327 results on '"Sing Lee"'
Search Results
2. Ultrahigh Lubricity between Two-Dimensional Ice and Two-Dimensional Atomic Layers
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Quoc Huy Thi, Ping Man, Haijun Liu, Lingli Huang, Xin Chen, Chun-Sing Lee, Jiong Zhao, Qingming Deng, Saba Saeed, and Thuc Hue Ly
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Mechanical Engineering ,General Materials Science ,Bioengineering ,General Chemistry ,Condensed Matter Physics - Published
- 2023
3. Nearly 100% exciton utilization in highly efficient red OLEDs based on dibenzothioxanthone acceptor
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Xiaoxiao Hu, Yuanyuan Qin, Zhiyi Li, Honglei Gao, Teng Gao, Guanhao Liu, Xiangyu Dong, Naxi Tian, Xiuxian Gu, Chun-Sing Lee, Pengfei Wang, and Ying Wang
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General Chemistry - Published
- 2022
4. Tuning Metal-Free Hierarchical Boron Nitride-like Catalyst for Enhanced Photocatalytic CO2 Reduction Activity
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Jianli Liang, Wei Zhang, Zheyang Liu, Qianqian Song, Zhaohua Zhu, Zhiqiang Guan, Heyi Wang, Pengjun Zhang, Jing Li, Min Zhou, Chen Cao, Hui Xu, Yang Lu, Xiangmin Meng, Li Song, Po Keung Wong, Zhifeng Jiang, and Chun-Sing Lee
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General Chemistry ,Catalysis - Published
- 2022
5. Planar Positive–Zero–Negative Thermal Expansion Transition in Crystalline Supramolecular Rotors
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Si-Yuan Ge, Rui-Kang Huang, Jia-bing Wu, Kiyonori Takahashi, Chi-Sing Lee, and Takayoshi Nakamura
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General Chemical Engineering ,Materials Chemistry ,General Chemistry - Published
- 2023
6. Epitaxial growth of highly symmetrical branched noble metal-semiconductor heterostructures with efficient plasmon-induced hot-electron transfer
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Li Zhai, Sara T. Gebre, Bo Chen, Dan Xu, Junze Chen, Zijian Li, Yawei Liu, Hua Yang, Chongyi Ling, Yiyao Ge, Wei Zhai, Changsheng Chen, Lu Ma, Qinghua Zhang, Xuefei Li, Yujie Yan, Xinyu Huang, Lujiang Li, Zhiqiang Guan, Chen-Lei Tao, Zhiqi Huang, Hongyi Wang, Jinze Liang, Ye Zhu, Chun-Sing Lee, Peng Wang, Chunfeng Zhang, Lin Gu, Yonghua Du, Tianquan Lian, Hua Zhang, and Xue-Jun Wu
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Multidisciplinary ,General Physics and Astronomy ,General Chemistry ,General Biochemistry, Genetics and Molecular Biology - Abstract
Epitaxial growth is one of the most commonly used strategies to precisely tailor heterostructures with well-defined compositions, morphologies, crystal phases, and interfaces for various applications. However, as epitaxial growth requires a small interfacial lattice mismatch between the components, it remains a challenge for the epitaxial synthesis of heterostructures constructed by materials with large lattice mismatch and/or different chemical bonding, especially the noble metal-semiconductor heterostructures. Here, we develop a noble metal-seeded epitaxial growth strategy to prepare highly symmetrical noble metal-semiconductor branched heterostructures with desired spatial configurations, i.e., twenty CdS (or CdSe) nanorods epitaxially grown on twenty exposed (111) facets of Ag icosahedral nanocrystal, albeit a large lattice mismatch (more than 40%). Importantly, a high quantum yield (QY) of plasmon-induced hot-electron transferred from Ag to CdS was observed in epitaxial Ag-CdS icosapods (18.1%). This work demonstrates that epitaxial growth can be achieved in heterostructures composed of materials with large lattice mismatches. The constructed epitaxial noble metal-semiconductor interfaces could be an ideal platform for investigating the role of interfaces in various physicochemical processes.
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- 2023
7. Intramolecular Cyclization: A Convenient Strategy to Realize Efficient BT.2020 Blue Multi‐Resonance Emitter for Organic Light‐Emitting Diodes
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Chen Cao, Ji‐Hua Tan, Ze‐Lin Zhu, Jiu‐Dong Lin, Hong‐Ji Tan, Huan Chen, Yi Yuan, Man‐Kit Tse, Wen‐Cheng Chen, and Chun‐Sing Lee
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General Chemistry ,General Medicine ,Catalysis - Abstract
Rationally tuning the emission position and narrowing the full width at half-maximum (FWHM) of an emitter is of great importance for many applications. By synergistically improving rigidity, strengthening the resonant strength, inhibiting molecular bending and rocking, and destabilizing the HOMO energy level, a deep-blue emitter (CZ2CO) with a peak wavelength of 440 nm and an ultranarrow spectral FWHM of 16 nm (0.10 eV) was developed via intramolecular cyclization in a carbonyl/N resonant core (QAO). The dominant u0-0 transition character of CZ2CO gives a Commission Internationale de I'Éclairage coordinates (CIE) of (0.144, 0.042), nicely complying with the BT.2020 standard. Moreover, a hyper-fluorescent device based on CZ2CO shows a high maximum external quantum efficiency (EQEmax) of 25.6% and maintains an EQE of 22.4% at a practical brightness of 1000 cd m-2.
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- 2023
8. Photo‐controllable Luminescence from Radicals Leading to Ratiometric Emission Switching via Dynamic Intermolecular Coupling
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Jia‐Ming Jin, Wen‐Cheng Chen, Ji‐Hua Tan, Yang Li, Yingxiao Mu, Ze‐Lin Zhu, Chen Cao, Shaomin Ji, Dehua Hu, Yanping Huo, Hao‐Li Zhang, and Chun‐Sing Lee
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General Chemistry ,General Medicine ,Catalysis - Abstract
The development of photoinduced luminescent radicals with dynamic emission color is still challenging. Herein we report a novel molecular radical system (TBIQ) that shows photo-controllable luminescence, leading to a wide range of ratiometric color changes via light excitation. The conjugated skeleton of TBIQ is decorated with steric-demanding tertiary butyl groups that enable appropriate intermolecular interaction to make dynamic intermolecular coupling possible for controllable behaviors. We reveal that the helicenic pseudo-planar conformation of TBIQ experiences a planarization process after light excitation, leading to more compactly stacked supermolecules and thus generating radicals via intermolecular charge transfer. The photo-controllable luminescent radical system is employed for a high-level information encryption application. This study may offer unique insight into molecular dynamic motion for optical manufacturing and broaden the scope of smart-responsive materials for advanced applications.
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- 2023
9. Perovskite-derived structure modulation in the iron sulfate family
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Yuanqi Lan, Qi Yan, Xinyuan Zhang, Wenjiao Yao, Chenchen Wang, Chun-Sing Lee, Philip Lightfoot, Yongbing Tang, University of St Andrews. EaSTCHEM, and University of St Andrews. School of Chemistry
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MCC ,Materials Chemistry ,Metals and Alloys ,Ceramics and Composites ,DAS ,QD ,General Chemistry ,RADII ,QD Chemistry ,Catalysis ,Surfaces, Coatings and Films ,Electronic, Optical and Magnetic Materials - Abstract
Funding: Authors acknowledge support from Shenzhen Key Laboratory of Energy Materials for Carbon Neutrality (China). The authors acknowledge support from the National Natural Science Foundation of China (52125105, 22005329, 51972329, 52061160484), the Shenzhen Science and Technology Planning Project (JCYJ20190807172001755, JCYJ20210324101016039, JCYJ20210324101203009), and the Science and Technology Planning Project of Guangdong Province (2019A1515110975, 2021A1515010184, 2019TX05L389). We report the first example of a perovskite sulfate [Na3(H2O)]Fe(SO4)3. Further structure modulation, by dimensional reduction or ligand extension, has resulted in two related layered perovskite-like compounds Na6Fe(SO4)4 and Na12Fe3(SO4)6F8. Taken together, these results open up a more general strategy for the future design of more complex perovskite-related materials. Postprint
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- 2022
10. A NIR molecular rotor photosensitizer for efficient PDT and synchronous mitochondrial viscosity imaging
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Liu Yang, Qingxin Chen, Yingpeng Wan, Shenglong Gan, Shengliang Li, Chun-Sing Lee, Yin Jiang, Huatang Zhang, and Hongyan Sun
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Photosensitizing Agents ,Photochemotherapy ,Viscosity ,Materials Chemistry ,Metals and Alloys ,Ceramics and Composites ,General Chemistry ,Triazenes ,Catalysis ,Mitochondria ,Surfaces, Coatings and Films ,Electronic, Optical and Magnetic Materials - Abstract
Herein, two mitochondria-targeting photosensitizers (PSs, CCVJ-Mito-1 and CCVJ-Mito-2) that exhibit a turn-on fluorescence response towards increasing viscosity are reported. Notably, CCVJ-Mito-2 exhibits absorption in the near-infrared (NIR) region, and can be employed as a NIR PS targeting mitochondria and a fluorescent probe for tracking mitochondrial viscosity changes during photodynamic therapy (PDT). This dual functional PS can help to shed light on the dynamic changes of the cellular microenvironment during PDT and further guide the PDT process.
