Article
Chemistry, Multidisciplinary
Yongseok Hong, Felix Schlosser, Woojae Kim, Frank Wurthner, Dongho Kim
Summary: This study presents the mechanism of ultrafast photoinduced symmetry-breaking charge separation (SB-CS) in a 1,7-bis(N-pyrrolidinyl) PBI dimer within a cyclophane. The authors demonstrate that ultrafast SB-CS in the dimer is enabled by the combination of vibrationally coherent charge-transfer resonance-enhanced excimer formation and breakdown of adiabaticity in the excimer state via structural and solvent fluctuation. Quantum chemical calculations support the crucial role of strong electron donating substituents in triggering the ultrafast SB-CS.
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY
(2022)
Article
Chemistry, Multidisciplinary
Hoang Long Nguyen, Thanh Nhut Do, Emek G. Durmusoglu, Merve Izmir, Ritabrata Sarkar, Sougata Pal, Oleg V. Prezhdo, Hilmi Volkan Demir, Howe-Siang Tan
Summary: In this study, the ultrafast spectral diffusion, vibronic dynamics, and energy relaxation of CdSe colloidal quantum wells (CQWs) at room temperature were measured using two-dimensional electronic spectroscopy (2DES). The energy relaxation from light-hole (LH) excitons to heavy-hole (HH) excitons was observed to occur within a time scale of approximately 210 fs. Equilibration dynamics between the spectroscopically accessible HH excitonic state and a dark state were found to take place within a time scale of approximately 160 fs. The spectral diffusion dynamics in HH excitons were analyzed using center line slope analysis, revealing a sub-200 fs decay and oscillatory features resolved at 4 and 25 meV. Quantum calculations were performed to replicate and explain the observed dynamics. The 4 meV mode was found to be in the near-critically damped regime and may mediate the transition between the bright and dark HH excitons. These findings demonstrate the capability of 2DES to comprehensively and detailedly characterize the ultrafast spectral properties in CQWs and similar nanomaterials.
Review
Physics, Multidisciplinary
Woojae Kim, Andrew J. Musser
Summary: The multitude of ultrafast photoinduced reactions in organic semiconductors are influenced by the interplay between nuclear and electronic degrees of freedom. Ultrafast time-domain Raman methods have been utilized to study singlet fission and improve solar cell efficiencies.
ADVANCES IN PHYSICS-X
(2021)
Article
Chemistry, Physical
M. J. Chithra, Probal Nag, Sivaranjana Reddy Vennapusa
Summary: This study investigates the formation of T-1 in 2-mercaptobenzothiazole and interprets the experimental decay constants reported by D. Koyama and A. J. Orr-Ewing. By conducting simulations, the decay constants of S-2-S-1 internal conversion and S-1-T-2 intersystem crossing are found to be in excellent agreement with experimental results. Furthermore, the observed ultrafast intersystem crossing is analyzed based on spin-vibronic coupling, leading to a reassignment of the decay constant previously attributed to the T-2-T-1 internal conversion process.
PHYSICAL CHEMISTRY CHEMICAL PHYSICS
(2021)
Article
Chemistry, Physical
Martha Yaghoubi Jouybari, James A. Green, Roberto Improta, Fabrizio Santoro
Summary: In this study, a quantum dynamical investigation of the decay process of photoexcited AT base pairs reveals that hydrogen bonding destabilizes internal population transfers and leads to minimal population transfer to charge transfer states.
JOURNAL OF PHYSICAL CHEMISTRY A
(2021)
Article
Chemistry, Multidisciplinary
Zixuan Deng, Hang Zhang, Arri Priimagi, Hao Zeng
Summary: This study reports an optically powered soft material strip that can perform nonreciprocal, cilia-like, self-sustained oscillation under water. The actuator is made of planar-aligned liquid crystal elastomer responding to visible light. Two laser beams from orthogonal directions allow for piecewise control over the strip deformation, enabling two self-shadowing effects coupled in one single material to yield nonreciprocal strokes. The results demonstrate autonomous microfluidic pumping, translocation of a micro-object, and coupling between two oscillating strips through liquid medium interaction, offering new concepts for non-equilibrium soft actuators that can perform bio-like functions under water.
