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Tip-induced directional charge separation on one-dimensional BiVO4 nanocones for asymmetric light absorption

Journal of energy Chemistry 2022年第9期31卷 326-332,I0009页

作者： Nengcong Yang Ruotian Chen Chenwei Ni Dongfeng Li Qi Sun Lifang Liu Yu Qi Shengye Jin Xiuli Wang Fengtao Fan Can Li Fuxiang Zhang state key laboratory of Catalysis Dalian Institute of Chemical PhysicsDalian National Laboratory for Clean EnergyChinese Academy of SciencesDalian 116023LiaoningChina State Key Laboratory of Molecular Reaction Dynamics and Dynamics Research Center for Energy and Environmental Materials Dalian Institute of Chemical PhysicsChinese Academy of SciencesDalian 116023LiaoningChina University of Chinese Academy of Sciences Beijing 100049China

One dimensional(1D)semiconductor is a class of extensively attractive materials for many emerging solar energy conversion technologies.However,it is still of shortage to assess the impact of 1D structural symmetry on spatial charge separation and understand its underlying mechanism.Here we take controllably-synthesized 1D BiVO_(4)nanocones and nanorods as prototypes to study the influence of 1D symmetry on charge separation.It is found that the asymmetric BiVO_(4)nanocones enable more effective charge separation compared with the symmetric nanorods.The unexpected spatial charge separation on the nanocones is mainly ascribed to uneven light absorption induced diffusion-controllable charge separation due to symmetry breaking of 1D nanostructure,as evidenced by spatial and temporal resolved spectroscopy.Moreover,the promotion effect of charge separation on the nanocones was quantitatively evaluated to be over 20 times higher than that in BiVO_(4)nanorods.This work gives the first demonstration of the influence of 1D structural symmetry on the charge separation behavior,providing new insights to design and fabricate semiconductor materials for efficient solar energy conversion.

关键词： Charge separation Tip-enhanced light absorption Surface photovoltage BiVO4 Photocatalysis

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A synergetic strategy of NIR-Ⅱ squaraine dyes with ultrahigh photothermal conversion efficiency for photothermal therapy

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Science China Chemistry 2024年第2期67卷 612-621页

作者： Yigang Wang Guomin Xia Junhui Wang Mingda Wang Weihan Guo Manman Tan Leilei Si Yang Yang Hua Wang Hongming Wang Institute for Advanced Study and School of Chemistry and Chemical Engineering Nanchang UniversityNanchang330031China State Key Laboratory of Molecular Reaction Dynamics and Dynamics Research Center for Energy and Environmental Materials Dalian Institute of Chemical PhysicsChinese Academy of SciencesDalian116023China The Second Affiliated Hospital of Nanchang University Nanchang330031China

Recent research on photothermal therapy(PTT) has sparked significant interest in the development of new organic photothermal agents(PTAs),ranging from single-molecule to aggregated levels.However,controlling aggregation pathways for PTAs with ultrahigh photothermal conversion efficiency(PCE) remains a major challenge.Herein,a two-pronged approach utilizing “Haggregation” and “intramolecular motion” was employed to enhance the PCE of an acceptor-substituted squaraine dye(NSQs).The C2vmolecular symmetry of the NSQs,which possess a ground state dipole moment(μg),promotes H-dimeric aggregates through dipole-dipole counteraction.Peripheral triphenylethylene or diphenylamine groups were added to this H-dimeric nanoplatform.This was done to enhance intramolecular motions for heat generation and also to extend conjugation,which redshifted the optical absorption and balanced the blue-shift induced by H-aggregation.With this technique,an organic PTA with NIR-II absorption was developed,and its nanoparticle achieved a remarkable PCE of 86.3% under 1,064 nm laser excitation.Femtosecond transient absorption spectroscopy and quantum mechanical calculations demonstrated the accelerated internal conversion process in NIR-II PTAs for rapid heat generation.The NSQs nanoparticles exhibit superior photothermal therapeutic properties for in vivo photoacoustic imaging-guided PTT,demonstrating the potential of bottom-up design to enable synergistic engineering strategies towards efficient phototheranostic agents.