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- 2022
11. A novel hypocrellin-based assembly for sonodynamic therapy against glioblastoma
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Chun-Sing Lee, Jiasheng Wu, Chuangli Zhang, Xiuli Zheng, Weimin Liu, Wenjun Zhang, and Pengfei Wang
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Intracranial tumor ,Ultrasonic Therapy ,medicine.medical_treatment ,Biomedical Engineering ,Antineoplastic Agents ,Biocompatible Materials ,Photodynamic therapy ,Ultrasound stimulation ,Deep tissue ,Cell Line, Tumor ,Materials Testing ,medicine ,Humans ,General Materials Science ,Particle Size ,Perylene ,Ultrasound irradiation ,Cell Proliferation ,Therapeutic strategy ,Molecular Structure ,Phenol ,business.industry ,Sonodynamic therapy ,Quinones ,food and beverages ,General Chemistry ,General Medicine ,medicine.disease ,Ultrasonic Waves ,Cancer research ,Drug Screening Assays, Antitumor ,Glioblastoma ,business - Abstract
The non-invasive treatment of glioblastoma (GBM) is of great significance and can greatly reduce the complications of craniotomy. Sonodynamic therapy (SDT) is an emerging tumor therapeutic strategy that overcomes some fatal flaws of photodynamic therapy (PDT). Different from PDT, SDT has deep tissue penetration and can be applied in the non-invasive treatment of deep-seated tumors. However, effective sonosensitizers that can be used for SDT of GBM are still very rare. Herein, we have prepared a suitable assembly based on a hypocrellin derivative (CTHB) with good biocompatibility. Excitedly, the hypocrellin-based assembly (CTHB NPs) can effectively produce reactive oxygen species under ultrasound stimulation. The inherent fluorescence and photoacoustic imaging characteristics of the CTHB NPs are conducive to the precise positioning of the tumors. It has been proved both in subcutaneous and in intracranial tumor models that CTHB NPs can be used as an effective sonosensitizer to inhibit tumor growth under ultrasound irradiation. This hypocrellin-based assembly has a good clinical prospect in the non-invasive treatment of GBM.
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- 2022
12. Preparation of Au@Pd Core–Shell Nanorods with fcc-2H-fcc Heterophase for Highly Efficient Electrocatalytic Alcohol Oxidation
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Xichen Zhou, Yangbo Ma, Yiyao Ge, Shangqian Zhu, Yu Cui, Bo Chen, Lingwen Liao, Qinbai Yun, Zhen He, Huiwu Long, Lujiang Li, Biao Huang, Qinxin Luo, Li Zhai, Xixi Wang, Licheng Bai, Gang Wang, Zhiqiang Guan, Ye Chen, Chun-Sing Lee, Jinlan Wang, Chongyi Ling, Minhua Shao, Zhanxi Fan, and Hua Zhang
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Colloid and Surface Chemistry ,General Chemistry ,Biochemistry ,Catalysis - Published
- 2021
13. Characterizing the Conformational Distribution in an Amorphous Film of an Organic Emitter and Its Application in a 'Self‐Doping' Organic Light‐Emitting Diode
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Cai-Jun Zheng, Xue Mei Ou, Chihaya Adachi, Chun-Sing Lee, Yi Ting Lee, Xiao Chun Fan, Shao Li Zhang, Gaole Dai, Jia Xiong Chen, Jia Yu, Jiansheng Jie, Xiaohong Zhang, Kai Wang, Yi-Zhong Shi, Shiyun Xiong, and Yoichi Tsuchiya
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Materials science ,Photoluminescence ,Dopant ,business.industry ,Exciton ,Doping ,General Chemistry ,Catalysis ,Amorphous solid ,Condensed Matter::Materials Science ,OLED ,Optoelectronics ,Quantum efficiency ,business ,Common emitter - Abstract
The conformational distribution and mutual interconversion of thermally activated delayed fluorescence (TADF) emitters significantly affect the exciton utilization. However, their influence on the photophysics in amorphous film states is still not known due to the lack of a suitable quantitative analysis method. Herein, we used temperature-dependent time-resolved photoluminescence spectroscopy to quantitatively measure the relative populations of the conformations of a TADF emitter for the first time. We further propose a new concept of "self-doping" for realizing high-efficiency nondoped OLEDs. Interestingly, this "compositionally" pure film actually behaves as a film with a dopant (quasi-equatorial form) in a matrix (quasi-axial form). The concentration-induced quenching that may occur at high concentrations is thus expected to be effectively relieved. The "self-doping" OLED prepared with the newly developed TADF emitter TP2P-PXZ as a neat emitting layer realizes a high maximum external quantum efficiency of 25.4 % and neglectable efficiency roll-off.
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- 2021
14. A Highly Twisted Carbazole‐Fused DABNA Derivative as an Orange‐Red TADF Emitter for OLEDs with Nearly 40 % EQE
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Ying‐Chun Cheng, Xiao‐Chun Fan, Feng Huang, Xin Xiong, Jia Yu, Kai Wang, Chun‐Sing Lee, and Xiao‐Hong Zhang
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General Medicine ,General Chemistry ,Catalysis - Abstract
Multiple resonance (MR) type thermally activated delayed fluorescence (TADF) material is currently a research hotspot in organic light-emitting diodes (OLEDs) due to their high color purity and high exciton utilization. However, there are only a handful of MR-TADF emitters with emissions beyond the blue-to-green region. The very limited emission colors for MR-TADF emitters are mainly caused by the fact that so far molecular modifications of MR-TADF do not offer much change in the emission colors. Here, we report a new approach to modifying a prototypical MR core of DABNA by fusing carbazoles to the MR framework. The carbazole-fused molecule (TCZ-F-DABNA) basically maintains the MR-dominated features of DABNA while red-shifting the emission. Its OLED achieves an external quantum efficiency of 39.2 % with a peak at 588 nm, which is a record-high efficiency for OLEDs with peaks beyond 560 nm. This work provides a new approach for significantly tunning emission colors of MR-TADF emitters.
- Published
- 2022
15. Amphiphilic Diketopyrrolopyrrole Derivatives for Efficient Near-Infrared Fluorescence Imaging and Photothermal Therapy
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Chun-Sing Lee, Chuangli Zhang, Weimin Liu, Pengfei Wang, Jiasheng Wu, Shuaishuai Bian, Xiuli Zheng, Haohui Ren, and Wenjun Zhang
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Near-Infrared Fluorescence Imaging ,Biocompatibility ,General Chemical Engineering ,education ,technology, industry, and agriculture ,Nanoparticle ,Nanotechnology ,General Chemistry ,Photothermal therapy ,Fluorescence ,Article ,Chemistry ,chemistry.chemical_compound ,chemistry ,Amphiphile ,Side chain ,QD1-999 ,Ethylene glycol - Abstract
The design and synthesis of single-molecule amphiphilic and multifunctional phototherapeutic agents are important to cancer diagnosis and therapy. In this work, we developed three amphiphilic diketopyrrolopyrrole derivatives (TPADPP, DTPADPP, and TPADDPP) with different donor–acceptor structures and poly(ethylene glycol) side chains. The corresponding nanoparticles (NPs) were obtained via a self-assembly from three amphiphilic DPP derivatives and used as smart phototherapeutic agents for tumor diagnosis and treatment. The three amphiphilic DPP NPs exhibited near-infrared (NIR) emissions and good biocompatibility. Thus, they could be used as fluorescence (FL) imaging agents for guided therapy. DTPADPP NPs and TPADDPP NPs also displayed excellent photothermal performance and high accumulation in the tumor. Owing to these beneficial features, the DTPADPP NPs and TPADDPP NPs synthesized herein are suitable for NIR FL imaging and effective photothermal therapy against the tumor in vivo.
