Article
Chemistry, Physical
Rachel K. Swedin, Andrew T. Healy, Jacob W. Schaffner, Ilya A. Kuzmin, Yuriy V. Zatsikha, Victor N. Nemykin, David A. Blank
Summary: The excited state dynamics in two fully characterized pyridoneBODIPY-fullerene complexes were investigated. Efficient energy transfer and internal conversion were observed in the presence of the fullerene, allowing the excited state energy to be transferred back to the pyridoneBODIPY chromophore. The attachment chemistry of the fullerene affected the triplet-triplet energy transfer and the relaxation rate of the final triplet state.
JOURNAL OF PHYSICAL CHEMISTRY LETTERS
(2022)
Article
Chemistry, Multidisciplinary
Hui Liang, Manlin Lu, Zafar Mahmood, Zheng Li, Zeduan Chen, Guowei Chen, Ming-De Li, Yanping Huo, Shaomin Ji
Summary: Designing efficient heavy atom-free triplet photosensitizers based on through bond charge transfer features is a challenge. In this study, efficient triplet photosensitizers with through space intramolecular charge transfer process were proposed. The photosensitizers exhibited efficient intersystem crossing and long-lived triplet excited states compared to conventional donor-acceptor systems, demonstrating the superiority of this approach.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2023)
Article
Chemistry, Multidisciplinary
Maximilian Maylaender, Theresia Quintes, Michael Franz, Xavier Allonas, Andreas Vargas Jentzsch, Sabine Richert
Summary: Photogenerated organic triplet-doublet systems have attracted increasing attention in molecular spintronics due to their versatility and suitability for technological applications. The formation of chromophore triplet states and subsequent quartet states depends on the enhanced intersystem crossing (EISC) and exchange interaction J(TR). Factors influencing the EISC process and quartet state formation were studied using a series of BODIPY-nitroxide dyads, suggesting that dipolar interactions mediate triplet formation and the absolute magnitude of J(TR) affects quartet state formation.
Article
Chemistry, Multidisciplinary
Jiri Dolezel, Anna Poryvai, Tomas Slanina, Josef Filgas, Petr Slavicek
Summary: This study developed a combined experimental and theoretical approach to accurately describe intersystem crossing (ISC) in BODIPY dyes using spin-vibronic coupling. The heavy-atom effect of iodine atoms in BODIPY derivatives was found to be site specific, and this site-specific ISC was explained by El-Sayed rules.
CHEMISTRY-A EUROPEAN JOURNAL
(2023)
Article
Chemistry, Applied
Liting Tang, Dan Lin, Noreen Rehmat, Manlin Lu, Zafar Mahmood, Hui Liang, Ming-de Li, Zujin Zhao, Yanping Huo, Shaomin Ji
Summary: In this study, a series of n-conjugated selenophene-substituted boron dipyrromethene dyes were synthesized and their excited state properties were investigated. It was found that although these dyes have nearly identical molecular profiles, their photophysical properties and excited state dynamics are significantly different. These dyes showed excellent J-aggregation capabilities and NIR emission, and also exhibited potential in triplet fusion upconversion.
Article
Chemistry, Multidisciplinary
Marc Alias-Rodriguez, Coen de Graaf, Miquel Huix-Rotllant
Summary: Research shows that xanthone undergoes rapid transitions in a very short period of time, with a sequential mechanism of internal conversion and intersystem crossing processes.
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY
(2021)
Article
Chemistry, Multidisciplinary
Meng-Jia Sun, Olga Anhalt, Menyhart B. Sarosi, Matthias Stolte, Frank Wuerthner
Summary: This study reports the formation of a hybrid cocrystal using Pt(acac)2 and NDIs, which exhibits high photoluminescence quantum yield and long lifetime, benefiting from the noncovalent electronic and spin-orbital coupling between the constituents.
ADVANCED MATERIALS
(2022)
Article
Chemistry, Physical
Yu Dong, Prashant Kumar, Partha Maity, Ivan Kurganskii, Shujing Li, Ayhan Elmali, Jianzhang Zhao, Daniel Escudero, Huijian Wu, Ahmet Karatay, Omar F. Mohammed, Matvey Fedin
Summary: The photophysical properties of a heavy atom-free BODIPY derivative with a twisted pi-conjugated framework were investigated, showing efficient intersystem crossing and a long-lived triplet state. The electron spin selectivity of the twisted structure was found to differ from that of the spin orbital coupling effect, with potential applications in photodynamic therapy demonstrated through efficient singlet oxygen photosensitizing.