关键词： squaraine dyes second near-infrared window H-aggregation intramolecular motion photothermal therapy

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Tailoring morphology symmetry of bismuth vanadate photocatalysts for efficient charge separation

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Science China Chemistry 2023年第12期66卷 3611-3619页

作者： Yuting Deng Hongpeng Zhou Chenwei Ni Fengke Sun Wenchao Jiang Ruotian Chen Wenming Tian Can Li Rengui Li state key laboratory of Catalysis Dalian National Laboratory for Clean EnergyiChEM(Collaborative Innovation Center of Chemistry for Energy Materials)Dalian Institute of Chemical PhysicsChinese Academy of SciencesDalian 116023China center of materials Science and Optoelectronics Engineering University of Chinese Academy of SciencesBeijing 100049China state key laboratory of molecular reaction dynamics and the Dynamic research center for energy and environmental materials Dalian Institute of Chemical PhysicsChinese Academy of SciencesDalian 116023China

Although spatial charge separation between different facets of semiconductor crystals has been recognized as a general strategy in photocatalysis, the vital role of crystal morphology symmetry in charge separation properties still remains elusive. Herein,taking monoclinic bismuth vanadate(BiVO_(4)) as a platform, we found distinct charge separation difference via rationally tailoring the morphology symmetry from octahedral to truncated octahedral crystals. For octahedral BiVO_(4), photogenerated electrons and holes can be separated between edges and quasi-equivalent facets. However, as for truncated octahedral crystals,photogenerated electrons tend to transfer to {010} facets while photogenerated holes prefer to accumulate on {120} facets, thus realizing the spatial separation of photogenerated charge between different facets. Morphology tailoring of BiVO_(4) crystals leads to a significantly improved photogenerated charge separation efficiency and photocatalytic water oxidation activity. The built-in electric field for driving the separation of photogenerated electrons and holes is considered to be modulated by tuning the morphology symmetry of BiVO_(4) crystals. This work discloses the significant roles of morphology symmetry in photogenerated charge separation and facilitates the rational design of artificial photocatalysts.

关键词： bismuth vanadate morphology symmetry tailoring photocatalysis spatial charge separation

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Carrier diffusion coefficient is independent of defects in CH_(3)NH_(3)PbBr_(3) single crystals:Direct evidence

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Journal of energy Chemistry 2021年第7期30卷 441-445页

作者： Chunyi Zhao Qi Sun Rongrong Cui Jing Leng Wenming Tian Shengye Jin state key laboratory of molecular reaction dynamics and the Dynamic research center for energy and environmental materials Dalian Institute of Chemical PhysicsChinese Academy of SciencesDalianChina University of Chinese Academy of Sciences Beijing 100049China

Organolead halide perovskite solar cells have attracted extensive interests in recent years. Thanks to innovations in materials process and technology, the power conversion efficiency (PCE) of perovskites-based solar cells increases from 3.8% to 25.2%[1–4].In evaluating the quality of perovskite materials, a few key photophysical properties such as the lifetime, mobility and diffusion length of photogenerated carriers are usually measured.

关键词： Perovskite Defects Charge mobility Carrier lifetime Diffusion length

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A positive correlation between local photocurrent and grain size in a perovskite solar cell

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Journal of energy Chemistry 2022年第9期31卷 8-13,I0001页

作者： Xiaoxia Zhao Zhiyong Wang Wenming Tian Xianchang Yan Yantao Shi Yudi Wang Zhonggao Sun Shengye Jin School of Physics and Electronic Technology Liaoning Normal UniversityDalian 116029LiaoningChina state key laboratory of molecular reaction dynamics and the Dynamic research center for energy and environmental materials Dalian Institute of Chemical PhysicsChinese Academy of SciencesDalian 116023LiaoningChina state key laboratory of Fine Chemicals Department of ChemistrySchool of Chemical EngineeringDalian University of TechnologyDalian 116024LiaoningChina

