1
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Carlotto S, Babetto L, Bortolus M, Carlotto A, Rancan M, Bottaro G, Armelao L, Carbonera D, Casarin M. Nature of the Ligand-Centered Triplet State in Gd 3+ β-Diketonate Complexes as Revealed by Time-Resolved EPR Spectroscopy and DFT Calculations. Inorg Chem 2021; 60:15141-15150. [PMID: 34612628 PMCID: PMC8763374 DOI: 10.1021/acs.inorgchem.1c01123] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Abstract
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A series of Gd3+ complexes
(Gd1–Gd3) with the general formula
GdL3(EtOH)2, where L is a β-diketone ligand
with polycyclic aromatic hydrocarbon
substituents of increasing size (1–3), was studied by combining time-resolved electron paramagnetic resonance
(TR-EPR) spectroscopy and DFT calculations to rationalize the anomalous
spectroscopic behavior of the bulkiest complex (Gd3)
through the series. Its faint phosphorescence band is observed only
at 80 K and it is strongly red-shifted (∼200 nm) from the intense
fluorescence band. Moreover, the TR-EPR spectral analysis found that
triplet levels of 3/Gd3 are effectively
populated and have smaller |D| values than those
of the other compounds. The combined use of zero-field splitting and
spin density delocalization calculations, together with spin population
analysis, allows us to explain both the large red shift and the low
intensity of the phosphorescence band observed for Gd3. The large red shift is determined by the higher delocalization
degree of the wavefunction, which implies a larger energy gap between
the excited S1 and T1 states. The low intensity
of the phosphorescence is due to the presence of C–H groups
which favor non-radiative decay. These groups are present in all complexes;
nevertheless, they have a relevant spin density only in Gd3. The spin population analysis on NaL models, in which Na+ is coordinated to a deprotonated ligand, mimicking the coordinative
environment of the complex, confirms the outcomes on the free ligands. A series of Gd3+ complexes
(Gd1−Gd3) were studied by combining
TR-EPR spectroscopy and DFT
calculations to rationalize the deviant spectroscopic behavior of
the bulkiest complex (Gd3). The combination of ZFS calculations
and the spin density delocalization analysis ascribed the larger red
shift to the higher degree of delocalization of the wavefunction and
the low intensity of the phosphorescence band to the presence of C−H
groups with relevant spin density that favor non-radiative decay.
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Affiliation(s)
- Silvia Carlotto
- Department of Chemistry, University of Padova, via F. Marzolo 1, 35131 Padova, Italy.,Institute of Condensed Matter Chemistry and Technologies for Energy (ICMATE), National Research Council (CNR), c/o Department of Chemistry, University of Padova, via F. Marzolo 1, 35131 Padova, Italy
| | - Luca Babetto
- Department of Chemistry, University of Padova, via F. Marzolo 1, 35131 Padova, Italy
| | - Marco Bortolus
- Department of Chemistry, University of Padova, via F. Marzolo 1, 35131 Padova, Italy
| | - Alice Carlotto
- Department of Chemistry, University of Padova, via F. Marzolo 1, 35131 Padova, Italy
| | - Marzio Rancan
- Institute of Condensed Matter Chemistry and Technologies for Energy (ICMATE), National Research Council (CNR), c/o Department of Chemistry, University of Padova, via F. Marzolo 1, 35131 Padova, Italy
| | - Gregorio Bottaro
- Institute of Condensed Matter Chemistry and Technologies for Energy (ICMATE), National Research Council (CNR), c/o Department of Chemistry, University of Padova, via F. Marzolo 1, 35131 Padova, Italy
| | - Lidia Armelao
- Department of Chemistry, University of Padova, via F. Marzolo 1, 35131 Padova, Italy.,Department of Chemical Sciences and Technology of Materials (DSCTM), National Research Council (CNR), Piazzale A. Moro 7, 00185 Roma, Italy
| | - Donatella Carbonera
- Department of Chemistry, University of Padova, via F. Marzolo 1, 35131 Padova, Italy
| | - Maurizio Casarin
- Department of Chemistry, University of Padova, via F. Marzolo 1, 35131 Padova, Italy
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2
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Mu Y, Xu B, Yang Z, Wen H, Yang Z, Mane SKB, Zhao J, Zhang Y, Chi Z, Tang BZ. Reversible and Continuous Color-Tunable Persistent Luminescence of Metal-Free Organic Materials by "Self"-Interface Energy Transfer. ACS APPLIED MATERIALS & INTERFACES 2020; 12:5073-5080. [PMID: 31876136 DOI: 10.1021/acsami.9b19919] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Persistent luminescence from metal-free organic materials is attractive for their ultralong exciton lifetimes. Color-tunable persistent luminescence from single-component organic materials is fascinating but still challenging. By utilizing an efficient approach of "self"-interface energy transfer (IET), the persistent luminescence color of an organic phosphor (CTXO) can be reversibly and continuously tuned by external physical stimuli. Its color circularly changes between green (lifetime = 0.24 s) and deep-yellow (lifetime = 0.10 s) when CTXO is repeatedly triggered with thermal annealing and mechanical grinding. Self-IET from the crystalline part (donor), which exhibits persistent room-temperature phosphorescence, to the amorphous part (acceptor) inside its semicrystal during these treatments is found to be the key exciton process for such novel color modulation. This also provides opportunity for designing stimuli-responsive smart materials with controlled persistent luminescence.
