Thermodynamics and Kinetics of Hybrid Perovskite Amino-Deliquescence and Efflorescence

杂化钙钛矿氨基潮解和风化的热力学和动力学

• 批准号: 2102469
• 负责人: James Cahoon
• 金额: $ 50万
• 依托单位: University of North Carolina at Chapel Hill
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2021
• 资助国家: 美国
• 起止时间: 2021-09-01 至 2024-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2102469&HistoricalAwards=false
• 关键词: Thermodynamics; Kinetics; Hybrid; Perovskite; Amino

With support from the Chemical Structure, Dynamics and Mechanisms-A (CSDM-A) Program of the Division of Chemistry, James F. Cahoon and his research group at the University of North Carolina-Chapel Hill will investigate deliquescence, the phenomenon in which a salt takes up water to form a liquid droplet. An analogous set of phenomena that can occur with a class of materials termed hybrid perovskites will be investigated in this research. When hybrid perovskites are exposed to nitrogen-containing amines, the amines play the same role as water, causing the liquefaction and crystallization of the hybrid perovskite material through processes that have been termed amino-deliquescence and amino-efflorescence, respectively. Although by appearances one may think that the salt has melted, what has occurred at a microscopic scale is the condensation of water from the atmosphere to dissolve the salt crystal. The reverse of this phenomenon, termed efflorescence, can occur when the humidity decreases, causing evaporation of water from the droplet and crystallization of the salt. Hybrid perovskites are an exciting class of materials that are being widely studied because of their tunable properties, including strong light absorption and emission, that make them amenable to a range of potential technologies. This project will examine the fundamental physical chemistry that governs the amino-deliquescence/efflorescence process. The results of this study should provide guidelines that can be used to control composition and morphology of such materials to engender them with specific physical characteristics. This project at the interface of physical chemistry and materials science will form the basis of a well-rounded research experience for the high school, undergraduate and graduate students involved.Hybrid perovskites such as methylammonium lead halide are composed of organic and inorganic constituents that have found unique functionality as thin films, macroscopic single crystals, and colloidal nanocrystals. In this project, the liquefaction/crystallization of hybrid perovskites when exposed to amines (e.g. methylamine, butylamine, etc.) at controlled temperatures and pressures will be quantitatively analyzed using a set of in situ measurements and microscopies in a home-built reactor. Analysis of amino-deliquescence and amino-efflorescence phase transitions should permit a detailed thermodynamic and kinetic analysis of the processes, to extract the relevant enthalpic and entropic parameters for these transitions. Understanding nucleation and growth kinetics should provide a means to also understand and control crystallinity, orientation, morphology, and composition. Both three-dimensional and two-dimensional layered perovskites will be studied using small and large organic ammonium or diammonium cations and their corresponding amines or diamines. The project is expected to provide information on an important, fundamental phenomenon seen with hybrid perovskites, yielding insights that could motivate further theoretical study and assist in future chemical and structural modifications of these systems.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.

在化学系化学结构、动力学和机理-A（CSDM-A）项目的支持下，James F。卡洪和他在北卡罗来纳大学教堂山分校的研究小组将研究潮解现象，即盐吸收水分形成液滴的现象。在这项研究中，将研究一类称为混合钙钛矿的材料可能发生的类似现象。当混合钙钛矿暴露于含氮胺时，胺起到与水相同的作用，通过分别被称为氨基潮解和氨基风化的过程引起混合钙钛矿材料的液化和结晶。虽然从表面上看，人们可能认为盐已经融化了，但在微观尺度上发生的是大气中的水冷凝溶解盐晶体。当湿度降低时，这种现象的逆转，称为风化，可能发生，导致水从液滴蒸发和盐结晶。 混合钙钛矿是一类令人兴奋的材料，由于其可调特性（包括强光吸收和发射）而被广泛研究，这使得它们适用于一系列潜在技术。这个项目将研究控制氨基潮解/风化过程的基本物理化学。本研究的结果应提供可用于控制此类材料的组成和形态以使其具有特定物理特性的指南。这个物理化学和材料科学的交叉点项目将为高中生、本科生和研究生提供全面的研究经验。混合钙钛矿（如甲基铵卤化铅）由有机和无机成分组成，具有薄膜、宏观单晶和胶体纳米晶体的独特功能。在该项目中，当暴露于胺（例如甲胺、丁胺等）时，混合钙钛矿的液化/结晶将在自制反应器中使用一组原位测量和显微镜进行定量分析。氨基潮解和氨基风化相变的分析应允许详细的热力学和动力学分析的过程中，提取这些过渡相关的热力学和熵参数。了解成核和生长动力学应该提供一种手段，也了解和控制结晶度，取向，形态和组成。将使用小的和大的有机铵或二铵阳离子及其相应的胺或二胺来研究三维和二维层状钙钛矿。该项目预计将提供有关混合钙钛矿的重要基本现象的信息，产生的见解可以激励进一步的理论研究，并有助于这些系统的未来化学和结构修改。该奖项反映了NSF的法定使命，并被认为值得通过使用基金会的智力价值和更广泛的影响审查标准进行评估来支持。

项目成果

Identifying a “Raoult’s Law” Relationship To Modulate the Stoichiometry of Hybrid Perovskite Films by Amino-Deliquescence/Efflorescence in Mixed Amine Vapors

确定“拉乌尔定律”关系，通过混合胺蒸气中的氨基潮解/风化来调节混合钙钛矿薄膜的化学计量

• DOI: 10.1021/acs.jpcc.3c01900
• 发表时间: 2023
• 期刊: The Journal of Physical Chemistry C
• 作者: Serafin, Lorenzo Y.;Meyers, Jonathan K.;Bryan, Alicia C.;Broun, Katherine G.;Cahoon, James F.
• 通讯作者: Cahoon, James F.