Developing an interplay between the local morphological character and its local photovoltaic(PV)parameters in a perovskite thin film is essential for guiding the construction of highly-efficient perovskite solar cells(PSCs). To achieve a higher PSC performance, great efforts have been devoted to the growth of larger perovskite grains;however, how the gain size can influence the PSC performance in a working device remains unclear. Herein, using laser-scanned confocal microscopy coupled with a photocurrent detection module, we realize local photocurrent, photoluminescence(PL) intensity and PL lifetime mappings directly in a working PSC. For perovskite grains of various sizes(from ~500 nm to a few micrometers), their local photocurrent exhibit a statically positive correlation with the grain size, but anti-correlated with the grain’s local PL intensity. This result suggests that a larger perovskite grain likely has fewer defects and more importantly better interfacial contact with the charge collection layers and thus leads to higher charge collection efficiency, and the optimum grain size is found to be ≥2 μm.Our result provides important guidance to the growth and control of perovskite microstructures toward the further improvement of PSC performance.

关键词： Photocurrent mapping Photoluminescence mapping Perovskite solar cell Grain size

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Early Stage Solvation of Protonated Methanol by Carbon Dioxide

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Chinese Journal of Chemical Physics 2015年第4期28卷 -页

作者： Zhi Zhao Xiang-tao Kong Xin Lei Bing-bing Zhang Ji-jun Zhao Ling Jiang key laboratory of materials Modification by Laser Ion and Electron Beams Dalian University of Technology Ministry of Education Dalian 116024 ChinaState Key Laboratory of Molecular Reaction Dynamics Collaborative Innovation Center of Chemistry for Energy and Materials Dalian Institute of Chemical Physics Chinese Academy of Sciences Dalian 116023 China state key laboratory of molecular reaction dynamics Collaborative Innovation Center of Chemistry for Energy and Materials Dalian Institute of Chemical Physics Chinese Academy of Sciences Dalian 116023 China state key laboratory of molecular reaction dynamics Collaborative Innovation Center of Chemistry for Energy and Materials Dalian Institute of Chemical Physics Chinese Academy of Sciences Dalian 116023 ChinaState Key Laboratory of Fine Chemicals Dalian University of Technology Dalian 116024 China key laboratory of materials Modification by Laser Ion and Electron Beams Dalian University of Technology Ministry of Education Dalian 116024 China

The solvation of protonated methanol by carbon dioxide has been studied via a cluster model. Quantum chemical calculations of the H+(CH3OH)(CO2)n (n=1–7) clusters indicate that the first solvation shell of the OH groups is completed at n=3 or 4. Besides hydrogen-bond interaction, the CCO2 ⋯ OCO2 intermolecular interaction is also responsible for the stabilization of the larger clusters. The transfer of the proton from methanol onto CO2 with the formation of the OCOH+ moiety might be unfavorable in the early stage of solvation process. Simulated IR spectra reveal that vibrational frequencies of free O–H stretching, hydrogen-bonded O–H stretching, and O–C–O stretching of CO2 unit afford the sensitive probe for exploring the solvation of protonated methanol by carbon dioxide. IR spectra for the H+(CH3OH)(CO2)n (n=1–7) clusters could be readily measured by the infrared photodissociation technique and thus provide useful information for the understanding of solvation processes.