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Affiliation(s)
- Yingxiao Mu
- PCFM Lab, GDHPPC Lab, Guangdong Engineering Technology Research Center for High-Performance Organic and Polymer Photoelectric Functional Films, State Key Laboratory of Optoelectronic Material and Technologies, School of Chemistry , Sun Yat-Sen University , Guangzhou 510275 , China
| | - Bingjia Xu
- PCFM Lab, GDHPPC Lab, Guangdong Engineering Technology Research Center for High-Performance Organic and Polymer Photoelectric Functional Films, State Key Laboratory of Optoelectronic Material and Technologies, School of Chemistry , Sun Yat-Sen University , Guangzhou 510275 , China
| | - Zhan Yang
- PCFM Lab, GDHPPC Lab, Guangdong Engineering Technology Research Center for High-Performance Organic and Polymer Photoelectric Functional Films, State Key Laboratory of Optoelectronic Material and Technologies, School of Chemistry , Sun Yat-Sen University , Guangzhou 510275 , China
| | - Hanhui Wen
- Instrumental Analysis and Research Center , Sun Yat-Sen University , Guangzhou 510275 , China
| | - Zhiyong Yang
- PCFM Lab, GDHPPC Lab, Guangdong Engineering Technology Research Center for High-Performance Organic and Polymer Photoelectric Functional Films, State Key Laboratory of Optoelectronic Material and Technologies, School of Chemistry , Sun Yat-Sen University , Guangzhou 510275 , China
| | - Sunil Kumar Baburao Mane
- PCFM Lab, GDHPPC Lab, Guangdong Engineering Technology Research Center for High-Performance Organic and Polymer Photoelectric Functional Films, State Key Laboratory of Optoelectronic Material and Technologies, School of Chemistry , Sun Yat-Sen University , Guangzhou 510275 , China
| | - Juan Zhao
- PCFM Lab, GDHPPC Lab, Guangdong Engineering Technology Research Center for High-Performance Organic and Polymer Photoelectric Functional Films, State Key Laboratory of Optoelectronic Material and Technologies, School of Chemistry , Sun Yat-Sen University , Guangzhou 510275 , China
| | - Yi Zhang
- PCFM Lab, GDHPPC Lab, Guangdong Engineering Technology Research Center for High-Performance Organic and Polymer Photoelectric Functional Films, State Key Laboratory of Optoelectronic Material and Technologies, School of Chemistry , Sun Yat-Sen University , Guangzhou 510275 , China
| | - Zhenguo Chi
- PCFM Lab, GDHPPC Lab, Guangdong Engineering Technology Research Center for High-Performance Organic and Polymer Photoelectric Functional Films, State Key Laboratory of Optoelectronic Material and Technologies, School of Chemistry , Sun Yat-Sen University , Guangzhou 510275 , China
| | - Ben Zhong Tang
- Department of Chemistry, Institute of Molecular Functional Materials, Hong Kong Branch of Chinese National Engineering Research Center for Tissue Restoration and Reconstruction , Hong Kong University of Science and Technology , Clear Water Bay, Kowloon , 999077 Hong Kong, China
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3
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Zhao W, Cheung TS, Jiang N, Huang W, Lam JWY, Zhang X, He Z, Tang BZ. Boosting the efficiency of organic persistent room-temperature phosphorescence by intramolecular triplet-triplet energy transfer. Nat Commun 2019; 10:1595. [PMID: 30962451 PMCID: PMC6453937 DOI: 10.1038/s41467-019-09561-8] [Citation(s) in RCA: 119] [Impact Index Per Article: 23.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2018] [Accepted: 03/18/2019] [Indexed: 11/11/2022] Open
Abstract
Persistent luminescence is a fascinating phenomenon with exceptional applications. However, the development of organic materials capable of persistent luminescence, such as organic persistent room-temperature phosphorescence, lags behind for their normally low efficiency. Moreover, enhancing the phosphorescence efficiency of organic luminophores often results in short lifetime, which sets an irreconcilable obstacle. Here we report a strategy to boost the efficiency of phosphorescence by intramolecular triplet-triplet energy transfer. Incorpotation of (bromo)dibenzofuran or (bromo)dibenzothiophene to carbazole has boosted the intersystem crossing and provided an intramolecular triplet-state bridge to offer a near quantitative exothermic triplet–triplet energy transfer to repopulate the lowest triplet-state of carbazole. All these factors work together to contribute the efficient phosphorescence. The generation and transfer of triplet excitons within a single molecule is revealed by low-temperature spectra, energy level and lifetime investigations. The strategy developed here will enable the development of efficient phosphorescent materials for potential high-tech applications. The potential of organic materials with persistent room-temperature phosphorescence for high-tech application is limited by their low efficiency. Here, the authors report a strategy to enhance persistent room-temperature phosphorescence efficiency via intramolecular triplet-triplet energy transfer.
