钙钛矿光催化：在 CsPbBr3 纳米晶体和功能化二茂铁分子的界面实现长寿命电荷分离状态,Journal of Materials Chemistry A

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钙钛矿光催化：在 CsPbBr3 纳米晶体和功能化二茂铁分子的界面实现长寿命电荷分离状态
Journal of Materials Chemistry A ( IF 10.7 ) Pub Date : 2022-09-06 , DOI: 10.1039/d2ta05692e
Siddharth Singh ₁ , Diksha Mittal _{1,

2} , Vinithra Gurunarayanan ₁ , Ankita Sahu _{1,

2} , Ramesh Ramapanicker ₁ , Vishal Govind Rao ₁

Affiliation

铯铅卤化物（CsPbX ₃）钙钛矿在太阳能电池应用中脱颖而出，现在在光催化领域也受到关注。由于在复合前及时提取电荷载流子的光催化存在根本性挑战，考虑到最近使用类似方法开发的太阳能电池的功率转换效率为 25%，结合基于二茂铁 (Fc) 的功能可以在卤化铅钙钛矿中提供显着的电荷提取效率. 在这里，我们将 Fc 与氨基酸残基共价连接，以设计三种分子氧化还原继电器，它们的 -COOH 与 Fc 单元的比例不同，并用它们来探测 CsPbBr _{3中的空穴转移动力学。}用于光催化应用的钙钛矿纳米晶体（NCs）。由于 Fc 形成疏水尾的一部分，极性羧酸 (-COOH) 头基的存在赋予分子表面活性剂型性质，使其可以在胶体溶液中与 CsPbBr ₃ NCs 表面结合。有趣的是，当在 CsPbBr ₃中的电子和表面结合的 Fc 衍生物中的空穴之间产生偶极子时，所有三种情况下的增强结合（如 XPS 峰位移所示）导致形成长寿命的电荷分离状态. _{这在瞬态吸收光谱中很明显，当 CsPbBr 3}异常持续漂白时在 Fc 衍生物存在下观察到激子峰。电荷分离态的这种长期存在无疑反映了分子系统的效用与钙钛矿 NC 中的 Fc 衍生物一样具有成本效益，以进行光催化反应，其中及时提取电荷载流子始终是一个需要克服的挑战。

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Perovskite photocatalysis: realizing long-lived charge-separated states at the interface of CsPbBr3 nanocrystals and functionalized ferrocene molecules

Cesium lead halide (CsPbX₃) perovskites, having stood out for solar cell applications, are now garnering attention in the field of photocatalysis as well. With a fundamental challenge in photocatalysis of timely charge carrier extraction before recombination, incorporating ferrocene (Fc)-based functionalities can offer remarkable charge extraction efficiency in lead halide perovskites, given a recent 25% power conversion efficiency in a solar cell developed with a similar approach. Here, we have covalently linked Fc with amino acid residues to design three molecular redox relays differing in the ratio of –COOH to Fc units and employed them to probe the hole transfer dynamics in CsPbBr₃ perovskite nanocrystals (NCs) for photocatalytic applications. With Fc forming a part of the hydrophobic tail, the presence of the polar carboxylic acid (–COOH) headgroup endowed the molecule with a surfactant-type nature so that it could bind to the CsPbBr₃ NCs' surface in colloidal solution. Interestingly, the enhanced binding in all three cases, as evident by the XPS peak shift, led to the formation of a long-lived charge-separated state when a dipole was created between the electrons in CsPbBr₃ and holes in surface-bound Fc derivatives. This was evident in the transient absorption spectra when an unusually sustained bleach of the CsPbBr₃ excitonic peak was observed in the presence of Fc derivatives. Such prolonged existence of the charge-separated state undoubtedly reflects upon the utility of molecular systems as cost-effective as Fc derivatives in perovskite NCs to carry out photocatalytic reactions where timely extraction of charge carriers is always a challenge to overcome.

更新日期：2022-09-06

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