【公開日：2024.07.25】【最終更新日：2024.04.19】

課題データ / Project Data

課題番号 / Project Issue Number

23HK0056

利用課題名 / Title

Electron transfer on Au nanoparticle multi-layer structure 

利用した実施機関 / Support Institute

北海道大学 / Hokkaido Univ.

機関外・機関内の利用 / External or Internal Use

内部利用（ARIM事業参画者以外）/Internal Use (by non ARIM members)

技術領域 / Technology Area

【横断技術領域 / Cross-Technology Area】（主 / Main）計測・分析/Advanced Characterization（副 / Sub）加工・デバイスプロセス/Nanofabrication

【重要技術領域 / Important Technology Area】（主 / Main）量子・電子制御により革新的な機能を発現するマテリアル/Materials using quantum and electronic control to perform innovative functions（副 / Sub）革新的なエネルギー変換を可能とするマテリアル/Materials enabling innovative energy conversion

キーワード / Keywords

電子顕微鏡/ Electronic microscope,電子分光/ Electron spectroscopy,蒸着・成膜/ Vapor deposition/film formation,ALD,スパッタリング/ Sputtering,フォトニクス/ Photonics,太陽電池/ Solar cell,電極材料/ Electrode material

利用者と利用形態 / User and Support Type

利用者名（課題申請者）/ User Name (Project Applicant)

ISHIHARA Minori

所属名 / Affiliation

北海道大学　情報科学研究科

共同利用者氏名 / Names of Collaborators in Other Institutes Than Hub and Spoke Institutes

ARIM実施機関支援担当者 / Names of Collaborators in The Hub and Spoke Institutes

利用形態 / Support Type

（主 / Main）機器利用/Equipment Utilization（副 / Sub）-

利用した主な設備 / Equipment Used in This Project

HK-404：超高分解能電界放出形走査電子顕微鏡
HK-611：多元スパッタ装置
HK-617：原子層堆積装置（粉末対応型）
HK-626：光学干渉式膜厚計

報告書データ / Report

概要（目的・用途・実施内容）/ Abstract (Aim, Use Applications and Contents)

Previously, it was reported that Au nanoparticle/titanium dioxide/Au film (Au-NP/TiO₂/Au-film, ATA) structures exhibit high light absorption and photochemical reaction efficiency by forming a mode strong coupling between the localized surface plasmon resonance (LSPR) of AuNPs and the Fabry-Perot (FP) nanocavity. It is believed that AuNPs not only contribute to the formation of the strong coupling by the enhanced electric field of the LSPR, but also facilitate the oxidation reaction of water in the vicinity of the particles by their ability to generate hot carriers through their own electronic excitation. To isolate and understand these roles, we focused on the geometrical arrangement of the AuNPs. We fabricated ATA structures by changing the spatial arrangement of AuNPs in the TiO₂ layer of the nanocavity and observed their optical properties and electron transfer behavior.

実験 / Experimental

A multilayer structure (ATA₁₊₂) containing Au-NPs layers on the TiO2 surface (AuNP₁) and inside (AuNP₂) was prepared by an atomic layer deposition system for the TiO₂ layers and by annealing thin gold films for the AuNPs. For comparison, structures without AuNP₁ (ATA₂) and without AuNP₂ (ATA₁) were also fabricated in the same way. Transient absorption measurements were performed to evaluate the electron injection efficiency. The pump light wavelength was set to 580-730 nm to excite the strong-coupling hybridization level, and the probe light wavelength was set to 2000 nm to observe the absorption of electrons injected into the conduction band of TiO2. In addition, photoelectrochemical measurements were performed under the condition of 0.3 V applied to the Ag/AgCl reference electrode in 0.1 mol dm^-3 KOH aqueous solution in a three-electrode system to evaluate the incident photocurrent conversion efficiency (IPCE).

結果と考察 / Results and Discussion

Multilayer placement of Au nanoparticles resulted in an increase in the coupling strength. With this increase in coupling strength, the multilayer structure had the highest electron injection at most excitation wavelengths. The decay rate of electrons injected into the conduction band of titanium dioxide was also compared and found to be faster than that of the conventional structure due to the increased recombination establishment by the particles embedded in the titanium dioxide. When this multilayer structure was used as a photoelectrode, the IPCE at wavelengths from 400 to 800 nm was reduced by a factor of about 0.75, or about one-fourth, compared to the conventional ATA. The complete embedding of Au nanoparticles in TiO₂ increased the bonding strength, resulting in an increase in electron injection efficiency. However, in order to use the nanoparticles as photoelectrodes, it is necessary to redesign the structure, considering the suppression of recombination between electrons and holes generated by the internal particles and the possibility that electrons are trapped in TiO₂.

図・表・数式 / Figures, Tables and Equations

その他・特記事項（参考文献・謝辞等） / Remarks(References and Acknowledgements)

成果発表・成果利用 / Publication and Patents

論文・プロシーディング（DOIのあるもの） / DOI (Publication and Proceedings)

口頭発表、ポスター発表および、その他の論文 / Oral Presentations etc.

特許 / Patents

特許出願件数 / Number of Patent Applications：0件
特許登録件数 / Number of Registered Patents：0件