Chemical Research in Chinese Universities ›› 2023, Vol. 39 ›› Issue (5): 763-771.doi: 10.1007/s40242-023-3167-1

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Non-conjugated Polynorbornene Hosts with High Triplet Energy Levels for Solution-processed Narrowband Blue OLEDs

LI Qiang1,2, CHEN Liang1,2, WANG Xingdong1, WANG Shumeng1, SHAO Shiyang1,3, WANG Lixiang1,2   

  1. 1. State Key Laboratory of Polymer Physics and Chemistry, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun 130022, P. R. China;
    2. School of Applied Chemistry and Engineering, University of Science and Technology of China, Hefei 230026, P. R. China;
    3. State Key Laboratory of Marine Resource Utilization in South China Sea, School of Materials Science and Engineering, Hainan University, Haikou 570228, P. R. China
  • Received:2023-07-20 Online:2023-10-01 Published:2023-09-26
  • Contact: WANG Lixiang, SHAO Shiyang E-mail:lixiang@ciac.ac.cn;ssyang@hainanu.edu.cn
  • Supported by:
    This work was supported by the National Natural Science Foundation of China (Nos.52073282, 52122309, 21975247, 51833009, 52261135541), the CAS-Croucher Funding Scheme for Joint Laboratories, the Open Project of the State Key Laboratory of Supramolecular Structure and Materials, China (No.sklssm2023019) and the Start-up Scientific Research Foundation from Hainan University, China[No.KYQD(ZR)22174].

Abstract: Three polymer hosts (namely PNB-tBuCz, PNB-Ac, PNB-TAc) containing non-conjugated polynorbornene (PNB) backbone and hole-transporting arylamine segments (carbazole, acridan and dendritic teracridan) in side chains are developed for solution-processed narrowband blue organic light-emitting diodes (OLEDs). It is found that the non-conjugated polynorbornenes can keep high triplet energy (ET) levels in range of 3.12-3.20 eV by interrupting the conjugation of repeating units, making them capable as host materials for blue emitters. Meanwhile, by increasing the electron-donating capability of side chain arylamine from carbazole to acridan and dendritic teracridan, the highest occupied molecular orbital (HOMO) levels for the polymer hosts are elevated from -5.50 eV to -5.11 eV, beneficial for reducing the hole injection barrier from anode to emissive layer. As a result, solution-processed OLEDs employing polynorbornenes with dendritic teracridan side chain (PNB-TAc) as host and boron, selenium, nitrogen-containing multiple resonance thermally activated delayed fluorescence emitter as dopant reveal efficient narrowband blue electroluminescence with emission peak at 474 nm, full-width at half maximum of 30 nm, together with maximum external quantum efficiency of 20.2%, representing the state-of-the-art device efficiency for solution-processed OLEDs with narrowband blue emission.

Key words: Polymer host, Polynorbornene, Organic light-emitting diode, Solution-processed, Narrowband, Blue emission