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- 2021
16. Unveiling the Critical Intermediate Stages During Chemical Vapor Deposition of Two-Dimensional Rhenium Diselenide
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Ran Huang, Thuc Hue Ly, Xin Chen, Fangyuan Zheng, Lingli Huang, Lok-Wing Wong, Qingming Deng, Chun-Sing Lee, Jiong Zhao, and Shu Ping Lau
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Diselenide ,Materials science ,chemistry ,General Chemical Engineering ,Inorganic chemistry ,Materials Chemistry ,chemistry.chemical_element ,General Chemistry ,Chemical vapor deposition ,Rhenium - Published
- 2021
17. Lower vaccine-acquired immunity in the elderly population following two-dose BNT162b2 vaccination is alleviated by a third vaccine dose
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Laurent, Renia, Yun Shan, Goh, Angeline, Rouers, Nina, Le Bert, Wan Ni, Chia, Jean-Marc, Chavatte, Siew-Wai, Fong, Zi Wei, Chang, Nicole Ziyi, Zhuo, Matthew Zirui, Tay, Yi-Hao, Chan, Chee Wah, Tan, Nicholas Kim-Wah, Yeo, Siti Naqiah, Amrun, Yuling, Huang, Joel Xu En, Wong, Pei Xiang, Hor, Chiew Yee, Loh, Bei, Wang, Eve Zi Xian, Ngoh, Siti Nazihah Mohd, Salleh, Guillaume, Carissimo, Samanzer, Dowla, Alicia Jieling, Lim, Jinyan, Zhang, Joey Ming Er, Lim, Cheng-I, Wang, Ying, Ding, Surinder, Pada, Louisa Jin, Sun, Jyoti, Somani, Eng Sing, Lee, Desmond Luan Seng, Ong, Yee-Sin, Leo, Paul A, MacAry, Raymond Tzer Pin, Lin, Lin-Fa, Wang, Ee Chee, Ren, David C, Lye, Antonio, Bertoletti, Barnaby Edward, Young, and Weiyi, Tang
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Vaccines, Synthetic ,COVID-19 Vaccines ,Multidisciplinary ,SARS-CoV-2 ,Vaccination ,COVID-19 ,General Physics and Astronomy ,Viral Vaccines ,General Chemistry ,Middle Aged ,Antibodies, Viral ,General Biochemistry, Genetics and Molecular Biology ,Antibody Formation ,Humans ,mRNA Vaccines ,BNT162 Vaccine ,Aged - Abstract
Understanding the impact of age on vaccinations is essential for the design and delivery of vaccines against SARS-CoV-2. Here, we present findings from a comprehensive analysis of multiple compartments of the memory immune response in 312 individuals vaccinated with the BNT162b2 SARS-CoV-2 mRNA vaccine. Two vaccine doses induce high antibody and T cell responses in most individuals. However, antibody recognition of the Spike protein of the Delta and Omicron variants is less efficient than that of the ancestral Wuhan strain. Age-stratified analyses identify a group of low antibody responders where individuals ≥60 years are overrepresented. Waning of the antibody and cellular responses is observed in 30% of the vaccinees after 6 months. However, age does not influence the waning of these responses. Taken together, while individuals ≥60 years old take longer to acquire vaccine-induced immunity, they develop more sustained acquired immunity at 6 months post-vaccination. A third dose strongly boosts the low antibody responses in the older individuals against the ancestral Wuhan strain, Delta and Omicron variants.
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- 2022
18. Enhancing the electrochemical reduction of carbon dioxide to multi-carbon products on copper nanosheet arrays via cation-catalyst interaction
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Jinli Yu, Mingzi Sun, Juan Wang, Yunhao Wang, Yang Li, Pengyi Lu, Yangbo Ma, Jingwen Zhou, Wenze Chen, Xichen Zhou, Chun-Sing Lee, Bolong Huang, and Zhanxi Fan
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General Energy ,General Engineering ,General Physics and Astronomy ,General Materials Science ,General Chemistry - Published
- 2023
19. Highly Efficient Sky-Blue Perovskite Light-Emitting Diode Via Suppressing Nonradiative Energy Loss
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Zhaohua Zhu, Sai-Wing Tsang, Yang Shen, Dong Shen, Jihua Tan, Yan Wu, Zhiqiang Guan, Chun-Sing Lee, Jian-Xin Tang, Wenjun Zhang, Yi Yuan, Menglin Li, and Ming-Fai Lo
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Energy loss ,Materials science ,business.industry ,General Chemical Engineering ,media_common.quotation_subject ,General Chemistry ,law.invention ,law ,Sky ,Materials Chemistry ,Optoelectronics ,business ,Light-emitting diode ,media_common ,Perovskite (structure) - Published
- 2021
20. Water‐Soluble Organic Nanoparticles with Programable Intermolecular Charge Transfer for NIR‐II Photothermal Anti‐Bacterial Therapy
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Shuang Tian, Weimin Liu, Zhongming Huang, Pengfei Wang, Xiaozhen Li, Yafang Xiao, Shengliang Li, Xiao Cui, Chun-Sing Lee, Haotian Bai, Ben Zhong Tang, Dong Shen, and Jihua Tan
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Staphylococcus aureus ,Materials science ,Infrared Rays ,Static Electricity ,Nanoparticle ,Microbial Sensitivity Tests ,010402 general chemistry ,Photochemistry ,01 natural sciences ,Catalysis ,chemistry.chemical_compound ,Nitriles ,Benzene Derivatives ,Escherichia coli ,Molecule ,Polycyclic Compounds ,Sulfhydryl Compounds ,Perylene ,010405 organic chemistry ,Near-infrared spectroscopy ,Intermolecular force ,Water ,General Chemistry ,Photothermal therapy ,Acceptor ,Anti-Bacterial Agents ,0104 chemical sciences ,Solubility ,chemistry ,Nanoparticles ,Absorption (chemistry) - Abstract
Extensive recent efforts have been put on the design of high-performance organic near-infrared (NIR) photothermal agents (PTAs), especially over NIR-II bio-window (1000-1350 nm). So far, the development is mainly limited by the rarity of molecules with good NIR-II response. Here, we report organic nanoparticles of intermolecular charge-transfer complexes (CTCs) with easily programmable optical absorption. By employing different common donor and acceptor molecules to form CTC nanoparticles (CT NPs), absorption peaks of CT NPs can be controllably tuned from the NIR-I to NIR-II region. Notably, CT NPs formed with perylene and TCNQ have a considerably red-shifted absorption peak at 1040 nm and achieves a good photothermal conversion efficiency of 42 % under 1064 nm excitation. These nanoparticles were used for antibacterial application with effective activity towards both Gram-negative and Gram-positive bacteria. This work opens a new avenue into the development of efficient PTAs.
- Published
- 2021
21. Enantio‐ and Regioselective Construction of 1,4‐Diamines via Cascade Hydroamination of Methylene Cyclopropanes
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Jian Zhou, Qingjing Yang, Chi Sing Lee, and Jun (Joelle) Wang
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Cyclopropanes ,Esters ,Stereoisomerism ,General Medicine ,General Chemistry ,Diamines ,Catalysis - Abstract
Despite the widespread existence of chiral 1,4-diamines in bioactive molecules and their applications in asymmetric catalysis, the catalytic and asymmetric synthesis of such structures from readily accessible substrates remains a long-standing challenge. Here, we report a Cu-catalyzed asymmetric cascade hydroamination protocol to construct a wide range of chiral 1,4-diamine derivatives in high yields with excellent enatioselectivities (up to 95 % yield and up to99 % ee). The use of two hydroxylamine esters containing different functionalized amino groups allowed us to increase the complexity of the final 1,4-diamine structures. The desired products could be easily transformed into chiral 1,4-diamines and chiral NH
- Published
- 2022
22. Optimizing Intermolecular Interactions and Energy Level Alignments of Red TADF Emitters for High-Performance Organic Light-Emitting Diodes
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Jia‐Xiong Chen, Hui Wang, Ya‐Fang Xiao, Kai Wang, Ming‐Hui Zheng, Wen‐Cheng Chen, Lu Zhou, Dehua Hu, Yanping Huo, Chun‐Sing Lee, and Xiao‐Hong Zhang
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Biomaterials ,General Materials Science ,General Chemistry ,Biotechnology - Abstract
Adequately harvesting all excitons in a single molecule and inhibiting exciton losses caused by intermolecular interactions are two important factors for achieving high efficiencies thermally activated delayed fluorescence (TADF). One potential approach for optimizing these is to tune alignment of various excited state energy levels by using different doping concentrations. Unfortunately, emission efficiencies of most TADF emitters decrease rapidly with concentrations which limits the window for energy level tunning. In this work, by introducing a spiro group to increase steric hindrance of a TADF emitter (BPPXZ) with a phenoxazine and a dibenzo[a,c]phenazine, emission efficiency of the resulting molecule (BPSPXZ) is much less affected by concentration increase. This enables exploitation of the concentration effects to tune energy levels of its excited states for obtaining simultaneously small singlet-triplet energy offset and large spin-orbital coupling, leading to high-efficiency reverse intersystem crossing. With these merits, organic light-emitting diodes (OLEDs) using the BPSPXZ emitter from 5 to 60 wt% doping can all deliver EQE of over 20%. More importantly, record-high EQEs of 33.4% and 15.8% are respectively achieved in the optimized and nondoped conditions. This work proposes a strategy for developing red TADF emitters by optimizing the intermolecular interaction and energy level alignments to facilitate exciton utilization over wide doping concentrations.
- Published
- 2022
23. Trilayer organic narrowband photodetector with electrically-switchable spectral range and color sensing ability
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Chun-Sing Lee, Sai-Wing Tsang, Zhiqiang Guan, Menglin Li, Dong Shen, Ming-Fai Lo, and Wenjun Zhang
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Photocurrent ,Materials science ,business.industry ,Photodetector ,02 engineering and technology ,General Chemistry ,010402 general chemistry ,021001 nanoscience & nanotechnology ,01 natural sciences ,Acceptor ,0104 chemical sciences ,Wavelength ,Narrowband ,Materials Chemistry ,Optoelectronics ,Quantum efficiency ,0210 nano-technology ,business ,Voltage ,Ultraviolet photoelectron spectroscopy - Abstract
Conventional photodetectors are usually “color blind” and require additional dispersive components or complicated structures to recognize colors. In this work, an organic photodetector (OPD) is designed with a layer of molybdenum(VI) oxide (MoO3) stacked on an organic donor/acceptor charge transfer interface. The band structure of the OPD is designed with multiple charge separation channels that can be activated/deactivated under reverse and forward biases. The combination of a high or low photocurrent under reverse and forward biases determines the colors of the received light, and that forms the heart of “non-color blind” ability to recognize light colors in the OPD. The energy structure and charge collection pathways in the OPD are investigated with biased external quantum efficiency (EQE), ultraviolet photoelectron spectroscopy (UPS) and current density–voltage (J–V) studies. The OPD with the ability of color and wavelength determination demonstrates its potential to recognize colors without using additional components and the dual mode operation enables it to work under different conditions via switching its detection ranges with bias voltages. This design principle can be utilized to fabricate multifunctional devices by simply selecting different donor–acceptor materials according to the desired detection ranges.
