Article
Nanoscience & Nanotechnology
Lin Cui, Siyuan Zhu, Mengtao Sun
Summary: This paper investigates the effects of external electric fields on sequential and super-exchange charge transfer in D-B-A systems, showing that the orientation and absorption strength of charge transfer excitons can be manipulated effectively. The results provide new opportunities for achieving strong absorption with different charge transfer characteristics in TPA, highlighting the role of external electric fields in controlling charge transfer processes.
PHYSICA E-LOW-DIMENSIONAL SYSTEMS & NANOSTRUCTURES
(2021)
Article
Spectroscopy
Wenjun Wang, Xuesong Xu, Zijiang Yang
Summary: The photoinduced charge transfer mechanisms of two Donor-pi-Donor-pi-Acceptor conjugates are analyzed based on density functional theory calculations and visualization methods. The effects of the linkage between the two donors on the excitation characteristics are studied. The results show that the efficiency of superexchange charge transfer is affected by the change of bridge in one-photon absorption process, while the advantage of superexchange charge transfer is influenced by the linkage change in two-photon absorption process.
SPECTROCHIMICA ACTA PART A-MOLECULAR AND BIOMOLECULAR SPECTROSCOPY
(2022)
Article
Multidisciplinary Sciences
Jianwei Shen, Ajay Jha, Meng Lv, Guanyu Jiang, Qixu Zhao, Zihui Liu, Jinquan Chen, Yan Yang, Haitao Sun, Hong-Guang Duan, Zhenrong Sun
Summary: Merocyanine dyes are of great interest due to their nonlinear optical properties and solvatochromism. In this study, the excited state dynamics of a merocyanine dye known as HB194 were investigated, revealing solvent-dependent charge transfer dynamics. The excited state decays in different solvents showed multi-exponential components, with polar solvents inducing conformationally relaxed intramolecular charge transfer states and nonpolar solvents exhibiting solvent-stabilized ICT states. An anomalously red-shifted emission was observed in ethylene glycol, which was attributed to the presence of molecular dimers. This work emphasizes the importance of gaining molecular-level insight into system-solvent interactions for designing next-generation merocyanine-based solvatochromic dyes.
SCIENTIFIC REPORTS
(2022)
Article
Spectroscopy
Xinyue Wang, Hongxiang Wang, Meixia Zhang, Tonu Pullerits, Peng Song
Summary: Based on Marcus theory, the photoinduced electron transfer properties of D-A type non-fullerene acceptor organic solar cells (OSCs) under the dependence of external electric field (F-ext) were investigated. The research found that the charge transfer mode changes with the intensity of external electric field and the important parameters (delta G, lambda, and V-DA) play a crucial role in the charge transfer rate.
SPECTROCHIMICA ACTA PART A-MOLECULAR AND BIOMOLECULAR SPECTROSCOPY
(2023)
Article
Chemistry, Physical
Xinyue Wang, Di Wang, Jia Li, Meixia Zhang, Peng Song
Summary: The theoretical study investigated the photoinduced charge transfer process of D-D-pi-A molecules, showing red shift in absorption spectrum and increased absorption intensity due to donor insertion. Visualization method was used to observe charge transfer in one- and two-photon absorption processes, with the thiazolo[5,4-d]thiazole donor insertion showing the largest TPA cross-section. This work contributes to understanding D-D-pi-A molecules and designing molecules with large cross-section TPA properties.
Article
Chemistry, Physical
Siyuan Zhu, Dawei Kang, Zhiyu Liu, Meixia Zhang, Yong Ding, Peng Song
Summary: This article theoretically studies the photoinduced charge transfer of rigid D-B-A molecules in two-photon absorption adjusted by the external electric fields. The results demonstrate that adjusting the field direction and intensity significantly affects the position of the absorption peak, thereby changing the electron-hole coherence length and degree of dispersion.