PHYSICAL CHEMISTRY CHEMICAL PHYSICS
(2021)
Article
Chemistry, Physical
Alexandra N. N. Stuart, Patrick C. C. Tapping, Tak W. W. Kee, David M. M. Huang
Summary: Singlet fission (SF), the process of generating two triplet excitons from one singlet exciton, has the potential to improve the efficiency of single-junction solar cells. Accurate identification and quantification of SF and differentiation from intersystem crossing (ISC) are crucial. In this study, the upper bound of ISC rate in two commonly studied SF chromophores, TIPS-pentacene and TIPS-tetracene, is quantified using transient absorption spectroscopy. The results show that previous misidentification of SF as ISC and vice versa has occurred, emphasizing the importance of accurate quantification of ISC.
JOURNAL OF CHEMICAL PHYSICS
(2022)
Article
Chemistry, Physical
Wen Tian, Andrey A. Sukhanov, Laura Bussotti, Junhong Pang, Jianzhang Zhao, Violeta K. Voronkova, Mariangela Di Donato, Ming -De Li
Summary: Naphthalimide homo- and hetero-dimers with orthogonal geometry were prepared to study photo-induced symmetry-breaking charge transfer and charge recombination-induced intersystem crossing. The hetero-dimer showed significant charge transfer and the most efficient charge recombination-induced intersystem crossing. The absence of symmetry-breaking charge transfer in the homo-dimer was attributed to its high oxidation potential and low reduction potential.
JOURNAL OF PHYSICAL CHEMISTRY B
(2022)
Article
Chemistry, Physical
Meng Lv, Xueli Wang, Danhong Wang, Xiuhua Li, Yangyi Liu, Haifeng Pan, Sanjun Zhang, Jianhua Xu, Jinquan Chen
Summary: When organic electron donor and acceptor chromophores are linked together, electron transfer state can occur. In compact organic chromophores, the most common decay pathway for the charge transfer state is charge recombination, leading to either longer wavelength fluorescence emission or non-radiative dissipation of excited state energy.
PHYSICAL CHEMISTRY CHEMICAL PHYSICS
(2021)
Article
Optics
Hui Liang, Mahmood Zafar, Junhong Pang, Zeduan Chen, Ming-De Li, Shaomin Ji, Yanping Huo, Haoli Zhang
Summary: Donor-acceptor dyads with efficient charge recombination induced intersystem crossing capability were studied, revealing that solvent polarity affects the choice of ISC channel and the triplet yield.
JOURNAL OF LUMINESCENCE
(2021)
Article
Physics, Applied
Yongxia Ren, Yoshimasa Wada, Katsuaki Suzuki, Yu Kusakabe, Jan Geldsetzer, Hironori Kaji
Summary: The highly efficient blue TADF emitter MCz-TXO exhibits close energy level matching and a large k (RISC) value due to the heavy atom effect of sulfur in its molecular structure. The organic light-emitting diodes based on MCz-TXO show blue emission with a high external quantum efficiency.
APPLIED PHYSICS EXPRESS
(2021)
Article
Chemistry, Multidisciplinary
Arpita Mukherjee, Johannes Feist, Karl Borjesson
Summary: Strong interactions between excitons and photons lead to the formation of exciton-polaritons. The relaxation of polaritonic states enables a new kind of energy transfer event. The rate of intersystem crossing from the polariton to the triplet states depends on the energy alignment of the excited polaritonic states. In the strong coupling regime, the rate of intersystem crossing can be substantially enhanced, which has potential applications in molecular photophysics/chemistry and organic electronics.
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY
(2023)
Article
Chemistry, Multidisciplinary
Arpita Mukherjee, Johannes Feist, Karl Borjesson
Summary: Strong interactions between excitons and photons lead to the formation of exciton-polaritons, which possess completely different properties compared to their constituents. The rate of intersystem crossing from the polariton to the triplet states depends on the energy alignment of the excited polaritonic states. In the strong coupling regime, the rate of intersystem crossing can be substantially enhanced to the point where it approaches the rate of the radiative decay of the polariton.