- Published
- 2021
24. Triplet harvesting aryl carbonyl-based luminescent materials: progress and prospective
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Chun-Sing Lee, Shaomin Ji, Yanping Huo, Zhiwen Yang, Hao-Li Zhang, Wen-Cheng Chen, Jihua Tan, and Chen Lifen
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chemistry.chemical_classification ,Materials science ,Aryl ,Supramolecular chemistry ,General Chemistry ,Electron acceptor ,Photochemistry ,Fluorescence ,chemistry.chemical_compound ,Intersystem crossing ,chemistry ,Atomic orbital ,Materials Chemistry ,Phosphorescence ,Luminescence - Abstract
Triplet harvesting of organic materials is of great significance in many applications, including organic optoelectronic devices, anti-counterfeiting, and biological and chemical sensors. Aryl carbonyl-based luminescent materials have been widely studied in the above-mentioned fields because they possess intrinsic n–π* transitions as a result of the lone electron pairs of the carbonyl oxygen. Consequently, efficient intersystem crossing and reverse intersystem crossing can be achieved and triplet energy can be utilized through the narrow singlet–triplet offsets arose from the orthogonal overlaps between n and π* orbitals. It has also been revealed that they exhibit versatility in molecular tailoring and supramolecular engineering for various functional materials. This review presents a systematic summary of the recent research on aryl carbonyl (including moieties derived from aryl carbonyl) derivatives, with particular focus on their applications as electron acceptors, discussing the various strategies for the construction of luminescent materials with thermally activated delayed fluorescence and room-temperature phosphorescence, respectively. Finally, the perspectives and challenges concerning aryl carbonyl for triplet harvesting luminescent applications are also discussed.
- Published
- 2021
25. Mechanisms of sodiation in anatase TiO2 in terms of equilibrium thermodynamics and kinetics
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Chun-Sing Lee, Jianming Wu, Hui Wang, Tianxing Kang, Zhongqiu Tong, Rui Yang, Yongbing Tang, Yan Wu, and Ruqian Lian
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Anatase ,Phase transition ,Materials science ,Kinetics ,General Engineering ,chemistry.chemical_element ,Bioengineering ,02 engineering and technology ,General Chemistry ,Crystal structure ,010402 general chemistry ,021001 nanoscience & nanotechnology ,01 natural sciences ,Atomic and Molecular Physics, and Optics ,0104 chemical sciences ,Crystal ,chemistry ,Equilibrium thermodynamics ,Chemical physics ,Phase (matter) ,General Materials Science ,Lithium ,0210 nano-technology - Abstract
Anatase TiO2 is a promising anode material for sodium-ion batteries (SIBs). However, its sodium storage mechanisms in terms of crystal structure transformation during sodiation/de-sodiation processes are far from clear. Here, by analyzing the redox thermodynamics and kinetics under near-equilibrium states, we observe, for the first time, that upon Na-ion uptake, the anatase TiO2 undergoes a phase transition and then an irreversible crystal structure disintegration. Additionally, unlike previous theoretical studies which investigate only the two end points of the sodiation process (i.e., TiO2 and NaTiO2), we study the progressive crystal structure changes of anatase TiO2 upon step-by-step Na-ion uptake (NaxTiO2, x = 0.0625, 0.125, 0.25, 0.5, 0.75, and 1) for the first time. It is found that the anatase TiO2 goes through a thermodynamically unstable intermediate phase (Na0.25TiO2) before reaching crystalline NaTiO2, confirming the inevitable crystal structure disintegration during sodiation. These combined experimental and theoretical studies provide new insights into the sodium storage mechanisms of TiO2 and are expected to provide useful information for further improving the performance of TiO2-based anodes for SIB applications.
- Published
- 2021
26. Constructing deep-blue bis-tridentate Ir(<scp>iii</scp>) phosphors with fluorene-based dianionic chelates
- Author
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Chun-Sing Lee, Wen-Cheng Chen, Shao-Fei Ni, Yun Chi, Sheng Fu Wang, Han-Yan Tsai, Li-Wen Fu, Jie Yan, and Ze-Lin Zhu
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Materials science ,Phosphor ,General Chemistry ,Fluorene ,Photochemistry ,Blueshift ,chemistry.chemical_compound ,chemistry ,Emission efficiency ,Materials Chemistry ,OLED ,Chelation ,Quantum efficiency ,Deep blue - Abstract
High efficiency and stable blue phosphors have been a persistent pursuit in the field of organic light-emitting diodes (OLEDs). Bis-tridentate Ir(III) complexes are considered as promising alternatives because of their excellent emission efficiency and good photostability. However, the emission colors of photostable bis-tridentate Ir(III) emitters reported so far do not reach the deep blue region. Herein, fluorene is introduced in the design of blue bis-tridentate Ir(III) complexes. By modifying a fluorene-based dianionic chelate with tert-butyl, methoxy, pyrrolidinyl and triazolyl appendages, five blue emitting bis-tridentate Ir(III) phosphors were successfully designed and prepared. Emissions of the new phosphors exhibited a gradual blue shift from the sky blue to the deep blue region according to the electron donating abilities of the added substituents. A deep blue OLED was successfully fabricated based on Flu-4 and presented an excellent maximum external quantum efficiency of 22.3% with CIE coordinates of (0.17, 0.19), which are comparable to the state-of-the-art deep blue phosphors.
- Published
- 2021
27. DTX@VTX NPs synergy PD-L1 immune checkpoint nanoinhibitor to reshape immunosuppressive tumor microenvironment for enhancing chemo-immunotherapy
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Hongying Lv, Yingpeng Wan, Rui Zhang, Chun-Sing Lee, and Futian Li
- Subjects
Biomedical Engineering ,Antineoplastic Agents ,Docetaxel ,CD8-Positive T-Lymphocytes ,B7-H1 Antigen ,Small Molecule Libraries ,Mice ,Cell Line, Tumor ,Neoplasms ,PD-L1 ,Tumor Microenvironment ,medicine ,Animals ,Immunologic Factors ,Transplantation, Homologous ,Cytotoxic T cell ,General Materials Science ,Mice, Inbred BALB C ,Tumor microenvironment ,biology ,Chemistry ,Drug Synergism ,General Chemistry ,General Medicine ,Benzazepines ,Immune checkpoint ,Cancer cell ,biology.protein ,Cancer research ,Nanoparticles ,Female ,Immunotherapy ,Antibody ,CD8 ,medicine.drug - Abstract
Immunosuppressed tumor microenvironment (TME) is a major cause of the low response rate in solid tumor patients during PD-1/PD-L1 checkpoint blockade therapy. In this study, a series of small molecule nanomedicines with a 100% drug loading rate were prepared via the nanoprecipitation method. They were used in synergistic chemo-immunotherapy for 4T1 tumors. Among four PD-L1 small-molecule nanoinhibitors, BMS-1 NP with the best anti-tumor performance was selected to replace the therapeutic PD-L1 antibody. The core-shell small-molecule nanomedicine DTX@VTX NP (DTX: Docetaxel and VTX: VTX-2337 or Motolimod) was used to reverse immunosuppressed TME through the depletion of myeloid-derived suppressor cells (MDSCs) and the polarization of macrophages from an M2-like phenotype to M1-like phenotype. Thus, the frequency of cytotoxic CD8+ T cells was significantly increased, resulting in an effective attack on cancer cells. Combining BMS-1 NPs with DTX@VTX NPs, synergistic chemo-immunotherapy of 4T1 tumors was performed, and the results indicate that the inhibition rates of primary and rechallenge tumors achieved 90.5% and 94.3%, respectively. These results indicate that DTX@VTX NPs can synergize PD-L1 nanoinhibitor BMS-1 NPs to reshape the immunosuppressive tumor microenvironment for enhancing the anti-tumor effect of chemo-immunotherapy for breast.
