二维少层钙钛矿异质结的制备及应用研究进展

Research progress on preparation methods of two-dimensional few-layer perovskite and its heterojunction

摘要:

二维少层钙钛矿材料以其高光吸收系数、长载流子寿命和高载流子迁移率等优异的性质，在光电领域展现出巨大的应用潜力，为高效能量转换与存储、光电探测等光电子器件的开发提供了前所未有的机遇。二维少层钙钛矿的异质结可以通过化学组分和晶格结构的调控，以及表面修饰等手段，获得不同的能带结构以满足多样化的光电应用需求。然而，二维钙钛矿异质结在制备过程中面临的重大挑战在于如何理解并控制其离子在面内和面外方向上的各向异性扩散行为。这一行为存在众多尚未被充分研究的潜在影响因素，严重制约了高结晶质量的大面积二维钙钛矿异质结构的可控制备。针对现有进展，论文首先简述二维钙钛矿材料的基本特性以及二维钙钛矿材料的高质量制备方法，介绍近几年二维钙钛矿异质结的构建快速兴起的趋势。随后介绍当前制备二维少层钙钛矿异质结的方法，包括组装法、溶液生长法及气相交换法。组装法重点介绍基于机械转移方法进行堆叠组装形成异质结构的效果，分析其在抑制阴离子迁移、扩大应用范围和提高异质结结构质量方面的优势与限制；溶液生长法重点介绍二维钙钛矿异质结生长形态的调控，探讨垂直异质结和横向异质结的制备方法及其在组成、形态和界面稳定性的调控机制；气相交换法重点介绍在钙钛矿基底上通过气相离子交换形成异质结的方法，探讨生长时间控制、前驱体源选择、分子交换及扩散的原理及其调控机制，揭示了量子阱厚度、间隔阳离子和A位阳离子对阴离子交换行为的影响。第三，介绍当前二维钙钛矿异质结在光电领域的应用。最后总结了上述三种方法的优缺点，并且对未来二维钙钛矿异质结制备机理研究和技术的优化的方向和重点提出了看法，相信通过相应的研究，有望实现更高质量的异质结结构，并推动相应器件在光电应用领域的的发展。

Abstract:

Two-dimensional few-layer perovskite materials have great application potential in the optoelectronic field due to their excellent properties such as high light absorption coefficient, long carrier lifetime and high carrier mobility, providing unprecedented opportunities for the development of optoelectronic devices such as efficient energy conversion and storage, photodetection, etc. The heterojunction of two-dimensional few-layer perovskite can obtain different band structures to meet the diverse needs of optoelectronic applications through the regulation of chemical composition and lattice structure, as well as surface modification. However, the major challenge faced by two-dimensional perovskite heterojunctions in the preparation process is how to understand and control the anisotropic diffusion behavior of its ions in the in-plane and out-of-plane directions. There are many potential influencing factors that have not been fully studied in this behavior, which seriously restricts the controllable preparation of large-area two-dimensional perovskite heterostructures with high crystalline quality. In view of the existing progress, the paper first briefly describes the basic properties of two-dimensional perovskite materials and the high-quality preparation methods of two-dimensional perovskite materials, and introduces the rapid rise of the construction of two-dimensional perovskite heterojunctions in recent years. Then, the current methods for preparing two-dimensional few-layer perovskite heterojunctions are introduced, including assembly method, solution growth method and gas exchange method. The assembly method focuses on the effect of stacking and assembling to form heterostructures based on the mechanical transfer method, and analyzes its advantages and limitations in inhibiting anion migration, expanding the scope of application and improving the quality of heterojunction structures; the solution growth method focuses on the regulation of the growth morphology of two-dimensional perovskite heterojunctions, and explores the preparation methods of vertical heterojunctions and lateral heterojunctions and their regulation mechanisms in composition, morphology and interface stability; the gas phase exchange method focuses on the method of forming heterojunctions by gas phase ion exchange on perovskite substrates, and explores the principles and regulation mechanisms of growth time control, precursor source selection, molecular exchange and diffusion, and reveals the influence of quantum well thickness, spacer cations and A-site cations on anion exchange behavior. Third, the current application of two-dimensional perovskite heterojunctions in the field of optoelectronics is introduced. Finally, the advantages and disadvantages of the above three methods are summarized, and the direction and focus of future research on the preparation mechanism of two-dimensional perovskite heterojunctions and the optimization of technology are proposed. It is believed that through corresponding research, it is expected to achieve higher quality heterojunction structures and promote the development of corresponding devices in the field of optoelectronic applications.