钙钛矿太阳电池材料结构设计与优化

发布时间：2018-03-21 05:54

本文选题：钙钛矿太阳电池　切入点：DFT　出处：《华北电力大学(北京)》2017年硕士论文　论文类型：学位论文

【摘要】：近年来,钙钛矿太阳电池因其制作工艺简单、成本低、光电转化效率高等优点而引起了国内外研究者的广泛关注。目前钙钛矿太阳电池的最高光电转化效率已达到22.1%,其进一步发展有望解决太阳电池成本和效率的发展瓶颈。然而钙钛矿太阳电池的长期稳定性和因含有重金属元素铅而对生态环境可持续发展不利等问题,严重制约其产业化发展。因此,钙钛矿材料的稳定性和铅取代问题成为该类电池研究领域的重点。由于目前对钙钛矿型材料的结构与其稳定性和光电性能关系研究相对缺乏,因此限制了新型材料的合理设计和选择。为深入揭示该类材料的元素组成、几何结构、电子结构对其光电性能和稳定性的影响规律,本文首先通过对ABX_3型钙钛矿材料的A位、B位、X位各基团/原子的有序替换,探讨各个位置基团对材料电子结构和稳定性的影响规律;其次,通过对一种新型类钙钛材料MA3Bi2I9(MBI)的结构稳定性和电子结构的理论计算,分析其对铅取代的可行性;最后,系统分析了钙钛矿材料在潮湿环境中的稳定性机理。本论文的第一部分首先对本工作的背景和研究现状进行了系统总结。第二部分则主要对第一性原理计算方法本身以及计算软件和参数进行了系统介绍。第三到第五部分为论文主体。其中,第三部分基于密度泛函理论,以CH_3NH_3PbI_3结构为基础,通过CASTEP软件建立ABX_3结构模型并进行优化;用第一性原理的计算方法,计算各体系的结构和电子性能等;对各体系的能带结构、态密度、内聚能等的差异进行详细分析。对X位上Cl、Br、I、拟卤素进行掺杂计算,替换不同小分子基团A和B位金属阳离子,分别研究A、B、X位结构和元素的改变对ABX_3型钙钛矿材料结构和电子性能的影响;第四部分主要通过CASTEP软件建立MBX模型并进行优化,分析二维层状类钙钛矿材料是否可作为钙钛矿太阳电池的吸光材料,并分析卤素的改变对MBX类钙钛矿材料的结构和电子性能的影响。第五部分通过VASP软件研究MAPbI_3、FAPbI_3和MAPbI_3-CHONH_3PbI_3材料对水分子的吸附性能,分析其在湿气环境中稳定性。通过计算来分析哪种材料更适合作为钙钛矿太阳电池的吸光层。第六部分为总结与展望。
[Abstract]:In recent years, perovskite solar cells have been made with simple process and low cost. At present, the highest photoconversion efficiency of perovskite solar cells has reached 22.1. its further development is expected to solve the cost and efficiency of solar cells. However, the long-term stability of perovskite solar cells and the adverse effects of lead containing heavy metals on the sustainable development of the ecological environment, Therefore, the stability and lead substitution of perovskite materials have become the focus in the research field of this kind of batteries. At present, the research on the relationship between the structure of perovskite materials and their stability and optoelectronic properties is relatively scarce. Therefore, the reasonable design and selection of new materials are limited. In order to reveal the influence of element composition, geometric structure and electronic structure on the optoelectronic properties and stability of this kind of materials, In this paper, we first discuss the influence of each group / atom on the electronic structure and stability of ABX_3 perovskite by the orderly substitution of the groups / atoms at the A and B position of perovskite. Based on the theoretical calculation of the structural stability and electronic structure of a new type of titanium-like material MA3Bi2I9 MBI, the feasibility of its substitution for lead is analyzed. The stability mechanism of perovskite materials in wet environment is systematically analyzed. The first part of this paper summarizes the background and research status of this work. The second part is mainly about the first principle calculation method. The third to 5th parts are the main body of the thesis. The third part is based on the density functional theory, based on the CH_3NH_3PbI_3 structure, establishes and optimizes the ABX_3 structure model by CASTEP software, calculates the structure and electronic properties of each system by first-principle calculation method, and the energy band structure of each system. The difference of density of states, cohesive energy and so on were analyzed in detail. The doping calculation was carried out to replace the metal cations at different small molecular groups A and B on the X site. The effects of the changes of the X site structure and elements on the structure and electronic properties of ABX_3 perovskite materials are studied respectively. Part 4th establishes the MBX model and optimizes it by means of CASTEP software. This paper analyzes whether two-dimensional layered perovskite-like materials can be used as absorbent materials for perovskite solar cells. The effects of the change of halogen on the structure and electronic properties of MBX perovskite materials were analyzed. Part 5th was used to study the adsorption properties of MAPbI_3-CHONH_3PbI_3 and MAPbI3FAPbI3 materials for water molecules by VASP software. The stability of perovskite solar cells in wet atmosphere is analyzed. The best material is calculated to be the absorbent layer of perovskite solar cells. Part 6th is a summary and prospect.
【学位授予单位】：华北电力大学(北京)
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TM914.4

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