- Published
- 2021
28. Armoring SiOx with a conformal LiF layer to boost lithium storage
- Author
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Tianxing Kang, Zhongming Huang, Zhongqiu Tong, Dong Shen, Yan Wu, Yang Lu, Chun-Sing Lee, Jihua Tan, Hui Wang, Jianli Liang, and Xiaocui Li
- Subjects
Suboxide ,Materials science ,Renewable Energy, Sustainability and the Environment ,chemistry.chemical_element ,02 engineering and technology ,General Chemistry ,Electrolyte ,Conductivity ,010402 general chemistry ,021001 nanoscience & nanotechnology ,Electrochemistry ,01 natural sciences ,Cathode ,0104 chemical sciences ,law.invention ,Anode ,Chemical engineering ,chemistry ,law ,Electrode ,General Materials Science ,Lithium ,0210 nano-technology - Abstract
The LiF-rich solid electrolyte interphase (SEI) is an emerging research hotspot to improve battery performance. Its high Li-ion conductivity and high interfacial energy result in fast lithiation/de-lithiation in electrode materials while at the same time protect materials from pulverization. Currently, the developed LiF-rich SEI fabrication methods are based on electrolyte decomposition upon cycling, but so far have only been applied to Li metal or Si anodes. Furthermore, the influences of LiF on the electrochemical behavior of the electrolyte are not fully understood. Here, a new pre-coating approach is proposed to fabricate a conformal LiF layer on both anode and cathode materials (silicon suboxide (SiOx) and LiNi0.8Co0.1Mn0.1O2 (NCM811) as examples). LiF assisted the increase in the specific capacity of a SiOx electrode from 301 to 1034 mA h g−1 after 100 cycles at 500 mA g−1. In addition, a full cell assembled with a prepared anode (SiOG@LiF3) and cathode (NCM811@LiF3) showed outstanding cycling stability. Combining density functional theory (DFT) calculation with SEM and XPS characterization revealed for the first time that the pre-coating LiF layer had a strong preferential adsorption of LiPF6 molecules on the surface, leading to the formation of inorganic-rich SEI during cycling; thereby enabling a fast Li-ion uptake/removal process and improving the electrode integrity.
- Published
- 2021
29. Oxygen-vacancy-induced charge localization and atomic site activation in ultrathin Bi4O5Br2 nanotubes for boosted CO2 photoreduction
- Author
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Danjun Mao, Yuan Hu, Shuxue Yang, Jianli Liang, Huan He, Shaogui Yang, Zhaoyi Xu, Cheng Sun, Shourong Zheng, Zhifeng Jiang, Xiaolei Qu, and Chun-Sing Lee
- Subjects
General Chemical Engineering ,Environmental Chemistry ,General Chemistry ,Industrial and Manufacturing Engineering - Published
- 2023
30. Managing Locally Excited and Charge‐Transfer Triplet States to Facilitate Up‐Conversion in Red TADF Emitters That Are Available for Both Vacuum‐ and Solution‐Processes
- Author
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Dianming Sun, Xiao-Chun Fan, Ming Zhang, Kai Wang, Fengxia Geng, Chun-Sing Lee, Xiaohong Zhang, Yafang Xiao, Jia-Xiong Chen, Jia Yu, Xiang Zhang, and Yi-Zhong Shi
- Subjects
Materials science ,010405 organic chemistry ,business.industry ,Exciton ,Charge (physics) ,General Chemistry ,010402 general chemistry ,01 natural sciences ,Catalysis ,0104 chemical sciences ,Intersystem crossing ,Excited state ,OLED ,Optoelectronics ,Quantum efficiency ,Up conversion ,business - Abstract
Developing red thermally activated delayed fluorescence (TADF) emitters for high-performance OLEDs is still facing great challenge. Herein, three red TADF emitters, pDBBPZ-DPXZ, pDTBPZ-DPXZ, and oDTBPZ-DPXZ, are designed and synthesized with same donor-acceptor (D-A) backbone with different peripheral groups attaching on the A moieties. Their lowest triplet states change from locally excited to charge transfer character leading to significantly enhance reverse intersystem crossing process. In particular, oDTBPZ-DPXZ exhibits efficient TADF feature and exciton utilization. It not only achieves an external quantum efficiency (EQE) of 20.1 % in red vacuum-processed OLED, but also realize a high EQE of 18.5 % in a solution-processed OLED, which is among the best results in solution-processed red TADF OLEDs. This work provides an effective strategy for designing red TADF molecules by managing energy level alignments to facilitate the up-conversion process and thus enhance exciton harvesting.
- Published
- 2020
31. Co-assembled Monolayers as Hole-Selective Contact for High-Performance Inverted Perovskite Solar Cells with Optimized Recombination Loss and Long-Term Stability
- Author
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Xiang Deng, Feng Qi, Fengzhu Li, Shengfan Wu, Francis R. Lin, Zhuomin Zhang, Zhiqiang Guan, Zhengbao Yang, Chun‐Sing Lee, and Alex K.‐Y. Jen
- Subjects
General Medicine ,General Chemistry ,Catalysis - Abstract
Self-assembled monolayers (SAMs) have been widely employed as an effective way to modify interfaces of electronic/optoelectronic devices. To achieve a good control of the growth and molecular functionality of SAMs, we develop a co-assembled monolayer (co-SAM) for obtaining efficient hole selection and suppressed recombination at the hole-selective interface in inverted perovskite solar cells (PSCs). By engineering the position of methoxy substituents, an aligned energy level and favorable dipole moment can be obtained in our newly synthesized SAM, ((2,7-dimethoxy-9H-carbazol-9-yl) methyl) phosphonic acid (DC-PA). An alkyl ammonium containing SAM is co-assembled to further optimize the surface functionalization and interaction with perovskite layer on top. A champion device with an excellent power conversion efficiency (PCE) of 23.59 % and improved device stability are achieved. This work demonstrates the advantage of using co-SAM in improving performance and stability of PSCs.
- Published
- 2022
32. Rational Design Strategy of Novel Energy Storage Systems: Toward High-Performance Rechargeable Magnesium Batteries
- Author
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Xin Lei, Xiao Liang, Rui Yang, Fan Zhang, Chenchen Wang, Chun‐Sing Lee, and Yongbing Tang
- Subjects
Biomaterials ,General Materials Science ,General Chemistry ,Biotechnology - Abstract
Rechargeable magnesium batteries (RMBs) are promising candidates to replace currently commercialized lithium-ion batteries (LIBs) in large-scale energy storage applications owing to their merits of abundant resources, low cost, high theoretical volumetric capacity, etc. However, the development of RMBs is still facing great challenges including the incompatibility of the electrolyte and the lack of suitable cathode materials with high reversible capacity and fast kinetics of Mg
- Published
- 2022
33. Plant-Derived Single-Molecule-Based Nanotheranostics for Photoenhanced Chemotherapy and Ferroptotic-Like Cancer Cell Death
- Author
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Pengfei Wang, Jinfeng Zhang, Junfang Zhao, Xiao Cui, Xiang-Min Meng, Yingpeng Wan, Jipsa Chelora, and Chun-Sing Lee
- Subjects
Chemotherapy ,medicine.medical_treatment ,Ferroptosis ,Biochemistry (medical) ,Biomedical Engineering ,Cancer therapy ,food and beverages ,General Chemistry ,Biomaterials ,chemistry.chemical_compound ,chemistry ,Piperine ,Cancer cell ,medicine ,Cancer research - Abstract
Although piperine-an extract from pepper-has a mild chemotherapeutic effect, its poor water solubility has limited its applications for cancer therapy. With self-assembling of piperine into nanoparticles along with PEG (Pip NPs), both the water dispersibility and the chemotherapeutic efficacy can be substantially enhanced. It is further shown that the NPs can generate reactive oxygen species (ROS) with or without additional white light irradiation. Interestingly, the Pip NP induced cell death can be suppressed by ferroptosis inhibitors such as liproxstatin-1 and deferoxamine. Lipid ROS production is also observed in Pip NP treated cells. In addition to their cancer cell killing ability, the Pip NPs also show strong green fluorescence. These multiple functions make the Pip NPs a promising and low-cost nanotheranostic agent with herbal origin.
- Published
- 2022
34. Hypocrellin-Based Multifunctional Phototheranostic Agent for NIR-Triggered Targeted Chemo/Photodynamic/Photothermal Synergistic Therapy against Glioblastoma
- Author
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Chuangli Zhang, Jiasheng Wu, Pengfei Wang, Xiuli Zheng, Chun-Sing Lee, Wenjun Zhang, and Weimin Liu
- Subjects
Biomaterials ,Chemotherapy ,Chemistry ,medicine.medical_treatment ,Biochemistry (medical) ,Biomedical Engineering ,medicine ,Cancer research ,General Chemistry ,Photothermal therapy ,medicine.disease ,nervous system diseases ,Glioblastoma - Abstract
A huge challenge exists in the diagnosis and treatment of malignant glioblastoma (GBM) due to the presence of the blood-brain barrier (BBB). Herein, a multifunctional phototheranostic agent is designed on the basis of an octadecane-modified temozolomide (
- Published
- 2022
35. Near‐Infrared Hypocrellin Derivatives for Synergistic Photodynamic and Photothermal Therapy
- Author
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Jiechao Ge, Pengfei Wang, Xiuli Zheng, Haohui Ren, Ying Ding, Jiasheng Wu, Chun-Sing Lee, Weimin Liu, and Wenjun Zhang
- Subjects
Cell Survival ,Infrared Rays ,Photothermal Therapy ,medicine.medical_treatment ,Substituent ,Antineoplastic Agents ,Photodynamic therapy ,Photochemistry ,Biochemistry ,Theranostic Nanomedicine ,Mice ,chemistry.chemical_compound ,In vivo ,Cell Line, Tumor ,medicine ,Animals ,Absorption (electromagnetic radiation) ,Perylene ,Photosensitizing Agents ,Aqueous solution ,Phenol ,Singlet oxygen ,Optical Imaging ,Organic Chemistry ,Quinones ,Mammary Neoplasms, Experimental ,General Chemistry ,Photothermal therapy ,chemistry ,Absorption band ,Female - Abstract
Hypocrellin B (HB) derived from naturally produced hypocrellins has attracted considerable attention in photodynamic therapy (PDT) because of its excellent photosensitive properties. However, the weak absorption within a "phototherapy window" (600-900 nm) and poor water solubility of HB have limited its clinical application. In this study, two HB derivatives (i. e., HE and HF) were designed and synthesized for the first time by introducing two different substituent groups into the HB structure. The obtained derivatives showed a broad absorption band covering the near-infrared (NIR) region, NIR emission (peaked at 805 nm), and singlet oxygen quantum yields of 0.27/0.31. HE-PEG-NPs were also prepared using 2-distearoyl-sn-glycero-3-phosphoethanolamine-N-[methoxy(polyethyleneglycol)-2000] (DSPE-mPEG2000) to achieve excellent dispersion in water and further explored their practical applications. HE-PEG-NPs not only retained their 1 O2 -generating ability, but also exhibited a photothermal conversion efficiency of 25.9%. In vitro and in vivo therapeutic results revealed that the synergetic effect of HE-PEG-NPs on PDT and photothermal therapy (PTT) could achieve a good performance. Therefore, HE-PEG-NPs could be regarded as a promising phototheranostic agent.