JOURNAL OF PHYSICAL CHEMISTRY A
(2022)
Review
Chemistry, Multidisciplinary
Meera Madhu, Remya Ramakrishnan, Vishnu Vijay, Mahesh Hariharan
Summary: This review discusses the recent advancements in hierarchical organization of molecular building blocks for improved photoconversion in organic solar cells. The self-sorted donor-on-donor/acceptor-on-acceptor arrangements have shown enhanced charge separation efficiency through ultrafast excited state dynamics. The controlled interface and electronic coupling between covalently linked donors and acceptors provide better charge carrier generation efficiency and offer new possibilities for functional supramolecular architectures.
Article
Multidisciplinary Sciences
Jing Wang, Xudong Jiang, Hongbo Wu, Guitao Feng, Hanyu Wu, Junyu Li, Yuanping Yi, Xunda Feng, Zaifei Ma, Weiwei Li, Koen Vandewal, Zheng Tang
Summary: This study demonstrates that high voltage losses in organic solar cells can be suppressed by controlling the spacing between the donor and acceptor materials, leading to improved power conversion efficiency. Increasing the DA spacing reduces non-radiative decay of charge carriers and enhances device voltage, pointing to a new research direction for breaking the performance bottleneck of organic solar cells.
NATURE COMMUNICATIONS
(2021)
Article
Chemistry, Physical
Lloyd Fisher, Ricardo Javier Vazquez, Madeleine Howell, Angelar K. Muthike, Meghan E. Orr, Hanjie Jiang, Betsy Dodgen, Dong Ryun Lee, Jun Yeob Lee, Paul Zimmerman, Theodore Goodson
Summary: This study investigates the excited-state dynamics of organic chromophores with thermally activated delayed fluorescent (TADF) characteristics using multiple time-resolved and nonlinear optical measurements, as well as quantum chemical simulations. The influence of a phenylene linker on the photophysical properties of emitters composed of carbazole-based donors linked to either a phthalonitrile (PN) or diphenyltriazine (Trz) acceptor is of particular interest. The results show that PN-acceptor compounds exhibit a near double-fluorescence quantum yield enhancement in oxygen-free conditions, while Trz-acceptor compounds are more efficient fluorescence emitters and quickly transition from a delocalized to localized state. Only PN-acceptor compounds display a long-lived emissive lifetime component associated with TADF activity. Nanosecond transient absorption spectra and kinetics analysis reveal long-lived excited-state absorption (ESA) bands associated with triplet states for the PN-acceptor compounds. No ESA bands are observed for the Trz-acceptor compounds, despite a quantum yield enhancement after oxygen purging. Quantum chemical calculations indicate that the inclusion of the phenylene linker prevents sufficient energy separation and suppresses TADF activity, while directly linking multiple donors to the acceptor would aid in achieving TADF activity.
CHEMISTRY OF MATERIALS
(2022)
Article
Chemistry, Physical
Zoltan Szakacs, Florian Glocklhofer, Felix Plasser, Eric Vauthey
Summary: This study investigates excited-state symmetry breaking in a series of symmetric 9,10-dicyanoanthracenes with electron-donating groups linked at different positions via various spacers. The results show that as the donor-acceptor distance increases, electronic excitation becomes unevenly distributed.
PHYSICAL CHEMISTRY CHEMICAL PHYSICS
(2021)
Article
Chemistry, Multidisciplinary
Nadeema Appukutti, Alex H. de Vries, Prashant G. Gudeangadi, Bini R. Claringbold, Michelle D. Garrett, Michael R. Reithofer, Christopher J. Serpell
Summary: The researchers have developed a series of phosphoester-linked trimers of aromatic donor/acceptors that participate in charge-transfer interactions. Each sequence exhibits distinct self-assembly properties, and complementary sequences interact with each other to form new nanostructures and exhibit thermochromism. This opens up new possibilities for the development of functional nanomaterials that utilize sequence control to tune structure.
