Article
Chemistry, Multidisciplinary
Hanbo Yu, Xiaoxian Song, Ning Xie, Jiaxuan Wang, Chenglong Li, Yue Wang
Summary: The study introduces a novel multifunctional molecule TPA-DQP, which exhibits polymorphism, efficient TADF emission, and MCL property, with reversible crystal-to-crystal phase transitions in response to external stimuli. The TPA-DQP-based OLED device achieves high external quantum efficiency and represents the best performance for deep-red OLEDs based on MCL-active TADF emitters, providing insight into the relationship between molecular packing modes and photoluminescent behavior.
ADVANCED FUNCTIONAL MATERIALS
(2021)
Article
Chemistry, Multidisciplinary
Dmitry A. Gruzdev, Angelina A. Telegina, Evgeny N. Chulakov, Galina L. Levit, Victor P. Krasnov
Summary: In this study, planar-chiral carborane derivatives were obtained for the first time through deboronation and separation of diastereomeric derivatives. The absolute configuration of structurally simple nido-carborane derivatives was also assigned using an alternative synthetic route.
NEW JOURNAL OF CHEMISTRY
(2022)
Article
Chemistry, Physical
Yongyu Cha, Shuai Li, Zuofang Feng, Rongjiao Zhu, Hongbing Fu, Zhenyi Yu
Summary: This article presents a multifunctional gain material with high optical gain and triplet utilization, serving as both a thermally activated delayed fluorescence emitter and a phosphorescence source.
JOURNAL OF PHYSICAL CHEMISTRY LETTERS
(2022)
Article
Chemistry, Multidisciplinary
Yang Liu, Yulin Xu, Hao Peng, Jingsheng Miao, He Liu, Chuluo Yang
Summary: A new acridine donor with trispiro junctions was developed to assemble a highly efficient thermally activated delayed fluorescence emitter. The multispiro junctions ensure a rigid geometry that leads to a well-suppressed nonradiative decay. The resulting electroluminescent devices achieve a high external quantum efficiency of 34.2%.
CHEMICAL COMMUNICATIONS
(2023)
Review
Materials Science, Multidisciplinary
Nengquan Li, Fan Ni, Xialei Lv, Zhongyan Huang, Xiaosong Cao, Chuluo Yang
Summary: Organic light-emitting diodes (OLEDs) with purely organic thermally activated delayed fluorescence (TADF) emitters offer advantages of high efficiency and low cost, however, research on host materials lags behind, calling for attention from the research community.
ADVANCED OPTICAL MATERIALS
(2022)
Article
Physics, Applied
Natsuko Kanno, Yongxia Ren, Yu Kusakabe, Katsuaki Suzuki, Katsuyuki Shizu, Hiroyuki Tanaka, Yoshimasa Wada, Hiromichi Nakagawa, Jan Geldsetzer, Hironori Kaji
Summary: Accelerating reverse intersystem crossing (RISC) without sacrificing fast radiative decay is effective in suppressing efficiency roll-off (eRO) in thermally activated delayed fluorescence (TADF)-based organic light-emitting diodes. We here report a TADF emitter, CC-TXO-I, combining a bicarbazole donor (CC) and a sulfur-containing acceptor (TXO). We realized very large rate constants of RISC (k (RISC)s) of similar to 10(7) s(-1). Both k (RISC)s and rate constants of radiative decay of CC-TXO-I increased with increasing doping concentration, resulting in improved eROs.
APPLIED PHYSICS EXPRESS
(2023)
Article
Chemistry, Multidisciplinary
Ranran Pei, Yulin Xu, Jingsheng Miao, Hao Peng, Zhanxiang Chen, Changjiang Zhou, He Liu, Chuluo Yang
Summary: Simultaneously achieving high efficiency and low efficiency roll-off is crucial for the further application of thermally activated delayed fluorescent (TADF) emitters. This study proposes a quinolino-acridine (QAc) donor, composed of two acridine units with planar (pAc) and bended (bAc) geometries, combined with triazine to assemble a TADF emitter QAc-TRZ. The pAc ensures decent TADF behavior through interaction with triazine, while the bAc enhances radiative decay through delocalization of the highest occupied molecular orbital (HOMO). Notably, QAc-TRZ enables a highly efficient organic light emitting diode (OLED) with a maximum external quantum efficiency (EQE) of 37.3%, and maintains efficiencies of 36.3% and 31.7% under 100/1000 cd m(-2), respectively, even at 10,000 cd m(-2).
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2023)
Article
Chemistry, Multidisciplinary
A. A. Kaltenberg, A. M. Zimina, A. D. Bashilova, Yu. B. Malysheva, D. L. Vorozhtsov, A. V. Piskunov, N. V. Somov, I. D. Grishin
Summary: The reactions of complex 5,6,10-{Cl(Ph3P)(2)Ru}-[5,6,10-(mu-H)(3)-10-H-exo-nido-7,8-C2B9H8] (1) with 1,2-bis(diphenylphosphino)benzene (dppbz) and bis(diphenylphosphino)methane (dppm) in the presence of amines were investigated. New closo-ruthenacarborane complexes with a formal oxidation state of +2 were synthesized. The reaction with dppbz led to the formation of a complex containing a coordinated acetonitrile molecule, while the reaction with dppm resulted in a tris(phosphine) complex with a sterically shielded ruthenium center. The reversibility of the Ru-II -> Ru-III redox transition in these compounds was studied using cyclic voltammetry and the effect of the ligand environment on the redox potentials was evaluated.
