Optical modeling of wide-bandgap perovskite and perovskite/silicon tandem solar cells using complex refractive indices for arbitrary-bandgap perovskite absorbers
Optical modeling of wide-bandgap perovskite and perovskite/silicon tandem solar cells using complex refractive indices for arbitrary-bandgap perovskite absorbers
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DOI：
10.1364/oe.26.027441
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发表时间：
2018-10-15
期刊：
影响因子：
3.8
通讯作者：
Holman, Zachary C.
中科院分区：
文献类型：
--
作者：
Manzoor, Salman;Haeusele, Jakob;Holman, Zachary C.
宽禁带钙钛矿是极具吸引力的串联光伏顶电池材料。全面的光学建模对于最大限度地减少最先进的钙钛矿/钙钛矿、钙钛矿/CIGS和钙钛矿/硅串联的光学损耗至关重要。这种模型需要精确的宽禁带钙钛矿光学常数。在这里，我们报告了用椭圆偏振法和分光光度法测定两种新的宽带隙铯-甲脒基钙钛矿的光学常数。我们通过比较模拟的量子效率和反射光谱与半透明单结钙钛矿电池的测量结果来验证光学常数，并发现短路电流密度误差小于0.3 mA/cm(2)。这些模拟进一步揭示了前ITO层的反射和寄生吸收以及电子接触是造成最大光学损失的原因。我们还表明，三碘化铅甲基铵（太阳能电池中最常见的钙钛矿吸收剂）的复折射率可以通过沿波长轴平移数据来生成任意宽禁带钙钛矿的近似光学常数。最后，利用这些光学常数绘制了纹理化的双端钙钛矿/硅串联太阳能电池的短路电流密度随钙钛矿厚度和带隙的函数图，并给出了当钙钛矿带隙在1.56 ~ 1.68 eV之间时，电流密度接近20 mA/cm(2)的匹配值。(C) 2018年美国光学学会根据OSA开放获取出版协议的条款
Wide-bandgap perovskites are attractive top-cell materials for tandem photovoltaic applications. Comprehensive optical modeling is essential to minimize the optical losses of state-of-the-art perovskite/perovskite, perovskite/CIGS, and perovskite/silicon tandems. Such models require accurate optical constants of wide-bandgap perovskites. Here, we report optical constants determined with ellipsometry and spectrophotometry for two new wide-bandgap, cesium-formamidinium-based perovskites. We validate the optical constants by comparing simulated quantum efficiency and reflectance spectra with measured cell results for semi-transparent single-junction perovskite cells and find less than 0.3 mA/cm(2) error in the short-circuit current densities. Such simulations further reveal that reflection and parasitic absorption in the front ITO layer and electron contact are responsible for the biggest optical losses. We also show that the complex refractive index of methylammonium lead triiodide, the most common perovskite absorber for solar cells, can be used to generate approximate optical constants for an arbitrary wide-bandgap perovskite by translating the data along the wavelength axis. Finally, these optical constants are used to map the short-circuit current density of a textured two-terminal perovskite/silicon tandem solar cell as a function of the perovskite thickness and bandgap, providing a guide to nearly 20 mA/cm(2) matched current density with any perovskite bandgap between 1.56 and 1.68 eV. (C) 2018 Optical Society of America under the terms of the OSA Open Access Publishing Agreement