作为当前国际前沿研究热点,钙钛矿太阳能电池被认为是最具产业化实力的新型太阳能电池。高效及低成本是实现产业化的先决条件。柔性器件适于规模化生产，但效率相比刚性有较大差距。叠层电池是提高效率的有效手段，理论效率达32-45%，仍有巨大提升空间。针对上述关键问题，本项目提出一种新思路，以拓宽电池吸收、大幅提高效率为目标，以开发新型低成本离子液体电荷传输材料为核心，辅以不同带隙的钙钛矿材料构建高效柔性叠层电池，利用其协同作用，大幅拓宽吸收，实现效率的突破。该方法适合低温工艺、带隙调适性强、电荷流动性高、工艺简单、成本低，可有效避免传统拓宽光谱手段共敏化不利的相互作用、传统叠层电池相互制约等问题。揭示离子液体电荷传输材料对器件光电性能的调控规律，明确柔性叠层电池叠加原理及优化机制，建立太阳能全光谱利用的新理论和新方法，为柔性电池的高效、低成本及大面积化提供一定的理论依据和应用基础，促进其产业化进程。

As the current hot topic of the international research frontiers, perovskite solar cell (PSCs) is considered to be the most promising for industrialization. High efficiency and low cost are the necessary prerequisites to realize industrialization. The flexible device is especially suitable for roll-to-roll large-scale production. However, the efficiency of flexible PSC is still lower than that of the rigid device. The tandem structure with the theoretical efficiency of 32-45% is an efficient method for broadening the absorption spectrum and improving the conversion efficiency of PSCs. To resolve the above key issues, in this work, aiming at broadening the absorption and improving the conversion efficiency, new series of ionic liquid-based electron/hole transport materials for flexible PSCs are explored. To achieve a breakthrough on the conversion efficiency and absorption spectrum, the perovskite materials with different band gaps are investigated for constructing high-efficient flexible tandem devices. This method is attractive for the features of the low-temperature process, flexible band gaps, high electron/hole mobility, simple fabrication technology and low cost. Moreover, this method can also effectively overcome the disadvantages of traditional strategies, such as the unfavorable interactions of co-sensitization and the low efficiencies arise from the interactions of the subcells in traditional tandem cells. Furthermore, the effects of the ionic liquid-based electron/hole transport materials on efficiencies of devices are revealed. The superposition principle and optimization mechanism on the flexible tandem PSCs are clearly clarified. To provide the new strategy for full use of solar energy, this work should have some theoretical and practical implications for improving the photovoltaic performance, lowing the cost, realizing large-area production and promoting the industrialization process of flexible PSCs.