Perovskite/CIGS Spectral Splitting Double Junction Solar Cell with 28% Power Conversion Efficiency
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Updated: Nov 2, 2025
Fabrication of High Contrast Gratings for the Spectrum Splitting Dispersive Element in a Concentrated Photovoltaic System
Published on: July 18, 2015
Motoshi Nakamura1,2, Keishi Tada3, Takumi Kinoshita3
1Advanced Technology Research Laboratories, Idemitsu Kosan Co.,Ltd., 123-1 Shimokawairi, Atsugi, Kanagawa 243-0206, Japan.
Abstract:
The highest theoretical efficiency of double junction solar cells is predicted for architectures with the bottom cell bandgap (E ) of approximately 0.9-1.0 eV, which is lower than that of a typical Si cell (1.1 eV). Cu(In,Ga)(Se,S)2 (CIGS) solar cells exhibit a tunable E depending on their elemental composition and depth profile. In this study, various CIGS solar cells with E ranging from 1.02 to 1.14 eV are prepared and a spectrum splitting system is used to experimentally demonstrate the effect of using lower-E cells as the bottom cell of two-junction solar cells. The four-terminal tandem cell configuration fabricated using a mixed-halide perovskite top cell (E = 1.59 eV; stand-alone efficiency = 21.0%) and CIGS bottom cell (E = 1.02 eV; stand-alone efficiency = 21.5%) with a 775-nm spectral splitting mirror exhibits an efficiency of 28.0% at the aperture area of 1 cm2.
