957065-96-2Relevant articles and documents
Benchmarking of Density Functionals for the Description of Optical Properties of Newly Synthesized π-Conjugated TADF Blue Emitters
Ivanova, Georgia,Bozova, Nadezhda,Petkov, Nikolay,An, Cunbin,Hu, Benlin,Mutovska, Monika,Konstantinov, Konstantin,Zagranyarski, Yulian,Videva, Vladimira,Yordanova, Adelina,Baumgarten, Martin,Ivanova, Anela
supporting information, (2022/02/22)
Computational modeling of the optical characteristics of organic molecules with potential for thermally activated delayed fluorescence (TADF) may assist markedly the development of more efficient emitting materials for organic light-emitting diodes. Recent theoretical studies in this area employ mostly methods from density functional theory (DFT). In order to obtain accurate predictions within this approach, the choice of a proper functional is crucial. In the current study, we focus on testing the performance of a set of DFT functionals for estimation of the excitation and emission energy and the excited singlet-triplet energy gap of three newly synthesized compounds with capacity for TADF. The emitters are designed specifically to enable charge transfer by π-electron conjugation, at the same time possessing high-energy excited triplet states. The functionals chosen for testing are from various groups ranging from gradient-corrected through global hybrids to range-separated ones. The results show that the monitored optical properties are especially sensitive to how the long-range part of the exchange energy is treated within the functional. The accurate functional should also be able to provide well balanced distribution of the π-electrons among the molecular fragments. Global hybrids with moderate (less than 0.4) share of exact exchange (B3LYP, PBE0) and the meta-GGA HSE06 are outlined as the best performing methods for the systems under study. They can predict all important optical parameters correctly, both qualitatively and quantitatively.
Synthesis and physical properties of meta-terphenyloxadiazole derivatives and their application as electron transporting materials for blue phosphorescent and fluorescent devices
Wu, Cheng-An,Chou, Ho-Hsiu,Shih, Cheng-Hung,Wu, Fang-Iy,Cheng, Chien-Hong,Huang, Heh-Lung,Chao, Teng-Chih,Tseng, Mei-Rurng
, p. 17792 - 17799 (2012/09/22)
Two m-terphenyloxadiazole-based electron transporting materials, bis(2-tert-butyl-1,3,4-oxadiazole-5-diyl)-3,3′-m-terphenyl (tOXD-mTP) and bis(2-(4-tert-butylphenyl)-1,3,4-oxadiazole-5-diyl)-3,3′-m-terphenyl (tpOXD-mTP) were synthesized and characterized. These two molecules contained two oxadiazolyl groups and a m-terphenyl linkage as the core structure achieving high triplet energy gaps (ET) of 2.83 and 2.90 eV, respectively. The application of tOXD-mTP and tpOXD-mTP as the electron transporting materials (ETM) in bis(4′,6′-difluorophenylpyridinato)-iridium(iii) picolinate (FIrpic)-based blue phosphorescent light-emitting devices effectively confines the triplet exciton in the emitting layers. One of the electroluminescent (EL) devices using FIrpic as the dopant showed an excellent current efficiency of 43.3 cd A-1 and an external quantum efficiency (EQE) of 23.0% with CIE (Commission International de l'Eclairage) coordinates of (0.13, 0.29). The bis(4′,6′-difluorophenylpyridinato)-iridium(iii) tetra(1-pyrazolyl)borate (FIr6)-based deeper blue EL device exhibited a high current efficiency of 42.5 cd A-1 and external quantum efficiency of 25.0% with CIE coordinates of (0.14, 0.23). These two tOXD-mTP and tpOXD-mTP based devices show device efficiencies two to three times higher than that based on the well-known electron transporting material 1,3-bis[(4-tertbutylphenyl)-1, 3,4-oxadiazolyl]phenylene (OXD-7).