文献类型：期刊文献

英文题名：Insights into energy transfer pathways between the exciplex host and fluorescent guest: attaining highly efficient 710 nm electroluminescence

作者：Huang, Chun-Ying[1];Ho, Ssu-Yu[1];Lai, Chien-Hsun[2];Ko, Chang-Lun[2];Wei, Yu-Chen[1];Lin, Jia-An[1];Chen, Deng-Gao[1];Ko, Tzu-Yu[1];Wong, Ken-Tsung[1];Zhang, Zhiyun[3,4];Hung, Wen-Yi[2,5];Chou, Pi-Tai[1]

机构：[1]Natl Taiwan Univ, Dept Chem, Taipei 10617, Taiwan;[2]Natl Taiwan Ocean Univ, Dept Optoelect & Mat Technol, Keelung 202, Taiwan;[3]East China Univ Sci & Technol, Key Lab Adv Mat, Shanghai 200237, Peoples R China;[4]East China Univ Sci & Technol, Inst Fine Chem, Shanghai 200237, Peoples R China;[5]Natl Taiwan Ocean Univ, Ctr Excellence Ocean Engn, Keelung 202, Taiwan

年份：2020

卷号：8

期号：17

起止页码：5704

外文期刊名：JOURNAL OF MATERIALS CHEMISTRY C

收录：;EI(收录号：20202008663561);WOS:【SCI-EXPANDED(收录号:WOS:000534232300004)】；

基金：This work was supported by the funding from the Ministry of Science and Technology (MOST), featured areas research program within the framework of the Higher Education Sprout Project administrated by the Ministry of Education (MOE) of Taiwan. We are grateful to the National Center for the High-performance Computing (NCHC) of Taiwan for the valuable computer time and facilities. We are thankful for the TGA data from Thermal Analysis System of Instrumentation Center, National Taiwan University. Z. Z. thanks the financial support from the NSFC/China (21905090), the Program for Professor of Special Appointment (Eastern Scholar) at Shanghai Institutions of Higher Learning, and Natural Science Foundation of Shanghai (19ZR1412200).

语种：英文

外文关键词：Molar ratio - Electroluminescence - Fluorescence - Organic light emitting diodes (OLED) - Chromophores - Infrared devices - Quantum efficiency

摘要：Energy transfer between the exciplex host and fluorescent guest is a demanding process for attaining high-performance organic light-emitting diodes (OLEDs), particularly in the near-infrared (NIR) region, and insight into the dynamics of energy transfer has been elusive. In this study, new deep-red/NIR chromophores, NOz-TPA and NOz-t-TPA where NOz and TPA denote naphthobisoxadiazole and triphenylamine, respectively, have been developed with an electron donor-acceptor-donor (D-A-D) configuration. The optimized 1 wt% doped films for NOz-TPA and NOz-t-TPA blended with the Tris-PCz:CN-T2T (1 : 1 in molar ratio) exciplex host showed similar deep red/NIR emissions with photoluminescence quantum yields (PLQY) of 42 (680 nm) and 28%, (709 nm), respectively. Comprehensive time-resolved measurements and dynamics analyses revealed significant differences in the energy transfer pathways, i.e. Forster versus Dexter-type energy transfer between the exciplex host and the fluorescent guest, in which the introduction of bulky tert-butyl groups in the NOz-t-TPA doped film greatly suppressed the Dexter-type energy transfer pathway. Despite the lower PLQY, the analytical simulation predicted NOz-t-TPA to be a better candidate for realizing highly efficient electroluminescence. Confirmation was provided by the performance of the NOz-t-TPA-doped OLED, showing an external quantum efficiency (EQE) of 6.6% with peak wavelength at 710 nm, which is among the best records for the metal-free NIR OLEDs around 710 nm. Insight into energy transfer pathways thus plays a pivotal role in achieving the high-performance OLEDs that incorporate the exciplex host and fluorescent guest.