Article
Chemistry, Multidisciplinary
Nan Gong, Runchen Lai, Shiyu Xing, Zhengzheng Liu, Junyao Mo, Tao Man, Zicheng Li, Dawei Di, Juan Du, Dezhi Tan, Xiaofeng Liu, Jianrong Qiu, Beibei Xu
Summary: This study proposes a novel strategy to enhance triplet-triplet annihilation upconversion (TTA-UC) by incorporating ionic-bonded CsPbBr3 and lanthanide Ce3+ ions into composite nanocrystals. This electronic state engineering increases the population of triplet excitons participating in energy transfer, enhances coupling strength and driving force, and ultimately leads to a nonlinear enhancement of UC efficiency. The findings clarify the functions of electronic state engineering in inorganic sensitizers and TTA-UC.
Article
Chemistry, Multidisciplinary
Martin L. Kirk, David A. Shultz, Patrick Hewitt, Ju Chen, Art van der Est
Summary: Photoinduced electron spin polarization (ESP) in the ground state of luminescent materials is investigated, and the phenomenon is found to be influenced by the connecting structure and have a relatively long duration.
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY
(2022)
Article
Chemistry, Multidisciplinary
Xi Chen, Andrey A. Sukhanov, Yuxin Yan, Damla Bese, Cagri Bese, Jianzhang Zhao, Violeta K. Voronkova, Antonio Barbon, Halime Gul Yaglioglu
Summary: A long-lived charge transfer (CT) state was observed in a novel orthogonal compact electron donor-acceptor dyads, where the torsion between the donor and acceptor is completely inhibited to prolong the CT state lifetime.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2022)
Article
Chemistry, Multidisciplinary
Yu-Ying Jiang, Hui Liu, Ting Li, Kun Zhang, Peng-Fu Gao, Meng-Shu Zhou, Li-Lei Zhang, Hong-Ru Fu
Summary: Controlling molecular packing has a significant impact on the aggregate states and optoelectronic characteristics. In this study, two coordination polymers with different molecular packing modes were synthesized through coordination-driven self-assembly. It was found that the molecular packing mode has a profound effect on the emission characteristics. Compound 1, which features a monomer packing mode, exhibits both blue fluorescence and ultralong phosphorescence at room temperature, while compound 2, which lacks phosphorescence, shows excimer-dominated green fluorescence emission.
CRYSTAL GROWTH & DESIGN
(2022)
Article
Chemistry, Multidisciplinary
Meng Lv, Xicun Lu, Yanrong Jiang, Maria E. Sandoval-Salinas, David Casanova, Haitao Sun, Zhenrong Sun, Jianhua Xu, Youjun Yang, Jinquan Chen
Summary: The study focuses on enhancing triplet generation efficiency and uncovering the mechanism of intersystem crossing by designing spiro-compounds. By fine-tuning the energy levels between spiro-charge transfer and high energy states, near-unity triplet generation quantum yield was achieved.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2022)
Article
Chemistry, Applied
Ying Zeng, Xiangxiang Zhai, Guangming Wang, Yuming Su, Minjian Wu, Biaobing Wang, Kaka Zhang
Summary: Organic afterglow materials, featuring small rate constants of key photophysical processes, such as phosphorescence decay and nonradiative decay of triplet excited states, have become an important class of luminescent materials. The transformation of afterglow mechanism from room-temperature phosphorescence to thermally-activated delayed fluorescence in intramolecular charge transfer systems has been reported. This transformation is achieved by increasing the acceptor strength of the ICT molecules, reducing singlet-triplet splitting energy, and enabling reverse intersystem crossing pathway to harvest triplet energies. These findings provide deep understanding of the behaviors of organic triplets with small photophysical rate constants. In addition, these organic ICT molecules have shown promising applications when incorporated into aqueous emulsion systems.
Article
Chemistry, Applied
Xiaoyu Zhao, Ivan Kurganskii, Ayhan Elmali, Jianzhang Zhao, Ahmet Karatay, Gloria Mazzone, Matvey Fedin
Summary: A series of compact coumarin-anthracene donor-acceptor dyads were synthesized to investigate the relationship between molecular configuration, electronic coupling, and intersystem crossing (ISC) efficiency. The results showed that the orthogonal geometry of the dyads was beneficial to the spin-orbit charge transfer ISC (SOCT-ISC) mechanism. Singlet oxygen quantum yields were solvent polarity-dependent, and the orthogonal dyads exhibited higher yields compared to the coplanar dyad. Transient absorption spectra revealed different localized and delocalized triplet states in the dyads, with varied lifetimes. Time-resolved electron paramagnetic resonance (TREPR) spectra confirmed the involvement of the SOCT-ISC mechanism in orthogonal dyads, while both SOCT-ISC and spin-orbit ISC (SO-ISC) mechanisms contributed to the triplet state formation in the coplanar dyad. The electron spin polarization (ESP) pattern of the triplet states depended on not only the molecular geometry but also the electron donor and acceptor structure.