CHEMICAL COMMUNICATIONS
(2022)
Review
Chemistry, Inorganic & Nuclear
Carolin Mueller, Sebastian Bold, Murielle Chavarot-Kerlidou, Benjamin Dietzek-Ivansic
Summary: In recent years, dyads in which molecular donor and acceptor moieties are chemically linked by a bridging ligand have shown promise in light-driven catalysis. The modular structure, control-lable donor-acceptor distance, and light-driven charge transfer abilities make these systems attractive for light-driven charge-transfer reactions and light-driven redox catalysis. This review discusses the role of 1,2,3-triazole bridging motif in driving electron transfer in triazole-bridged donor-acceptor dyads upon photoexcitation, and how the structural and electronic properties of the bridge influence charge separation and recombination rates. Criteria for designing dyads with different electron transfer properties are also derived.
COORDINATION CHEMISTRY REVIEWS
(2022)
Article
Chemistry, Multidisciplinary
Jun Yang, Jianfang Jing, Wenlu Li, Yongfa Zhu
Summary: This work successfully constructed an electron donor-acceptor (D-A) interface with high charge separation for boosting photocatalytic H-2 evolution. The TPPS/PDI with D-A interface showed significantly improved H-2 evolution rate, stronger internal electric field, and longer excited state lifetime compared to pure TPPS and PDI. This study provides new ideas for designing materials with D-A interface to achieve high photocatalytic activity.
Article
Chemistry, Applied
Zhen Chen, Chenghu Dai, Qian Zhou, Huitian Du, Jihui Fan, Shenghao Han, Chuang Zhang, Zhiyong Pang
Summary: Exciplex-based TADF materials exhibit excellent optical properties by converting non-radiative states to radiative states, showing potential for nonlinear optical applications.
Review
Chemistry, Multidisciplinary
Leendert van Dalsen, Rachel E. Brown, James A. Rossi-Ashton, David J. Procter
Summary: The photoactivation of electron donor-acceptor complexes is a sustainable and versatile strategy for generating radicals. However, the electronic constraints of the donor and acceptor components can limit the range of radicals that can be generated. By using sulfonium salts in electron donor-acceptor complexation, radicals can now be generated from native functionality. This approach relaxes the electronic constraints and expands the range of radicals that can be generated.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2023)
Review
Instruments & Instrumentation
Yi Cao, Yuqing Cheng, Mengtao Sun
Summary: Graphene with its unique structure and excellent properties, combined with metal nanoparticles, can generate plasmon coupling effects, which have wide-ranging applications. Graphene-based SERS sensors and catalytic devices have great potential in medical monitoring, food inspection, and biomedical fields.
APPLIED SPECTROSCOPY REVIEWS
(2023)
Article
Chemistry, Physical
Ning Li, Mengtao Sun
Summary: In this paper, the optical and spectral properties of figure-of-eight helicene carbon nanohoop with Mobius topology are theoretically studied. The analysis is done using the visualization method of transition density matrix and charge density difference, revealing the unique characterization of carbon nanohoop with Mobius topology.
Article
Physics, Multidisciplinary
Yuqing Cheng, Mengtao Sun
Summary: This study investigates the optical properties of coupled metallic nanoparticles (MNPs) under vertical polarization, revealing unique characteristics such as three coupling coefficients, positive coupling terms, and blue-shifts of peaks with increasing coupling strength. The model shows that resonant MNPs exhibit a single blue-shifted mode, while non-resonant MNPs exhibit two splitting modes, one blue-shifted and one red-shifted. The relative intensity of the modes varies with coupling strength. Comparison with experimental results validates the model and enhances understanding of coupled MNPs for relevant applications.