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY
(2023)
Review
Chemistry, Multidisciplinary
Xi Chen, Xue Zhang, Xiao Xiao, Zhijia Wang, Jianzhang Zhao
Summary: Charge transfer is crucial in molecular electron donor-acceptor systems for artificial photosynthesis, photocatalysis, photovoltaics, and fundamental photochemistry. We summarized recent developments in the study of charge transfer and discussed its application in thermally activated delayed fluorescence (TADF) emitters.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2023)
Article
Chemistry, Multidisciplinary
Haiqing Wang, Andrey A. Sukhanov, Alessandro Iagatti, Laura Bussotti, Xiaoyu Zhao, Jianzhang Zhao, Violeta K. Voronkova, Mariangela Di Donato
Summary: To obtain long-lived charge separated (CS) states in electron donor-acceptor dyads, a series of AQ-PTZ dyads with adamantane as the linker were synthesized. UV-vis absorption spectra showed no electronic interaction between AQ and PTZ units at the ground state, but CT emission bands were observed. Nanosecond transient absorption showed the population of (3)AQ and formation of (CS)-C-3 states in different solvents. Similarly, femtosecond transient absorption spectra demonstrated the formation of (3)AQ and (CS)-C-3 states with varying lifetimes. Time-resolved electron paramagnetic resonance (TREPR) spectra revealed the presence of radical ion pairs in AQ-PTZ and AQ-PTZ-M, while only (3)AQ state was observed in dyads with the oxidized PTZ unit.
CHEMISTRY-A EUROPEAN JOURNAL
(2023)
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, Inorganic & Nuclear
Kaiyue Ye, Peili Wang, Minjie Li, Yuqi Hou, Jianzhang Zhao, Yan Wan
Summary: We synthesized a N boolean AND N Pt(II) bisacetylide complex with strong absorption of visible light (molar absorption coefficients epsilon=6.7x10(4) M-1 cm(-1) at 570 nm) and high singlet oxygen quantum yield (phi(Delta) = 78% ). The complex exhibits an intersystem crossing (ISC) of 81.8 ps and a triplet excited state lifetime of 7.6 μs. Density functional theory (DFT) calculations revealed that the S-1 and T-1 states are mainly localized on the perylenemonoimide (PMI) ligands, with noticeable involvement of the Pt(II) center. The complex acts as a triplet photosensitizer to generate delayed fluorescence with perylenebisimide (PBI) via triplet-triplet energy transfer (TTET) and triplet-triplet annihilation (TTA), resulting in a delayed fluorescence lifetime of 52.5 μs under the experimental conditions.
EUROPEAN JOURNAL OF INORGANIC CHEMISTRY
(2023)
Editorial Material
Chemistry, Inorganic & Nuclear
Xinwen Guo, Jianzhang Zhao
EUROPEAN JOURNAL OF INORGANIC CHEMISTRY
(2023)
Article
Chemistry, Physical
Muhammad Imran, Huaiman Cao, Jianzhang Zhao, Gloria Mazzone
Summary: In this study, the photophysical properties of a heavy atom-free organic chromophore with near-IR absorption and intersystem crossing ability were investigated. The compound consisting of naphthalenediimide and pentacyclic1,8-diazabicyclo[5.4.0]-undec-7-ene showed strong charge-transfer absorption in the near-IR region, but had poor intersystem crossing efficiency despite its twisted molecular structure.
JOURNAL OF PHYSICAL CHEMISTRY A
(2023)
Article
Chemistry, Physical
Zhibin Yu, Andrey A. Sukhanov, Xiao Xiao, Alessandro Iagatti, Sandra Doria, Valeria Butera, Jianzhang Zhao, Violeta K. Voronkova, Mariangela Di Donato, Gloria Mazzone
Summary: A series of PTZ-AQ dyads with different linkers were prepared to study the relationship between molecular structures and charge transfer and intersystem crossing. The results showed that conformation restriction on the linker led to the observation of thermally activated delayed fluorescence. The presence of charge-separated and locally excited states with similar energy was found to be essential for the occurrence of TADF.
JOURNAL OF PHYSICAL CHEMISTRY B
(2023)
Review
Biochemistry & Molecular Biology
Xiao Xiao, Xiaoyu Zhao, Xi Chen, Jianzhang Zhao
Summary: Photodynamic therapy (PDT) is a promising treatment for cancer due to its low toxicity, non-drug-resistant nature, and targeting capability. However, the current PDT reagents face challenges in their synthesis, purification, and derivatization. This article summarizes recent developments in heavy atom-free triplet photosensitizers (PSs) from a photophysical perspective, including methods such as radical-enhanced intersystem crossing (REISC), twisted pi-conjugation system-induced ISC, and the use of fullerene C-60 as an electron spin converter. The potential application of these compounds in PDT is also briefly discussed.
