Article
Chemistry, Multidisciplinary
Callum Prentice, James Morrison, Andrew D. Smith, Eli Zysman-Colman
Summary: The donor-acceptor thermally activated delayed fluorescent compounds DiKTa and Mes(3)DiKTa were found to have comparable or better product yields than 4CzIPN in a range of photocatalytic reactions. Among them, DiKTa stands out due to its lower cost, making it a valuable addition to any chemist's collection of photocatalysts.
CHEMISTRY-A EUROPEAN JOURNAL
(2023)
Article
Chemistry, Multidisciplinary
Sergio Ramirez-Barroso, Fernando Romeo-Gella, Jesus M. Fernandez-Garcia, Siyang Feng, Lara Martinez-Fernandez, David Garcia-Fresnadillo, Ines Corral, Nazario Martin, Reinhold Wannemacher
Summary: The intriguing photophysical properties of three curved nanographenes were investigated using time-resolved and temperature-dependent photoluminescence spectroscopy. The study found that CNG 7 and 8 exhibited dual fluorescence and phosphorescence at low temperature, as well as thermally activated delayed fluorescence in a narrow temperature range of 100-140 K.
ADVANCED MATERIALS
(2023)
Article
Chemistry, Multidisciplinary
Sergio Ramirez-Barroso, Fernando Romeo-Gella, Jesus M. Fernandez-Garcia, Siyang Feng, Lara Martinez-Fernandez, David Garcia-Fresnadillo, Ines Corral, Nazario Martin, Reinhold Wannemacher
Summary: The photophysical properties of three curved nanographenes (CNG 6, 7, and 8) are investigated using time-resolved and temperature-dependent photoluminescence spectroscopy. Dual fluorescence and phosphorescence are observed in CNG 7 and 8 at low temperatures. Thermally activated delayed fluorescence (TADF) is observed in a narrow temperature range, and non-Kasha behavior is observed due to the optimization of higher-lying S-2 minimum. The presence of higher-lying dark triplet states provides mechanistic evidence for the observed TADF phenomena.
ADVANCED MATERIALS
(2023)
Article
Engineering, Environmental
Jin-Feng Cheng, Fan-Cheng Kong, Kai Zhang, Jia-Heng Cai, Yue Zhao, Chuan-Kui Wang, Jian Fan, Liang-Sheng Liao
Summary: Isotope effect has been widely used in the study of organic reactions and semiconductor transport behaviors. This study investigated the isotope effect in TADF materials by designing and synthesizing deuterium-substituted TADF emitters, which showed an enhancement in luminescence efficiency and thermal stability. The positive isotope effect was attributed to the increase in normal mode displacement and Huang-Rhys factor of deuterated TADF, leading to improved electroluminescence performance.
CHEMICAL ENGINEERING JOURNAL
(2022)
Article
Chemistry, Multidisciplinary
Yu Fu, Zecong Ye, Denghui Liu, Yingxiao Mu, Jingping Xiao, Dehua Hu, Shaomin Ji, Yanping Huo, Shi-Jian Su
Summary: In this study, a series of thermally activated delayed fluorescence (TADF) macrocycles are synthesized using a modularly tunable strategy by introducing xanthones as acceptors and phenylamine derivatives as donors. Detailed analysis of their photophysical properties reveals their characteristics of high performance. The corresponding devices exhibit record-high external quantum efficiencies of 31.6% and 26.9%, respectively, in the field of TADF macrocycles, owing to the high photoluminescence quantum yields and excellent dipole orientation of the macrocycles.
ADVANCED MATERIALS
(2023)
Review
Chemistry, Multidisciplinary
Megan Amy Bryden, Eli Zysman-Colman
Summary: Organic compounds with Thermally Activated Delayed Fluorescence (TADF) properties have gained popularity as next-generation emitters in OLEDs, and have also been increasingly used as photocatalysts since 2016. This review highlights the wide potential of organic TADF compounds as photocatalysts, showcasing their versatility in various reactions and discussing the benefits they bring to photocatalysis. The analysis presented in the review reveals a promising future for the development of organic photocatalysts.
