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Energy Transfer Dynamics between Carbon Quantum Dots and Molybdenum Disulfide Revealed by transient absorption spectroscopy

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Chinese Journal of Chemical Physics 2023年第5期36卷 503-508,I0001页

作者： Ruixiang Wu Xin Liu Xiaoshuai Wang Jingjing Luo Bin Li Shengzhi Wang Xiangyang Miao Key Laboratory of Spectral Measurement and Analysis of Shanxi Province College of Physics and Information EngineeringShanxi Normal UniversityTaiyuan 030031China

Zero-dimensional environmentally friendly carbon quantum dots(CQDs)combined with two-di-mensional materials have a wide range of applications in optoelec-tronic *** combined steady-state and transient absorp-tion spectroscopies to study the energy transfer dynamics between CQDs and molybdenum disulfide(MoS_(2)).transient absorption plots showed photoinduced absorption and stimulated emission features,which involved the intrinsic and defect states of *** MoS_(2)to CQDs solution,the lowest unoccupied molecular orbital of CQDs transferred energy to MoS_(2),which quenched the intrinsic emission at 390 *** addition of MoS_(2),CQD-MoS_(2)composites quenched defect emission at 490 nm and upward absorption,which originated from another energy transfer from the defect *** energy transfer paths between CQDs and MoS_(2)were efficiently manipulated by changing the concentration of MoS_(2),which laid a foundation for improving device performance.

关键词： Energy transfer transient absorption spectroscopy Carbon quantum dot Molybdenum disulfide

Hidden Relaxation Channels in Aqueous Methylene Blue after Functionalization of Graphene Oxide Probed by transient absorption spectroscopy

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Chinese Journal of Chemical Physics 2017年第4期30卷 389-394,I0001页

作者：柯达隋来志刘敦利王禹苏李苏宇姜远飞陈安民金明星吉林大学原子与分子物理研究所长春130012 吉林省应用原子与分子光谱学重点实验室长春130012

The mixture of graphene oxide （GO） and dye molecules may provide some new applications due to unique electronic, optical, and structural properties. Methylene blue （MB）, a typ- ical anionic dye, can attach on GO via π-π stacking and electrostatic interaction, and the molecule removal process on GO has been observed. However, it remains unclear about the ultrafast carrier dynamics and the internal energy transfer pathways of the system which is composed of GO and MB. We have employed ultrafast optical pump-probe spectroscopy to investigate the excited dynamics of the GO-MB system dispersed in water by exciting the samples at 400 nm pump pulse. The pristine MB and GO dynamics are also analyzed in tandem for a direct comparison. Utilizing the global analysis to fit the measured signal via a sequential model, five lifetimes are acquired：（0.61±0.01） ps, （3.52±0.04） ps, （14.1±0.3） ps, （84±2） ps, and （3.66±0.08） ns. The ultrafast dynamics corresponding to these lifetimes was analyzed and the new relaxation processes were found in the GO-MB system, compared with the pristine MB. The results reveal that the functionalization of GO can alter the known decay pathways of MB via the energy transfer from GO to MB in system, the increased intermediate state, and the promoted energy transfer from triplet state MB to ground state oxygen molecules dissolved in aqueous sample.

关键词： transient absorption spectroscopy Methylene blue Functionalization of graphene oxide Relaxation channels

Investigation of charge transfer between donor and acceptor for small-molecule organic solar cells by scanning tunneling microscopy and ultrafast transient absorption spectroscopy

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Nano Research 2022年第9期15卷 8019-8027页

作者： Yuchuan Xiao Linxiu Cheng Xinyu Sui Qi Wang Jie Chen Dan Deng Jianqi Zhang Xuan Peng Xiaokang Li Xunwen Xiao Ke Deng Xinfeng Liu Zhixiang Wei Qingdao Zeng CAS Key Laboratory of Standardization and Measurement for Nanotechnology CAS Center for Excellence in NanoscienceNational Center for Nanoscience and Technology(NCNST)Beijing 100190China Jiangxi Provincial Key Laboratory of Low-Carbon Solid Waste Recycling School of Geography and Environmental EngineeringGannan Normal UniversityGanzhou 341000China CAS Key Laboratory of Nanosystem and Hierarchical Fabrication CAS Center for Excellence in NanoscienceNational Center for Nanoscience and TechnologyBeijing 100190China Center of Materials Science and Optoelectronics Engineering University of Chinese Academy of SciencesBeijing 100049China College of Chemistry and Chemical Engineering Gannan Normal UniversityGanzhou 341000China School of Materials and Chemical Engineering Ningbo University of TechnologyNingbo 315211China