NEW JOURNAL OF PHYSICS
(2023)
Article
Chemistry, Multidisciplinary
Jizhe Song, Yi Cao, Jun Dong, Mengtao Sun
Summary: In this paper, the energy bands, interlayer interactions, and thermoelectric effects of twisted bilayer borophene (TBB) synthesized on Ag (111) are theoretically studied. The results show the advantages of twistronics, where the high electrical conductivity and large Seebeck coefficient are regulated to the same range, leading to a significantly increased figure of merit (ZT) compared to bilayer borophene (BB) without twist. The TBB synthesized on Ag (111) film demonstrates strong coupling between TBB and Ag, making TBB a metallic 2D material with semiconducting and metallic borophene layers. TBB exhibits excellent thermoelectric efficiency due to charge transfer bonding, reduced electron localization, and the regulation of Seebeck coefficient, electrical conductivity, and ZT through twistronics, offering the possibility of applying TBB in thermoelectric devices.
Article
Spectroscopy
Yuqiang Wu, Mengtao Sun
Summary: In this paper, the optical properties of beta 1-phase borophene-black phosphorus heterostructures (BBPHs) were theoretically investigated using first principle calculations. The results showed that constructing BBPHs could enhance the stability of the crystal structure and significantly affect the optical properties compared to the individual borophene and black phosphorus monomers. The BBPHs exhibited excellent polarization characteristics in the visible or infrared region. These findings have important implications for the future application of optoelectronic devices based on two-dimensional heterostructures.
SPECTROCHIMICA ACTA PART A-MOLECULAR AND BIOMOLECULAR SPECTROSCOPY
(2023)
Article
Spectroscopy
Ning Li, Mengtao Sun, Shuo Cao
Summary: This paper presents a theoretical investigation on the optical absorption and molecular chirality of p-conjugated mechanically interlocked nanocarbons, using one photon absorption (OPA) and two photon absorption (TPA) as well as electronic circular dichroism (ECD) spectra. The study reveals the optical excitation properties and chirality resulting from interlocked mechanical bonds. TPA and ECD can effectively discriminate between interlocked and non-interlocked molecules, as well as differentiate [2]catenanes from [3]catenanes.
SPECTROCHIMICA ACTA PART A-MOLECULAR AND BIOMOLECULAR SPECTROSCOPY
(2023)
Article
Spectroscopy
Lichun Sun, Mengtao Sun, Youjin Zheng
Summary: In this paper, we theoretically investigate the fluorescence origin and chirality mechanism of graphene quantum dots with non-twist and twist geometries, respectively. It is revealed that twist is not necessary for fluorescence; but twist is a must for chirality, which can significantly enhance the intensity of chirality as demonstrated by ECD spectra. Our results provide a deeper understanding of the physical mechanism of fluorescence and chirality in graphene quantum dots influenced by geometric twist.
SPECTROCHIMICA ACTA PART A-MOLECULAR AND BIOMOLECULAR SPECTROSCOPY
(2023)
Article
Spectroscopy
Wenwen Li, Mengtao Sun
Summary: We theoretically investigate the local electron density, electronic band structure, density of state, dielectric function, and optical absorption of the bulk and monolayer C60 network structures, based on the latest experimental synthesis. The results show that the ground state electrons are concentrated on the bridge bonds between clusters, the bulk and monolayer C60 network structures have strong absorption peaks in the visible and near infrared regions, and the monolayer quasi-tetragonal phase C60 network structure shows strong polarization dependence. Our results not only provide insights into the physical mechanism of optical absorption of the monolayer C60 network structure, but also reveal potential applications of the C60 network structure in photoelectric devices.
SPECTROCHIMICA ACTA PART A-MOLECULAR AND BIOMOLECULAR SPECTROSCOPY
(2023)
Review
Chemistry, Multidisciplinary
Yichuan Chen, Mengtao Sun
Summary: Plexcitonics is an interdisciplinary field with great potential in the development of innovative optical technologies and devices. It focuses on the interactions between plasmons and excitons in hybrid systems. This review provides an overview of the fundamental principles of plasmonics and plexcitonics, and discusses recent advancements in the field, including the manipulation of plasmon-exciton interactions, tip-enhanced spectroscopy, and advancements in optical chirality and nonlinearity. These developments have spurred further research and inspire the design of advanced materials and devices with enhanced optical properties and functionalities.