CHEMICAL SOCIETY REVIEWS
(2021)
Article
Nanoscience & Nanotechnology
Yunlong Zhu, Cheng Qu, Jianjiang Ye, Yincai Xu, Zuolun Zhang, Yue Wang
Summary: In this study, TADF compounds with a D-A-type fused-ring core skeleton are developed. The challenging compatibility between a planarized D-A arrangement and the TADF property is achieved through linking the D and A moieties with two oxygen atoms within a six membered ring. These fused-ring compounds show higher performance in terms of photoluminescence spectra and electroluminescent devices.
ACS APPLIED MATERIALS & INTERFACES
(2022)
Article
Engineering, Environmental
Chia-Hsun Chen, Shih-Chun Lin, Bo-Yen Lin, Che-Yu Li, Yu-Cheng Kong, Yi-Sheng Chen, Shao-Cheng Fang, Ching-Huang Chiu, Jiun-Haw Lee, Ken-Tsung Wong, Chi-Feng Lin, Wen-Yi Hung, Tien-Lung Chiu
Summary: Four bipolar molecules with carbazole donor and benzonitrile-substituted pyrimidine or triazine acceptor were synthesized to tune energy levels and TADF characteristics. These molecules as TADF host materials achieved high-performing green OLEDs, with m-CzPym-hosted devices reaching a maximum EQE of 31.5% and p-CzPym-hosted devices showing impressive efficiency roll-off performance. The high efficiency was attributed to the balanced carrier-transporting character, high PLQY, and outstanding light outcoupling efficiency of the host materials.
CHEMICAL ENGINEERING JOURNAL
(2022)
Article
Chemistry, Multidisciplinary
Xingwen Tong, Zhennan Zhao, Lei Hua, Yuzhuo Zhang, Bowei Xu, Yuchao Liu, Shouke Yan, Zhongjie Ren
Summary: A strategy of local conjugation is proposed to construct high-efficiency blue-emitting conjugated polymers. The prepared alternative copolymers Alt-PB36 with local conjugated main-chains effectively suppress the accumulation of long-lived triplet excitons and achieve efficient energy transfer. Alt-PB36-based solution-processed OLEDs exhibit a peak EQE of 11.6% and very low efficiency roll-off rates of 2.8% at 100 cd m(-2) and 15.2% at 500 cd m(-2), representing the highest efficiency among blue light-emitting conjugated polymer-based OLEDs under high luminance.
ADVANCED FUNCTIONAL MATERIALS
(2023)
Article
Materials Science, Multidisciplinary
Suyu Qiu, Jianmin Yu, Tao Zhou, Kaizhi Zhang, Yu Duan, Xinxin Ban, Qingzheng Zhu, Linxing Shi, Dongen Zhang
Summary: A novel TADF sensor, designed with efficient reverse intersystem crossing and high photoluminescence quantum yield, demonstrates the ability to recognize various metal ions with low detection limits.
Article
Chemistry, Multidisciplinary
Yuhao Shi, Huili Ma, Zhiyu Sun, Weijun Zhao, Guangyan Sun, Qian Peng
Summary: The twisted donor-acceptor (D-A) organic formwork with a large dihedral angle (theta(DA)) is found to play a crucial role in achieving excellent thermally activated delayed fluorescence (TADF) emitters. The overall TADF properties depend on the value of theta(DA), with a peak at around 80 degrees. The introduction of a methyl moiety allows for the regulation of theta(DA) and enables the on/off switching of TADF emission.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2022)
Article
Chemistry, Multidisciplinary
Gary Chen, John R. Swartzfager, John B. Asbury
Summary: In this study, we investigated the interplay between matrix dynamics and thermally activated delayed fluorescence (TADF) emitter to identify the factors influencing the photophysical processes leading to TADF. The results showed the competition between conformational motion needed to undergo TADF and larger amplitude structural fluctuations that lead to non-radiative decay.
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY
(2023)
Article
Chemistry, Multidisciplinary
Katsuyuki Shizu, Hironori Kaji
Summary: This study provides a comprehensive understanding of the emission mechanism of a representative multiple resonance-type thermally activated delayed fluorescence (MR-TADF) molecule. Through calculations, the rate constants and photoluminescence quantum yield related to the emission mechanism were quantified.