Article
Chemistry, Organic
Liyuan Cao, Xi Liu, Xue Zhang, Jianzhang Zhao, Fabiao Yu, Yan Wan
Summary: A series of electron donor-acceptor dyads were prepared to study the TADF properties. The photophysical properties of the dyads were tuned by changing the electron-donating and the electron-withdrawing capability of the PTZ and NI moieties. TADF was observed for the dyads containing the native PTZ unit, and the prompt and delayed fluorescence lifetimes changed with different aryl substituents on the imide part.
BEILSTEIN JOURNAL OF ORGANIC CHEMISTRY
(2023)
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
Xiao Xiao, Yuxin Yan, Andrey A. Sukhanov, Sandra Doria, Alessandro Iagatti, Laura Bussotti, Jianzhang Zhao, Mariangela Di Donato, Violeta K. Voronkova
Summary: In this study, a series of dyads based on naphthalimide (NI) and phenothiazine (PTZ) were prepared to prolong the charge separation (CS) state lifetime by exploiting the electron spin control effect. The electron coupling magnitude was tuned by conformational restriction exerted by the methyl groups on the phenyl linker. Unlike previously reported analogues, these dyads exhibited a significant CS emission band and thermally activated delayed fluorescence (TADF). Nanosecond transient absorption spectroscopy revealed different states in different solvents, confirming the spin-vibronic coupling theoretical model. Femtosecond transient absorption spectroscopy indicated charge separation in both nonpolar and polar solvents, with varying time constants. Time-resolved electron paramagnetic resonance (TREPR) spectra supported the existence of (NI)-N-3* and CS states in the dyads upon photoexcitation. The electron spin-spin dipole interaction magnitude suggested the contribution of electron spin control to the long CS-state lifetime.
JOURNAL OF PHYSICAL CHEMISTRY B
(2023)
Article
Biochemistry & Molecular Biology
Wenhui Zhu, Yanran Wu, Yiyan Zhang, Andrey A. Sukhanov, Yuqi Chu, Xue Zhang, Jianzhang Zhao, Violeta K. Voronkova
Summary: We synthesized a rhodamine-TEMPO chromophore-radical dyad (RB-TEMPO) to investigate the radical enhanced intersystem crossing (REISC). The covalent connection between the visible light-harvesting chromophore rhodamine and the nitroxide radical TEMPO was established through a C-N bond. The fluorescence of the rhodamine moiety is effectively quenched in RB-TEMPO, attributed to the intramolecular electron spin-spin interaction between the nitroxide radical and the photoexcited rhodamine chromophore. Nanosecond transient absorption spectra confirmed the occurrence of REISC in RB-TEMPO, with the detection of the rhodamine chromophore triplet excited state. The application of RB-TEMPO as a photoinitiator for the photopolymerization of PETA was explored.
INTERNATIONAL JOURNAL OF MOLECULAR SCIENCES
(2023)
Article
Chemistry, Multidisciplinary
Xue Zhang, Andrey A. Sukhanov, Xi Liu, Maria Taddei, Jianzhang Zhao, Anthony Harriman, Violeta K. Voronkova, Yan Wan, Bernhard Dick, Mariangela Di Donato
Summary: To investigate the relationship between twisted pi-conjugation framework and efficacy of intersystem crossing (ISC), a study on a distorted N,N,O,O-boron-chelated Bodipy derivative was conducted. Surprisingly, this chromophore exhibited high fluorescence and inefficient ISC. It was attributed to a large singlet-triplet energy gap. The introduction of an anthryl unit increased ISC yield, possibly due to the presence of a T2 state with similar energy to the S1 state.
Article
Chemistry, Multidisciplinary
Jieyu Tang, Xi Liu, Xue Zhang, Jianzhang Zhao, Yan Wan
Summary: In this study, the effect of the relative energy order of charge transfer (CT) state and locally excited (3LE) state on the photophysical properties of electron donor-acceptor dyads, specifically their thermally activated delayed fluorescence (TADF) property, was investigated. It was found that the presence of the 3LE state sharing a similar energy with the CT states is critical for the occurrence of TADF.
NEW JOURNAL OF CHEMISTRY
(2023)
Article
Chemistry, Physical
Xiao Xiao, Tong Mu, Andrey A. Sukhanov, Yihang Zhou, Peiran Yu, Fabiao Yu, Ayhan Elmali, Jianzhang Zhao, Ahmet Karatay, Violeta K. Voronkova
Summary: A long-lived charge transfer state was obtained in a compact rhodamine-thionated naphthalimide electron donor-acceptor dyad through electron spin control, and the solvent polarity affected its energy level and lifetime.
PHYSICAL CHEMISTRY CHEMICAL PHYSICS
(2023)
