Innovative light emitting device using chiral induced spin selective effects

2023 Fiscal Year Final Research Report

• Project/Area Number: 20K21167
• Research Category: Grant-in-Aid for Challenging Research (Exploratory)
• Allocation Type: Multi-year Fund
• Review Section: Medium-sized Section 32:Physical chemistry, functional solid state chemistry, and related fields
• Research Institution: Ibaraki University
• Principal Investigator: Nishikawa Hiroyuki 茨城大学, 理工学研究科(理学野), 教授 (40264585)
• Project Period (FY): 2020-07-30 – 2024-03-31
• Keywords: 円偏光発光 / キラル誘起スピン選択 / キラル伝導体 / 発光デバイス / CP-OLED / キラル輸送材料

Outline of Final Research Achievements

The purpose of this study is to develop circularly polarized organic light-emitting diodes (CP-OLEDs) that exhibit high dissymmetry factors (g-values) by introducing the chiral-induced spin selectivity (CISS) effect into the charge transport layer. We have investigated CP-OLED using chiral hole transport materials, in which a chiral side chain was introduced into the well-known hole transport material PEDOT, and incorporating an organic-inorganic hybrid perovskite layer as the CISS layer between the hole transport layer and the light emitting layer. As a result, we successfully observed circularly polarized electroluminescence (CPEL) from the achiral emitting layer. Additionally, we succeeded in developing CP-OLED with relatively high g-values by using thin films of achiral luminescent polymers doped with chiral molecules.

Free Research Field

物理化学

Academic Significance and Societal Importance of the Research Achievements

本研究では，高い円偏光特性を示すCP-OLEDの開発を目的として，キラル誘起スピン選択（CISS）効果が期待されるキラルなホール輸送材料の新規合成ならびにデバイス化を行うとともに，有機-無機ハイブリッドペロブスカイト層を導入したデバイスの作製を行った。CISS効果によるCP-OLEDは従来の円偏光発光デバイスの開発原理とは全く異なる新しい概念であり，本研究の成果は円偏光発光デバイスの開発において重要な知見を与えるものである。また，CISS効果によるスピンへ極電流の再結合を利用していることから，本結果は円偏光発光とスピンの相関に関する新しい学理を拓く端緒となる結果であり，その学術的意義は大きい。