COMMUNICATIONS CHEMISTRY
(2022)
Article
Nanoscience & Nanotechnology
Sen Wu, Wenbo Li, Kou Yoshida, David Hall, Subeesh Madayanad Suresh, Thomas Sayner, Junyi Gong, David Beljonne, Yoann Olivier, Ifor D. W. Samuel, Eli Zysman-Colman
Summary: By decorating different numbers and types of electron donors around a MR-TADF core, the emission properties can be tuned to achieve red-shifting or improved luminescence efficiency.
ACS APPLIED MATERIALS & INTERFACES
(2021)
Review
Chemistry, Multidisciplinary
Tiantian Zhang, Yuxin Xiao, Hailan Wang, Shuting Kong, Rongjuan Huang, Vonika Ka-Man Au, Tao Yu, Wei Huang
Summary: Thermally activated delayed fluorescence (TADF) materials, particularly highly twisted TADF emitters, have shown great potential in the field of organic light-emitting diodes (OLEDs). These highly twisted TADF emitters exhibit multi-channel charge-transfer characters and rigid molecular structures, suppressing non-radiative decay processes and enhancing exciton utilization for efficient OLED performance. This review summarizes recent progress, molecular design strategies, photophysical studies, and device performances of highly twisted TADF materials and OLEDs, while also discussing the challenges and future prospects in this area.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2023)
Article
Chemistry, Organic
Matthias Hempe, Alastair K. Harrison, Jonathan S. Ward, Andrei S. Batsanov, Mark A. Fox, Fernando B. Dias, Martin R. Bryce
Summary: This study presents a synthetic methodology to covalently link donors to form cyclophane-based thermally activated delayed fluorescence (TADF) molecules, showing that the cyclophane molecular architecture alters the conformational distribution of the donor units and retains rotational freedom crucial for efficient TADF. Despite their different structures, cyclophanes and their nonbridged precursors exhibit similar photophysical properties emitting through similar excited states. Linking donor units to form a cyclophane suppresses detrimental conformations, establishing a versatile strategy while maintaining excellent photophysical properties.
JOURNAL OF ORGANIC CHEMISTRY
(2021)
Article
Optics
Ines G. Tavares, Erki Enkvist, Joosep Kaimre, Asko Uri, Fernando B. Dias
Summary: This work investigates the intramolecular energy transfer between two thiophene donors and a perylene bisimide acceptor, demonstrating the transfer of energy from the thiophene donor's excited triplet state to the perylene bisimide acceptor's singlet state. The designed organic luminophore, ARC-1467, shows delayed fluorescence of perylene bisimide upon excitation of the donor unit, indicating the occurrence of energy transfer from the triplet state of the donor unit to the perylene bisimide acceptor.
JOURNAL OF LUMINESCENCE
(2021)
Article
Engineering, Environmental
Xialei Lv, Xiaosong Cao, Han Wu, Hong Lin, Fan Ni, Hong Huang, Yang Zou, Chuluo Yang
Summary: This study presents a twisted donor-acceptor (D-A) system by simple conjugation of acridan and aryl halide to construct efficient and ultralong room-temperature phosphorescence (RTP) luminogens, demonstrating high phosphorescence quantum efficiency and long lifetime. This offers rare examples of efficient and long-lived phosphors based on acridan building block, shedding light on the inherent photophysical mechanism of RTP materials and paving a way to design highly promising RTP luminogens.
CHEMICAL ENGINEERING JOURNAL
(2021)
Article
Chemistry, Multidisciplinary
Chensen Li, Alastair K. Harrison, Yuchao Liu, Zhennan Zhao, Cheng Zeng, Fernando B. Dias, Zhongjie Ren, Shouke Yan, Martin R. Bryce
Summary: The mechanism of thermally activated delayed fluorescence (TADF) in dendrimers is not clear. This study focuses on fully-conjugated or fully-nonconjugated structures and their impact on TADF efficiency. The researchers synthesized asymmetrical half-dendronized and half-dendronized-half-encapsulated emitters to eliminate degenerate excited states and enhance the spin-flip process. By utilizing a encapsulating tricarbazole unit, nonradiative decay is reduced and TADF performance is improved. The non-doped solution-processed devices achieved high external quantum efficiency (EQE) with low efficiency roll-off at different brightness levels.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2022)
Article
Materials Science, Multidisciplinary
Piotr Pander, Andrey Zaytsev, Amit Sil, J. A. Gareth Williams, Valery N. Kozhevnikov, Fernando B. Dias
Summary: In this study, we investigated the influence of chloro-to-iodo exchange on the thermally activated delayed fluorescence (TADF) of a dinuclear platinum(ii) complex featuring monodentate halide ancillary ligands. The results showed that the iodine analogue exhibited improved luminescence properties with a significantly higher radiative decay rate constant compared to the chloro analogue. This study provides the first practical strategy to enhance the TADF properties of diplatinum(ii) complexes by iodination.