- Published
- 2020
36. Catalyzed Kinetic Growth in Two-Dimensional MoS2
- Author
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Chun-Sing Lee, Quoc Huy Thi, Fangyuan Zheng, Xin Chen, Yee Wa Chu, Thuc Hue Ly, Jiong Zhao, and Lingli Huang
- Subjects
Chemistry ,General Chemistry ,Chemical vapor deposition ,010402 general chemistry ,Kinetic energy ,01 natural sciences ,Biochemistry ,Catalysis ,0104 chemical sciences ,Crystal ,Faceting ,Colloid and Surface Chemistry ,Transition metal ,Chemical physics ,Molecule ,Diffusion (business) - Abstract
It remains difficult to control the morphology of two-dimensional (2D) materials via direct chemical vapor deposition (CVD) growth. In particular, off-equilibrium (kinetic) growth may produce flakes with non-Wulff shapes (e.g., high-index edges, symmetrical shapes, etc.), which are potentially useful; however, a general controllable approach for the kinetic growth of 2D materials is currently lacking. In this work, we pushed the CVD growth of 2D MoS2 into deep kinetic regime, by using potassium chloride (KCl) as catalyst and plasma pretreatment on growth substrates. The unprecedented nonequilibrium high-index faceting and unusual high-symmetry shapes in 2D materials have been realized. The growth mechanism of high-index facets is rationalized based on the theory of kinetic instability on crystal surfaces. This new vapor-liquid-adatom-solid (VLAS) growth mechanism-synergistic capture of multiple vapor phase molecules by the catalyst particles on corners and the oversaturated adatom diffusion along adjacent edges can offer great opportunities for shape engineering on 2D materials. The high-quality, rapid, and controllable synthesis of high-index facets (edges) and other non-Wulff shapes of 2D transition metal dichalcogenides will benefit the developments in 2D materials.
- Published
- 2020
37. Synthesis and Evaluation of Novel Anticancer Compounds Derived from the Natural Product Brevilin A
- Author
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Sibao Chen, Tsz Wing Leung, Chi Sing Lee, Brandon Dow Chan, Junrong Huang, Wing Yan Wong, Zhao Qu, Lizhi Zhu, Magnolia Muk-Lan Lee, and William Chi-Shing Tai
- Subjects
Natural product ,business.industry ,General Chemical Engineering ,Cancer ,General Chemistry ,medicine.disease ,Article ,Chemistry ,chemistry.chemical_compound ,chemistry ,Breast cancer cell line ,Cancer research ,Medicine ,Cancer cell lines ,business ,QD1-999 ,Cause of death - Abstract
Cancer is the second leading cause of death globally, responsible for an estimated 9.6 million deaths in 2018, and this burden continues to increase. Therefore, there is a clear and urgent need for novel drugs with increased efficacy for the treatment of different cancers. Previous research has demonstrated that brevilin A (BA) exerts anticancer activity in various cancers, including human multiple myeloma, breast cancer, lung cancer, and colon carcinoma, suggesting the anticancer potential present in the chemical scaffold of BA. Here, we designed and synthesized a small library of 12 novel BA derivatives and evaluated the biological anticancer effects of the compounds in various cancer cell lines. The results of this structure–activity relationship study demonstrated that BA derivatives BA-9 and BA-10 possessed significantly improved anticancer activity toward lung, colon, and breast cancer cell lines. BA-9 and BA-10 could more effectively reduce cancer cell viability and induce DNA damage, cell-cycle arrest, and apoptosis when compared with BA. Our findings represent a significant step forward in the development of novel anticancer entities.
- Published
- 2020
38. In Situ Cu-Loaded Porous Boron Nitride Nanofiber as an Efficient Adsorbent for CO2 Capture
- Author
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Jianli Liang, Zhonglu Guo, Chun-Sing Lee, Chengchun Tang, Jing Lin, Yi Fang, Gen Li, Qianqian Song, and Yang Huang
- Subjects
Materials science ,Renewable Energy, Sustainability and the Environment ,General Chemical Engineering ,Nucleation ,02 engineering and technology ,General Chemistry ,010402 general chemistry ,021001 nanoscience & nanotechnology ,01 natural sciences ,0104 chemical sciences ,Boric acid ,chemistry.chemical_compound ,Electron transfer ,Adsorption ,chemistry ,Chemical engineering ,Boron nitride ,Nanofiber ,Environmental Chemistry ,0210 nano-technology ,Melamine ,Porosity - Abstract
Porous boron nitride (BN) materials have been considered as a promising material for CO₂ capture and storage. It was found that the Cu²⁺ ion can modify the nucleation mechanism during the synthetic reaction between boric acid and melamine leading to the formation of Cu-loaded BN nanofibers with uniform and smaller diameter. Interestingly, the introduction of Cu was found to dramatically enhance the CO₂ adsorption capacity of the BN nanofibers from 1.34 to 2.77 mmol g–¹ (at 1 bar, 273 K). The Cu-loaded BN nanofiber not only shows a CO₂ adsorption capacity comparable to those of state-of-the-art BN-based CO₂ absorbents but also shows unprecedented high recyclability for repeated uses. The mechanisms of the copper-induced CO₂ adsorption capacity enhancement were investigated with density-functional theory calculations. It was found that the incorporation of Cu can change the electron transfer between porous BN and CO₂ to promote the affinity and adsorption capacity of CO₂.
- Published
- 2020
39. Oxygen/nitrogen-related surface states controlled carbon nanodots with tunable full-color luminescence: Mechanism and bio-imaging
- Author
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Lu-Ning Wang, Lei Wang, Kun Yang, Xuehui Zhang, and Chun-Sing Lee
- Subjects
Photoluminescence ,Materials science ,Biocompatibility ,02 engineering and technology ,General Chemistry ,010402 general chemistry ,021001 nanoscience & nanotechnology ,Photochemistry ,01 natural sciences ,Fluorescence ,0104 chemical sciences ,Oxidation state ,General Materials Science ,0210 nano-technology ,Luminescence ,Absorption (electromagnetic radiation) ,Surface states ,Visible spectrum - Abstract
Fluorescent carbon nanodots (CNDs) have exhibited attractive potential for biomedical applications due to their intriguing luminescent properties and good biocompatibility. One interesting properties of CNDs is that they typically show different emission colors upon optical excitation using different wavelengths. However, it is still a challenge to obtain emissions covering the entire visible spectrum with comparable intensity with only one type of CND. Herein, CNDs with tunable full-color luminescence is successful prepared by a solvothermal approach, show broad absorption (200–700 nm) and fluorescence emission (nearly cover the entire visible region: from 400 to 700 nm) with comparable fluorescence intensities. The oxidation (o-CNDs) and reduction (r-CNDs) of CNDs surface would lead to the shifting of photoluminescence band into blue/green and red-light region, respectively. Further spectroscopic analyses and structural characterizations of CNDs (pristine state), o-CNDs (oxidation state) and r-CNDs (reduction state) demonstrate that O-related defect states (C O) and N-related defect states (C N) on surface of CNDs should be responsible for blue/green and red fluorescence emissions, respectively. Moreover, the CNDs are found to be biocompatible, as verified by in vitro cells assay and in vivo histological analysis. In vivo fluorescence imaging assay demonstrates that CNDs can be excreted through intestine and bladder system. The tunable full-color emission, good biocompatibility and metabolism suggest that the CNDs are promising fluorescent probes for biomedical applications.
- Published
- 2020
40. Solid-State Fluorophore Based on π-Extended Heteroaromatic Acceptor: Polymorphism, Mechanochromic Luminescence, and Electroluminescence
- Author
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Ying Zhang, Dawei Jiang, Chun-Sing Lee, Bin Huang, Qiang Zhao, Xiaomin Gu, Gu Dai, Yigang Ji, Wen-Cheng Chen, and Yan Feng
- Subjects
Mechanochromic luminescence ,Materials science ,Fluorophore ,010405 organic chemistry ,Solid-state ,General Chemistry ,Electroluminescence ,010402 general chemistry ,Condensed Matter Physics ,Photochemistry ,01 natural sciences ,Acceptor ,0104 chemical sciences ,chemistry.chemical_compound ,chemistry ,Polymorphism (materials science) ,General Materials Science ,Quantum efficiency - Abstract
A novel light-emitting material, 4-(4-diphenylaminophenyl)-benzo[d,e]benzo[4,5]imidazo[2,1-a]isoquinolin-7-one (4-TPA-BBI) is synthesized and characterized. 4-TPA-BBI exhibits excellent polymorphis...
