Clarification of operation mechanisms of next-generation organic/perovskite hybrid devices

2022 Fiscal Year Final Research Report

• Project/Area Number: 20H02817
• Research Category: Grant-in-Aid for Scientific Research (B)
• Allocation Type: Single-year Grants
• Section: 一般
• Review Section: Basic Section 35030:Organic functional materials-related
• Research Institution: Kyushu University
• Principal Investigator: Matsushima Toshinori 九州大学, カーボンニュートラル・エネルギー国際研究所, 准教授 (40521985)
• Project Period (FY): 2020-04-01 – 2023-03-31
• Keywords: ２次元ペロブスカイト / 発光性有機アミン / LED / エネルギー移動 / キャリア輸送

Outline of Final Research Achievements

In LEDs with a two-dimensional perovskite emitter, in which a benzothiadiazole (BT) derivative is used as the large organic cation for the structural organization, the electrons and holes injected from external electrodes are transported through inorganic metal halogen sheets. Then, the excitons are formed in inorganic metal halogen sheets by the recombination between the electrons and the holes. The bright exciton number is higher by three-fold than the dark exciton number, and the conversion from the dark excitons to the bright excitons efficiently happens. Therefore, all the excitons formed inside LEDs can be used to induce the energy transfer to the emissive singlet state of the BT moiety in the two-dimensional perovskite structure. In that case, 100% internal quantum efficiency is achieved in organic-fluorophore-containing two-dimensional perovskite LEDs.

Free Research Field

有機エレクトロニクス

Academic Significance and Societal Importance of the Research Achievements

有機EL素子において、通常は非発光性である三重項励起状態を発光に利用するためには、高価なりん光性イリジウム化合物もしくは精密な分子設計が必要な熱活性化遅延蛍光性(TADF)化合物を用いる必要があった。ところが、本研究で見出した、２次元ペロブスカイト構造中に蛍光性有機アミンを導入する方法を用いれば、りん光及びTADF型有機EL素子に匹敵する高い外部量子効率が得られるようになり、従って、将来的にディスプレイ及び照明産業に大きなインパクトを与える。