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Affiliation(s)
- Weijun Zhao
- Department of Chemistry, The Hong Kong Branch of Chinese National Engineering Research Center for Tissue Restoration and Reconstruction, Institute of Molecular Functional Materials and The Hong Kong University of Science and Technology and the Institute for Advanced Study, Clear Water Bay, Kowloon, Hong Kong, 999077, China
| | - Tsz Shing Cheung
- Department of Chemistry, The Hong Kong Branch of Chinese National Engineering Research Center for Tissue Restoration and Reconstruction, Institute of Molecular Functional Materials and The Hong Kong University of Science and Technology and the Institute for Advanced Study, Clear Water Bay, Kowloon, Hong Kong, 999077, China
| | - Nan Jiang
- School of Science, Harbin Institute of Technology, Shenzhen, HIT Campus of University Town, 518055, Shenzhen, China
| | - Wenbin Huang
- School of Science, Harbin Institute of Technology, Shenzhen, HIT Campus of University Town, 518055, Shenzhen, China
| | - Jacky W Y Lam
- Department of Chemistry, The Hong Kong Branch of Chinese National Engineering Research Center for Tissue Restoration and Reconstruction, Institute of Molecular Functional Materials and The Hong Kong University of Science and Technology and the Institute for Advanced Study, Clear Water Bay, Kowloon, Hong Kong, 999077, China.,HKUST Shenzhen Research Institute, No. 9 Yuexing 1st RD, 518055, South Area, Hi-tech Park, Nanshan, Shenzhen, China
| | - Xuepeng Zhang
- Department of Chemistry, The Hong Kong Branch of Chinese National Engineering Research Center for Tissue Restoration and Reconstruction, Institute of Molecular Functional Materials and The Hong Kong University of Science and Technology and the Institute for Advanced Study, Clear Water Bay, Kowloon, Hong Kong, 999077, China.,HKUST Shenzhen Research Institute, No. 9 Yuexing 1st RD, 518055, South Area, Hi-tech Park, Nanshan, Shenzhen, China
| | - Zikai He
- School of Science, Harbin Institute of Technology, Shenzhen, HIT Campus of University Town, 518055, Shenzhen, China.
| | - Ben Zhong Tang
- Department of Chemistry, The Hong Kong Branch of Chinese National Engineering Research Center for Tissue Restoration and Reconstruction, Institute of Molecular Functional Materials and The Hong Kong University of Science and Technology and the Institute for Advanced Study, Clear Water Bay, Kowloon, Hong Kong, 999077, China. .,HKUST Shenzhen Research Institute, No. 9 Yuexing 1st RD, 518055, South Area, Hi-tech Park, Nanshan, Shenzhen, China. .,Center for Aggregation-Induced Emission, SCUT-HKUST Joint Research Institutes, State Key Laboratory of Luminescent Materials and Devices, South China University of Technology, 510640, Guangzhou, China.
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4
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Jayabharathi J, Ramya R, Thanikachalam V, Nethaji P. Optical and electroluminescent performances of dihydrobenzodioxin phenanthroimidazoles based blue-emitting materials. J Photochem Photobiol A Chem 2018. [DOI: 10.1016/j.jphotochem.2018.02.013] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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5
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Karpiuk J, Majka A, Karolak E, Nowacki J. Intramolecular Electron Transfer in Frozen Solvents: Charge Transfer and Local Triplet States Population Dynamics Revealed by Dual Phosphorescence. J Phys Chem Lett 2017; 8:4659-4667. [PMID: 28892399 DOI: 10.1021/acs.jpclett.7b02020] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
In frozen solvents at 77 K, ultrafast (≤250 fs) photoinduced intramolecular electron transfer (ET) in bichromophoric donor-acceptor ([D-A]) diarylmethane lactones produces a covalently linked radical ion pair, 1[D•+-A•-]. Steady state and time-resolved luminescence measurements reveal that 1[D•+-A•-] decays to charge-separated (3[D•+-A•-]) and donor-centered ([3D*-A]) triplets, which display dual phosphorescence. 3[D•+-A•-] and [3D*-A] are formed in parallel via two intersystem crossing mechanisms: spin orbit charge transfer (SOCT) and hyperfine coupling (HFC), with solvent dependent branching ratio. The solvent drives the D-A alignment during the freezing process to adapt to increasing solvent polarity, producing inhomogeneous ground-state population distribution with solvent-dependent D-A exchange interaction, which plays a key role in partitioning into SOCT and HFC mechanisms. In polar glasses, a third phosphorescence band appears due to dissociative back ET in 3[D•+-A•-] resulting in excited open ring biradical.
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Affiliation(s)
- Jerzy Karpiuk
- Institute of Physics, Polish Academy of Sciences , Al. Lotników 32/46, 02-668 Warsaw, Poland
| | - Alina Majka
- Institute of Physical Chemistry, Polish Academy of Sciences , Kasprzaka 44/52, 01-224 Warsaw, Poland
| | - Ewelina Karolak
- Institute of Physical Chemistry, Polish Academy of Sciences , Kasprzaka 44/52, 01-224 Warsaw, Poland
| | - Jacek Nowacki
- Institute of Physics, Polish Academy of Sciences , Al. Lotników 32/46, 02-668 Warsaw, Poland
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6
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Higginbotham HF, Etherington MK, Monkman AP. Fluorescence and Phosphorescence Anisotropy from Oriented Films of Thermally Activated Delayed Fluorescence Emitters. J Phys Chem Lett 2017; 8:2930-2935. [PMID: 28548498 DOI: 10.1021/acs.jpclett.7b00729] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Anisotropy within three TADF materials has been observed using steady-state fluorescence polarization. This technique has allowed for the observation of differences in polarization within dilute solution, and both unstretched and stretched films; the latter producing highly aligned molecules within the sample. Using these aligned films differences in anisotropy can be observed between the emission from the 1LE and 1CT states and upon exciting different absorption bands. Furthermore, polarization observed from time-resolved measurements highlights the strong vibronic coupling between charge-transfer and local triplet states.