- Published
- 2020
41. Membrane‐Anchoring Photosensitizer with Aggregation‐Induced Emission Characteristics for Combating Multidrug‐Resistant Bacteria
- Author
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Huan Chen, Kenry, Bin Liu, Chun-Sing Lee, Shengliang Li, Zhongming Huang, and Min Wu
- Subjects
medicine.medical_treatment ,Photodynamic therapy ,Microbial Sensitivity Tests ,010402 general chemistry ,medicine.disease_cause ,01 natural sciences ,Catalysis ,chemistry.chemical_compound ,Drug Resistance, Multiple, Bacterial ,medicine ,Humans ,Photosensitizer ,Photosensitizing Agents ,biology ,010405 organic chemistry ,Singlet oxygen ,General Medicine ,General Chemistry ,Antimicrobial ,biology.organism_classification ,Combinatorial chemistry ,0104 chemical sciences ,Membrane ,chemistry ,Staphylococcus aureus ,Antibacterial activity ,Bacteria - Abstract
Traditional photosensitizers (PSs) show reduced singlet oxygen (1 O2 ) production and quenched fluorescence upon aggregation in aqueous media, which greatly affect their efficiency in photodynamic therapy (PDT). Meanwhile, non-targeting PSs generally yield low efficiency in antibacterial performance due to their short lifetimes and small effective working radii. Herein, a water-dispersible membrane anchor (TBD-anchor) PS with aggregation-induced emission is designed and synthesized to generate 1 O2 on the bacterial membrane. TBD-anchor showed efficient antibacterial performance towards both Gram-negative (Escherichia coli) and Gram-positive bacteria (Staphylococcus aureus). Over 99.8 % killing efficiency was obtained for methicillin-resistant S. aureus (MRSA) when they were exposed to 0.8 μm of TBD-anchor at a low white light dose (25 mW cm-2 ) for 10 minutes. TBD-anchor thus shows great promise as an effective antimicrobial agent to combat the menace of multidrug-resistant bacteria.
- Published
- 2020
42. Origin of thermally activated delayed fluorescence in a donor–acceptor type emitter with an optimized nearly planar geometry
- Author
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Chen Cao, Yafang Xiao, Fengxia Geng, Yi-Zhong Shi, Jia-Xiong Chen, Kai Wang, Xiao-Chun Fan, Chun-Sing Lee, Xiaohong Zhang, Jia Yu, Wen-Cheng Chen, and Xiang Zhang
- Subjects
education.field_of_study ,Materials science ,Population ,General Chemistry ,Molecular physics ,Fluorescence ,Excited state ,Metastability ,Materials Chemistry ,Molecule ,Molecular orbital ,education ,Ground state ,HOMO/LUMO - Abstract
Thermally activated delayed fluorescence (TADF) emitters generally require good separation of highest occupied molecular orbital (HOMO)–lowest unoccupied molecular orbital (LUMO) overlaps to minimize the singlet–triplet energy offset. Observations of excellent TADF performance in several planar emitters with large HOMO–LUMO overlaps are counter-intuitive and not fully explained. To understand this, we prepared two isomeric TADF molecules, 7-methyl-2-(10H-phenoxazin-10-yl)-5H-pyrano[4,3-b]pyridin-5-one (PXZ-PPO) and 2-methyl-7-(10H-phenoxazin-10-yl)-4H-benzo[d][1,3]oxazin-4-one (PXZ-BOO). PXZ-BOO has a stable highly-twisted configuration with a small HOMO–LUMO overlap leading to good TADF performance as expected. PXZ-PPO has a stable nearly-planar form and a large HOMO–LUMO overlap and is not expected to give TADF. While the solid crystal of PXZ-PPO only shows conventional fluorescence at 420 nm, its diluted solution is dominated by TADF at 610 nm. With a combined experimental and theoretical approach, PXZ-PPO is shown to have a stable nearly-planar form and a metastable highly-twisted form in the ground state. While the highly-twisted form only has a small population (
- Published
- 2020
43. Methoxy substituents activated carbazole-based boron dimesityl TADF emitters
- Author
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Deng-Gao Chen, Meng-Chi Chen, Chun Ying Huang, Chun-Sing Lee, Yun Chi, Jia-An Lin, Paramaguru Ganesan, Pi-Tai Chou, Wen-Cheng Chen, and Premkumar Gnanasekaran
- Subjects
Materials science ,Carbazole ,General Chemistry ,Photochemistry ,Acceptor ,chemistry.chemical_compound ,Intersystem crossing ,chemistry ,Acridine ,Materials Chemistry ,OLED ,Molecule ,Quantum efficiency ,Phenoxazine - Abstract
N-Borylated emitters bearing both boron dimesityl acceptor (Mes)2B and phenoxazine or acridine donors are a class of efficient TADF emitters; however, switching to a carbazole donor nullifies the TADF characteristics. This work is targeted at improving the TADF characteristics of the carbazole based (Mes)2B emitters by introducing up to two methoxy substituents at the carbazoles. We hereby report the design and synthesis of three methoxy substituted carbazoles (Cz-1, Cz-2 and Cz-3) and the corresponding directly N-borylated emitters, CzBM-1, CzBM-2 and CzBM-3. Moreover, a p-phenylene spacer was also introduced between the (Mes)2B unit and carbazole, giving CzPBM-2 and CzPBM-3. As confirmed by the bi-exponential transient decay analyses, all title compounds exhibit prominent TADF character, while the parent molecules CzBM-0 and CzPBM-0 without methoxy groups show no TADF characteristics. The results manifest the importance of the donor strength of substituents and degrees of spatial orthogonality in harnessing the charge transfer properties, minimalizing the S1–T1 energy gap and facilitating the reverse intersystem crossing process. OLED devices with doped CzBM-2 and CzPBM-3 emitters exhibited a maximum external quantum efficiency of 12.5% and 13.3%, respectively, confirming the potential of methoxy substituents in improving their TADF characteristics.
- Published
- 2020
44. Isomerization enhanced quantum yield of dibenzo[a,c]phenazine-based thermally activated delayed fluorescence emitters for highly efficient orange OLEDs
- Author
-
Nengquan Li, Changjiang Zhou, Xiaosong Cao, Youming Zhang, Wen-Cheng Chen, Chuluo Yang, Chun-Sing Lee, and He Liu
- Subjects
Photoluminescence ,Materials science ,Phenazine ,Quantum yield ,General Chemistry ,Photochemistry ,Acceptor ,chemistry.chemical_compound ,Intersystem crossing ,chemistry ,Materials Chemistry ,OLED ,Luminescence ,Isomerization - Abstract
Photoluminescence quantum yield (PLQY) and the reverse intersystem crossing (RISC) process are critical for next-generation highly efficient organic light-emitting diodes (OLEDs). However, it is not easy to simultaneously obtain high PLQY and fast RISC, especially in TADF emitters with twisted donor–acceptor structures due to their conflicting requirements for wave function overlapping. Herein, based on a rigid planar dibenzo[a,c]phenazine (DPPZ) unit as an acceptor, four emitters (isomers of DMAC-11-DPPZ and DMAC-10-DPPZ, and isomers of PXZ-11-DPPZ and PXZ-10-DPPZ) with 9,9-dimethylacridine (DMAC) and 10H-phenoxazine (PXZ) as donors substituted via 11- and 10-positions were designed and synthesized to balance the wave function overlapping and explore the relationship between their structures and luminescence properties. Photophysical characterization and theoretical calculations suggest small energy gaps (ΔEST) featuring fast RISC rates in all these compounds. Meanwhile, DMAC-11-DPPZ and PXZ-11-DPPZ achieve higher PLQYs due to the largely suppressed non-radiative transition as revealed by the decreased Huang–Rhys factors. As a result, high external quantum efficiencies (EQEmax) of 23.8% for DMAC-11-DPPZ and 13.7% for PXZ-11-DPPZ are obtained. This work provides a promising strategy to improve the PLQY of TADF materials by adjusting the substituted site, and also shows the potential of phenazine derivatives for OLED applications.
- Published
- 2020
45. Defect engineering of nanostructured electrocatalysts for enhancing nitrogen reduction
- Author
-
Tianpeng Jiao, Chun-Sing Lee, Hui-Qing Peng, Bin Liu, Junye Cheng, Shuyu Bu, Guo Hong, Wenjun Zhang, Xin Kong, and Qili Gao
- Subjects
Materials science ,Renewable Energy, Sustainability and the Environment ,Design elements and principles ,Defect engineering ,chemistry.chemical_element ,Nanotechnology ,02 engineering and technology ,General Chemistry ,010402 general chemistry ,021001 nanoscience & nanotechnology ,01 natural sciences ,Amorphous phase ,Nitrogen ,0104 chemical sciences ,Characterization (materials science) ,Catalysis ,Electronic states ,Reduction (complexity) ,chemistry ,General Materials Science ,0210 nano-technology - Abstract
The electrocatalytic nitrogen reduction reaction (e-NRR), an eco-friendly and economical approach to convert nitrogen to ammonia under mild conditions, has received widespread attention in recent years. Defect engineering has been illustrated to be an effective strategy to improve the catalytic activity and selectivity of electrocatalysts via changing the electronic states as well as creating additional active sites for reduction reactions. Thus far, various approaches have been adopted to tune the physical and chemical properties of catalyst materials by means of inducing defects of different types and varying their concentrations or locations in host materials. In this review, the mechanisms and design principles of defective electrocatalysts for the NRR are introduced, and the refined synthesis and characterization techniques of defect engineering are systematically summarized. Based on the recent advances in defect engineering of electrocatalysts for the NRR, the roles of various defect states, such as vacancies and the amorphous phase, in the catalytic enhancement mechanism are comprehensively discussed. Finally, perspectives on the challenges and opportunities in developing new cost-effective and high-efficiency NRR catalysts for practical applications are outlined.
