高效钙钛矿/HIT叠层太阳能电池的制备与性能研究

Recently, the efficiencies of solar cells based on a perovskite light absorber have been remarkably improved. However, most materials with a fixed band-gap suffer from the inherent disadvantages of lacking a broad absorption range, which limits the use of the full solar spectrum. Tandem solar cells provide an effective way to harvest a broader spectrum of solar radiation by combining two or more solar cells with different band-gaps, leading to high power conversion efficiency (PCE). In the present project, we propose a tandem device architecture for photovoltaic cells that employ a wide band-gap perovskite based sub-cell as the top sub-unit, and a low band-gap Si heterojunction with intrinsic thin-layer (HIT) solar cell as the bottom sub-unit, targeting on higher efficiency. To reduce the manufacturing cost of solar cells, a low-temperature processing technique will be adopted to fabricate the planar perovskite solar cells. Besides reducing cost, a low-temperature processing approach offers a wider selection of potential substrates and electrode materials that could be used in the devices. Systematical study will focus on the effects of the electron/hole transport layer, transparent top electrode and tunneling junction on the performance of tandem solar cells. The goal of the present project is revealing the transport and recombination mechanism of carrier in the tandem solar cells. We expect the proposed perovskite/HIT tandem solar cells will enable PCE>27%, which will paves the way for developing high-efficiency and low-cost tandem solar cells.

近年来，钙钛矿太阳电池的效率迅速提升，然而由于太阳光光谱的能量分布较宽，采用单一材料成分制备的单结太阳电池的效率提高受到限制。将不同带隙宽度的太阳电池串叠起来构成多结叠层电池，是大幅度提高电池效率的最有效方法。本项目中，我们拟采用低温溶液方法制备平面结构钙钛矿太阳电池，并将其与薄膜硅/晶体硅异质结（HIT）太阳电池集成，构建钙钛矿/HIT叠层太阳电池，以拓宽电池吸收光谱范围，提高其光电转换效率。叠层电池的全部器件工艺均在低温（<200℃）下完成，不仅可显著降低成本，也扩展了衬底及电极材料的选择范围。我们将系统研究电子/空穴传输层、透明顶电极以及隧道结对叠层太阳电池性能的影响，探明叠层太阳电池中载流子的分离、传输与复合机制，揭示叠层太阳电池的光电转换机理。通过本项目的研究，期望将钙钛矿/HIT叠层电池的光电转换效率提高到27%以上，为发展高效低成本叠层太阳能电池奠定基础。

本项目中，我们拟采用低温溶液方法制备平面结构钙钛矿太阳电池，并将其与薄膜硅/晶体硅异质结（HIT）太阳电池集成，构建钙钛矿/HIT叠层太阳电池，以拓宽电池吸收光谱范围，提高其光电转换效率。叠层电池的全部器件工艺均在低温（<200℃）下完成，不仅可显著降低成本，也扩展了衬底及电极材料的选择范围。我们将系统研究电子/空穴传输层、透明顶电极以及隧道结对叠层太阳电池性能的影响，探明叠层太阳电池中载流子的分离、传输与复合机制，揭示叠层太阳电池的光电转换机理。通过本项目的研究，期望将钙钛矿/HIT叠层电池的光电转换效率提高到27%以上，为发展高效低成本叠层太阳能电池奠定基础。..通过该项目的开展，我们研发出基于石墨烯透明电极的钙钛矿/HIT四端叠层电池，光电转换效率为25.6%, 并经过第三方检测中心认证；提出了卤素盐钝化钙钛矿表面缺陷的思路，先后研制出转换效率为23.3%和23.7%的钙钛矿太阳能电池，连续两次创造了钙钛矿太阳能电池转换效率世界纪录；提出了溶剂控制生长高质量无机钙钛矿的方法以及通过界面调控减少无机钙钛矿界面复合的方法，先后研制出转换效率14.67%和18.6%无机钙钛矿电池。发表国际SCI论文8篇，包括Nature Energy 1篇，Nature Photonics 1篇， Nature Communications 3篇。我们已完成或超额完成了项目设定的考核指标。