Creation of ultimate photon upconversion materials based on a novel triplet generation method

2022 Fiscal Year Final Research Report

• Project/Area Number: 20H02713
• Research Category: Grant-in-Aid for Scientific Research (B)
• Allocation Type: Single-year Grants
• Section: 一般
• Review Section: Basic Section 32020:Functional solid state chemistry-related
• Research Institution: Kyushu University
• Principal Investigator: Yanai Nobuhiro 九州大学, 工学研究院, 准教授 (90649740)
• Project Period (FY): 2020-04-01 – 2023-03-31
• Keywords: フォトン・アップコンバージョン / 光物性 / 励起三重項

Outline of Final Research Achievements

It has been difficult to achieve high efficiency in photon upconversion (UC), which converts lower-energy light to higher-energy light, at excitation light intensities as low as sunlight. UC from visible light to ultraviolet light is also important for photocatalysis and production of useful compounds, but its efficiency was low. In this study, the problem of phase separation between sensitizer and emitter was solved by forming charge-transfer (CT) complexes, and two types of UC, green light to blue light and blue light to UV light, were successfully achieved in solids and established as a highly general method. Furthermore, by developing new chromophores, the highest UC efficiency from visible light to UV light was achieved, enabling the use of excitation light as weak as sunlight.

Free Research Field

光機能性材料

Academic Significance and Societal Importance of the Research Achievements

固体中でのフォトン・アップコンバージョン（UC）は太陽電池や光触媒などのデバイスへの応用において重要であり、本研究で開発した新しい励起三重項生成法は固体中において様々な波長を高効率に変換する一般的な手法となりうる。また、本研究において可視光から紫外光へのUCの効率を過去の報告より大幅に増大させ、太陽光や室内光程度の弱い励起光を利用可能にしたことは、人工光合成や有用化合物の製造、殺菌や水中の有害物質の分解といった多様な応用に繋がる重要な基礎的知見が得られたと考えられる。