ドーパントレベルMnを三角化する (II) 磁気共鳴スペクトロスコーピーを用いてCs2NaBiCl6に挿入する
Abhoy Karmakar1, Guy M Bernard1, Arkadii Pominov1
1Department of Chemistry, University of Alberta, Edmonton, Alberta T6G 2G2, Canada.
Journal of the American Chemical Society
|February 14, 2023
まとめ
この研究では,磁気共鳴を用いて,マンガンのドーピングを受けた無鉛の二重ペロブスキットを調査した. マンガンのドーピングはビスムート部位で発生し,材料に影響します.
科学分野:
- 材料科学
- 固体化学
- スペクトロスコーピー
背景:
- 無鉛の金属ハリド二重ペロブスキットは光電子工学にとって有望である.
- トランジションメタルのドーピングは 光学バンドギャップを調節します
- 低ドーピングレベルでは,Cs2NaBiCl6の組み込み部位は十分に理解されていません.
研究 の 目的:
- Cs2NaBiCl6の原子レベル構造を決定する.
- 先進的な光電子アプリケーションの構造-特性関係を理解する.
- 磁気共鳴技術を使用してMn ((II) の挿入部位を明らかにする.
主な方法:
- 固体核磁共振 (NMR),ダイナミック核偏振 (DNP),電子パラマグネティック共振 (EPR) のスペクトロスコピーを組み合わせたマルチテクニックのアプローチ.
- 多核性NMR (Na,23,Cl,35,Cs,209,Bi) で,局所的な環境を調査する.
- 酸化状態,対称性,相互作用を特定するためのEPRとHYPERFINEサブレベルCORrelation (HYSCORE) のスペクトロスコーピー.
主要な成果:
- パラマグネティック・リラクゼーション・エンハンスメント (PRE) を示す影響を受けたスピンで,低レベルのMn (II) の組み込みが検出されました.
- HYSCOREではBi相関がなく,Bi部位での置換が示唆されている.
- NMRとEPRは室温で立方体構造を示し,30K未満の偏差を示した.DNP NMRは均質なMn (II) 分布を支持した.
結論:
- Mn ((II) は,Cs2NaBiCl6の二重ペロブスキート構造におけるBiの代替物である.
- 材料は室温では立方体対称性を保ちますが,低温では偏差を示します.
- 磁気共鳴技術により,Mn2の組み込み部位と分布が明らかにされ,光電子アプリケーションの理解が進みました.
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