Article
Chemistry, Physical
Ning Li, Mengtao Sun
Summary: It is crucial to investigate the optical properties and physical mechanisms of electron transitions in planar and pi-extended cyclic phenylenes (CPPs) with full armchair edges for nanoscience and nanotechnology. The optical properties of a planar and pi-extended ring extracted from the Au(111) surface are examined theoretically, based on the most recent experimental synthesis. The research findings reveal a blue-shift of absorption peaks in non-planar systems compared to planar systems, and demonstrate that fluorescence only occurs in open loops rather than closed loops using charge density differences and transition densities as evidence. The two-photon absorption (TPA) method is employed to achieve a transition from a weak excited state to a strong excited state, while the resonance Raman spectrum confirms the dark excited state of the non-planar closed loop. Additionally, non-planar charged systems exhibit a red-shift of absorption peaks compared to non-planar uncharged systems. The visualization of charge transfer through absorption and fluorescence spectroscopy is also investigated, providing valuable insights into the optical properties and potential design of optical nanodevices.
PHYSICAL CHEMISTRY CHEMICAL PHYSICS
(2023)
Article
Chemistry, Physical
Jizhe Song, Mengtao Sun
Summary: This study investigates a twisted bilayer borophene (TBB) with a twist angle of 21.79 degrees on a Ag(111) film. The large cell size of the 21.79 degrees TBB creates favorable conditions for the short-range disordered phonon liquid state, leading to a decrease in thermal conductivity and excellent ZT values.
JOURNAL OF MATERIALS CHEMISTRY A
(2023)
Article
Materials Science, Multidisciplinary
Rui Yang, Mengtao Sun
Summary: Borophene, a 2D material with excellent properties, has gained significant attention for its potential applications in various fields. Its unique properties make it an ideal candidate for device design and energy storage materials. Recent advances in its synthesis have opened up new possibilities for nanodevice applications.
JOURNAL OF MATERIALS CHEMISTRY C
(2023)
Article
Chemistry, Physical
Yuqing Cheng, Mengtao Sun
Summary: Plexciton is a new hybridized energy state formed by the coupling of a plasmon and an exciton, and its optical properties are described using a classic oscillator model. In the case of strong coupling, absorption spectra show a phenomenon similar to electromagnetically induced transparency, and the splitting behavior of modes depends on the effective number of electrons and resonance coupling. Photoluminescence spectra exhibit significant changes in strong coupling, while the emission intensity of the exciton is greatly enhanced by the plasmon. Comparisons with published experiments validate the model's validity. This study is important for understanding Plexciton mechanism and the development of new applications.
JOURNAL OF PHYSICAL CHEMISTRY C
(2023)
Article
Chemistry, Physical
Wenwen Li, Jing Li, Mengtao Sun
Summary: In this study, the fluorescence resonance energy transfer (FRET) and intermolecular charge transfer (ICT) in the donor-acceptor system for efficient organic solar cells (OSCs) of the Y6:PM6 heterostructure were investigated. The physical mechanisms of FRET and ICT in the donor-acceptor system were studied theoretically and experimentally, providing valuable references for the rational design of FRET- and ICT-based OSCs.
PHYSICAL CHEMISTRY CHEMICAL PHYSICS
(2023)
Article
Spectroscopy
Yu Chen, Lichun Sun, Mengtao Sun, Youjin Zheng
Summary: This paper presents a theoretical study on the optical properties of carbon nanobelts with various edges and interlocked structures, focusing on their chirality. The results show that two photon absorption and electronic circular dichroism techniques can effectively distinguish carbon nanoribbons with different boundaries, providing insights into their relationship and unique features. This research contributes to a better understanding of carbon nanoribbons, mechanically interlocked molecules, and chirality.
SPECTROCHIMICA ACTA PART A-MOLECULAR AND BIOMOLECULAR SPECTROSCOPY
(2024)