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Affiliation(s)
| | - Marc K Etherington
- Department of Physics, Durham University , South Road, Durham DH1 3LE, United Kingdom
| | - Andrew P Monkman
- Department of Physics, Durham University , South Road, Durham DH1 3LE, United Kingdom
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7
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Kapturkiewicz A. Electrochemical Generation of Excited Intramolecular Charge-Transfer States. ChemElectroChem 2017. [DOI: 10.1002/celc.201600865] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Affiliation(s)
- Andrzej Kapturkiewicz
- Institute of Chemistry, Faculty of Sciences; Siedlce University of Natural Sciences and Humanities; 3 Maja 54 08-110 Siedlce Poland
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8
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Matsubara R, Shimada T, Kobori Y, Yabuta T, Osakai T, Hayashi M. Photoinduced Charge-Transfer State of 4-Carbazolyl-3-(trifluoromethyl)benzoic Acid: Photophysical Property and Application to Reduction of Carbon-Halogen Bonds as a Sensitizer. Chem Asian J 2016; 11:2006-10. [PMID: 27305449 DOI: 10.1002/asia.201600538] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2016] [Revised: 05/26/2016] [Indexed: 11/10/2022]
Abstract
The photoinduced persistent intramolecular charge-transfer state of 4-carbazolyl-3-(trifluoromethyl)benzoic acid was confirmed. It showed a higher catalytic activity in terms of yield and selectivity in the photochemical reduction of alkyl halides compared to the parent carbazole. Even unactivated primary alkyl bromides could be reduced by this photocatalyst. The high catalytic activity is rationalized by considering the slower backward single-electron transfer owing to the spatial separation of the donor and acceptor subunits.
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Affiliation(s)
- Ryosuke Matsubara
- Department of Chemistry, Kobe University, Nada-ku, Kobe, Hyogo, 657-8501, Japan.
| | - Toshiyuki Shimada
- Department of Chemistry, Kobe University, Nada-ku, Kobe, Hyogo, 657-8501, Japan
| | - Yasuhiro Kobori
- Department of Chemistry, Kobe University, Nada-ku, Kobe, Hyogo, 657-8501, Japan.
| | - Tatsushi Yabuta
- Department of Chemistry, Kobe University, Nada-ku, Kobe, Hyogo, 657-8501, Japan
| | - Toshiyuki Osakai
- Department of Chemistry, Kobe University, Nada-ku, Kobe, Hyogo, 657-8501, Japan
| | - Masahiko Hayashi
- Department of Chemistry, Kobe University, Nada-ku, Kobe, Hyogo, 657-8501, Japan
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9
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Radotić K, Melø TB, Leblanc RM, Yousef YA, Naqvi KR. Fluorescence and phosphorescence of tryptophan in peptides of different length and sequence. JOURNAL OF PHOTOCHEMISTRY AND PHOTOBIOLOGY B-BIOLOGY 2016; 157:120-8. [PMID: 26916609 DOI: 10.1016/j.jphotobiol.2016.02.011] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/05/2015] [Revised: 02/09/2016] [Accepted: 02/10/2016] [Indexed: 11/27/2022]
Abstract
To interpret accurately protein fluorescence and phosphorescence, it is essential to achieve a better understanding of the luminescence properties of tryptophan (Trp, or W) in peptides. In published literature data on luminescence of peptides of varied length are scarce. This article describes studies of fluorescence and phosphorescence properties of the eight Trp-containing synthetic peptides: WAK, AWK, SWA, KYLWE, AVSWK, WVSWAK, WAKLAWE, and AVSWAKLARE. The aim was to investigate which factors influence the fluorescence yield and phosphorescence-spectra and lifetimes. Absorption spectra, room temperature fluorescence emission and corresponding excitation spectra and time-resolved phosphorescence spectra (77K) have been recorded; the dependence of the fluorescence quantum yield on the specific peptide and its variation with the wavelength of excitation has been studied. The changes in fluorescence yield and shape of phosphorescence spectra are explained in terms of internal electron and proton transfer. The structured phosphorescence spectrum originates from proton transfer occurring upon excitation of Trp, while electron transfer gives rise to a non-structured luminescence spectrum. There is also electron transfer from higher vibronic S1 states. In the peptides there is higher probability of electron transfer than in Trp alone. The obtained data are interpreted in light of the peptides' sequence, length and conformation.
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Affiliation(s)
- Ksenija Radotić
- Institute for Multidisciplinary Research, University of Belgrade, Kneza Višeslava 1, 11000, Belgrade, Serbia.
| | - Thor Bernt Melø
- Department of Physics, Norwegian University of Science and Technology (NTNU), N-7491 Trondheim, Norway.
| | - Roger M Leblanc
- Department of Chemistry, University of Miami, FL, United States.
| | - Yaser A Yousef
- Department of Chemistry, Yarmouk University, Irbid, Jordan.
| | - K Razi Naqvi
- Department of Physics, Norwegian University of Science and Technology (NTNU), N-7491 Trondheim, Norway
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10
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Lifshits LM, Budkina DS, Singh V, Matveev SM, Tarnovsky AN, Klosterman JK. Solution-state photophysics of N-carbazolyl benzoate esters: dual emission and order of states in twisted push–pull chromophores. Phys Chem Chem Phys 2016; 18:27671-27683. [DOI: 10.1039/c6cp04619c] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
The stepwise photoinduced charge transfer in a series ofN-carbazolyl benzoate ester push–pull chromophores has been studied in solution.