Article
Chemistry, Multidisciplinary
Guangming Wang, Xuefeng Chen, Jiahui Liu, Shuhui Ding, Kaka Zhang
Summary: By incorporating advanced charge transfer (CT) technology, we designed difluoroboron beta-diketonate (BF(2)bdk) CT compounds with moderate singlet-triplet splitting energy and relatively large spin-orbit coupling matrix elements, achieving efficient intersystem crossing (ISC) and moderate rates of reverse intersystem crossing (RISC). The organic matrices suppress nonradiative decay of BF(2)bdk's T-1 states, leading to high afterglow efficiency, long lifetimes, and excellent processability for TADF-type organic afterglow materials.
SCIENCE CHINA-CHEMISTRY
(2023)
Article
Biochemistry & Molecular Biology
Shiro Koseki, Mamoru Haruta, Nozomi Sawada, Toshio Asada
Summary: The study explores the reaction paths of methylenecyclopropane on different potential energy surfaces, revealing the possibility of fast inter-state transitions during the formation of cyclobutylidene. Multiple low-energy transition states were found along the reaction path. The introduction of phenyl groups lowers the energy barriers in the reactions.
PHOTOCHEMISTRY AND PHOTOBIOLOGY
(2021)
Article
Chemistry, Multidisciplinary
Xi Chen, Noreen Rehmat, Ivan V. Kurganskii, Partha Maity, Ayhan Elmali, Jianzhang Zhao, Ahmet Karatay, Omar F. Mohammed, Matvey V. Fedin
Summary: Bodipy (BDP)-perylenebisimide (PBI) donor-acceptor dyads/triad were synthesized to investigate the spin-orbit charge-transfer intersystem crossing (SOCT-ISC). Different quantum yields of singlet oxygen were observed for the dyads/triad, and various processes including FRET, CS, CR, and TTET were observed in the excited state dynamics. Time-resolved electron paramagnetic resonance spectroscopy revealed the involvement of both radical pair ISC and SOCT-ISC in the intersystem crossing. The triad BDP-PBI-2 showed an unusual electron spin polarization pattern of (e, e, e, e, e, e) in the triplet state formed via the RP ISC mechanism.
CHEMISTRY-A EUROPEAN JOURNAL
(2023)
Article
Chemistry, Physical
Takayoshi Tonami, Hajime Miyamoto, Masayoshi Nakano, Ryohei Kishi, Yasutaka Kitagawa
Summary: Singlet fission (SF) occurs when a singlet exciton state is converted into a double-triplet exciton state through interactions with nuclear motions. In this study, the effects of static disorder on SF in pentacene crystal models were investigated using quantum dynamics simulation and classical molecular mechanics/molecular dynamics. It was found that static disorder accelerates the relaxation pathways from singlet exciton to double-triplet exciton through faster decay of coherence between the states.
JOURNAL OF PHYSICAL CHEMISTRY A
(2023)
Review
Chemistry, Multidisciplinary
Zihao Xu, Zhiyuan Huang, Tao Jin, Tianquan Lian, Ming L. Tang
Summary: The review focuses on the advancements made in the semiconductor-nanocrystal-sensitized, three-component upconversion system over the past 5 years. It discusses the critical roles of the triplet photosensitizer, mediator, and emitter in determining the overall quantum efficiency of the system, as well as the mechanisms involved in triplet energy transfer between the components. Through optimization of the sensitizer, mediator, and emitter, an increase in anti-Stokes shift and total quantum efficiency can be achieved.
ACCOUNTS OF CHEMICAL RESEARCH
(2021)
Article
Chemistry, Physical
Sina Wrede, Lanlan He, Gerrit Boschloo, Leif Hammarstrom, Lars Kloo, Haining Tian
Summary: To gain a deeper understanding of charge processes in dye-sensitized photocathodes, lateral electron hopping across dye-sensitized NiO photocathodes was investigated. The results show the existence of a second electron hopping pathway between NiO surface states, which dominates recombination kinetics. The study highlights the importance of fast electron transport in sensitized NiO photocathodes.
PHYSICAL CHEMISTRY CHEMICAL PHYSICS
(2022)
Article
Chemistry, Physical
Zoltan Varga, Yang Liu, Jun Li, Yuliya Paukku, Hua Guo, Donald G. Truhlar
Summary: This study presents potential energy surfaces for high-energy collisions between oxygen molecules and nitrogen atoms, which are useful for modeling chemical dynamics in shock waves. Two approaches are developed for fitting the surfaces, with one utilizing neural networks and permutationally invariant polynomials showing significantly better performance than the other method, despite requiring more computational time. The development of these surfaces aids in understanding chemical dynamics in shock waves.
JOURNAL OF CHEMICAL PHYSICS
(2021)
Article
Multidisciplinary Sciences
Wenjun Ni, Licheng Sun, Gagik G. Gurzadyan
Summary: Singlet exciton fission (SF) is a spin-allowed process that can enhance the efficiency of photovoltaic devices by creating two triplet excitons from one singlet exciton. The study of excited state dynamics in perylene film shows potential for high triplet formation quantum yield, singlet fission, and the competition of other relaxation channels. Exciton self-trapping by crystal lattice distortions within picoseconds highlights the simplicity and potential of perylene films in SF-based photovoltaic applications.
SCIENTIFIC REPORTS
(2021)