Unveiling Hot Carrier Relaxation Process in Spiropyran Derivatives-Semiconductor Quantum Dots Hybrid Systems

2023 Fiscal Year Final Research Report

• Project/Area Number: 21K14480
• Research Category: Grant-in-Aid for Early-Career Scientists
• Allocation Type: Multi-year Fund
• Review Section: Basic Section 28010:Nanometer-scale chemistry-related
• Research Institution: Kwansei Gakuin University
• Principal Investigator: Eguchi Daichi 関西学院大学, 理学部, 助教 (50844677)
• Project Period (FY): 2021-04-01 – 2024-03-31
• Keywords: PbS量子ドット / スピロピラン / フェムト秒過渡吸収分光測定

Outline of Final Research Achievements

We analyzed the effect of the electric field of organic ligands on the elementary exciton process in hybrid systems of spiropyran derivative and PbS quantum dots (QDs). Femtosecond transient absorption spectroscopy measurements showed that the growth of 1S bleach signal corresponding to the relaxation process of hot electrons did not change before and after photoisomerization. However, luminescence quenching was observed in this hybrid systems, despite the absence of carrier or energy transfer from the PbS QDs to the organic ligands. This quenching may be attributed to the induction of surface distortion on the QDs by photoisomerization, potentially representing a novel luminescence switching mechanism.

Free Research Field

ナノ材料化学

Academic Significance and Societal Importance of the Research Achievements

これまでは、半導体量子ドット (QDs) から有機配位子へ電子移動やエネルギー移動により、QDsの発光強度の制御を行っていた。そのため、可能なQDsと有機配位子の組み合わせに限りがあった。今回、提唱する新たな発光スイッチング過程は、電子移動やエネルギー移動によるものではないため、赤外や近赤外領域に吸収端や発光帯を持つQDsに適用可能であり、これまで発光スイッチングが達成できなかった発光帯でのスイッチングを可能とする。