ADVANCED MATERIALS
(2023)
Article
Materials Science, Multidisciplinary
Anita Bagri, D. M. Phase, Ram Janay Choudhary
Summary: Artificial multiferroics with tunable magnetoelastic and magnetoelectric coupling offer potential for various device applications. In this study, we demonstrate the manipulation of magnetoelastic and magnetoelectric coupling in an epitaxial SrRuO3/BaTiO3 multiferroic heterostructure using polarized visible light illumination. The light-induced ferroelastic domain wall motion in BaTiO3 leads to changes in magnetic properties of the SrRuO3 layer. Additionally, we observed significant changes in the heterostructure when electrically biased, due to the modification of the interfacial magnetoelectric coupling. These findings provide a novel prospective for opto-spintronics device applications.
Article
Engineering, Marine
Tianchi Zhang, Qian Li, Yusong Li, Xing Liu
Summary: This paper investigates the underwater optical image restoration method for underwater target detection based on optical vision in AUVs. It examines the restoration of underwater optical images in both natural light and artificial light conditions. To solve the problem of image blurring, an improved underwater optical image restoration method based on the scattering model is proposed. Experimental results verify the effectiveness of the presented method.
JOURNAL OF MARINE SCIENCE AND ENGINEERING
(2023)
Article
Chemistry, Physical
Nuha Wazzan, Ahmad Irfan, Taghreed M. Fagieh
Summary: According to the report, the power conversion efficiencies of photosensitized solar cells using four natural dyes from Ixora floral were less than 1% due to poor light absorption in the visible and near infrared regions. However, when these dyes were hybridized with graphene quantum dots, the light harvesting efficiency was significantly improved, leading to a higher power conversion efficiency. The study also showed that the nanocomposites formed by the hybridization had better intramolecular charge transfer properties and were able to covalently adsorb on TiO2, resulting in enhanced nonlinear optical properties. This research is important for developing efficient visible light harvesters for dye-sensitized solar cell applications.
JOURNAL OF MOLECULAR LIQUIDS
(2022)
Article
Engineering, Multidisciplinary
Salim Chelouche, Djalal Trache, Ilyas Maamache, Ahmed Fouzi Tarchoun, Kamel Khimeche, Abderrahmane Mezroua
Summary: This study proposed a new experimental method to estimate the real/equivalent in-service time of rocket propellants, taking into account the impact of natural aging. The approach successfully predicted the in-service time of two similar DBRPs with high accuracy and provided more reliable values for accelerated aging conditions.
DEFENCE TECHNOLOGY
(2021)
Article
Chemistry, Physical
Adrian Dominguez-Castro, Thomas Frauenheim
Summary: Theoretical calculations are used to complement and understand experimental results in atomistic detail, while Ehrenfest molecular dynamics simulations reveal the electron dynamics for charge separation of pyrene-functionalized gold nanoclusters. The proposed mechanism involves ultrafast and irreversible photoinduced charge transfer, with the Au108S24(PPh3)(15)PPh(2)Pyr system showing the best performance for charge separation.
PHYSICAL CHEMISTRY CHEMICAL PHYSICS
(2021)
Article
Chemistry, Multidisciplinary
Vilas Venunath Patil, Ha Lim Lee, Inkoo Kim, Kyung Hyung Lee, Won Jae Chung, Joonghyuk Kim, Sangho Park, Hyeonho Choi, Won-Joon Son, Soon Ok Jeon, Jun Yeob Lee
Summary: Efficient OLED design was achieved using ultrapure blue emitters assisted by SVC, demonstrating excellent emission characteristics and quantum efficiency.
Article
Construction & Building Technology
Chuloh Jung, Mohammad Arar
Summary: Indoor landscaping is an environmentally friendly approach that enriches the environment and fosters productivity and comfort for occupants. The study compares the impact of natural and artificial light on the growth and physiological responses of Codiaeum variegatum and Ardisia japonica. The findings suggest that natural light offers a more advantageous environment for plant growth.