JOURNAL OF MATERIALS CHEMISTRY C
(2022)
Article
Chemistry, Physical
Antonio Maggiore, Yangyang Qu, Regis Guillot, Piotr Pander, Marharyta Vasylieva, Przemyslaw Data, Fernando B. Dias, Pierre Audebert, Gilles Clavier, Fabien Miomandre
Summary: This study investigates the photophysical and electrochemical properties of a new class of fluorinated benzonitrile compounds that are substituted with mixed phenoxazine and carbazole units. The compounds exhibit dual broad emission due to both localized and charge-transfer absorptions over a large range of the UV-vis spectrum. In solution, their photoluminescence quantum yields vary from a few percent to 18% in a more rigid environment. Additionally, the compounds demonstrate thermally activated delayed fluorescence, which is influenced by the number of phenoxazine substituents. Electrochemistry also reveals significant changes in the reduction mechanisms based on the remaining fluorine atoms on the benzonitrile core.
JOURNAL OF PHYSICAL CHEMISTRY B
(2022)
Article
Chemistry, Analytical
Paulina Powroznik, Barbara Solecka, Piotr Pander, Wieslaw Jakubik, Fernando B. Dias, Maciej Krzywiecki
Summary: Rapid and accurate detection of lethal volatile compounds is crucial for current and future societal security. This study utilizes thermal desorption spectroscopy (TDS) to investigate the adsorption of DMMP, a sarin analogue, on ZnPc, and employs quantum chemistry calculations to determine desorption activation energies. The comprehensive understanding of the DMMP desorption processes from ZnPc obtained in this work serves as the foundation for successful future applications of sarin ZnPc-based sensors. Impedance spectroscopy confirms the sensing capability of the studied material at room temperature, demonstrating ZnPc's potential as a promising sarin sensor candidate.
Article
Chemistry, Inorganic & Nuclear
Piotr Pander, Larissa Gomes Franca, Fernando B. Dias, Valery N. Kozhevnikov
Summary: Alkylation of a phenolic hydroxyl group in a salen-type ligand changes its coordination mode and allows the synthesis of a new luminescent Pt(II) complex 2. While the complex is not luminescent in solution, it exhibits emission in the solid state, making it suitable for organic light-emitting diodes. Complex 2 shows high external quantum efficiency and luminance in a vacuum-deposited device. Comparative analysis shows that the luminescent properties of O<^>N<^>N<^>O and C<^>N<^>N<^>O complexes are coincidental, and the two complexes display different electrochemical behavior.
INORGANIC CHEMISTRY
(2023)
Article
Chemistry, Inorganic & Nuclear
Piotr Pander, Andrey V. Zaytsev, Larissa Gomes Franca, Fernando B. Dias, Valery N. Kozhevnikov
Summary: In this work, we introduced a spiro-fluorene unit into a phenylpyridine (CN)-type ligand to deplanarize the structure and increase the solubility of a platinum(II) complex. This approach is highly important in the design of platinum(II) complexes to overcome low solubility and offers an alternative to using bulky alkyl groups. The nonplanar structure is also beneficial for vacuum-deposition techniques and eliminates the undesired feature of containing sp(3) hybridized carbon atoms.
