ACS Applied Nano Materials
·
2024
·
IF 5.3
Xin Bao,Ke Zhao,Zhen Tian,Wenquan Sun,Hui Wang,Zixuan Liu,Lijia Zhao,Hui Li,Xi Yuan
Long-lived thermally activated delayed fluorescence (TADF) emission has gained extensive attention due to its potential application in information encryption, illumination, and bioimaging. However, developing visible light-excited TADF materials is still a significant challenge. Herein, visible light triggered TADF emission was achieved by embedding chlorine doped carbon dots (Cl-CDs) into a g-C3N4 nanosheet matrix through a simple microwave treatment. The strong electron-withdrawing effect of the chlorine dropping redshifts the excitation wavelength, and the covalent bonds between Cl-CDs and the matrix significantly stabilize the triplet state. Green TADF with a peak at 520 nm could be obtained in the Cl-CD composite when excited by the UV to visible light, and the afterglow signal can be observed by the naked eye for up to 5 s after a mobile phone flashlight irradiation. The composite also exhibited temperature-responsive color stability under UV light irradiation. Consequently, the Cl-CD composite was successfully employed in concepts of information encryption and single-component time delay WLED development. This research provides materials and strategies that may motivate the visible light-excited TADF applied in advanced information encryption and illumination areas.
研究领域:
材料科学
·
光电技术
·
纳米技术
✓ 已验证
DOI
高影响因子
ACS Applied Nano Materials
·
2022
·
IF 6.14
Xiuming Teng,Xiaobo Sun,Wei Pan,Zuwei Song,Jinping Wang
Room temperature afterglow (RTA) carbon dots (CDs) are supposed to provide a promising alternative to inorganic and purely organic phosphors whose toxicity and high cost are always a major concern. However, it remains a formidable challenge to realize tunable and water-processable RTA from CDs. In this work, a strategy is proposed to achieve tunable and water-processable RTA from CDs with triplet-to-singlet Föster resonance energy-transfer-induced delayed fluorescence (TS-FRET DF). This strategy is realized by just mixing room temperature phosphorescence CDs with green emission confined in silica nanoparticles (GCDs@SiO2) as the energy donors with FRET-matched orange-emissive CDs (OCDs) as the energy acceptors in aqueous solution. The TS-FRET DF of GCDs@SiO2–OCDs can be tuned from green to orange by the amount of OCDs, pH, and organic solvents, respectively. Finally, GCDs@SiO2–OCDs with interesting room temperature water-processable TS-FRET DF can be successfully used in information security and fingerprint recognition.
研究领域:
材料科学
·
光学
·
化学
✓ 已验证
DOI
高影响因子
Small
·
2025
·
IF 12.1
Dongbo Chen,Yu-e Shi,Song Shen,Song Liu,Dongpeng Yan,Zhenguang Wang
Dual-mode afterglow, integrating ultralong phosphorescence and delayed fluorescence, offers promising opportunities for developing high-temperature resistant luminescent materials. However, there is an obvious gap between the emission lifetime of delayed fluorescence and phosphorescence. In this work, a dehydration-induced doping strategy is proposed to achieve high-temperature resistant afterglow by balancing phosphorescence and delayed fluorescence lifetime. The critical role of structural defects is demonstrated in the afterglow mechanism, where energy transferred between the defect states and guest molecules determines the lifetime of afterglow. In addition, efficient reverse intersystem crossing processes are achieved between the defect states and singlet states, facilitating the long-lived fluorescence. These synergistic effects result in the prolonged lifetime of delayed fluorescence to approach that of phosphorescence, which produced high-temperature resistant afterglow materials, even up to 125 °C. These results provide a clue for modulating the emission dynamics of afterglow materials for applications in information security, biomedical diagnosis, and chemical sensing.
研究领域:
材料科学
·
光学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
Small
·
2021
·Vol. 18
·期 1
·2105415
·
IF 13.281
Jinyang Zhu,Junhua Hu,Qiang Hu,Xiaoyu Zhang,Elena V. Ushakova,Kaikai Liu,Shixun Wang,Xu Chen,Chongxin Shan,Andrey L. Rogach,Xue Bai
Carbon dot (CD) based long-lived afterglow emission materials have attracted attention in recent years, but demonstration of white-light room-temperature afterglow remains challenging, due to the difficulty of simultaneous generation of multiple long-lived excited states with distinct chromatic emission. In this work, a white-light room-temperature long-lived afterglow emission from a CD powder with a high efficiency of 5.8% and Commission International de l'Eclairage (CIE) coordinates of (0.396, 0.409) is realized. The afterglow of the CDs originates from a synergy between the phosphorescence of the carbon core and the delayed fluorescence associated with the surface CN moieties, which is accomplished by matching the singlet state of the surface groups of the CDs with the long-lived triplet state of the carbon core, resulting in an efficient energy transfer. It is demonstrated how the long-lived afterglow emission of CDs can be utilized for fabrication of white light emitting devices and in anticounterfeiting applications.