RUSSIAN CHEMICAL BULLETIN
(2023)
Review
Chemistry, Multidisciplinary
Christian Sandoval-Pauker, Mireya Santander-Nelli, Paulina Dreyse
Summary: This work describes the photophysical characteristics of [Cu(N boolean AND N)(2)](+) and [Cu(N boolean AND N)(P boolean AND P)](+) complexes, as well as the concept and development of thermally activated delayed fluorescence (TADF). The importance of Delta E-(S1-T-1) and spin-orbital coupling (SOC) values on the TADF behavior of these complexes is discussed. Examples of Delta E-(S1-T-1) values reported in the literature are collected and trends are proposed. The methods used for determining Delta E-(S1-T-1) values and the effect of SOC in TADF are also described. Lastly, the applications and challenges for industrial use of these TADF complexes are addressed.
Article
Chemistry, Applied
You-Ping Ma, Guoliang Wang, Min Zhao, Zi-Fa Shi, Yanqin Miao, Xiao-Ping Cao, Hao-Li Zhang
Summary: A series of materials (BTD-PXZ, BTD-PTZ, and BTD-DMAC) were designed and synthesized with facile synthesis process and high synthesis yield, by directly connecting electron donor to position 5 of benzo[c][1,2,5]thiadiazole (BTD). The thermally activated delayed fluorescence property of BTD-PXZ was proven and its photophysical characteristics were discussed through various experiments. The doped organic light-emitting diode with BTD-PXZ as the emissive layer exhibited a specific emitting peak wavelength, CIE coordinate, and external quantum efficiency.
Article
Chemistry, Physical
Tommaso Francese, Arpan Kundu, Francois Gygi, Giulia Galli
Summary: In this study, we investigate the prototypical NAI-DMAC thermally activated delayed fluorescence (TADF) emitter in the gas phase and high-packing fraction limits at finite temperature. By combining first principles molecular dynamics with a quantum thermostat, we account for nuclear quantum effects (NQE). Our findings show that the singlet-triplet energy gap has a weak dependence on temperature, but a substantial effect of packing. The transition probability between the HOMOs and LUMOs has a stronger dependence on temperature, which is desirable for thermally activated fluorescence.
PHYSICAL CHEMISTRY CHEMICAL PHYSICS
(2022)
Article
Materials Science, Multidisciplinary
Xuan Zeng, Yu-Hsin Huang, Shaolong Gong, Xuguang Yin, Wei-Kai Lee, Xiao Xiao, Yu Zhang, Weixuan Zeng, Chen-Han Lu, Chang-Cheng Lee, Xiu-Qin Dong, Cheng Zhong, Chung-Chih Wu, Chuluo Yang
Summary: This study successfully achieved active control of the dipole orientation of organic emitters by designing a linear TADF molecule, PhNAI-PMSBA, with an emitting dipole orientation ratio of 95%, substantially higher than traditional emitters. This unique feature is attributed to the inherently horizontal molecular orientation of the molecule and the good agreement between its transition dipole moment direction and molecular long axis.
SCIENCE CHINA-MATERIALS
(2021)
Article
Chemistry, Multidisciplinary
Pachaiyappan Rajamalli, Federica Rizzi, Wenbo Li, Michael A. Jinks, Abhishek Kumar Gupta, Beth A. Laidlaw, Ifor D. W. Samuel, Thomas J. Penfold, Stephen M. Goldup, Eli Zysman-Colman
Summary: This study characterizes rotaxanes based on a carbazole-benzophenone thermally activated delayed fluorescence luminophore, demonstrating that the mechanical bond can lead to an improvement in key photophysical properties of the emitter. Computational simulations and X-ray crystallography suggest that weak interactions enforced by the mechanical bond between the axle and macrocycle result in the tuning of properties. The use of mechanical bonds to refine existing luminophores provides a new avenue for emitter optimization, ultimately increasing the performance of these molecules.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2021)
Article
Chemistry, Multidisciplinary
Wiebke Haselbach, Jeremy M. Kaminski, Laura N. Kloeters, Thomas J. J. Mueller, Oliver Weingart, Christel M. Marian, Peter Gilch, Barbara E. Nogueira de Faria
Summary: The emitters for TADF-based OLEDs need to have small S-1-T-1 energy gaps and fast ISC transitions. Vibronic mixing with higher excited states S-n and T-n can mediate these transitions. By using time-resolved NIR spectroscopy, it is demonstrated that the energetically located higher states can be found in a prototypical TADF emitter consisting of a triarylamine and a dicyanobenzene moiety (TAA-DCN).
CHEMISTRY-A EUROPEAN JOURNAL
(2023)
Article
Engineering, Environmental
Hao-Yu Yang, Heng-yuan Zhang, Ming Zhang, Xiao-chun Fan, Hui Lin, Si-Lu Tao, Cai-Jun Zheng, Xiao-Hong Zhang
Summary: In this study, three new thermally activated delayed fluorescence (TADF) emitters were developed with improved molecular rigidity and enhanced fluorescence process by forming appropriate intramolecular hydrogen bond. These emitters showed significantly improved radiative rate and reduced non-radiative decay rate, leading to multiplied external quantum efficiency (EQE) in red organic light-emitting diodes (OLEDs).
CHEMICAL ENGINEERING JOURNAL
(2022)