高性能叠层钙钛矿太阳电池的研究

Solar cells based on organometal trihalide perovskites as light absorbers are emerging as a low-cost and high performance photovoltaic technology. Over the past few years, significant progress was made in perovskite solar cells with power conversion efficiencies shot up from 3% to 20%. Recent studies revealed that perovskite materials exhibit several desired properties for photovoltaic applications including high absorption coefficient, high ambipolar mobilities, and long carrier-diffusion lengths, making them a very appealing class of material for new generation photovoltaic technology. Although the rapid increase in efficiencies, perovskite solar cells are still far away from commercialization as they are still facing several scientific and technical challenges including poor stability, poor device reproducibility and high toxicity remains unclear. .In this proposal, the applicant will tackle the current challenges of perovskite solar cells by an integrated strategy including: 1) design and synthesis new perovskite composites, particularly on lead-free materials; 2) develop new interfacial materials tailored to improve the interfacial property in perovskite solar cells and 3) develop new processing technique to control the crystal growth and morphology of perovskite thin films. Finally we will further develop new device architecture based on tandem design to construct very high efficiency perovskite tandem solar cells. Through these complementary studies, we target to provide new solutions to improve both the reliability and performance of this new generation solar cell technology.

以钙钛矿为基础的太阳电池近年来在国际上引起了广泛关注, 钙钛矿材料具有迁移率高、载流子寿命长、光吸收能力强、可溶液加工等突出优点，并于近几年在效率方面取得了重大突破，被视为极具潜力的太阳电池技术。尽管钙钛矿太阳电池发展迅猛，但仍有许多基础科学及技术上的问题亟待解决，如器件稳定性和重复性较差、材料高毒性等。本项目结合申请人在高效有机及有机／无机杂化太阳电池研究方向的经验，从多角度出发，交叉研究解决目前钙钛矿电池领域的关键科学问题，主要包括1）新型钙钛矿杂化材料的设计合成；2）发展适合于钙钛矿太阳电池的新型界面材料及界面调控；3）开发新的加工方法以控制钙钛矿晶体的生长及薄膜形貌等。基于以上研究基础，我们将进一步发展新型钙钛矿叠层结构的太阳电池，致力于大幅度提升钙钛矿太阳电池的效率，更加突显这一新型太阳电池的优势。

近年来，有机-无机杂化钙钛矿太阳电池以其优异的光电性能和加工特性引起了国际上的光泛关注，并在近几年效率取得突飞猛进的发展。但材料的高毒性和器件的稳定性问题仍亟待解决。在本项目的研究中，为了降低钙钛矿材料的毒性，我们通过有机小分子添加剂，成功地调控了锡/铅基钙钛矿薄膜的形貌和钙钛矿晶体的生长，并制备出竖直生长的二维及三维杂化钙钛矿结构，实现高稳定窄带隙钙钛矿太阳电池；为了提高器件的稳定性，我们研究热稳定性更好的全无机钙钛矿太阳电池，通过双界面调控来减小全无机CsPbI2Br钙钛矿太阳电池的能量损失，引入与钙钛矿能级更匹配的SnO2/ZnO双电子传输层，能够有效抑制界面缺陷复合，全无机CsPbI2Br钙钛矿太阳电池的开路电压达到1.23V；通过氨基官能化聚合物（PN4N）作为阴极界面层以及非掺杂的空穴传输聚合物（PDCBT）替代Spiro-OMeTAD作为阳极空穴传输层，实现双界面协同钝化表面缺陷并抑制CsPbI2Br薄膜的光诱导卤化物分离。最终成功制备了高效率、高光照稳定性的CsPbI2Br无机混合卤化物钙钛矿电池。发展新型界面材料，对钙钛矿太阳电池的阴阳极界面进行修饰,通过器件制作、器件界面工程的全面优化和理论计算指导，在高效钙钛矿太阳电池领域有重大突破。而项目中分别发展了高效稳定的宽带及窄带钙钛矿太阳电池，为构建高效钙钛矿/钙钛矿叠层电池奠定了重要基础。