基于有机太阳能电池的4H-Cyclopenta[1,2-b:5,4-b']dithiophene受体的近红外小分子的系统工程
Muzammil Hussain1, Muhammad Adnan2, Zobia Irshad2
1Department of Chemistry, University of Okara, Okara 56300, Pakistan.
ACS omega
|July 8, 2024
概括
新的近红外非富勒烯受体 (NFAs) 对高效的有机太阳能电池 (OSC) 显示出前景. 计算研究显示,与现有材料相比,电荷移动性得到改善,吸收光谱更广泛.
科学领域:
- 材料科学 材料科学 材料科学
- 有机电子 有机电子
- 计算化学的计算化学
背景情况:
- 非富勒烯受体 (NFAs) 由于可调节的特性,正在推进批量异质连接有机太阳能电池 (OSCs).
- 与富勒烯相比,NFAs提供了优势,从而提高了功率转换效率.
研究的目的:
- 引入新的近红外NFA系列 (AY1-AY8) 以提高OSC性能.
- 调查这些NFA的结构-财产关系.
- 探索它们的光学,光电子,光物理和光伏特征.
主要方法:
- 利用先进的量子化学模拟,包括密度函数理论 (DFT) 和时间依赖的DFT.
- 估计的关键几何和电子性质:边界分子轨道,电荷流动性,结合和激发能,以及能量差距.
- 分析了供体/接受体复合体 (PTB7-Th/AY8),以了解电荷转移动态.
主要成果:
- 与参考分子 (R) 相比,设计的NFA (AY1-AY8) 表现出红移吸收和改善的电荷流动性.
- 这些NFAs显示了显著更窄的电子能量差距 (1.89-1.71 eV),促进了增强的电荷传输和更广泛的吸收光谱.
- 对于设计的NFAs,观察到低的结合和激发能.
结论:
- 设计的AY1-AY8 NFA系列在OSC应用中表现出卓越的电子和光学性能.
- 这些NFA推用于高效的有机太阳能电池的实验开发.
- 该研究为下一代光伏设备的NFA设计提供了宝贵的见解.
相关概念视频
Photochemical Electrocyclic Reactions: Stereochemistry
The absorption of UV–visible light by conjugated systems causes the promotion of an electron from the ground state to the excited state. Consequently, photochemical electrocyclic reactions proceed via the excited-state HOMO rather than the ground-state HOMO. Since the ground- and excited-state HOMOs have different symmetries, the stereochemical outcome of electrocyclic reactions depends on the mode of activation; i.e., thermal or photochemical.
Selection Rules: Photochemical Activation
Selection Rules: Photochemical Activation
[4+2] Cycloaddition of Conjugated Dienes: Diels–Alder Reaction
The Diels–Alder reaction is an example of a thermal pericyclic reaction between a conjugated diene and an alkene or alkyne, commonly referred to as a dienophile. The reaction involves a concerted movement of six π electrons, four from the diene and two from the dienophile, forming an unsaturated six-membered ring. As a result, these reactions are classified as [4+2] cycloadditions.
Thermal Electrocyclic Reactions: Stereochemistry
The stereochemistry of electrocyclic reactions is strongly influenced by the orbital symmetry of the polyene HOMO. Under thermal conditions, the reaction proceeds via the ground-state HOMO.
Selection Rules: Thermal Activation
Conjugated systems containing an even number of π-electron pairs undergo a conrotatory ring closure. For example, thermal electrocyclization of (2E,4E)-2,4-hexadiene, a conjugated diene containing two π-electron pairs, gives trans-3,4-dimethylcyclobutene.
Selection Rules: Thermal Activation
Conjugated systems containing an even number of π-electron pairs undergo a conrotatory ring closure. For example, thermal electrocyclization of (2E,4E)-2,4-hexadiene, a conjugated diene containing two π-electron pairs, gives trans-3,4-dimethylcyclobutene.
Cycloaddition Reactions: Overview
Cycloadditions are one of the most valuable and effective synthesis routes to form cyclic compounds. These are concerted pericyclic reactions between two unsaturated compounds resulting in a cyclic product with two new σ bonds formed at the expense of π bonds. The [4 + 2] cycloaddition, known as the Diels–Alder reaction, is the most common. The other example is a [2 + 2] cycloaddition.
Cycloaddition Reactions: MO Requirements for Photochemical Activation
Some cycloaddition reactions are activated by heat, while others are initiated by light. For example, a [2 + 2] cycloaddition between two ethylene molecules occurs only in the presence of light. It is photochemically allowed but thermally forbidden.
Thermal and Photochemical Electrocyclic Reactions: Overview
Electrocyclic reactions are reversible reactions. They involve an intramolecular cyclization or ring-opening of a conjugated polyene. Shown below are two examples of electrocyclic reactions. In the first reaction, the formation of the cyclic product is favored. In contrast, in the second reaction, ring-opening is favored due to the high ring strain associated with cyclobutene formation.