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Affiliation(s)
- Liubov M. Lifshits
- Center for Photochemical Sciences
- Department of Chemistry
- Bowling Green State University
- Bowling Green
- USA
| | - Darya S. Budkina
- Center for Photochemical Sciences
- Department of Chemistry
- Bowling Green State University
- Bowling Green
- USA
| | - Varun Singh
- Center for Photochemical Sciences
- Department of Chemistry
- Bowling Green State University
- Bowling Green
- USA
| | - Sergey M. Matveev
- Center for Photochemical Sciences
- Department of Chemistry
- Bowling Green State University
- Bowling Green
- USA
| | - Alexander N. Tarnovsky
- Center for Photochemical Sciences
- Department of Chemistry
- Bowling Green State University
- Bowling Green
- USA
| | - Jeremy K. Klosterman
- Center for Photochemical Sciences
- Department of Chemistry
- Bowling Green State University
- Bowling Green
- USA
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11
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Shizu K, Lee J, Tanaka H, Nomura H, Yasuda T, Kaji H, Adachi C. Highly efficient electroluminescence from purely organic donor–acceptor systems. PURE APPL CHEM 2015. [DOI: 10.1515/pac-2015-0301] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
AbstractThermally activated delayed fluorescence (TADF) emitters are third-generation electroluminescent materials that realize highly efficient organic light-emitting diodes (OLEDs) without using rare metals. Here, after briefly reviewing the principles of TADF and its use in OLEDs, we report a sky-blue TADF emitter, 9-(4-(benzo[d]thiazol-2-yl)phenyl)-N3,N3,N6,N6-tetraphenyl-9H-carbazole-3,6-diamine (DAC-BTZ). DAC-BTZ is a purely organic donor–acceptor-type molecule with a small energy difference between its lowest excited singlet state and lowest triplet state of 0.18–0.22 eV according to fluorescence and phosphorescence spectra of a DAC-BTZ-doped film. In addition, the doped film exhibits a high photoluminescence quantum yield of 0.82. Time-resolved photoluminescence measurements of the doped film confirm that DAC-BTZ emits TADF. An OLED containing DAC-BTZ as an emitter exhibits a maximum external quantum efficiency (EQE) of 10.3%, which exceeds those obtained with conventional fluorescent emitters (5–7.5%). TADF from DAC-BTZ makes a large contribution to the high EQE of its OLED.
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Affiliation(s)
| | - Jiyoung Lee
- 4Department of Automotive Science, Graduate School of Integrated Frontier Sciences, Kyushu University, 744 Motooka, Nishi, Fukuoka 819-0395, Japan
| | - Hiroyuki Tanaka
- 1Center for Organic Photonics and Electronics Research (OPERA), Kyushu University, 744 Motooka, Nishi, Fukuoka 819-0395, Japan
| | - Hiroko Nomura
- 1Center for Organic Photonics and Electronics Research (OPERA), Kyushu University, 744 Motooka, Nishi, Fukuoka 819-0395, Japan
| | | | - Hironori Kaji
- 2Institute for Chemical Research, Kyoto University, Uji, Kyoto 611-0011, Japan
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12
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Kuno S, Akeno H, Ohtani H, Yuasa H. Visible room-temperature phosphorescence of pure organic crystals via a radical-ion-pair mechanism. Phys Chem Chem Phys 2015; 17:15989-95. [PMID: 26027521 DOI: 10.1039/c5cp01203a] [Citation(s) in RCA: 94] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
The afterglow of phosphorescent compounds can be distinguished from background fluorescence and scattered light by a time-resolved observation, which is a beneficial property for bioimaging. Phosphorescence emission accompanies spin-forbidden transitions from an excited singlet state through an excited triplet state to a ground singlet state. Since these intersystem crossings are facilitated usually by the heavy-atom effect, metal-free organic solids are seldom phosphorescent, although these solids have recently been refurbished as low-cost, eco-friendly phosphorescent materials. Here, we show that crystalline isophthalic acid exhibits room-temperature phosphorescence with an afterglow that lasts several seconds through a nuclear spin magnetism-assisted spin exchange of a radical ion pair. The obvious afterglow that facilitates a time-resolved detection and the unusual phosphorescence mechanism that enables emission intensification by nuclear spin managements are promising for exploiting the phosphorescence materials in novel applications such as bioimaging.
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Affiliation(s)
- Shinichi Kuno
- Department of Life Science, Graduate School of Bioscience and Biotechnology, Tokyo Institute of Technology, 4259 J2-10, Nagatsutacho, Midoriku, Yokohama 226-8501, Japan.