Article
Chemistry, Applied
Tingting Zhang, Charfedinne Ayed, Ian D. Fisk, Tong Pan, Jianhua Wang, Ni Yang, Qun Sun
Summary: This study compared the VOCs of sweet corn seeds between artificial aging (AA) and natural aging (NA), and constructed an effective AS-PLS-R model based on 3 volatile markers, achieving the best performance for predicting seed vigour. Coupling Gas Chromatography-Ion Mobility Spectrometry (GC-IMS) with chemometrics can be an effective way to monitor and predict stored seeds vigour.
Article
Chemistry, Inorganic & Nuclear
Ren Itagaki, Shin-ya Takizawa, Ho-Chol Chang, Akinobu Nakada
Summary: This study demonstrates an approach to achieve efficient photocatalysis through spatial charge separation at the liquid-liquid interface. The key finding is that Fc(+), generated by photooxidation of Fc in the DCE phase, migrates to the aqueous phase due to a drastic change in its partition coefficient, facilitating the reduction of Bn-Br in the DCE phase and suppressing charge recombination. The presence of anions can further modify the phase migration of Fc(+) and enhance the photocatalytic activity.
DALTON TRANSACTIONS
(2022)
Article
Chemistry, Physical
Constantin Heshmatpour, Juergen Hauer, Frantisek Sanda
Summary: This study demonstrates the use of 2D line shapes from fifth-order coherent electronic signals (R-5-2D) to investigate correlated spectral fluctuations in molecular aggregates. A stochastic approach was developed to analyze fluctuations in correlated site and bi-exciton binding energies in the optical dynamics of Frenkel excitons. The peak tilt dynamics were found to be a measure for site energy disorder, inter-site correlation, and the strength of bi-exciton binding energy fluctuations.
JOURNAL OF CHEMICAL PHYSICS
(2022)
Article
Multidisciplinary Sciences
Veronica R. Policht, Andrew Niedringhaus, Rhiannon Willow, Philip D. Laible, David F. Bocian, Christine Kirmaier, Dewey Holten, Tomas Mancal, Jennifer P. Ogilvie
Summary: This article reports two-dimensional electronic spectroscopy experiments on the bacterial reaction center, revealing hidden vibrational and excitonic structures. By analyzing the coherent dynamics of the reaction center, multiple quasi-resonances between pigment vibrations and excitonic energy gaps are identified, as well as vibronic coherence transfer processes that are often neglected in standard models. These findings provide insights into the energy transfer and charge separation processes in photosynthesis.
Article
Chemistry, Physical
Vladislav Slama, Sayeh Rajabi, Tomas Mancal
Summary: This study investigates the potential use of a two-dimensional material, fluorographene, as a mimic of natural photosynthetic antennas. Quantum chemical calculations demonstrate that graphene isles in a fluorographene sheet can act as quasi-molecules, allowing for the construction of structures similar to photosynthetic antennas. The study examines the properties, stability, and interactions of these building blocks, as well as the constraints imposed by the two-dimensionality and discrete nature of the material. A hypothetical energetic funnel is constructed to illustrate how a limited number of building blocks can bridge the energy gap and spatial separation in excitation energy transfer. The study concludes that near unity quantum efficiency of energy transfer is likely achievable in fluorographene with controlled arrangement of quasi-molecules.
JOURNAL OF CHEMICAL PHYSICS
(2022)
Article
Chemistry, Multidisciplinary
Richard Foja, Alexandra Walter, Christian Jandl, Erling Thyrhaug, Juergen Hauer, Golo Storch
Summary: Flavoenzymes are highly active enzymes that catalyze a variety of chemical reactions in different oxidation states and covalent adducts. The use of simplified molecular flavins to transfer this catalytic activity to organic laboratories is desirable and has been established in (photo)oxidation reactions. In this study, we report a catalytic method using reduced molecular flavins as photoreductants and gamma-terpinene as a sacrificial reductant. We also propose a design for air-stable, reduced flavin catalysts that prevents rapid reduction of O2 from air. Using this catalytic strategy, we successfully replaced superstoichiometric amounts of the rare-earth reductant SmI2 in a 5-exo-trig cyclization reaction of substituted barbituric acid derivatives. Flavin-catalyzed reductions are expected to be beneficial for other transformations as well and their straightforward synthesis indicates potential use in stereo- and site-selective transformations.