关键词： Methanol Carbon dioxide Solvation Infrared photodissociation spectroscopy Quantum chemical calculation

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Probing molecular orientation at bulk heterojunctions by polarization-selective transient absorption spectroscopy

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Science China Chemistry 2021年第9期64卷 1569-1576页

作者： Cankun Zhang Yuzhe Zhang Zhiye Wang Yuming Su Zhixiang Wei Jianhui Hou Shan He Kaifeng Wu Chang He Jianqi Zhang Cheng Wang state key laboratory for Physical Chemistry of Solid Surfaces iChEMCollege of Chemistry and Chemical EngineeringXiamen UniversityXiamen361005China Innovation laboratory for Sciences and Technologies of energy materials of Fujian Province(IKKEM) FuzhouChina CAS key laboratory of Nanosystem and Hierarchical Fabrication CAS Center for Excellence in NanosciecneNational Center for Nanoscience and TechnologyBeijing100190China state key laboratory of Polymer Physics and Chemistry Institute of ChemistryChinese Academy of SciencesBeijing100190China State Key Laboratory of Molecular Reaction Dynamics and Dynamics Research Center for Energy and Environmental Materials Dalian Institute of Chemical PhysicsChinese Academy of SciencesDalian116023China

A bulk heterojunction in organic solar cells is where charge separation and recombination occur.molecular orientation at the interface is one of the key factors that dictate solar cell efficiency.Although X-ray scattering-based methods can determine donor/acceptor domain orientations between an anisotropic phase and an isotropic fullerene-based phase,the rise of nonfullerene solar cells presents a new challenge in delineating local molecular directions at the interface between two anisotropic donor/acceptor domains.Here,we determine interfacial molecular orientations of three high-efficiency small molecule solar cells(ZR1:Y6,B1:BO-4 Cl,and BTR:BO-4 Cl)using polarization-selective transient absorption spectroscopy.The polarization anisotropy of charge separation dynamics indicates an angle of~90°between ZR1 and Y6 molecules at the interface,an angle close to 0°between B1 and BO-4 Cl,and random orientations between BTR and BO-4 Cl.These observations provide complementary information to X-ray scattering measurements and highlight polarization-selective transient absorption spectroscopy as a tool to probe interfacial structure and dynamics of key photophysical steps in energy conversion.

关键词： polarization-selective transient absorption spectroscopy bulk heterojunction organic solar cell molecular orientation

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Biexciton Auger recombination in mono-dispersed, quantum-confined CsPbBr3 perovskite nanocrystals obeys universal volume-scaling

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Nano research 2019年第3期12卷 619-623页

作者： Yulu Li Tao Ding Xiao Luo Zongwei Chen Xue Liu Xin Lu Kaifeng Wu Departmental of Chemistry College of Chemistry and Chemical Engineering Xiamen University Xiamen 361005 China State Key Laboratory of Molecular Reaction Dynamics and Dynamics Research Center for Energy and Environmental Materials Dalian Institute oj Chemical Physics Chinese Academy of Sciences Dalian 116023 China

Auger recombination has been a long?standing obstacle to many prospective applications of colloidal quantum dots (QDs) ranging from lasing, light-emitting diodes to bio-labeling. As such, understanding the physical underpinnings and scaling laws for Auger recombination is essential to these applications. Previous studies of biexciton Auger recombination in various QDs established a universal scaling of biexciton lifetime (rxx) with QD volume (V):τxx =γV. However, recent measurements on perovskite nanocrystals (NCs), an emerging class of enablers for light harvest!ng and emitting applications, showed significant deviations from this universal scaling law, likely because the measured NCs are weakly-confined and also have relatively broad size-distributions. Here we study biexciton Auger recombination in mono-dispersed (size distributions within 1.7%—9.0%), quantunvconfined CsPbBr3 NCs (with confinement energy up to 410 meV) synthesized using a latest approach based on thermodynamic equilibrium control. Our measurements clearly reproduce the volume-scaling of τxx in confined CsPbBb QDs. However, the scaling factor γ(0.085 ± 0.001 ps/nm^3) is one order of magnitude lower than that reported for CdSe and PbSe QDs (1.00 ± 0.05 ps/nm^3), suggest!ng unique mechanisms enhancing Auger recombination rate in perovskite NCs.