Small-molecule organic solar cell is a category of clean energy potential device since charge transfers between donor and *** morphologies,co-assembly behavior,interaction sites,and charge transfer of BTID-nF(n=1,2)/PC71BM donor-acceptor system in the active layer of organic solar cell have been studied employing scanning tunneling microscopy(STM),scanning tunneling spectroscopy(STS),density functional theory(DFT)calculations,and transient absorption(TA)*** results show that BTID-1F and BTID-2F form bright strip structures,whereas BTID-nF(n=1,2)/PC71BM form ridge-like structures with each complex composed of one BTID-nF(n=1,2)molecule and four PC71BM molecules which adsorbed around the BTID-nF(n=1,2)molecule by S···π*** the assistance of S···πinteraction between BTID-nF(n=1,2)and PC71BM,BTID-nF(n=1,2)/PC71BM co-assembled ridge-like structures are more stable than the BTID-nF(n=1,2)ridge *** investigate the charge transfer of BTID-nF(n=1,2)/PC71BM system,STS measurements,DFT calculation,and TA spectroscopy are further *** results show that charge transfer occurs in BTID-nF(n=1,2)/PC71BM system with the electron transferring from BTID-nF(n=1,2)molecules to PC71BM.

关键词： organic solar cells scanning tunneling microscopy transient absorption spectroscopy charge transfer donor-acceptor system

Ultrafast Photophysics in Dibenzo Compounds by transient absorption spectroscopy

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Ultrafast Photophysics in Dibenzo Compounds by Transient Abs...

Ultrafast dynamics of trans-4-diethylaminoazobenzene studied by femtosecond transient absorption spectroscopy

第十三届全国化学动力学会议

作者： Song Zhang Kai Liu Yaping Wang Bing Zhang State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics Wuhan Institute of Physics and Mathematics Chinese Academy

＜正＞If the photo-excited state is a singlet 1 ππ* state the ISC will be efficient provided that a triplet 3 nπ* state is energetically accessible. In aromatic dibenzo compounds such a situation prevails and they ... 详细信息

关键词： Dibenzo Compounds transient absorption spectroscopy nonradiative deactivation

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Ultrafast dynamics of trans-4-diethylaminoazobenzene studied...

Dynamics of exciton energy renormalization in monolayer transition metal disulfides

中国化学会第29届学术年会

作者： Ya-ping Wang Song Zhang Si-mei Sun Kai Liu Bing Zhang State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics Wuhan Institute of Physics and Mathematics Chinese Academy of Sciences

The ultrafast excited state dynamics of trans-4-diethylaminoazobenzene with the S2 state excitation was investigated in several solvents by femtosecond transient absorption spectroscopy. Following excitation to the S2 state, the internal conversion to the S1 state was observed within 70 fs. The decay of the S1 state includes isomerization to the hot S0 state of cis isomer and internal conversion to the hot S0 state of trans isomer. Solvent effect was observed in the decay of the S1 state of trans isomer and the vibration relaxation of the hot S0 state of cis isomer. The lack of solvent viscosity dependence of the S1-state lifetime indicates that the photoisomerization is not by rotation mechanism but by inversion mechanism. The S1-state lifetime is slower with the increase of solvent polarity, since the energy gap between the S0 and S1 state is larger. The vibrational cooling of the hot S0 state of cis isomer is faster in protic solvents since the H-bond was formed.

关键词： trans-4-diethylaminoazobenzene photoisomerization transient absorption spectroscopy solvent effect ultrafast dynamics

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Nano Research 2020年第5期13卷 1399-1405页

作者： Jiaxin Zhao Weijie Zhao Wei Du Rui Su Qihua Xiong Division of Physics and Applied Physics School of Physical and Mathematical SciencesNanyang Technological UniversitySingapore 637371Singapore State Key Laboratory of Low-Dimensional Quantum Physics and Department of Physics Tsinghua UniversityBeijing 100084China

Fundamental understandings on the dynamics of charge carriers and excitonic quasiparticles in semiconductors are of central importance for both many-body physics and promising optoelectronic and photonic ***,we investigated the carrier dynamics and many-body interactions in two-dimensional(2D)transition metal dichalcogenides(TMDs),using monolayer WS2 as an example,by employing femtosecond broadband pump-probe *** time regimes for the exciton energy renormalization are unambiguously revealed with a distinct red-blue-red shift upon above-bandgap optical *** attribute the dominant physical process in the three typical regimes to free carrier screening effect,Coulombic exciton-exciton interactions and Auger photocarrier generation,respectively,which show distinct dependence on the optical excitation wavelength,pump fluences and/or lattice *** intrinsic exciton radiative lifetime of about 1.2 picoseconds(ps)in monolayer WS2 is unraveled at low temperature,and surprisingly the efficient Auger nonradiative decay of both bright and dark excitons puts the system in a nonequilibrium state at the nanosecond *** addition,the dynamics of trions at low temperature is observed to be significantly different from that of excitons,e.g.,a long radiative lifetime of^108.7 ps at low excitation densities and the evolution of trion energy as a function of delay *** findings elucidate the dynamics of excitonic quasiparticles and the intricate many-body physics in 2D semiconductors,underpinning the future development of photonics,valleytronics and optoelectronics based on 2D semiconductors.

