Article
Chemistry, Physical
Zhen Chen, Daoyuan Zheng, Ruiling Zhang, Haiwen Wei, Xin Mao, Feng Liu, Keli Han
Summary: In this study, a novel electron donor-acceptor binary system was designed and investigated for its outstanding organic long-persistent luminescence (OLPL) performance. The binary system exhibited effective OLPL emission that lasted for more than 100 s after 1 min of ultraviolet light irradiation at room temperature. It also showed temperature-sensitive thermally activated delayed fluorescence emission and the formation of a charge-separated state.
Article
Chemistry, Multidisciplinary
Paola Zimmermann Crocomo, Takahito Kaihara, Soki Kawaguchi, Patrycja Stachelek, Satoshi Minakata, Piotr de Silva, Przemyslaw Data, Youhei Takeda
Summary: Novel electron donor-acceptor-donor compounds were designed and synthesized with dibenzo[a,j]phenazine as the central acceptor core and two 7-membered diarylamines as the donors. Slight structural modification led to unique photophysical behavior, including dual emission from room-temperature phosphorescence and triplet-triplet annihilation, as revealed by physicochemical analysis and quantum chemical calculations. Electrochemical analysis suggested sigma-dimer formation and electrochemical polymerization on the electrode.
CHEMISTRY-A EUROPEAN JOURNAL
(2021)
Article
Chemistry, Multidisciplinary
Siyang Feng, Liangxuan Wang, Begona Milian-Medina, Alfred J. Meixner, Min Sang Kwon, Soo Young Park, Reinhold Wannemacher, Johannes Gierschner
Summary: The complex photokinetics of donor-acceptor-donor triads with varying flexible spacer lengths were investigated. Both liquid and solid solutions, as well as crystals, were studied using fluorescence spectroscopy and computational analysis. The study revealed dynamic charge-transfer state formation in liquid solutions and fluorescent CT static complexes in solid solutions. It was also found that external stimuli could induce on/off fluorescence switching or change the emission color in films of the triads.
ADVANCED MATERIALS
(2023)
Article
Chemistry, Physical
Thomas P. P. Fay, David T. T. Limmer
Summary: In this paper, a physically motivated framework is proposed to describe spin-selective recombination processes in chiral systems. Spin-selective reaction operators for recombination reactions of donor-bridge-acceptor molecules are derived based on chirality and spin-orbit coupling. It is found that spin polarization selectivity only arises in hopping-mediated electron transfer. The framework presented here can be extended to describe spin-selective recombination processes in more complex systems.
JOURNAL OF CHEMICAL PHYSICS
(2023)
Article
Optics
Hongke Zhou, Xiucun Feng, Zixuan Guo, Zengxin Zhuang, Shengjie Fu, Xingliang Liu, Defang Xu
Summary: In this study, two bisarylic methanone derivatives with phenoxazine or phenothiazine as electron donors and carbonyl group as electron acceptor were investigated. These molecules exhibited obvious intramolecular charge transfer (ICT) effects and effective solid-state emissions, as well as high-contrast mechanofluorochromic (MFC) properties. The fluorescence colors of the powders changed with external mechanical stimulation and red shifts were observed in the photoluminescence (PL) spectra. The MFC behavior was found to be reversible and attributed to crystalline-to-amorphous transitions in the material.
JOURNAL OF LUMINESCENCE
(2022)
Article
Chemistry, Physical
Ziran Liu, Zhixing Liu, Rui Wang, Zhi-Guo Zhang, Jide Wang, Chunfeng Zhang
Summary: In this study, the effect of polar environment on excited state dynamics in OPV molecules was investigated. The findings reveal that the excited states in molecules with strong electron push-pulling effects are stabilized and undergo faster intersystem crossing processes in polar solvents. These results suggest that manipulating the polar environment and electron push-pulling effect can improve device performance.