研究领域:
材料科学
·
光学
·
纳米技术
✓ 已验证
产品关联
DOI
PubMed
高影响因子
ADVANCED FUNCTIONAL MATERIALS
·
2024
·
IF 18.5
Wenxuan Sun,Yongqiang Zhang,Guangchao Yin,Siyu Lu
Comprehensive research into afterglow emission in the near-infrared (NIR) region of carbon dots (CDs) is currently lacking. In this study, highly efficient multicolor CDs are synthesized with fluorescence from blue to NIR using Rhodamine 6G. Boron oxide (B 2 O 3 ) is employed as a matrix for encapsulating and confining the CDs, inhibiting triplet exciton quenching. Furthermore, structural rigidity is enhanced due to the formation of carbon-boron (C─B) covalent bonds between CDs and B 2 O 3 , achieving tunable afterglow emission ranging from 463 to 722 nm with lifetimes up to 801 ms. The green–yellow afterglow composite exhibits an impressive quantum yield up to 37.67% while demonstrating thermally activated delayed fluorescence (TADF). Thus, this composite is coated onto a blue alternating-current light-emitting diode (BAC-LED) to fabricate a white AC-LED, which is successfully prepared with Commission Internationale de L'Eclairage (CIE) at coordinates of (0.32, 0.34), accompanied by the color rendering index (CRI) reaching 81.1. The bright afterglow compensates for zero-point flickering in the BAC-LED, resulting in stable and gentle emission. The potential applications of these luminescent materials in optoelectronic devices are undoubtedly widened by this remarkable advancement.
研究领域:
材料科学
·
光学
·
光电子学
✓ 已验证
产品关联
DOI
高影响因子
CHEMICAL ENGINEERING JOURNAL
·
2024
·
IF 13.3
Qingling Zhao,Chunyan Fan,He Bu,Jie Gao,Lanlan Li,Xiaofei Yu,Xiaojing Yang,Zunming Lu,Xinghua Zhang
Solid-state multicolor carbon dots (CDs) have attracted tremendous attention due to their wide applications. However, the fluorescence quenching of solid-state CDs occurs due to the π-π stacking or energy transfer between adjacent carbon dots. In addition, it is difficult to observe the afterglow of solid-state CDs due to their self-quenching and deliquescence. Here, electrochemically prepared multicolor CDs emit the solid-state fluorescence and afterglow emission with lifetimes up to 657 ms by embedding the CDs into urea matrix. More importantly, the surface amino groups and C = O bonds regulate the afterglow emission of CDs from phosphorescence and thermally activated delayed fluorescence at room temperature. Surface amino groups of multicolor CDs can enhance the spin–orbit coupling, increase the intersystem crossing (ISC) and reverse intersystem crossing (RISC). Thus it can promote the generation of triple excited states and regulate the singlet–triplet energy gap value from 0.384 to 0.026 eV. The formation of covalent bonds stabilizes the single and triple excited states and inhibits the non-radiative recombination, which achieves the enhanced fluorescence and visual afterglow of multicolor CDs. The fluorescence and afterglow CDs can be applied to dual signal imaging and anti-counterfeiting, which broadens the practical applications for solid-state CDs via surface state modulation.
研究领域:
材料科学
·
化学
✓ 已验证
产品关联
DOI
高影响因子
Nanoscale
·
2025
·
IF 5.1
Pengwei Wang,Peixi Cong,Jiachen Chen,Huaiyuan Cao,Qi Yue,Zixiao Xue,Junji Zhang,Long Zhang,Robert S. Weatherup,Jiabin Cui,Jin He
The confined synthesis of carbon dots (CDs) in solid matrixes is a promising avenue for developing new afterglow materials. Benefiting from the advantages of the sol–gel preparation of nanoporous glass, we report transparent glass-confined CDs with tunable afterglow luminescence. Switchable thermally-activated delayed fluorescence (TADF) and room-temperature phosphorescence (RTP) of CDs were achieved by adjusting the sintering temperature and ion doping. Our findings reveal that with an increase in sintering temperature from 500 °C to 600 °C, the energy gap (ΔEST) of CD-nanoporous glass (NG) increased from 0.05 eV to 0.21 eV, while the lifetime increased from 329 ms to 548 ms, which is attributed to the enhanced carbonization degree of the CDs. Pb2+ doping is also shown to achieve switchable TADF and RTP of glass-confined CDs attributed to the alteration of interfacial interactions between the glass and confined CDs. This design concept introduces a new perspective for developing transparent afterglow materials for various unique phosphorescence applications.
