Optical simulation of external quantum efficiency spectra of CuIn1-xGaxSe2 solar cells from spectroscopic ellipsometry inputs
Optical simulation of external quantum efficiency spectra of CuIn1-xGaxSe2 solar cells from spectroscopic ellipsometry inputs
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DOI：
10.1016/j.jechem.2017.10.029
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发表时间：
2018-07-01
影响因子：
13.1
通讯作者：
Collins, Robert W.
中科院分区：
文献类型：
--
作者：
Ibdah, Abdel-Rahman A.;Koirala, Prakash;Collins, Robert W.
应用原位和非原位椭圆偏振光谱（SE）的参数表达式，定义的真实的部和虚部（1），2）的薄膜太阳能电池组件的复介电函数谱的发展。然后，这些光谱可以用于分析完整的薄膜太阳能电池的结构。完整太阳能电池的光学和结构/组成模型通过对完整电池获得的SE数据进行最小二乘回归分析而开发，从而能够模拟外部量子效率（EQE），而无需可变参数。这种模拟可以直接与EQE测量进行比较。通过这些比较，可以详细了解薄膜光电子学（PV）技术中光学和电子增益和损耗的起源，以及由此产生的潜在性能限制。事实上，当带隙以上的光子没有被有源层吸收时发生的光学损耗可以与当有源层中产生的电子-空穴对没有被收集时发生的电子损耗区分开来。这种整体方法已被应用于铜铟镓二硒（CuIn 1-xGaxSe 2; CIGS）太阳能电池，一个关键的商业化薄膜光伏技术。CIGS太阳能电池具有标准厚度（>2 μ m）和薄（
Applications of in-situ and ex-situ spectroscopic ellipsometry (SE) are presented for the development of parametric expressions that define the real and imaginary parts (epsilon(1), epsilon(2)) of the complex dielectric function spectra of thin film solar cell components. These spectra can then be utilized to analyze the structure of complete thin film solar cells. Optical and structural/compositional models of complete solar cells developed through least squares regression analysis of the SE data acquired for the complete cells enable simulations of external quantum efficiency (EQE) without the need for variable parameters. Such simulations can be compared directly with EQE measurements. From these comparisons, it becomes possible to understand in detail the origins of optical and electronic gains and losses in thin film photovoltaics (PV) technologies and, as a result, the underlying performance limitations. In fact, optical losses that occur when above-bandgap photons are not absorbed in the active layers can be distinguished from electronic losses when electron-hole pairs generated in the active layers are not collected. This overall methodology has been applied to copper indium-gallium diselenide (CuIn1-xGaxSe2; CIGS) solar cells, a key commercialized thin film PV technology. CIGS solar cells with both standard thickness (>2 mu m) and thin (