電子極化が分子有機半導体における電荷輸送パラメータに与える影響
Edward F Valeev1, Veaceslav Coropceanu, Demetrio A da Silva Filho
1School of Chemistry and Biochemistry and Center for Organic Photonics and Electronics, Georgia Institute of Technology, Atlanta, Georgia 30332-0400, USA. edward.valeev@gatech.edu
Journal of the American Chemical Society
|July 27, 2006
まとめ
有機物質の積荷輸送は,標準的な方法によって不正確に予測されます. 偏極化効果は,しばしば無視され,単純分子結晶でも,サイトエネルギーと転送積分を大幅に変化させます.
科学分野:
- マテリアルサイエンス 材料科学
- 固体物理 固体物理学
- コンピューティング・ケミストリー
背景:
- 有機物質における理論的な電荷輸送の研究では,一般的に"エネルギーの二次分解"の方法を使用しています.
- この方法では,モノマー/ダイマー計算からの輸送パラメータが拡張システムに転送可能であると仮定します.
研究 の 目的:
- 有機物質における電荷輸送パラメータに対する極化効果の影響を調査する.
- 偏極化を考慮して,ダイマーから拡張システムへのパラメータの移転性を評価する.
主な方法:
- 理論的な調査のために"エネルギー分割 in dimer"の方法を使用しました.
- エチレンとペンタセンのダイマーおよび拡張システムのための計算されたサイトエネルギーと転送積分.
- 電子極化の影響,特に静電的貢献を分析した.
主要な成果:
- 極化効果により,ダイマーから拡張システムへのパラメータ移転性の失敗が実証されました.
- ポラライゼーションを無視すると,インテグラル値とトレンドを誤って転送することが示された.
- ダイマーシステムと拡張システム間のサイトエネルギー差の有意な変化が観察されました (例えば,ペンタセンの堆積量の30%増加).
結論:
- 電子的偏振は,有機分子結晶の電荷輸送パラメータに大きく影響する.
- "ダイマーでエネルギー分割"の方法は,拡張システムでの正確な予測のために,偏振を慎重に考慮する必要があります.
- 局所化されたモノメア軌道を使って直接計算された移転積分は,二重体と拡張系との間のよりよい類似性を示しています.
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