非铅钙钛矿材料的合成和表征及其太阳能电池研究

Inorganic-organic halide perovskite has drawn tremendous interest in the photovoltaic (PV) community because of its excellent optoelectronic properties and solution-processable features. Within a few years of development, the record efficiency of perovskite solar cells has surged above 21% through a solution process, making it the most efficient PV technology by solution processing. Moreover, the high efficiency of perovsksite solar cells has been widely achieved with a variety of cell structures, showing the great potential for further improvement in efficiencies. There are, however, problems that must be addressed before the lead halogen perovskites have a chance of becoming a competitive commercial technology. One is the growing concern of the use of lead, which is a well-known toxic heavy metal. Chemical degradation in a humid environment is the most recognized degradation pathway for perovskite materials. .Herein, we propose an investigation on new lead-free perovksite materials for photovoltaic application. By consideration of stabilizing perovskite structures in terms of tuning tolerance factor, we will start with synthesis of perovskite materials with replacing the Pb element with Sr etc, which should bring down the crystal formation energy and ionic migration barrier energy. The double perovskite with long carrier recombination lifetime will be investigated as well. Lately the film formation based on the obtained materials will be intensively investigated aiming for highly uniform and qualification. The light thermal stability of inorganic perovskite solar cells would be largely enhanced by combination with p-i-n scaffold inorganic oxides. The band gap engineering and interfacial engineering will be performed with dopping and artificial interface dipoles at the perovskite hetero-interfaces in these devices. In addition, the interfacial charge transfer processes in the new perovskite lead-free solar cells will be deeply understood by means of electrochemical impedance and transient voltage/current decay measurements as well.

在众多的新型太阳能电池里，钙钛矿太阳能电池最近脱颖而出，吸引了众多科研工作者的关注。采用溶液法制备的有机卤化铅钙钛矿太阳能电池的光电转换效率已经高于21%，具有良好的应用前景。热稳定性、水溶性、铅的毒性等限制了有机卤化铅新型电池的发展。本工作在考虑晶格容差因子的基础上，从晶体形成能、离子迁移能等基本物理化学特性出发，进行锶等元素取代铅、Bi2FeCrO6双钙钛矿等代表性新型非铅钙钛矿材料的合成和表征，探索薄膜制备，结合掺杂、界面偶极化等措施进行能带工程、界面工程调整新型材料的带隙以及钙钛矿和选择性电极形成的异质结特性，期望通过原子的电子特性改善材料的热/光稳定性，借助无机氧化物p-i-n异质结最终实现高效、稳定的非铅铅钙钛矿太阳能电池器件。应用电化学交流阻抗、暂态光电压/光电流衰减技术深入研究非铅钙钛矿太阳能电池中界面电荷传输。

基于有机无机杂化卤化铅钙钛矿材料的太阳电池，由于优异的光电性质和溶液加工的优势，吸引了众多科研工作者的关注。但是铅的毒性和环境稳定性差限制了这类电池的发展。本工作在考虑晶格容差因子的基础上，从晶体形成能、离子迁移能等基本物理化学特性出发，进行了少铅、非铅钙钛矿材料的合成和表征，结合掺杂、界面偶极化等措施调整新型传输材料的带隙以及钙钛矿和选择性电极形成的异质结特性，改善了材料的热/光稳定性，结合无机氧化物p-i-n异质结实现了高效、稳定的非铅钙钛矿太阳能电池器件。.取得的主要研究结果包括：A）研究Sr、Zn、Ni和Sn取代Pb，合成新型少（非）铅钙钛矿材料，发现了取代元素与Pb电负性相差越小，薄膜结晶质量越高的规律。B）研究碳量子点修饰二氧化钛、F掺杂SnO2、二维SnS2、石墨烯表面引入功能化基团萘二酰亚胺等新型电子传输层材料，钝化界面缺陷针，抑制传输层和钙钛矿层能级不匹配导致的电压损失以及界面缺陷导致载流子复合，钙钛矿电池器件能量转换效率实现>21%的研究目标。C）通过层状Ruddlesden-Popper二维钙钛矿进一步提高无机氧化物 p-i-n 异质结太阳电池效率和稳定性，在湿度 60%的空气氛围下器件保存4000h后效率仍保持其初始效率。.在项目资助下，发表包括Nano Energy, Nano Letters，Advanced Functional Materials等国际期刊SCI论文64论文。授权国内实用新型专利（ZL 2018 2 0457668.2.）一项，授权美国发明专利（US1051576B2）一项。3次受邀参加国际会议，培养了8名博士生，5名硕士生。