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13
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Li J, Jiang Y, Cheng J, Zhang Y, Su H, Lam JWY, Sung HHY, Wong KS, Kwok HS, Tang BZ. Tuning the singlet–triplet energy gap of AIE luminogens: crystallization-induced room temperature phosphorescence and delay fluorescence, tunable temperature response, highly efficient non-doped organic light-emitting diodes. Phys Chem Chem Phys 2015; 17:1134-41. [DOI: 10.1039/c4cp04052j] [Citation(s) in RCA: 63] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Tuning singlet–triplet energy gap of AIE luminogens: crystallization-induced phosphorescence, delay fluorescence and efficient non-doped OLEDs.
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Affiliation(s)
- Jie Li
- Department of Chemistry
- Institute for Advanced Study
- Division of Life Science
- Institute of Molecular Functional Materials
- Division of Biomedical Engineering and State Key Laboratory of Molecular Neuroscience
| | - Yibin Jiang
- Department of Electronic and Computer Engineering
- Center for Display Research
- HKUST
- Hong Kong
- China
| | - Juan Cheng
- Department of Physics
- HKUST
- Hong Kong
- China
| | | | - Huimin Su
- Department of Physics
- HKUST
- Hong Kong
- China
| | - Jacky W. Y. Lam
- Department of Chemistry
- Institute for Advanced Study
- Division of Life Science
- Institute of Molecular Functional Materials
- Division of Biomedical Engineering and State Key Laboratory of Molecular Neuroscience
| | - Herman H. Y. Sung
- Department of Chemistry
- Institute for Advanced Study
- Division of Life Science
- Institute of Molecular Functional Materials
- Division of Biomedical Engineering and State Key Laboratory of Molecular Neuroscience
| | | | - Hoi Sing Kwok
- Department of Electronic and Computer Engineering
- Center for Display Research
- HKUST
- Hong Kong
- China
| | - Ben Zhong Tang
- Department of Chemistry
- Institute for Advanced Study
- Division of Life Science
- Institute of Molecular Functional Materials
- Division of Biomedical Engineering and State Key Laboratory of Molecular Neuroscience
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14
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Kamecka A, Kapturkiewicz A. The luminescence properties of heteroleptic [OsCl(CO)(N∩N)(P∩P)]+complexes – radiative and non-radiative deactivation of the excited3*MLCT state. Phys Chem Chem Phys 2015; 17:23332-45. [DOI: 10.1039/c5cp03299g] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Combined Mulliken–Hush and Marcus–Jortner formalisms have been successfully used in the interpretation of the luminescence properties of the excited3*MLCT states.
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Affiliation(s)
- Anna Kamecka
- Institute of Chemistry
- Faculty of Sciences
- Siedlce University of Natural Sciences and Humanities
- 08-110 Siedlce
- Poland
| | - Andrzej Kapturkiewicz
- Institute of Chemistry
- Faculty of Sciences
- Siedlce University of Natural Sciences and Humanities
- 08-110 Siedlce
- Poland
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15
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Zhang Q, Kuwabara H, Potscavage WJ, Huang S, Hatae Y, Shibata T, Adachi C. Anthraquinone-based intramolecular charge-transfer compounds: computational molecular design, thermally activated delayed fluorescence, and highly efficient red electroluminescence. J Am Chem Soc 2014; 136:18070-81. [PMID: 25469624 DOI: 10.1021/ja510144h] [Citation(s) in RCA: 410] [Impact Index Per Article: 41.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Red fluorescent molecules suffer from large, non-radiative internal conversion rates (k(IC)) governed by the energy gap law. To design efficient red thermally activated delayed fluorescence (TADF) emitters for organic light-emitting diodes (OLEDs), a large fluorescence rate (k(F)) as well as a small energy difference between the lowest singlet and triplet excited states (ΔE(ST)) is necessary. Herein, we demonstrated that increasing the distance between donor (D) and acceptor (A) in intramolecular-charge-transfer molecules is a promising strategy for simultaneously achieving small ΔE(ST) and large k(F). Four D-Ph-A-Ph-D-type molecules with an anthraquinone acceptor, phenyl (Ph) bridge, and various donors were designed, synthesized, and compared with corresponding D-A-D-type molecules. Yellow to red TADF was observed from all of them. The k(F) and ΔE(ST) values determined from the measurements of quantum yield and lifetime of the fluorescence and TADF components are in good agreement with those predicted by corrected time-dependent density functional theory and are approximatively proportional to the square of the cosine of the theoretical twisting angles between each subunit. However, the introduction of a Ph-bridge was found to enhance k(F) without increasing ΔE(ST). Molecular simulation revealed a twisting and stretching motion of the N-C bond in the D-A-type molecules, which is thought to lower ΔE(ST) and k(F) but raise k(IC), that was experimentally confirmed in both solution and doped film. OLEDs containing D-Ph-A-Ph-D-type molecules with diphenylamine and bis(4-biphenyl)amine donors demonstrated maximum external quantum efficiencies of 12.5% and 9.0% with emission peaks at 624 and 637 nm, respectively.
