High efficiency OLEDs based on anthracene derivatives: The impact of electron donating and withdrawing group on the performance of OLED |
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| Affiliation: | 1. Department of Physics, Durham University, Durham DH1 3LE, United Kingdom;2. TUBITAK Marmara Research Center, Chemistry Institute, p.b. 21, Gebze 41470, Kocaeli, Turkey;3. Mu? Alparslan Üniversitesi, Education Faculty, Mu? 49100, Turkey;4. Uludag Universitesi, Science Faculty, Chemistry Department, Gorukle Kampusu, Nilufer 16059, Bursa, Turkey;1. Department of Polymer Science and Engineering, Dankook University, 126, Jukjeon-dong, Suji-gu, Yongin, Gyeonggi, 448-701, Republic of Korea;2. School of Chemical Engineering, Sungkyunkwan University, 2066, Seobu-ro, Jangan-gu, Suwon, Gyeonggi, 440-746, Republic of Korea;1. Department of Chemistry and Key Laboratory for Preparation and Application of Ordered Structural Material of Guangdong Province, Shantou University, Guangdong, 515063, China;2. School of Optoelectronic Science and Engineering, University of Electronic Science and Technology of China (UESTC), Chengdu, 610054, China;1. Department of Electrical Engineering, Indian Institute of Technology Madras, Chennai 600036, India;2. Department of Physics, Indian Institute of Technology Madras, Chennai 600036, India;1. Physics Department, Durham University, South Road, Durham, DH1 3LE, United Kingdom;2. Ossila Ltd, Solpro Business Park, Windsor Street, Sheffield, S4 7WB, United Kingdom;1. State Key Laboratory of Supramolecular Structure and Materials, Department of Chemistry, Jilin University, 2699 Qianjin Avenue, Changchun, 130012, PR China;2. Institute of Polymer Optoelectronic Materials and Devices, State Key Laboratory of Luminescent Materials and Devices, South China University of Technology, Guangzhou, 510640, PR China |
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| Abstract: | New well-defined bulky anthracene derivatives with side groups having electron donating or withdrawing properties 8a-d were synthesized. The compounds contain substituted anthracene as the central core attaching 2-(4-(2-pyridinyl)- phenyl)vinyl and 4-R-phenyl R: H (a), OMe (b) and CF3 (c), N(Ph)2 (d)] groups at 9- and 10- positions. The impact of electron donating, withdrawing and neutral groups and their influence on the molecules photophysical, charge transfer (CT), triplet transfer (TT) and triplet–triplet annihilation (TTA) properties has been investigated. Based on the photophysical studies the most promising molecule (8d) has been selected and high efficiency fluorescent OLEDs with EQE at very low current efficiency reaching 7% were obtained. The value at low current density implies a Triplet Fusion (TF) contribution of 45%, very close to the maximum theoretical value of 50% when only the singlet decay channel is open to TTA, however we believe that in this case both TTA and TADF contribute to the triplet harvesting to yield high EQE values, and this mixed triplet harvesting arises through the heterogeneity of the films. At high current density a brightness of 20000 cd/m2 was achieved and it is assigned partially to the material crystallisation. |
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| Keywords: | Anthracene derivatives TTA TADF Material crystalization |
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