose and the right-handed(acetyl) ethyl cellulose are up to +0.1 and -0.15, respectively. The study provides a straightforward approach for constructing solid organic upconversion CPL materials with large g_(lum), which may expand the application potentials of organic chiroptical materials. 展开更多
关键词 Circularly polarized luminescence Photon upconversion CELLULOSE CHIRALITY triplet-triplet annihilation
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Thermally activated delayed fluorescence molecules and their new applications aside from OLEDs 被引量:2
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作者 Wenlong Chen Fengling Song 《Chinese Chemical Letters》 SCIE CAS CSCD 2019年第10期1717-1730,共14页
Thermally activated delayed fluorescence(TADF) organic molecules feature with long-lived delayed fluorescence, because they can undergo not only efficient intersystem crossing(ISC), but also efficient reverse intersys... Thermally activated delayed fluorescence(TADF) organic molecules feature with long-lived delayed fluorescence, because they can undergo not only efficient intersystem crossing(ISC), but also efficient reverse intersystem crossing(RISC) at room temperature. As a new type of luminescent molecules, they have exhibited successful applications in organic light emitting diodes(OLEDs). Aside from OLEDs, they are also found to have potential applications in time-resolved luminescence imaging based on long-lived fluorescence property. Meanwhile, due to their excited triplet characteristic originated from efficient ISC,they were found to be applied in triplet-triplet annihilation upconversion(TTA-UC), photodynamic therapy(PDT) and organic photocatalytic synthesis. This review briefly summarizes the characteristics and excellent photophysical properties of TADF organic compounds, then covers their applications to date aside from OLEDs based on their highly efficient ISC ability and RISC ability at room temperature. 展开更多
关键词 Thermally ACTIVATED delayed fluorescence Intersystem crossing Time-resolved luminescence triplet-triplet ANNIHILATION UPCONVERSION Photodynamic therapy Organic photocatalytic synthesis
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Exceptionally efficient deep blue anthracene-based luminogens:design,synthesis,photophysical,and electroluminescent mechanisms 被引量:1
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作者 Runda Guo Wei Liu +8 位作者 Shian Ying Yuwei Xu Yating Wen Yaxiong Wang Dehua Hu Xianfeng Qiao Bing Yang Dongge Ma Lei Wang 《Science Bulletin》 SCIE EI CSCD 2021年第20期2090-2098,M0004,共10页
Achieving high-efficiency deep blue emitter with CIE_(y)<0.06(CIE,Commission Internationale de L’Eclairage)and external quantum efficiency(EQE)>10%has been a long-standing challenge for traditional fluorescent ... Achieving high-efficiency deep blue emitter with CIE_(y)<0.06(CIE,Commission Internationale de L’Eclairage)and external quantum efficiency(EQE)>10%has been a long-standing challenge for traditional fluorescent materials in organic light-emitting diodes(OLEDs).Here,we report the rational design and synthesis of two new deep blue luminogens:4-(10-(4’-(9 H-carbazol-9-yl)-2,5-dimethyl-[1,1’-biphe nyl]-4-yl)anthracen-9-yl)benzonitrile(2 M-ph-pCzAnBzt)and 4-(10-(4-(9 H-carbazol-9-yl)-2,5-dimethyl phenyl)anthracen-9-yl)benzonitrile(2 M-pCzAnBzt).In particular,2 M-ph-pCzAnBzt produces saturated deep blue emissions in a non-doped electroluminescent device with an exceptionally high EQE of 10.44% and CIE_(x,y)(0.151,0.057).The unprecedented electroluminescent efficiency is attributed to the combined effects of higher-order reversed intersystem crossing and triplet-triplet up-conversion,which are supported by analysis of theoretical calculation,triplet sensitization experiments,as well as nanosecond transient absorption spectroscopy.This research offers a new approach to resolve the shortage of high efficiency deep blue fluorescent emitters. 展开更多
关键词 Anthracene derivative Deep blue luminogen Hot excitons triplet-triplet annihilation up-conversion Non-doped device
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Recent research progress for upconversion assisted dye-sensitized solar cells 被引量:1
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作者 Xugeng Guo Wenpeng Wu +3 位作者 Yuanyuan Li Jinglai Zhang Li Wang Hans Ågren 《Chinese Chemical Letters》 CSCD 2021年第6期1834-1846,共13页
Upconversion(UC)technology makes it possible to harvest infrared(IR)light from the sun and has increasingly been employed in recent years to improve the efficiency of solar cells.The progress in the area concerns both... Upconversion(UC)technology makes it possible to harvest infrared(IR)light from the sun and has increasingly been employed in recent years to improve the efficiency of solar cells.The progress in the area concerns both research on fundamental principles and processes of UC and technologies of device fabrication.Significant increase of important solar cell parameters,like short-circuit photocurrent density and open-circuit photovoltage as well as the total photon-to-current efficiency,has been accomplished.We here review the research published during the last few years in the area,in particular we consider the two most cherished techniques,namely the incorporation of upconverting nanophosphors directly into the photoanodes of the solar cells and the introduction of plasmonic metal nanoparticles co-existing with the UC particles.Other ways to achieve strong field enhancement,and the use of the non-linear nature of UC,is to apply microlenses,with or without assisting plasmonic excitation.Further enhanced UC action has been demonstrated by broad band and effective harvesting by organic IR antennas,with subsequent mediation by an intermediate nanoshell of the energy into the upconverting core.Codoping,nanohybrid and layer-by-layer technologies involving upconverting particles as well as the use of upconverting nanoparticles in hole-transport and electrolyte layers,tested in recent works,are also reviewed.While most of these technologies employ upconverting rare earth metals for sequential photon absorption,the main alternative technique,namely triplet-triplet annihilation UC using organic materials,is also reviewed.It is our belief that all these approaches will be further much researched in the near future,with potentially great impact on solar cell technology. 展开更多
