ダイナミックな核極化により,ハイブリッドペロブスキート薄膜の表面受動剤のNMRが可能になる
Aditya Mishra1, Michael A Hope1, Masaud Almalki2
1Laboratory of Magnetic Resonance, Institut des Sciences et Ingénierie Chimiques, École Polytechnique Fédérale de Lausanne (EPFL), CH-1015 Lausanne, Switzerland.
Journal of the American Chemical Society
|August 12, 2022
まとめ
ダイナミックな核極化 (DNP) は,ペロブスキート太陽電池の核磁気共鳴 (NMR) 感度を高めます. この研究は,薄膜の原子レベルの特徴づけを可能にするDNP効率の鍵としてダイナミックカチオンを特定しています.
科学分野:
- 材料科学
- スペクトロスコーピー
- 再生可能エネルギー
背景:
- ハイブリッドペロブスキート太陽電池の効率と安定性を向上させるには 分子調節器の理解が必要です
- これらの調節器の原子レベルでの特徴付けは,濃度とサンプル質量が低いため困難です.
- 核磁共振 (NMR) スペクトロスコピーは原子レベルでの洞察を提供しますが,薄膜に対する感度には欠けています.
研究 の 目的:
- ペロブスキート太陽電池の薄膜を特徴付けるためのNMRの感度制限を克服する.
- ペロブスキート材料のダイナミック核極化 (DNP) NMR方法の調査と最適化.
- ペロブスキート太陽電池の表面および散発モデュレータの構造活動関係を確立する.
主な方法:
- DNP NMRの効率を制限する要因を特定するために,層状のハイブリッドペロブスキート類の体系的な研究.
- ダイナミックカチオン,マイクロ波吸収,粒子形態学の役割を調査した.
- 急速な緩解性ダイナミックカチオンによる制限を緩和するためにデュテレーションを使用します.
主要な成果:
- ペロブスキットのDNP効率の主要な制限として,迅速な緩解性ダイナミックカチオンが特定された.
- デュテレーションがDNPの効率を大幅に改善し,H DNP強化因数100まで達成することが示された.
- 単一のペロブスキート薄膜に20nmの受容層を特徴付け,乱れた2D層構造を明らかにしました.
結論:
- 最適化されたDNP NMR方法論は,ペロブスキート薄膜における低濃度種の高感度分析を可能にします.
- 特徴づけられた表面層は2Dの層状のペロブスキット構造を示し,散発材料と比較して乱れが増加している.
- この進歩により,ペロブスキート太陽電池のインターフェースの詳細な原子レベルの理解が容易になり,デバイスの性能が向上します.
関連する概念動画
01:27π Electron Effects on Chemical Shift: Overview
1.1K
An applied magnetic field causes loosely bound π-electrons in organic molecules to circulate, producing a local or induced diamagnetic field over a large spatial volume. As the molecules tumble in solution, the field generated by π-electrons in spherical substituents results in a zero net field. However, the net field generated by π-electrons in non-spherical substituents is not zero. The effect of this induced field depends on the orientation of the molecule with respect to B0,...
1.1K
01:15Insensitive Nuclei Enhanced by Polarization Transfer (INEPT)
476
Insensitive Nuclei Enhanced by Polarization Transfer (INEPT) is an advanced Nuclear Magnetic Resonance (NMR) technique specifically designed to detect and enhance the signals of low-abundance nuclei, such as carbon-13 and nitrogen-15, in small molecules. The fundamental principle behind INEPT is the transfer of polarization from a more abundant and highly polarizable nucleus, typically hydrogen-1, to the low-abundance nucleus of interest. This process effectively boosts the NMR signal of the...
476
01:20¹³C NMR: Distortionless Enhancement by Polarization Transfer (DEPT)
1.2K
When proton-coupled carbon-13 spectra are simplified by a broadband proton decoupling technique, structural information about the coupled protons is lost. Distortionless enhancement by polarization transfer (DEPT) is a technique that provides information on the number of hydrogens attached to each carbon in a molecule. While the DEPT experiment utilizes complex pulse sequences, the pulse delay and flip angle are specifically manipulated. The resulting signals have different phases depending on...
1.2K
01:07Nuclear Overhauser Enhancement (NOE)
805
Irradiation of a spin-active nucleus causes an increase or decrease in the signal intensity of neighboring nuclei that are not necessarily chemically bonded or involved in J-coupling. This phenomenon, called the Nuclear Overhauser Enhancement (NOE), results from through-space interactions between the nuclear spins. The NOE effect decreases with increasing internuclear distance and is generally not observed beyond 4 angstroms. In NOE, dipole-dipole interactions between neighboring...
805
01:13¹H NMR: Complex Splitting
1.3K
A proton M that is coupled to a proton X results in doublet signals for M. However, NMR-active nuclei can be simultaneously coupled to more than one nonequivalent nucleus. When M is coupled to a second proton A, such as in styrene oxide, each peak in the doublet is split into another doublet.
Splitting diagrams or splitting tree diagrams are routinely used to depict such complex couplings. While drawing splitting diagrams, the splitting with the larger coupling constant is usually applied...
Splitting diagrams or splitting tree diagrams are routinely used to depict such complex couplings. While drawing splitting diagrams, the splitting with the larger coupling constant is usually applied...
1.3K
01:29Potential Due to a Polarized Object
461
A neutral atom consists of a positively charged nucleus surrounded by a negatively charged electron cloud. When placed in an external electric field, the external electric force pulls the electrons and nucleus apart, opposite to the intrinsic attraction between the nucleus and the electrons. The opposing forces balance each other with a slight shift between the center of masses of the nucleus and the electron cloud, resulting in a polarized atom. On the other hand, a few molecules, like water,...
461