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY
(2022)
Article
Energy & Fuels
Nian Li, Renjun Guo, Anna Lena Oechsle, Manuel A. Reus, Suzhe Liang, Lin Song, Kun Wang, Dan Yang, Francesco Allegretti, Ajeet Kumar, Matthias Nuber, Jan Berger, Sigrid Bernstorff, Hristo Iglev, Juergen Hauer, Roland A. Fischer, Johannes V. Barth, Peter Mueller-Buschbaum
Summary: This study investigates the degradation mechanisms of solid-state dye-sensitized solar cells using grazing-incidence small-angle X-ray scattering. The results show that dye aggregation on the TiO2 surface leads to a decrease in device performance, and the decay is faster in small-pore TiO2 electrodes compared to big-pore ones.
Article
Chemistry, Physical
Sebastian J. Weishaeupl, Yang Cui, Simon N. Deger, Hamad Syed, Aleksandr Ovsianikov, Juergen Hauer, Alexander Poethig, Roland A. Fischer
Summary: Multiphoton absorption (MPA) is of great interest in modern materials research, and metal-organic frameworks and coordination polymers (CPs) are potential materials to overcome the limitations of commonly used chromophore molecules. This article reports the synthesis and characterization of three new highly MPA-active CPs, and demonstrates their large two-photon absorption cross-sections, which are among the highest reported for CPs to date.
CHEMISTRY OF MATERIALS
(2022)
Article
Chemistry, Physical
J. A. Nothling, Tomas Mancal, T. P. J. Kruger
Summary: The accuracy of approximate methods for calculating linear optical spectra is studied. The Full Cumulant Expansion (FCE) method is found to be the most accurate for all spectra calculations. The coherent time-dependent Redfield (ctR) method performs well for moderately coupled pigments but may differ significantly from exact spectra when strong interpigment coupling is present. The Redfield and modified Redfield methods generally perform worse than ctR, especially for strong interpigment coupling or small excitonic energy gap. The accuracy of approximate spectra is not affected by resonance with intramolecular modes for typical system-bath coupling and disorder values found in plant light-harvesting complexes.
JOURNAL OF CHEMICAL PHYSICS
(2022)
Article
Chemistry, Multidisciplinary
Daniel P. Schwinger, Martin T. Peschel, Thomas Rigotti, Piotr Kabacinski, Thomas Knoll, Erling Thyrhaug, Giulio Cerullo, Juergen Hauer, Regina de Vivie-Riedle, Thorsten Bach
Summary: In this work, Lewis acids were used as photocatalysts to activate carbonyl compounds. By UV photoexcitation, a Lewis acid-base complex can undergo homolytic cleavage of a covalent bond in the Lewis acid, expanding the scope of its mode of action. The BCl3-mediated hydroalkylation reaction of aromatic aldehydes was successfully carried out using this photolytic mechanism.
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY
(2022)
Article
Chemistry, Physical
Vladislav Slama, Frank Mueh, Thomas Renger, Torng Mancal
Summary: We proposed an extension of the QM/MM approach to investigate the excited state properties of embedded systems under environmental effects. Our model, based on perturbation theory, allows a more general description of the environment, considering frequency-dependent atomic polarizabilities. By comparing with full quantum chemistry calculations and standard polarizable QM/MM approach, we demonstrated the importance of frequency dependence for accurately treating the effects of the environment on transition energy shifts and interaction energies.
JOURNAL OF PHYSICAL CHEMISTRY C
(2023)
Article
Chemistry, Multidisciplinary
Sebastian Reiter, Ferdinand L. Kiss, Juergen Hauer, Regina de Vivie-Riedle
Summary: In this study, site energies of all 96 chlorophylls in a membrane-embedded model of PSI were calculated, revealing energy traps and barriers that affect energy transfer. It was found that at physiological temperatures, thermal fluctuations may lead to transient formation of energy transfer pathways. These findings provide a theoretical and experimental basis for further studies on the highly efficient energy transfer mechanisms in PSI.
