Thin film tandem solar cells provide a promising approach to achieve high efficiencies. These tandem cells require at least a bottom low bandgap and an upper high bandgap solar cell. In this contribution, 2 high‐performance Cu(In,Ga)Se₂ cells with bandgaps as low as 1.04 and 1.07 eV are presented. These cells have shown certified efficiencies of 15.7% and 16.6% respectively. Measuring these cells under a 780‐nm longpass filter, corresponding to the bandgap of a typical top cell in tandem applications (1.57 eV), they achieved efficiencies of 7.9% and 8.3%. Admittance measurements showed no recombination active deep defects. One additional high‐performance CuInSe₂ thin film solar cell with bandgap of 0.95 eV and efficiency of 14.1% is presented. All 3 cells have the potential to be integrated as bottom low bandgap cells in thin film tandem applications achieving efficiencies around 24% stacked with an efficient high bandgap top cell.

中文翻译：

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串联应用的高性能低带隙薄膜太阳能电池

薄膜串联太阳能电池为实现高效率提供了一种有前途的方法。这些串联电池至少需要底部低带隙和上部高带隙太阳能电池。在此贡献中，提出了2个带隙低至1.04和1.07 eV的高性能Cu（In，Ga）Se ₂电池。这些电池的认证效率分别为15.7％和16.6％。在780 nm长通滤波器下对这些电池进行测量，相当于串联应用中典型顶部电池的带隙（1.57 eV），它们的效率分别为7.9％和8.3％。导纳测量显示没有重组活性深层缺陷。另一种高性能CuInSe ₂提出了一种带隙为0.95 eV，效率为14.1％的薄膜太阳能电池。所有3个电池都有潜力被整合为薄膜串联应用中的底部低带隙电池，并通过高效的高带隙顶部电池实现约24％的堆叠效率。