研究领域:
材料科学
·
光学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
CHEMICAL ENGINEERING JOURNAL
·
2018
·
IF 6.735
Jiangling He,Youling He,Yonghao Chen,Xuejie Zhang,Chaofan Hu,Jianle Zhuang,Bingfu Lei,Yingliang Liu
Fluorescence of carbon dots (CDs) has grown well for substantial applications, but the long-lived photoluminescence, such as room temperature phosphorescence (RTP) and thermally activated delayed fluorescence (TADF), still catch less attention due to the serious deactivation of triplets under ambient conditions, leading to extremely low radiative efficiency. Herein, we simultaneously achieved both of them by incorporating CDs into poly(vinyl alcohol) (PVA) with the assistance of electrospinning technology. Through systematic investigation, ordered mesoporous structure from the electrospun CDs/PVA nanofibers can effectively stabilize the triplet states of CDs , thus enabling the reverse intersystem crossing (RISC) process for TADF and realizing the first example in CDs/polymer system. RTP is closely related to the triplet excited states of the carbonyls located at the surface of CDs and PVA molecule can rigidify these groups with hydrogen bonds, which can prevent quenching from atmospheric oxygen to promote the RTP and TADF behaviors in the air atmosphere. The afterglow spectrum of these nanofibers exhibits dual emission centered at 456 nm and 569 nm, originated from TADF and RTP, respectively. By changing the excitation wavelength or by adjusting the temperature of measurement, the color of the photoluminescence (PL) can be systematically tailored, the white-light emitting is promising. Moreover, these nanofibers show a long average afterglow lifetime of 1.61 s with visually recognizable period of 9 s. Moreover, CDs/PVA composites (nanofibers, solution, film, and aerogel) demonstrate potentialities in optical imaging, writing, anti-counterfeiting, temperature sensing.
研究领域:
材料科学
·
光学
·
化学
✓ 已验证
产品关联
DOI
高影响因子
Advanced Science
·
2023
·Vol. 10
·期 15
·2300139
·
IF 15.1
Zhen Zhang,Zhenguang Wang,Xiao Liu,Yu-e Shi,Zhiqiang Li,Yanli Zhao
Inorganic boric acid (BA) is generally not considered an efficient afterglow material, and several groups have reported its extremely weak room-temperature phosphorescence (RTP) in the blue spectral region. It is discovered that heat treatment of BA results in increased afterglow intensity (27-fold increase) and prolonged emission lifetime (from 0.83 to 1.59 s), attributed to enhanced through-space conjugation (TSC) of BA. The afterglow intensity of BA can be increased further (≈415 folds) by introducing p-hydroxybenzoic acid (PHA), which contains a conjugated molecular motif, to further promote the TSC of the BA system. This combination results in the production of afterglow materials with a photoluminescence quantum yield of 83.8% and an emission lifetime of 2.01 s. In addition, a tunable multicolor afterglow in the 420–490 nm range is achieved owing to the enhancement of the RTP and thermally activated delayed fluorescence of PHA, where BA exerts a confinement effect on the guest molecules. Thus, this study demonstrates promising afterglow materials produced from extremely abundant and simple precursor materials for various applications.
研究领域:
材料科学
·
光学
✓ 已验证
DOI
PubMed
高影响因子
Advanced Optical Materials
·
2022
·Vol. 10
·期 18
·2200629
·
IF 10.05
Donghui Wang,Zhangdi Lu,Xiaoman Qin,Zhen Zhang,Yu-e Shi,Jacky W. Y. Lam,Zhenguang Wang,Ben Zhong Tang
The construction of highly luminescent solid-state materials with long-lived afterglow through a straightforward method is promising but still a challenging task. Herein, a heat-treatment strategy is proposed to embed levofloxacin (Lev) in the matrix of boric acid (BA) to produce a complex with a photoluminescence quantum yield of 63.8% and an emission lifetime of 0.74 s (afterglow: >5 s). Detailed investigations suggest that the unique photophysical properties of the complex are attributed to the confinement effect of BA matrix to Lev, which reduces the probability of nonradiative relaxation and activates the radiative decays to result in the promoted emission efficiency. In addition, thermally activated delayed fluorescence is also activated due to the alteration of the π transition of Lev by the formation of boron–carbon bonds. The emission color and lifetime are also modulated through controlling the synthetic conditions, which endow their applications both in light-emitting diodes and information encryption. Thus, the present results are significant for the construction of solid-state luminescent materials, including fluorescence and room-temperature phosphorescence, and also provide a solid and universal theory to clarify their detailed emission profiles.