关键词： perovskite nanocrystals Auger recombination biexciton volume-scaling ultrafast spectroscopy

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Regulation of excitation energy transfer in Sb-alloyed Cs_(4)MnBi_(2)Cl_(12) perovskites for efficient CO_(2) photoreduction to CO and water oxidation toward H_(2)O_(2)

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Journal of energy Chemistry 2023年第7期82卷 18-24,I0001页

作者： Haiwen Wei Zhen Li Honglei Wang Yang Yang Pengfei Cheng Peigeng Han Ruiling Zhang Feng Liu Panwang Zhou Keli Han Institute of molecular Sciences and Engineering Institute of Frontier and Interdisciplinary ScienceShandong UniversityQingdao 266237ShandongChina state key laboratory of molecular reaction dynamics Dalian Institute of Chemical PhysicsChinese Academy of ScienceDalian 116023LiaoningChina

Lead(Pb)-free halide perovskites have recently attracted increasing attention as potential catalysts for CO_(2) photoreduction to CO due to their potential to capture solar energy and drive catalytic reaction.However,issues of the poor charge transfer still remain one of the main obstacles limiting their performance due to the overwhelming radiative and nonradiative charge-carrier recombination losses.Herein,Pb-free Sb-alloyed all-inorganic quadruple perovskite Cs_(4)Mn(Bi_(1-x)Sb_(x))_(2)Cl_(12)(0≤x≤1)is synthesized as efficient photocatalyst.By Sb alloying,the undesired relaxation of photogenerated electrons from conduction band to emission centers of[MnCl6]^(4-)is greatly suppressed,resulting in a weakened PL emission and enhanced charge transfer for photocatalyst.The ensuing Cs_(4)Mn(Bi_(1-x)Sb_(x))_(2)Cl_(12) photocatalyst accomplishes efficient conversion of CO_(2)into CO,accompanied by a surprising production of H_(2)O_(2),a high valueadded product associated with water oxidation.By optimizing Sb^(3+) concentration,a high CO evolution rate of 35.1μmol g^(-1)h^(-1)is achieved,superior to most other Pb and Pb-free halide perovskites.Our findings provide new insights into the mixed-cation alloying strategies for improved photocatalytic performance of Pb-free perovskites and shed light on the rational design of robust band structure toward efficient energy transfer.

关键词： Pb-free perovskites energy band modulation Perovskite photocatalysis photocatalytic CO_(2)reduction Water oxidation to H_(2)O_(2)

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Isotopic Effects on Stereodynamics of the C^+ + H_2→CH^+ + H reaction

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Communications in Theoretical Physics 2017年第5期67卷 549-553页

作者：郭璐杨云帆范晓星马凤才李永庆 Department of Physics Liaoning University state key laboratory of molecular reaction dynamics Dalian Institute of Chemical Physics Chinese Academy of Sciences

The effects of isotope substitution on stereodynamic properties for the reactions C^+ + H_2/HD/HT →CH^+ + H/D/T have been studied applying a quasi classical trajectory method occurring on the new ground state CH_2^+ potential energy surface [J. Chem. Phys. 142(2015) 124302]. In the center of mass coordinates applying the quasi classical trajectory method to investigate the orientation and the alignment of the product molecule. Differential cross section and three angle distribution functions P(θ_r), P(ф_r), P(θ_r, ф_r) on the potential energy surface that fixed the collision energy with a value is 40 kcal/mol have been studied. The isotope effect becomes more and more important with the reagent molecules H_2 changing into HD and HT. P(θ_r, ф_r) as the joint probability density function of both polar angles θ_r and ф_r, which can illustrate more detailed dynamics information. The isotope effect is obvious influence on the properties of stereodynamics in the reactions of C^+ + H_2/HD/HT → CH^+ + H/D/T.

关键词：同位素效应取代反应 CH2 C++ 立体联合概率密度函数质心坐标系角分布函数

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