Development of effective white-luminescent materials by control of ordered structure of luminogen aggregates

2020 Fiscal Year Final Research Report

• Project/Area Number: 18K05265
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Review Section: Basic Section 35030:Organic functional materials-related
• Research Institution: Ritsumeikan University
• Principal Investigator: TSUTSUMI OSAMU 立命館大学, 生命科学部, 教授 (00313370)
• Co-Investigator(Kenkyū-buntansha): 久野 恭平 立命館大学, 生命科学部, 助教 (30822845)
• Project Period (FY): 2018-04-01 – 2021-03-31
• Keywords: 発光 / 液晶 / 凝集誘起発光

Outline of Final Research Achievements

Highly luminescent materials are of great interest for use in light-emitting devices. However, the luminescence intensity of most organic molecules is abruptly reduced in condensed phases owing to aggregation-caused quenching. Recently, some types of organic molecules have shown strong photoluminescence in the condensed phase, where aggregation enhanced the photoluminescence through a phenomenon called aggregation-induced emission (AIE). The structure of their molecular aggregates, as well as their own molecular structure, must strongly affect the luminescence of AIE materials. We have developed liquid-crystalline (LC) luminophores with the AIE property (AIEgen). We observed that acrylate polymers having an LC AIEgen in their side chain changed the luminescent color from blue to white by the glassy-to-LC phase transition. In addition, we discovered that the size of the materials is crucial to control their materials’ properties.

Free Research Field

機能材料化学

Academic Significance and Societal Importance of the Research Achievements

機能分子を材料へと展開する場合，しばしば微粒子や薄膜として利用される。本研究の結果は，微粒子や薄膜などはバルク結晶から期待されるものとは全く異なる物性を示す可能性を示唆しており，機能材料の設計においてはサイズと物性の相関が非常に重要な知見となる。すなわち，特に有機機能材料の設計において従来重視されてきた「分子構造と機能の相関」だけでなく，同じ分子構造でも材料サイズによって機能・性能が変化するという「材料サイズと機能の相関」も考慮した設計が必要となる。