关键词 Upconversion nanoparticles Dye-sensitized solar cells Infrared light triplet-triplet annihilation Photovoltaic systems
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Molecular core–shell structure design:Facilitating delayed fluorescence in aggregates toward highly efficient solution-processed OLEDs 被引量:1
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作者 Dan Liu Meng Zhang +4 位作者 Wenwen Tian Wei Jiang Yueming Sun Zheng Zhao Ben Zhong Tang 《Aggregate》 2022年第2期132-142,共11页
Light has been sought and explored by human since ancient times.As the most important form of light,fluorescence is significant to applications in bioimaging and optoelectronic devices.However,fluorescence quenching p... Light has been sought and explored by human since ancient times.As the most important form of light,fluorescence is significant to applications in bioimaging and optoelectronic devices.However,fluorescence quenching problem constitutes a serious bottleneck in materials creation.Inspired from the core–shell structure in nature,we report an effective strategy to overcome this long-standing problem by utilizing a molecular core–shell structure.With an emissive core and multifunctional shell fragments,these compounds show aggregation-induced delayed fluorescence(AIDF)properties by restricting singlet oxygen(^(1)O_(2))generation and suppressing the triplet–triplet annihilation(TTA).Protected by the functional shell,the aggregation-induced emission luminogens(AIEgens)exhibit strong emission with high photoluminescent quantum yield and exciton utilization.Furthermore,because the shell materials can form exciplex with electron-transport materials,the fully solution-processed organic light-emitting diodes(OLEDs)based on these core–shell materials show low turnon voltages,excellent device performance with current efficiency of 61.4 cd A–1 and power efficiency of 42.8 lm W–1,which is a record-breaking efficiency based on all-solution processed organic multilayer systems among the AIE-OLEDs so far.This simple visualization strategy based on molecular core–shell structure provides a promising platform for AIEgens used in the fully wet-processed optoelectronic field. 展开更多
关键词 aggregation-induced emission(AIE) molecular core-shell structure organic light-emitting diodes(OLEDs) triplet-triplet annihilation(TTA)
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Photoinduced charge transfer in porphyrin-C_(60) oligomer
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作者 JIA MingLi WAN Yan +1 位作者 WANG XueFei XIA AnDong 《Science China Chemistry》 SCIE EI CAS 2010年第2期419-425,共7页
Photoinduced electron transfer (ET) between C60 and porphyrin (P) in a new polymer containing porphyrin, poly(p-phenyle nevinylene), and pendant fullerene units has been investigated by nanosecond transient absorption... Photoinduced electron transfer (ET) between C60 and porphyrin (P) in a new polymer containing porphyrin, poly(p-phenyle nevinylene), and pendant fullerene units has been investigated by nanosecond transient absorption and phosphorescence spectroscopy. Compared to the physically doping material systems, binding porphyrin/C60 through chemical bonds in a polymer detains the formation of the triplet states of porphyrins and C60. The formation of intermediate charge transfer state (CSS) of P·+-C60·? was observed, which led to the delayed formation of triplet states of porphyrins and C60. The reduced opto-electronic properties, such as optical limiting performance, were also observed, which resulted from the delayed formation of triplet states. The results presented in this article are significant in understanding the complicated spectral characteristics of the triplet state and charge transfer of the porphyrin and C60 complexes, and are therefore related to the controllable performance of the new materials in applications. 展开更多
关键词 intramolecular charge transfer(ICT) triplet-triplet absorption donor-acceptor compound
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Multiple Resonance Thermally Activated Delayed Fluorescence Sensitizers Enable Green-toUltraviolet Photon Upconversion:Application in Photochemical Transformations
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作者 Yaxiong Wei Ke Pan +3 位作者 Xiaosong Cao Yuanming Li Xiaoguo Zhou Chuluo Yang 《CCS Chemistry》 CAS 2022年第12期3852-3863,共12页
Efficient visible-to-ultraviolet(UV)triplet-triplet annihilation upconversion(TTA-UC)with large anti-Stokes shift is highly promising for solar-powered and indoor applications.Nonetheless,the excitationwavelengthis co... Efficient visible-to-ultraviolet(UV)triplet-triplet annihilation upconversion(TTA-UC)with large anti-Stokes shift is highly promising for solar-powered and indoor applications.Nonetheless,the excitationwavelengthis confined to the blue region(<450 nm),mainly due to large energy loss during triplet sensitization,resulting in reduced photon utilization efficiency in practical scenarios.Herein,a series of multiple resonance thermally activated delayed fluorescence(MR-TADF)compounds are developed as purely organic sensitizers for the purpose of energy-loss reduction,which also feature intense absorbance in the visible region,high intersystem crossing efficiencies,and long triplet lifetimes.By pairing the MR-TADF sensitizers with appropriate acceptors,green-to-UV TTA-UC systems were realized with an anti-Stokes shift up to 1.05 eV,upconversion quantum yield up to 8.6%,and threshold excitation intensity as low as 9.2 mW cm^(−2) in solution.The TTA-UC pairs were applied as internal or external sources of UV photons to trigger energy-demanding photopolymerization and photoligation reactions even under excitation of low-power-density green light-emitting diode light,revealing the broad utility of thesemolecular upconverters.This work unlocks the huge potential of MR-TADF-type sensitizers in upconversion applications. 展开更多
关键词 triplet-triplet annihilation upconversion visible-to-ultraviolet upconversion multiple resonance photochemical reactions
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