JOURNAL OF PHYSICAL CHEMISTRY LETTERS
(2022)
Article
Chemistry, Physical
Dongwei Sun, Yudong Wen, Jia-Min Jin, Lu Zhou, Qiang Liu, Bo Liu, Xiaohui Wu, Nian Tang, Yongyan Zhou, Shaomin Ji, Yanping Huo
Summary: A new phenanthroimidazole-based emitter with an electron-rich phenoxazine (PIPXZ) has been developed, which possesses a locally twisted donor-pi-acceptor conformation due to the introduction of phenoxazine. The unique molecular structure of PIPXZ leads to an intense charge-transfer excited state and good fluorescence efficiency. The emitter has been systematically investigated and successfully applied in an organic light-emitting device, demonstrating a high external quantum efficiency.
JOURNAL OF MOLECULAR STRUCTURE
(2022)
Article
Materials Science, Multidisciplinary
Yanan Zhu, Sergi Vela, Hong Meng, Clemence Corminboeuf, Maria Fumanal
Summary: Hot exciton materials have the potential to improve the efficiency of OLEDs, and D-A-D molecular systems show promise in enhancing the hRISC process. However, finding appropriate D-A-D combinations is still challenging. This study exposes the limitations of current design rules and proposes high-throughput screening as the optimal approach to find suitable candidates.
ADVANCED OPTICAL MATERIALS
(2022)
Article
Chemistry, Multidisciplinary
Qidi Huang, Jianai Chen, Shuanma Yan, Xiongchao Shao, Yujie Dong, Junlei Liu, Weijun Li, Cheng Zhang
Summary: A new donor-acceptor-donor monomer CDB-EDOT with a torsion angle of 39 degrees is designed and synthesized, leading to a conjugated polymer pCDBEDOT with excellent capacitive properties and reversible electrochromic capabilities. The polymer shows high specific capacitance and stability, making it a promising material for energy-sustainable intelligent devices.
ACS SUSTAINABLE CHEMISTRY & ENGINEERING
(2021)
Article
Materials Science, Multidisciplinary
Jonas Hoffmann, Denis Jacquemin, Muriel Hissler, Anne Staubitz
Summary: The study investigates the electronic properties of boron/nitrogen substituted polyaromatic hydrocarbons by tuning their properties through substitution at the B and/or N atoms. BN-PAH analogues showed enhanced absorption/emission properties and luminescence quantum yields compared to all-carbon analogues. The unique donor-acceptor-donor motif based on BN units exhibited interesting electronic behavior and solvent-dependent luminescence properties.
JOURNAL OF MATERIALS CHEMISTRY C
(2021)
Article
Chemistry, Physical
Mushraf Hussain, Ahmed M. El-Zohry, Yuqi Hou, Antonio Toffoletti, Jianzhang Zhao, Antonio Barbon, Omar F. Mohammed
Summary: Electron donor-acceptor triads based on carbazole and naphthalenediimide were prepared to study spin-orbit charge-transfer intersystem crossing. By varying the molecular conformation and electron-donating ability of the carbazole moieties, different charge-transfer absorption bands were observed, with thermal activated delayed fluorescence observed in specific configurations.
JOURNAL OF PHYSICAL CHEMISTRY B
(2021)
Article
Multidisciplinary Sciences
Hongbing Cai, Abdullah Rasmita, Qinghai Tan, Jia-Min Lai, Ruihua He, Xiangbin Cai, Yan Zhao, Disheng Chen, Naizhou Wang, Zhao Mu, Zumeng Huang, Zhaowei Zhang, John J. H. Eng, Yuanda Liu, Yongzhi She, Nan Pan, Yansong Miao, Xiaoping Wang, Xiaogang Liu, Jun Zhang, Weibo Gao
Summary: This study reveals the physical mechanism of the formation of localized interlayer excitons (LIXs) in two-dimensional moire superlattices, and demonstrates that the donor-acceptor pair (DAP) mechanism is one of the origins. This finding provides new insights for engineering interlayer exciton properties in moire superlattices.
