Highly Efficient Blue Fluorescent Organic Light-Emitting Devices Based on λ5-Phosphinine Derivatives

Ryo Sugiyama; Riku Okada; Taito Noda; Naoki Meguro; Naoto Yoshida; Keigo Hoshi; Hidetoshi Ohta; Minoru Hayashi; Hisahiro Sasabe; Junji Kido

doi:10.1002/chem.202304328

Highly Efficient Blue Fluorescent Organic Light-Emitting Devices Based on λ⁵-Phosphinine Derivatives

Chemistry. 2024 Apr 11;30(21):e202304328. doi: 10.1002/chem.202304328. Epub 2024 Feb 27.

Authors

Ryo Sugiyama^{1

2

3}, Riku Okada⁴, Taito Noda^{1

2

3}, Naoki Meguro^{1

2

3}, Naoto Yoshida^{1

2

3}, Keigo Hoshi^{1

2

3}, Hidetoshi Ohta⁴, Minoru Hayashi⁴, Hisahiro Sasabe^{1

2

3}, Junji Kido^{1

2

3}

Affiliations

¹ Department of Organic Materials Science, Graduate School of Organic Materials Science, Yamagata University, 4-3-16 Jonan, Yonezawa, Yamagata, 992-8510, Japan.
² Research Center for Organic Electronics (ROEL), Yamagata University, 4-3-16 Jonan, Yonezawa, Yamagata, 992-8510, Japan.
³ Frontier Center for Organic Materials (FROM), Yamagata University, 4-3-16 Jonan, Yonezawa, Yamagata, 992-8510, Japan.
⁴ Department of Applied Chemistry, Graduate School of Science and Engineering, Ehime University, 790-8577, Matsuyama, Japan.

PMID: 38332328
DOI: 10.1002/chem.202304328

Abstract

Although λ⁵-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 λ⁵-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 λ⁵-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 λ⁵-phosphinine-based blue OLEDs so far.

Keywords: blue emission; fluororescence; heteroatom; organic light-emitting device; phosphinine.

Abstract

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