8つの超原子電子を持つ原子的に精密なナノクラスターにおける発光と電子ダイナミクス
K L Dimuthu M Weerawardene1, Pratima Pandeya1, Meng Zhou2
1Department of Chemistry , Kansas State University , Manhattan , Kansas 66506 , United States.
Journal of the American Chemical Society
|November 5, 2019
まとめ
同様のコアを持つ金ナノクラスター, [Au25(SR) 18) -と [Au13(dppe) 5Cl2]3+は,異なる放出特性を示しています. この研究は,実験的および理論的な方法を使用して,それらの光動力学と興奮状態の寿命の違いを明らかにします.
科学分野:
- 材料科学
- ナノテクノロジー
- 物理化学
背景:
- ゴールドナノクラスター ([Au25(SR) 18]-と[Au13(dppe) 5Cl23+) は,13原子のイコサヘドラルコアと8電子の超原子構成を共有しています.
- 構造的な類似性にもかかわらず,光発光と時間分解の電子ダイナミクスには大きな違いがあります.
- これらの違いを理解することは 適した光学特性を有するナノクラスタの設計に不可欠です
研究 の 目的:
- [Au25(SR) 18-と[Au13(dppe) 5Cl23+ナノクラスターの放射特性における類似性と違いを明らかにする.
- [Au13(dppe) 5Cl2]3+の光力学特性を初めて理論的に調査する.
- 電子構造と衰退経路と観測された放出行動を相関させる.
主な方法:
- 光発光と光発光崩壊の実験的な測定
- 時間解像度の短時間吸収スペクトロスコーピー
- 時間依存密度関数理論 (TD-DFT) の放射性および非放射性崩壊特性および寿命の計算.
主要な成果:
- [Au13(dppe) 5Cl2]3+は,[Au25(SR) 18-の弱いバイモダル発光とは異なり,単一の強い発光ピークを示している.
- 両ナノクラスターの強い放出状態は,マイクロ秒の寿命を持つS1脱興奮から生じる.
- [Au13(dppe) 5Cl2]3+の高興奮状態は,空の軌道間のエネルギーギャップが小さいため, [Au25(SR) 18と比較して寿命が短い (<1 ps).
結論:
- 電子構造,特に退廃した空の軌道間のエネルギーギャップは,これらの金ナノクラスターの興奮状態のダイナミクスと放射特性を決定する.
- TD-DFT計算は,光物理学的プロセスを理解するための実験データを効果的に補完します.
- この研究は,金ナノクラスターの構造-特性関係に関する基本的な洞察を提供し,将来の材料設計を導くものです.
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