Article
Chemistry, Physical
Ajeet Kumar, Pavel Malevich, Lars Mewes, Shangze Wu, Joshua P. Barham, Juergen Hauer
Summary: We introduce a new transient absorption experiment based on a hollow-core fiber (HCF) that surpasses the capabilities of traditional titanium:sapphire setups. Our setup provides pump pulses centered at 425 nm and smooth probing spectra from 320 to 900 nm. By studying the ultrafast relaxation dynamics of a radical cationic photocatalyst, we demonstrate its pre-association with an arene substrate, which was previously undetectable using steady-state spectroscopic techniques. This detected preassembly validates the involvement of radical ionic photocatalysts in single electron transfer reactions, resolving recent controversy.
JOURNAL OF CHEMICAL PHYSICS
(2023)
Article
Chemistry, Multidisciplinary
Christoph Wallach, Yasmin Selic, Felix S. Geitner, Ajeet Kumar, Erling Thyrhaug, Jurgen Hauer, Antti J. Karttunen, Thomas F. Faessler
Summary: This study presents the synthesis of a highly red [Ge-9] cluster linked to an extended pi-electron system, showing intense optical properties. The compound has a close relation to fullerenes in terms of electronic structure and optical properties, which is significant for the design of photo-active cluster compounds.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2023)
Article
Chemistry, Physical
Jianmin Yang, Maxim F. Gelin, Lipeng Chen, Frantisek Sanda, Erling Thyrhaug, Juergen Hauer
Summary: We propose a novel UV/Vis femtosecond spectroscopic technique called two-dimensional fluorescence-excitation (2D-FLEX) spectroscopy, which combines spectral resolution during the excitation process with exclusive monitoring of the excited-state system dynamics at high time and frequency resolution. We discuss the experimental feasibility and realizability of 2D-FLEX, develop the necessary theoretical framework, and demonstrate the high information content of this technique through simulations. We show that 2D-FLEX is a highly efficient instrument for real-time monitoring of photophysical processes in polyatomic molecules and molecular aggregates.
JOURNAL OF CHEMICAL PHYSICS
(2023)
Article
Chemistry, Physical
Sebastian Reiter, Lena Baeuml, Juergen Hauer, Regina de Vivie-Riedle
Summary: This paper investigates the ultrafast relaxation process within the Q-bands of chlorophyll using non-adiabatic wave packet dynamics. By identifying the vibrational degrees of freedom that contribute to non-adiabatic coupling, reduced-dimensional coordinate spaces are constructed and wave packet dynamics are studied on the XMS-CASPT2 potential energy surfaces. The results show that the Q(x) and Q(y) potential energy surfaces do not cross in an energetically accessible region, and the population transfer is facilitated by non-adiabatic coupling. This suggests that chlorophyll a's Q-band system should be viewed as a strongly coupled system capable of efficient energy transfer between x and y-polarized electronic states in photosynthetic light-harvesting systems.
PHYSICAL CHEMISTRY CHEMICAL PHYSICS
(2022)
Review
Materials Science, Multidisciplinary
Sebastian J. Weishaeupl, David C. Mayer, Yang Cui, Pushpendra Kumar, Harald Oberhofer, Roland A. Fischer, Jurgen Hauer, Alexander Poethig
Summary: This review presents recent advances in metal-organic frameworks (MOFs) and coordination polymers (CPs) regarding their response properties to multiphoton absorption (MPA). It covers the theoretical background of MPA absorbing linker molecules, the effect of excitonic coupling within a rigid framework assembly, and compares different scanning and non-scanning measurement techniques for two-photon absorption (TPA) spectroscopy. Additionally, it comprehensively presents the latest progress of linker-based MPA materials and their relationship with framework structure and MPA cross section.
JOURNAL OF MATERIALS CHEMISTRY C
(2022)