- Published
- 2020
46. Aggregation-state engineering and emission switching in D–A–D′ AIEgens featuring dual emission, MCL and white electroluminescence
- Author
-
Shao-Fei Ni, Wen-Cheng Chen, Jihua Tan, Zhiwen Yang, Zhipeng Qiu, Chun-Sing Lee, Jingwen Xiong, Yingying Zhan, Chen Cao, and Yanping Huo
- Subjects
Mechanochromic luminescence ,Materials science ,General Chemistry ,Electroluminescence ,Photochemistry ,Crystal engineering ,Fluorescence ,law.invention ,law ,Excited state ,Intramolecular force ,Materials Chemistry ,Phosphorescence ,Light-emitting diode - Abstract
Thermally activated delayed fluorescence (TADF) and room-temperature phosphorescence (RTP) have attracted much recent attention for their capabilities to utilize triplet excitons for emission. Herein, we demonstrate a strategy for switching between intermolecular TADF and RTP through rational structure modulation and crystal engineering with two newly designed organic AIEgens, namely (4-(9H-carbazol-9-yl)phenyl) (dibenzo[b,d]thiophen-2-yl)methanone (CTM) and (4-(3,6-di-tert-butyl-9H-carbazol-9-yl) phenyl) (dibenzo[b,d]thiophen-2-yl) methanone (tCTM). Both materials exhibit intramolecular TADF and intermolecular TADF/RTP dual emission in single crystals. High contrast mechanochromic luminescence (MCL) was unveiled due to the polymorphism of both emitters in aggregated states. Using these materials as emitters, we demonstrate for the first time, such dual TADF–TADF/RTP emissions can be exploited to obtain white light organic light-emitting diodes with high color rendering indexes.
- Published
- 2020
47. Manipulating exciton dynamics of thermally activated delayed fluorescence materials for tuning two-photon nanotheranostics
- Author
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Jia-Xiong Chen, Zhongming Huang, Xiaohong Zhang, Wen-Wen Tao, Kai Wang, Yafang Xiao, Shengliang Li, Chun-Sing Lee, Xiao Cui, and Shuang Tian
- Subjects
Fluorescence-lifetime imaging microscopy ,Materials science ,Band gap ,Singlet oxygen ,business.industry ,Oscillator strength ,Exciton ,General Chemistry ,Fluorescence ,Chemistry ,chemistry.chemical_compound ,Two-photon excitation microscopy ,chemistry ,Excited state ,Optoelectronics ,Physics::Chemical Physics ,business - Abstract
Rational manipulation of energy utilization from excited-state radiation of theranostic agents with a donor–acceptor structure is relatively unexplored. Herein, we present an effective strategy to tune the exciton dynamics of radiative excited state decay for augmenting two-photon nanotheranostics. As a proof of concept, two thermally activated delayed fluorescence (TADF) molecules with different electron-donating segments are engineered, which possess donor–acceptor structures and strong emissions in the deep-red region with aggregation-induced emission characteristics. Molecular simulations demonstrate that change of the electron-donating sections could effectively regulate the singlet–triplet energy gap and oscillator strength, which promises efficient energy flow. A two-photon laser with great permeability is used to excite TADF NPs to perform as theranostic agents with singlet oxygen generation and fluorescence imaging. These unique performances enable the proposed TADF emitters to exhibit tailored balances between two-photon singlet oxygen generation and fluorescence emission. This result demonstrates that TADF emitters can be rationally designed as superior candidates for nanotheranostic agents by the custom controlling exciton dynamics., Exciton dynamics can be manipulated rationally in the design of TADF materials for nanotheranostics. Regulating the ΔEST and f promises efficient energy flow for tailoring balances between singlet oxygen generation and fluorescence emission.
- Published
- 2020
48. A broadband aggregation-independent plasmonic absorber for highly efficient solar steam generation
- Author
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Chun-Sing Lee, Shuang Tian, Shengliang Li, Xiao Cui, Zhongming Huang, Yingpeng Wan, Xiaozhen Li, Hui Wang, Yafang Xiao, and Qi Zhao
- Subjects
Nanostructure ,Materials science ,Renewable Energy, Sustainability and the Environment ,business.industry ,Energy conversion efficiency ,Nanoparticle ,Aerogel ,02 engineering and technology ,General Chemistry ,010402 general chemistry ,021001 nanoscience & nanotechnology ,01 natural sciences ,0104 chemical sciences ,Broadband ,Optoelectronics ,General Materials Science ,0210 nano-technology ,Solar desalination ,business ,Absorption (electromagnetic radiation) ,Plasmon - Abstract
Achieving efficient solar steam generation under natural sunlight has huge potential for sewage purification and seawater desalination. Plasmonic resonance has been extensively exploited for enhancing and extending the range of optical absorption. Until now, most reported broadband plasmonic solar absorbers have been designed by compact aggregation or engineering plasmonic architectures. In this work, we develop a new plasmonic absorber using gold nanostructures with the shape of a trepang (nano-trepang). By rationally regulating anisotropy at the single nanoparticle level, the nano-trepang shows good optical absorption over the entire solar spectrum (92.9%) with no requirement of engineering nanoparticle aggregation or constructing plasmonic architectures. The nano-trepang was then loaded into a polymeric aerogel and the network showed an excellent solar-to-vapor energy conversion efficiency of 79.3%. Under 1 sun AM1.5 G irradiation, a stable solar evaporation rate of 2.7 kg m−2 h−1 can be achieved, with high performance anti-salt precipitation in practical seawater steam generation. This work shows a broadband plasmonic absorber with aggregation-independent performance for highly efficient solar stream generation and provides a new strategy for practical solar desalination.
- Published
- 2020
49. A two-photon fluorescent probe for sensitive detection and imaging of γ-glutamyl transpeptidase
- Author
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Xiuli Zheng, Li-Ping Zhang, Ruijin Huo, Weimin Liu, Fan Li, Jiasheng Wu, Chun-Sing Lee, Pengfei Wang, and Wenjun Zhang
- Subjects
Fluorescence-lifetime imaging microscopy ,γ glutamyl transpeptidase ,digestive system ,Catalysis ,Two-photon excitation microscopy ,Cascade reaction ,Cell Line, Tumor ,Human Umbilical Vein Endothelial Cells ,Materials Chemistry ,Humans ,Fluorescent Dyes ,Detection limit ,Photons ,Molecular Structure ,Chemistry ,Optical Imaging ,Metals and Alloys ,gamma-Glutamyltransferase ,General Chemistry ,Fluorescence ,Molecular biology ,digestive system diseases ,Surfaces, Coatings and Films ,Electronic, Optical and Magnetic Materials ,Spectrometry, Fluorescence ,Ceramics and Composites ,Ovarian cancer cells - Abstract
A GGT-activated two-photon fluorescent probe (4F-2CN-GSH) was developed based on a cascade reaction. 4F-2CN-GSH could selectivily detect GGT with low detection limit and distinguish ovarian cancer cells from normal cells using both one-photon and two-photon fluorescence imaging.
- Published
- 2020
50. Charge transport properties of co-evaporated organic–inorganic thin film charge transfer complexes: effects of intermolecular interactions
- Author
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Yan Wu, Ming-Fai Lo, Chun-Sing Lee, and Dong Shen
- Subjects
Materials science ,Intermolecular force ,Oxide ,chemistry.chemical_element ,General Chemistry ,Electron ,Chemical state ,chemistry.chemical_compound ,chemistry ,Chemical physics ,Molybdenum ,Molecular vibration ,Materials Chemistry ,Molecular orbital ,Thin film - Abstract
Novel charge transport properties distinguished from their parental materials are intriguing features of charge transfer complexes (CTCs). In this work, co-evaporated molybdenum(VI)oxide and sexithiophene (MoO3 : 6T) CTC thin film is prepared and its electron and hole transport properties are studied. While the MoO3 : 6T CTC material shows both electron and hole transport, detailed changes in molecular orbital hybridization are further studied under an external stimulus. Using a simple rubbing process, the intermolecular interaction of the CTC material can be tuned such that changes in optical properties, vibrational modes, chemical states and electronic structures are observed. These changes in properties and charge transport behaviors enable us to understand the influences of CTC frontier molecular orbitals (FMOs) and their degree of coupling on the charge transport properties. This work provides insight into the understanding of the intermolecular interactions and their influence on the charge transport properties of thin film CTCs.
- Published
- 2020
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