A paper related to Ayato ARAI (M2) and Associate Professor Hisahiro SASABE (Kido/Sasabe/Chiba Lab) titled "π-Extended carbazole derivatives as host materials for highly efficient and long-life green phosphorescent OLEDs" was published on Chemistry A European Journal (IF: 4.857) (Wiely). 

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Title: π-Extended carbazole derivatives as host materials for highly efficient and long-life green phosphorescent OLEDs
By Ayato Arai, Hisahiro Sasabe*, Kohei Nakao, Yuki Masuda, and Junji Kido*, Chem. Eur. J., 2020, accepted.

Abstract: High-performance OLEDs that use phosphorescent and/or thermally activated delayed fluorescence emitters are capable of realizing 100% electron-to-photon conversion. The host materials in these OLEDs play crucial roles in determining OLED performance. Carbazole derivatives are frequently used as host materials, among which 3,3-di(9H-carbazol-9- yl)biphenyl (mCBP) is often used for lifetime testing in scientific studies. In this study, we expanded the pai-conjugation of the carbazole unit to enhance OLED lifetime by designing and developing two benzothienocarbazole (BTCz)-based host materials, namely m1BTCBP and m4BTCBP. Among these host materials, m1BTCBP formed a highly efficient Ir(ppy)3-based OLED with an operational luminescence half-life (LT50) of over 300 h at an initial luminance of approximately 12000 cd m–2 (current density: 25 mA cm–2). LT50 at 1000 cd cm-2 is estimated to be about 23000 h. This performance is clearly greater than that of mCBP-based OLEDs (LT50 = ca. 8500 h).

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📚 Kido/Sasabe/Chiba Lab HP >> https://oled.yz.yamagata-u.ac.jp/view.cgi?p=383