NATURE COMMUNICATIONS
(2023)
Article
Chemistry, Multidisciplinary
Alexander Aster, Christopher Rumble, Anna-Bea Bornhof, Hsin-Hua Huang, Naomi Sakai, Tomas Solomek, Stefan Matile, Eric Vauthey
Summary: The study focuses on the charge-transfer dynamics of electron donor-acceptor dyads based on NDI chromophores, demonstrating long-lived charge separation in the triplet state can be achieved by controlling the mutual orientation of the donor-acceptor sub-units.
Article
Chemistry, Multidisciplinary
Prakalp Gautam, Iram Shahnawaz, Iram Siddiqui, Dovydas Blazevicius, Gintare Krucaite, Daiva Tavgeniene, Jwo-Huei Jou, Saulius Grigalevicius
Summary: Organic light-emitting diodes (OLEDs) have made significant technological advancements in various industries and are considered a mainstream technology. This study introduces new bicarbazole-benzophenone-based twisted donor-acceptor-donor (D-A-D) derivatives as bi-functional materials for OLEDs. These materials exhibit excellent properties such as high decomposition and glass transition temperatures, high photoluminescence quantum yield, wide bandgap, and short decay time. They are utilized as blue emitters and host materials for deep-blue and green OLEDs, showing promising performance in terms of efficiency and quantum yield. These easily synthesized, economical materials have the potential to be used in cost-effective and high-performance OLED applications, particularly in displays.
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
Govind Lal Sidhardh, Adithi Ajith, Ebin Sebastian, Mahesh Hariharan, Anil Shaji
Summary: The purpose of this study is to explore the role of a structured immediate phonon environment in determining the exciton dynamics and its potential as an optimal design element. Through the case study of dithia-anthracenophane, we demonstrate that the observed coherent exciton dynamics can only be reproduced by considering the actual structure of the phonon environment. Strong vibronic coupling to high-frequency modes is responsible for the slow dephasing of quantum coherence, while vibronic quenching is the source of long oscillation periods in population transfer. This study highlights the crucial role of the structure of the immediate phonon environment in determining the exciton dynamics and proposes some design principles for maintaining long-lived coherence in molecular systems.
JOURNAL OF PHYSICAL CHEMISTRY A
(2022)
Article
Chemistry, Multidisciplinary
Ebin Sebastian, Mahesh Hariharan
Summary: We have discovered a long-lived charge-separated state in a chromophoric pair (DC-PDI2) that combines the advantages of symmetry-breaking charge-separation (SB-CS) and Marcus-inverted-region dependence. The DC-PDI2 exhibits ultrafast SB-CS evolution and slow charge recombination kinetics. In contrast, a benzyloxy (BnO)-substituted DC-BPDI2 shows accelerated charge recombination kinetics due to a decreased driving force. This study demonstrates the importance of molecular engineering in tuning the energetics and kinetics of SB-CS materials for future optoelectronic devices.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2023)
Article
Chemistry, Multidisciplinary
P. E. Swathi Krishna, Hruidya C. Babu, Nanditha G. Nair, Mahesh Hariharan
Summary: Non-covalent halogen bonding interactions play a crucial role in crystal engineering for the construction of unique supramolecular synthons. In this study, we present the first crystal evidence of boat and chair shaped cyclic hexahalogen synthons in the crystal structures of PBX and HBX. The nature and stability of these interactions were analyzed using quantum-chemical calculations, confirming the stability of Br...Br interactions and their contribution to the formation of boat and chair shaped synthons. Additionally, the packing forces influence the crystallization of PBX and HBX in different space groups, resulting in a chiral helix-like orientation for PBX and a centrosymmetric structure for HBX. The extended furcations in the pentabromo derivative form a molecular framework consisting of macrocycles through halogen bonding.
