D3 長村夏生君（Mr. Natsuo Nagamura）と笹部久宏准教授の高性能TADF 型有機 EL を実現する多機能性ホール輸送材料とマルチスケールシミュレーションによる定量的解析に関する論文が英国王立化学会（Royal Society of Chemistry）の J. Mater. Chem. C (IF: 7.393) に受理！長村さん、おめでとう！本研究は京都大学梶弘典研究室、山形大学横山大輔研究室との共同研究です。梶先生、横山先生、ご協力ありがとうございました！
本研究は、JSPS 科研費（基盤研究B, 20H02807）、JST センター・オブ・イノベーションプログラム（COI）、JSPS科研費 JP20H05840 (学術変革領域研究「動的エキシトン」)、および、京都大学化学研究所の共同利用・共同研究（#2020-103）の助成を受けたものです。計算には京大化研のスパコンシステムを利用しました。
Title: A multifunctional hole-transporter for high-performance TADF OLEDs and clarification of factors governing the transport property by multiscale simulation
By Natsuo Nagamura, Hisahiro Sasabe*, Hiroki Sato, Takahiro Kamata, Nozomi Ito, Suguru Araki, Shoki Abe, Yoshihito Sukegawa, Daisuke Yokoyama, Hironori Kaji*, Junji Kido*, J. Mater. Chem. C, 2022, accepted.
Abstract: To-this-date, a limited number of reports has been published on thermally activated delayed fluorescent (TADF) organic light-emitting devices (OLEDs) that simultaneously achieved high efficiencies and long operational lifetimes. The development of tailored-hole transporters is an effective solution because extensively used conventional hole-transport materials (HTMs), such as NPD or TAPC, are unsuitable for simultaneous realizations of high-efficiency and long-lifetime in TADF OLEDs. In this study, we developed a new four-dibenzofuran (DBF) end-capped hexaphenylbenzene (HPB)-based HTM, referred to as T4DBFHPB. Using this as the HTM, we simultaneously achieved high external quantum efficiency (hext = 22.0 %), long operational lifetime (LT50 = 28000 h), and low-drive voltage (3.83 V) at 1000 cd m−2 in green TADF OLEDs. Our research reveals the importance of multifunctional HTM with (i) high triplet energy (ET), (ii) high glass transition temperature (Tg), and (iii) high bond dissociation energy (BDE) of the C-N bonds in the anion state. Moreover, we conducted multiscale simulations to improve the hole-mobility (μh). Consequently, the simulation suggested that permanent-dipole-induced site energy and reorganization energy are critical factors for improving μh among HPB derivatives.