研究领域:
材料科学
·
光学
·
化学
✓ 已验证
DOI
高影响因子
JOURNAL OF CHEMICAL CRYSTALLOGRAPHY
·
2021
·Vol. 52
·期 1
·53-61
·
IF 0.603
Huang Bin
Abstract Understanding of relationship between structure and property of thermally activated delayed fluorescence (TADF) materials is essential for developing efficient TADF materials. To investigate the substituent effect of electron donors on luminescent properties of TADF materials, a series of single crystals based on triphenylamine (TPA)/anthraquinone (AQ) hybrids namely 1-TPA-AQ, 2-TPA-AQ, 1,8-2TPA-AQ, 2,6-2TPA-AQ have been prepared in this work. Interestingly, it is demonstrated that the substituent site of TPA unit has an important impact on the conformation of AQ for the first time. The planarity of the AQ units in these four molecules is in the order 2,6-2TPA-AQ > 2-TPA-AQ ≈ 1-TPA-AQ > 1,8-2TPA-AQ, which is associated with the molecule symmetry. In addition, intermolecular interactions in these crystals are also investigated. In α-substituted AQ derivatives (1-TPA-AQ and 1,8-2TPA-AQ) typical π–π intermolecular interactions may account for their normal TADF but weak emission in solid state. In contrast, β-substituted AQ derivatives (2-TPA-AQ and 2,6-2TPA-AQ) display weak intermolecular interactions, which are beneficial to restricting molecular motions and to suppressing the non-radiative decay, resulting in efficient TADF and aggregation-induced emission properties simultaneously. Graphic Abstract It is demonstrated that the substituent site of triphenylamine unit on anthraquinone (AQ) group has an important impact on the conformation of AQ.
研究领域:
材料科学
·
晶体学
·
计算化学
✓ 已验证
DOI
高影响因子
RSC Advances
·
2022
·Vol. 12
·期 18
·11477-11483
·
IF 4.036
Zhaoye Lv,Jun Hou,Junjie Yao,Ye Yuan,Yulan Qian,Junyang Zhu,Hongjuan Zhao,Xiaoqing Xiong,Chengqi Jiao
Fluorescein derivatives with thermally activated delayed fluorescence (TADF) show much stronger competition ability and vaster prospects than traditional fluorescein dyes due to their prominent long lifetime. It will be of great significance to synthesize more fluorescein derivatives with TADF. In this work, compounds DCF-MPYA and FL with TADF properties were obtained by fine tuning the substituents' structure on the basis of fluorescein derivative DCF-MPYM. Their long-lived triplet excited states (21.78 μs, 32.0 μs) were proved by nanosecond time-resolved transient difference absorption spectra. The steady-state and time-resolved fluorescence spectra showed that DCF-MPYA and FL exhibited red fluorescence around 645 nm and 651 nm, respectively. The results of sensitivity to oxygen and heavy atoms further demonstrated that the time-resolved fluorescence spectra originate from the delayed fluorescence. The time correlated single-photon counting (TCSPC) data indicated that DCF-MPYA and FL showed long-lived lifetimes of 13.16 μs and 23.72 μs, respectively. The energy gap (ΔEST) between the singlet (S1) and triplet (T1) states of DCF-MPYA and FL was calculated to be 3.32 meV and 9.98 meV from the decay rate of DF as a function of temperature. The small energy gap is conducive to the occurrence of efficient TADF at room temperature. Meanwhile, Gaussian calculation was employed to observe the electron density of DCF-MPYA and FL in the ground and excited states. The calculation results indicate that the shapes and energy levels of the highest occupied molecular orbitals (HOMOs), lowest unoccupied molecular orbitals (LUMOs), and LUMOs+1 for the monoanion and dianion forms are similar and thus DCF-MPYA and FL exhibit almost the same luminescence properties. Finally, DCF-MPYA and FL with low toxicity were used in confocal and time-resolved fluorescence imaging. Our construction strategy will be beneficial for developing more fluorescein derivatives with TADF in the future.
研究领域:
化学
·
生物学
·
医学成像
✓ 已验证
产品关联
DOI
PubMed
高影响因子
危险品化学品经营许可证（带存储）