城戸・笹部・千葉研究室M2 杉山遼君と笹部久宏准教授、城戸淳二教授らの青色ホスフィニン誘導体を用いた高効率有機ELの論文が Wiley の Chem. Eur. J. (IF: 4.3) に受理されました。本研究は愛媛大学林研究室との共同研究です。

本研究は、JST の COI プロジェクト、JSPS 科研費（基盤研究B, 20H02807, 23H02032）の助成を受けたものです。

Title: Highly efficient blue fluorescent organic light-emitting devices based on l5- phosphinine derivatives
By Ryo Sugiyama, Riku Okada, Taito Noda, Naoki Meguro, Naoto Yoshida, Keigo Hoshi, Hidetoshi Ohta,* Minoru Hayashi,* Hisahiro Sasabe,* Junji Kido*, Chem. Eur. J. accepted.

Abstract: Although l5-phosphinine derivatives are known as a promising class of blue fluorescent emitters, those photoluminescent quantum yield (PLQY) values have been reached up to 92%, however, only a few examples have been explored as an emitter for blue organic light-emitting device (OLED), and the external quantum efficiency (EQE) has been below 2.4% so far. In this study, we newly developed two types of blue l5-phosphinine derivatives namely CN-COCF3 and CO2Me-CHO, and investigated the photophysical properties in the solid states. The photophysical analyses in solid state films suggested that the strong electron-accepting nature of these l5-phosphinine derivatives caused the inferior PLQY values, and the exciplex formation with the host and neighboring materials should be avoided to improve the device efficiency. By choosing suitable host and neighboring materials with deep ionization potentials, we successfully realized efficient blue fluorescent OLEDs with EQE of over 4% and CIE (0.14, 0.18). This is among the best in l5-phosphinine-based blue OLEDs so far.

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