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Affiliation(s)
- Qisheng Zhang
- Center for Organic Photonics and Electronics Research (OPERA), Kyushu University , 744 Motooka, Nishi-ku, Fukuoka 819-0395, Japan
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Jayabharathi J, Thanikachalam V, Kalaiarasi V, Jayamoorthy K. Intramolecular excited charge transfer, radiative and radiationless charge recombination processes in donor–acceptor imidazole derivatives. J Photochem Photobiol A Chem 2014. [DOI: 10.1016/j.jphotochem.2013.11.006] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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17
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Thanikachalam V, Arunpandiyan A, Jayabharathi J, Ramanathan P. Photophysical properties of the intramolecular excited charge-transfer states of π-expanded styryl phenanthrimidazoles – effect of solvent polarity. RSC Adv 2014. [DOI: 10.1039/c3ra44994g] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
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18
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Jayabharathi J, Thanikachalam V, Sathishkumar R. Excited Charge Transfer States in Donor–Acceptor Fluorescent Phenanthroimidazole Derivatives. J Fluoresc 2013; 24:431-44. [DOI: 10.1007/s10895-013-1309-4] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2013] [Accepted: 09/27/2013] [Indexed: 10/26/2022]
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19
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Shelar DP, Patil SR, Rote RV, Toche RB, Jachak MN. Synthesis and Fluorescence Investigation of Differently Substituted Benzo[b][1,8]Naphthyridines: Interaction with Different Solvents and Bovine Serum Albumin (BSA). J Fluoresc 2010; 21:1033-47. [DOI: 10.1007/s10895-010-0783-1] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2010] [Accepted: 11/25/2010] [Indexed: 11/25/2022]
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20
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Galievsky VA, Druzhinin SI, Demeter A, Mayer P, Kovalenko SA, Senyushkina TA, Zachariasse KA. Ultrafast Intramolecular Charge Transfer with N-(4-Cyanophenyl)carbazole. Evidence for a LE Precursor and Dual LE + ICT Fluorescence. J Phys Chem A 2010; 114:12622-38. [DOI: 10.1021/jp1070506] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Affiliation(s)
- Victor A. Galievsky
- Spektroskopie und Photochemische Kinetik, Max-Planck-Institut für biophysikalische Chemie, 37070 Göttingen, Germany; B.I. Stepanov Institute of Physics, National Academy of Sciences of Belarus, pr. Nezavisimosti 68, 22072 Minsk, Belarus; Institute of Materials and Environmental Chemistry, Chemical Research Center, Hungarian Academy of Sciences, P.O. Box 17, 1525 Budapest, Hungary; Department Chemie und Biochemie, Ludwig-Maximilians-Universität, Butenandtstrasse 5-13, Haus F, 81377 München, Germany; and
| | - Sergey I. Druzhinin
- Spektroskopie und Photochemische Kinetik, Max-Planck-Institut für biophysikalische Chemie, 37070 Göttingen, Germany; B.I. Stepanov Institute of Physics, National Academy of Sciences of Belarus, pr. Nezavisimosti 68, 22072 Minsk, Belarus; Institute of Materials and Environmental Chemistry, Chemical Research Center, Hungarian Academy of Sciences, P.O. Box 17, 1525 Budapest, Hungary; Department Chemie und Biochemie, Ludwig-Maximilians-Universität, Butenandtstrasse 5-13, Haus F, 81377 München, Germany; and
| | - Attila Demeter
- Spektroskopie und Photochemische Kinetik, Max-Planck-Institut für biophysikalische Chemie, 37070 Göttingen, Germany; B.I. Stepanov Institute of Physics, National Academy of Sciences of Belarus, pr. Nezavisimosti 68, 22072 Minsk, Belarus; Institute of Materials and Environmental Chemistry, Chemical Research Center, Hungarian Academy of Sciences, P.O. Box 17, 1525 Budapest, Hungary; Department Chemie und Biochemie, Ludwig-Maximilians-Universität, Butenandtstrasse 5-13, Haus F, 81377 München, Germany; and
| | - Peter Mayer
- Spektroskopie und Photochemische Kinetik, Max-Planck-Institut für biophysikalische Chemie, 37070 Göttingen, Germany; B.I. Stepanov Institute of Physics, National Academy of Sciences of Belarus, pr. Nezavisimosti 68, 22072 Minsk, Belarus; Institute of Materials and Environmental Chemistry, Chemical Research Center, Hungarian Academy of Sciences, P.O. Box 17, 1525 Budapest, Hungary; Department Chemie und Biochemie, Ludwig-Maximilians-Universität, Butenandtstrasse 5-13, Haus F, 81377 München, Germany; and
| | - Sergey A. Kovalenko
- Spektroskopie und Photochemische Kinetik, Max-Planck-Institut für biophysikalische Chemie, 37070 Göttingen, Germany; B.I. Stepanov Institute of Physics, National Academy of Sciences of Belarus, pr. Nezavisimosti 68, 22072 Minsk, Belarus; Institute of Materials and Environmental Chemistry, Chemical Research Center, Hungarian Academy of Sciences, P.O. Box 17, 1525 Budapest, Hungary; Department Chemie und Biochemie, Ludwig-Maximilians-Universität, Butenandtstrasse 5-13, Haus F, 81377 München, Germany; and
| | - Tamara A. Senyushkina
- Spektroskopie und Photochemische Kinetik, Max-Planck-Institut für biophysikalische Chemie, 37070 Göttingen, Germany; B.I. Stepanov Institute of Physics, National Academy of Sciences of Belarus, pr. Nezavisimosti 68, 22072 Minsk, Belarus; Institute of Materials and Environmental Chemistry, Chemical Research Center, Hungarian Academy of Sciences, P.O. Box 17, 1525 Budapest, Hungary; Department Chemie und Biochemie, Ludwig-Maximilians-Universität, Butenandtstrasse 5-13, Haus F, 81377 München, Germany; and