CHEMISTRY-AN ASIAN JOURNAL
(2023)
Article
Chemistry, Multidisciplinary
Sehee Jeong, Natercia Barbosa, Akash Tiwari, Emma K. Holland, Ling-Yi Huang, Vinayak Bhat, Yongfan Yang, Yuze Zhang, St. John Whittaker, Min-Woo Kim, Aida Alaei, Pallavi Sundaram, Rochelle Spencer, Johanna Brazard, Dilhan M. Kalyon, Chad Risko, John E. Anthony, Takuji B. M. Adachi, Alexander G. Shtukenberg, Bart Kahr, Stephanie S. Lee
Summary: The optoelectronic properties of anisotropic crystals are direction-dependent, requiring control over the orientation of molecular organic semiconductor crystals for optimal performance in optoelectronic devices. This study presents a generalizable strategy to introduce periodic variations in the out-of-plane orientations of 5,11-bis(triisopropylsilylethynyl)anthradithiophene (TIPS ADT) crystals. The twisted TIPS ADT crystals exhibit band-dependent light absorption, photoluminescence, and Raman scattering, and also show orientation-dependent enhancement in charge injection and extraction compared to straight crystals.
ADVANCED FUNCTIONAL MATERIALS
(2023)
Review
Chemistry, Multidisciplinary
Vinayak Bhat, Connor P. Callaway, Chad Risko
Summary: Computational methods can complement experimental observations and provide deep physicochemical insights into the structure-processing-property relationships of organic semiconductors. This Review traces the evolution of these methods in the field of organic semiconductors, highlighting their limitations and the creation of sophisticated frameworks to overcome these limitations. Through various examples, this Review demonstrates the applications of computational methods in accelerating the deployment of organic semiconductors in various technologies.
Article
Chemistry, Physical
Athira T. John, Deepu George, Mahesh Hariharan
Summary: A variety of novel pi-conjugated materials have received significant attention in next-generation electronic devices due to their chemical programmability, mechanical flexibility, and lightweight properties. The manipulation of intermolecular interactions arising from pi-conjugated molecules plays a critical role in crystal packing and the design of molecular organic semiconductors. Understanding the dynamic origin of charge transport in organic crystals from a molecular perspective has been a challenging task. In this Perspective, effective methods for regulating the charge transport characteristics of functional organic materials in their crystalline phase are reviewed, with a focus on the theoretical design of advanced materials with desirable charge transport properties by our research group.
JOURNAL OF PHYSICAL CHEMISTRY C
(2023)
Article
Electrochemistry
Shruti Suriyakumar, Aniruddha Mazumder, Patoju Sai Dilip, Mahesh Hariharan, Manikoth M. Shaijumon
Summary: Establishing a sustainable energy solution is crucial for achieving a greener community. Due to limited cobalt resources, research is being conducted to explore alternative avenues for electric vehicles powered by lithium-ion batteries. This study focuses on utilizing organic electrodes, particularly polyimides, as cathode candidates to develop green and sustainable batteries. The authors demonstrate a dual modification strategy to tailor the reduction potential and enhance the cycling stability of a perylene polyimide-based organic cathode. The results show that the chlorine functionality and thiourea linker group play significant roles in improving electrochemical performance.
BATTERIES & SUPERCAPS
(2023)
Article
Chemistry, Physical
Marko R. Ivancevic, Melissa L. Ball, Vinayak Bhat, Jesse A. Wisch, Sean R. Parkin, Chad Risko, Barry P. Rand, Yueh-Lin Loo
Summary: Contorted polycyclic aromatic molecules have been studied as host molecules for fullerenes, but their association is generally weak. In this study, researchers designed and synthesized π-extended buckybowls with larger surface areas. These buckybowls can form stronger complexes with fullerenes, especially those with butoxy side chains, due to their larger dipole moments and preferred 1:2 stoichiometry.