INORGANIC CHEMISTRY
(2023)
Article
Chemistry, Multidisciplinary
Kaiwang Chen, Dengliang Zhang, Qing Du, Wei Hong, Yue Liang, Xingxing Duan, Shangwei Feng, Linfeng Lan, Lei Wang, Jiangshan Chen, Dongge Ma
Summary: This study presents a method to prepare stable pure red emission and high-PLQY-mixed-halide perovskite nanocrystals through simultaneous halide-exchange and ligand-exchange. By introducing ZnI2 for anion exchange, CsPbBr3 nanocrystals can be transformed to CsPbBrxI3-x nanocrystals. The luminescence properties can be regulated by the ZnI2 exchange process, allowing the fabrication of red CsPbBrxI3-x nanocrystals with near-unity PLQY and a stable emission peak.
Article
Chemistry, Inorganic & Nuclear
Carina B. Fialho, Tiago F. C. Cruz, Ana I. Rodrigues, Maria Jose Calhorda, Luis F. Vieira Ferreira, Piotr Pander, Fernando B. Dias, Jorge Morgado, Antonio L. Macanita, Pedro T. Gomes
Summary: Six new four-coordinate tetrahedral boron complexes with 9-borafluoren-9-yl and diphenylboron cores attached to 8-quinolinolato ligand chromophores have been synthesized and characterized. These complexes exhibit delayed fluorescence (DF) in solid films, originating from triplet-triplet annihilation (TTA). Density functional theory (DFT) and time-dependent density functional theory (TDDFT) studies provide insights into the physical properties and electronic structures of these new luminophores. Furthermore, these compounds have been successfully applied as emitters in organic light-emitting diodes (OLEDs), achieving green-blue electroluminescence with good external quantum efficiency (EQE) and high luminance.
DALTON TRANSACTIONS
(2023)
Article
Chemistry, Multidisciplinary
Piotr Pander, Andrey V. Zaytsev, Amit Sil, Glib V. Baryshnikov, Farhan Siddique, J. A. Gareth Williams, Fernando B. Dias, Valery N. Kozhevnikov
Summary: This study discovers a new luminescence mechanism called thermally activated delayed fluorescence (TADF) in iridium(III) complexes. By incorporating a faster fluorescent radiative decay pathway, the design of iridium(III) complexes can be improved in terms of luminescence efficiency and performance.
Article
Chemistry, Multidisciplinary
Rebecca J. Salthouse, Piotr Pander, Dmitry S. Yufit, Fernando B. Dias, J. A. Gareth Williams
Summary: We conducted a study on aggregate excited states formed by complexes of the type Pt(NC)X, where N<^>C<^>N represents a tridentate cyclometallating ligand, and X = SCN or I. We found that the identity of the monodentate ligand strongly influenced aggregation in film. The use of X = SCN promoted the formation of larger aggregates, while X = I limited aggregation to dimers. By exploiting the propensity of SCN complexes to form extended aggregates, we achieved an unprecedented NIR-emitting OLED.
Article
Materials Science, Multidisciplinary
Piotr Pander, Amit Sil, Rebecca J. Salthouse, Christopher W. Harris, Melissa T. Walden, Dmitry S. Yufit, J. A. Gareth Williams, Fernando B. Dias
Summary: This study presents an experimental and theoretical investigation on the aggregate excited states formed by Pt(NCN)Cl complexes. The complexes exhibit near-infrared photoluminescence in films and electroluminescence in OLED devices. The study provides insights into the kinetic properties of Pt-Pt excimers and proposes an alternative OLED architecture to reduce the use of precious-metal compounds.
JOURNAL OF MATERIALS CHEMISTRY C
(2022)
Article
Materials Science, Multidisciplinary
Piotr Pander, Andrey Zaytsev, Amit Sil, J. A. Gareth Williams, Pierre-Henri Lanoe, Valery N. Kozhevnikov, Fernando B. Dias
Summary: Through synthesis and analysis, we have discovered a di-Pt(ii) complex that exhibits dual luminescent behavior and activates thermally activated delayed fluorescence. Compared with the mono-Pt(ii) analogue, the di-Pt(ii) complex has a larger singlet radiative rate constant, a smaller singlet-triplet energy gap, and a longer phosphorescence decay lifetime. This bimetallic structure promotes conditions favorable for TADF, showcasing high efficiency in emitting near infrared electroluminescence.
JOURNAL OF MATERIALS CHEMISTRY C
(2021)