关键词： transitional metal disulfide exciton dynamics renormalization transient absorption spectroscopy carrier screening effect exciton-exciton interactions

Unraveling the influence of interface defects on antimony trisulfide solar cells

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Journal of Energy Chemistry 2023年第3期78卷 262-267,I0008页

作者： Hongyi Chen Cheng Wang Shaoying Wang Ruiming Li Yan Zeng Zhe Li Zhengwei Ou Qianqian Lin Jianmin Li Ti Wang Hongxing Xu School of Physics and Technology and Key Laboratory of Artiﬁcial Micro-and Nano-structures of Ministry of EducationWuhan UniversityWuhan 430072HubeiChina Wuhan Institute of Quantum Technology Wuhan 430206HubeiChina School of Microelectronics Wuhan UniversityWuhan 430072HubeiChina

Antimony trisulfide(Sb_(2)S_(3)) solar cells suffer from large open circuit voltage deficits due to their intrinsic defects which limit the power conversion ***,it is important to elucidate these defects’ origin and defects at the ***,we discover that sulfide radical defects have a significant impact on the performance of Sb_(2)S_(3)solar ***,it has been illustrated that these defects at the CdS/Sb_(2)S_(3)interface can be reduced by optimizing the deposition process.A trap distribution model is used to quantify the defect density at the CdS/Sb_(2)S_(3)*** shows that the interface defects can be reduced by24% by improving the deposition *** work reveals the importance of interface defects and guides the future optimization of Sb_(2)S_(3)solar cells.

关键词： Antimony trisulﬁde Interface defect transient absorption spectroscopy

Theoretical and Experimental Study of Photophysical Characteristics between Poly（9,9-dioctylfluorene） and Poly（9,9-dioctylfluorene-co-benzothiadiazole）

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Chinese Journal of Chemical Physics 2013年第4期26卷 387-392,J0001页

作者：张里荃王英惠隋宁康智慧黄田浩马於光张汉壮吉林大学物理学院飞秒激光实验室长春130012 吉林大学超分子结构和材料国家重点实验室长春130012 吉林大学和平校区公共教学中心长春130012

The photo-physical characteristics of semiconductor polymer are systematically stud- ied through comparing poly （9,9-dioctylfluorene）（PFO） and poly （9,9-dioctylfluorene-co- benzothiadiazole）（F8BT）. The quantum chemical calculation shows that the introduction of benzothiadiazole unit facilitates the intrachain charge transfer （ICT） and modulates the electronic transition mechanism of polymer. The transient absorption measurement exhibits that intrachain exciton relaxation is dominant in the decay of excited PFO in a monodis- perse system and intrachain exciton interaction could appear at high excitation intensity. In F8BT solution, the ICT state exists and participates in the relaxation of excited state. The relaxation processes of PFO and F8BT in the condensed phase both accelerate and show obvious exciton-exciton annihilation behavior at high excitation intensity. At the same excitation intensity, the mean lifetime of F8BT is longer than that of PFO, which may be assigned to the excellent delocalization of charge.

关键词： Conjugated polymer transient absorption spectroscopy Intrachain chargetransfer

Excited State Intramolecular Proton Transfer of 1-Hydroxyanthraquinone

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Chinese Journal of Chemical Physics 2015年第5期28卷 -页

作者： Si-mei Sun Song Zhang Kai Liu Ya-ping Wang Miao-miao Zhou Bing Zhang State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics Wuhan Institute of Physics and Mathematics Chinese Academy of Sciences Wuhan 430071 China

The excited state intra-molecular proton transferdynamics of 1-hydroxyanthraquinone in solution are investigated by femtosecond transient absorption spectroscopy and quantum chemistry calculations. Two characteristic bands of excited state absorption and stimulated emission are observed in transient absorption spectra with the excitation by the pump wavelength of 400 nm. From the delayed stimulated emission signal, the time scale of the intra-molecular proton transfer is determined to be about 32 fs. The quantum chemistry calculations show that the molecular orbits and the order of the S2 and S1 states are reversal and a conical intersection is demonstrated to exist along the proton transfer coordinate. After proton transfer, the second excited state of tautomer populated via the conical intersection undergoes the internal conversion with ～200 fs and the following intermolecular energy relaxation with ～16 ps. The longer component 300 ps can be explained in terms of the relaxation from excited-state tautomer to its ground state. From our observations, two proton transfer pathways via a conical intersection are proposed and the dominated one preserves the molecular orbits.

关键词： Proton transfer Conical intersection transient absorption spectroscopy 1-Hydroxyanthraquinone