| | - Klaas A. Zachariasse
- Spektroskopie und Photochemische Kinetik, Max-Planck-Institut für biophysikalische Chemie, 37070 Göttingen, Germany; B.I. Stepanov Institute of Physics, National Academy of Sciences of Belarus, pr. Nezavisimosti 68, 22072 Minsk, Belarus; Institute of Materials and Environmental Chemistry, Chemical Research Center, Hungarian Academy of Sciences, P.O. Box 17, 1525 Budapest, Hungary; Department Chemie und Biochemie, Ludwig-Maximilians-Universität, Butenandtstrasse 5-13, Haus F, 81377 München, Germany; and
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21
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Ghotekar BK, Kazi MA, Jachak MN, Toche RB. Effect of substituents on absorption and fluorescence properties of pyrazolo[3,4-b]pyrrolo[2,3-d]pyridines. CAN J CHEM 2008. [DOI: 10.1139/v08-155] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
A convenient route was successfully developed for the synthesis of novel heterocycles such as pyrazolo[3,4-b]pyrrolo[2,3-d]pyridines (PPP) from pyrazolo[3,4-b]pyridines in good yield. The PPP derivatives synthesized were further studied for their photophysical properties, and it was observed that absorption and emission λmax changed, owing to the substituent effect at 4 positions. These compounds were obtained from highly reactive starting materials, 5-aminopyrazoles and α-acetyl γ-butyrolactone.Key words: α-acetyl γ-butyrolactone, pyrazolo[3,4-b]pyrrolo[2,3-d] pyridine, absorption, emission, fluorescence.
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22
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Liu T, Wei YG, Yuan YQ, Guo QX. Charge Transfer in Excited Donor-acceptor Phenothiazine Derivatives. CHINESE J CHEM 2005. [DOI: 10.1002/cjoc.200591430] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
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23
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Rotkiewicz K, Rettig W, Köhler G, Rechthaler K, Danel A, Grabka D. Specific solute–solvent interactions and dual fluorescence of electron donor substituted bis-pyrazoquinoline in binary mixed solvents. Chem Phys 2004. [DOI: 10.1016/j.chemphys.2004.07.048] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Grabowski ZR, Rotkiewicz K, Rettig W. Structural Changes Accompanying Intramolecular Electron Transfer: Focus on Twisted Intramolecular Charge-Transfer States and Structures. Chem Rev 2003; 103:3899-4032. [PMID: 14531716 DOI: 10.1021/cr940745l] [Citation(s) in RCA: 2265] [Impact Index Per Article: 107.9] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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26
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Radiative and nonradiative electron transfer in donor–acceptor phenoxazine and phenothiazine derivatives. Chem Phys 1999. [DOI: 10.1016/s0301-0104(99)00265-7] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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27
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Kapturkiewicz A, Nowacki J. Properties of the Intramolecular Excited Charge-Transfer States of Carbazol-9-yl Derivatives of Aromatic Ketones. J Phys Chem A 1999. [DOI: 10.1021/jp990932t] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Andrzej Kapturkiewicz
- Institute of Physical Chemistry, Polish Academy of Sciences, Kasprzaka 44/52, 01-224 Warsaw, Poland
| | - Jacek Nowacki
- Department of Chemistry, Warsaw University, Pasteura 1, 02-093 Warsaw, Poland
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28
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29
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Herbich J, Kapturkiewicz A. Electronic Structure and Molecular Conformation in the Excited Charge Transfer Singlet States of 9-Acridyl and Other Aryl Derivatives of Aromatic Amines. J Am Chem Soc 1998. [DOI: 10.1021/ja972474c] [Citation(s) in RCA: 137] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Jerzy Herbich
- Contribution from the Institute of Physical Chemistry, Polish Academy of Sciences, Kasprzaka 44/52, 01-224 Warsaw, Poland
| | - Andrzej Kapturkiewicz
- Contribution from the Institute of Physical Chemistry, Polish Academy of Sciences, Kasprzaka 44/52, 01-224 Warsaw, Poland
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30
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Highly efficient electrochemical generation of fluorescent intramolecular charge-transfer states. Chem Phys Lett 1997. [DOI: 10.1016/s0009-2614(97)00775-6] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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31
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Kapturkiewicz A, Herbich J, Karpiuk J, Nowacki J. Intramolecular Radiative and Radiationless Charge Recombination Processes in Donor−Acceptor Carbazole Derivatives. J Phys Chem A 1997. [DOI: 10.1021/jp9634565] [Citation(s) in RCA: 125] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Andrzej Kapturkiewicz
- Institute of Physical Chemistry Polish Academy of Sciences, Kasprzaka 44/52, 01-224 Warsaw, Poland
| | - Jerzy Herbich
- Institute of Physical Chemistry Polish Academy of Sciences, Kasprzaka 44/52, 01-224 Warsaw, Poland
| | - Jerzy Karpiuk
- Institute of Physical Chemistry Polish Academy of Sciences, Kasprzaka 44/52, 01-224 Warsaw, Poland
| | - Jacek Nowacki
- Department of Chemistry, Warsaw University, Pasteura 1, 02-093 Warsaw, Poland
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