CHEMISTRY OF MATERIALS
(2023)
Article
Chemistry, Physical
Philip Daniel Maret, Devika Sasikumar, Ebin Sebastian, Mahesh Hariharan
Summary: This study aims to explore the excited-state dynamics of chiral organic bichromophores and provide guidance for the development of efficient chiral organic semiconductors and their applications in charge transport materials.
JOURNAL OF PHYSICAL CHEMISTRY LETTERS
(2023)
Review
Chemistry, Multidisciplinary
M. P. Lijina, Alfy Benny, Ebin Sebastian, Mahesh Hariharan
Summary: The study of supramolecular assemblies of organic chromophores and the development of design strategies have attracted great interest due to their exciting photophysical properties and optoelectronic applications. The discovery of dye aggregates by Jelley and Scheibe marked a significant advancement in the field. The exciton interactions in aggregates were later defined by Davydov, Kasha, and their co-workers, based on the long-range Coulombic coupling. This article discusses recent efforts to experimentally verify unusual exciton interactions and explores the potential of null exciton splitting in molecular assemblies.
CHEMICAL SOCIETY REVIEWS
(2023)
Article
Chemistry, Multidisciplinary
Renny Mathew, Aniruddha Mazumder, Praveen Kumar, Julie Matula, Sharmarke Mohamed, Petr Brazda, Mahesh Hariharan, Brijith Thomas
Summary: This study reveals the packing arrangement of partially disordered nitro-perylenediimide (NO2-PDI) using a synergistic approach that combines 3D ED, ssNMR, and DFT techniques. By overcoming these challenges, this methodology opens up new avenues for material characterization, driving exciting advancements in the field.
Article
Chemistry, Physical
Jeswin Sunny, Ebin Sebastian, Suvarna Sujilkumar, Frank Wuerthner, Bernd Engels, Mahesh Hariharan
Summary: Efficient population of triplet excited states has been a long-standing challenge in heavy metal-free organic chromophores. This study demonstrates the unprecedented population of triplet excited states in nitrogen-annulated perylene bisimide chromophores through the design strategy of nitrogen annulation. The enhancement in triplet population by bromine substitution is also observed.
PHYSICAL CHEMISTRY CHEMICAL PHYSICS
(2023)
Article
Chemistry, Physical
Jeswin Sunny, Ebin Sebastian, Suvarna Sujilkumar, Frank Wuerthner, Bernd Engels, Mahesh Hariharan
Summary: This study reports the unprecedented population of triplet excited states in a series of nitrogen-annulated perylene bisimide chromophores. Ultrafast intersystem crossing is found in Br-NPBI, leading to enhanced triplet population. The quantum chemical calculations reveal the important role of nitrogen annulation in tuning the excited state energy levels to favor intersystem crossing.
PHYSICAL CHEMISTRY CHEMICAL PHYSICS
(2023)
Article
Chemistry, Physical
Keerthy P. Sudhakaran, Alfy Benny, Athira T. John, Mahesh Hariharan
Summary: Theoretical investigations were conducted on the influence of graphene fragments on the antiaromaticity of pentalene using multiple aromaticity descriptors based on magnetic, geometric, and electronic criteria. The NICS value as the sole descriptor for analyzing the antiaromaticity of pentalene on graphene fragments needs to be carefully considered when looking at other aromatic indicators.
PHYSICAL CHEMISTRY CHEMICAL PHYSICS
(2023)
Article
Electrochemistry
Shruti Suriyakumar, Aniruddha Mazumder, Patoju Sai Dilip, Mahesh Hariharan, Manikoth M. Shaijumon
Summary: Establishing a sustainable energy solution is crucial for achieving a greener community. In this study, a dual modification strategy was employed to tailor the reduction potential and enhance the cycling stability of a perylene polyimide-based organic cathode. The results showed significantly improved electrochemical performance, indicating the potential for enhancing the performance of other organic battery chemistries.
BATTERIES & SUPERCAPS
(2023)
