A study on the optics of copper indium gallium (di)selenide (CIGS) solar cells with ultra-thin absorber layers

Abstract

Abstract:We present a systematic study of the effect of variation of the zinc oxide (ZnO) and copper indium gallium (di)selenide (CIGS) layer thickness on the absorption characteristics of CIGS solar cells using a simulation program based on finite element method (FEM). We show that the absorption in the CIGS layer does not decrease monotonically with its layer thickness due to interference effects. Ergo, high precision is required in the CIGS production process, especially when using ultra-thin absorber layers, to accurately realize the required thickness of the ZnO, cadmium sulfide (CdS) and CIGS layer. We show that patterning the ZnO window layer can strongly suppress these interference effects allowing a higher tolerance in the production process.

Review on light management by nanostructures in chalcopyrite solar cells

“…In a trade off against losses we therefore usually chose d = 100/130/240 nm for the front contact layers (no MgF2) of ultra-thin devices which are prone to shunting through pinholes in the thin absorber. The influence of the ZnO as well as of the CIGSe thickness itself on the device reflection and absorption has also been studied by Xu et al [9] and variations as a results of Fabry-Perot resonances were visualized. One result was that a 450 nm thick absorber may even perform better than a 500 nm thick one.…”

Spectral Properties and Energy Transfer of a Potential Solar Energy Converter

“…Oil price collapse, geopolitical instability, trends in CO 2 emissions, and energy inefficiency all provoke us to seek renewable and stable energy resources. Recent developments in flexible copper indium gallium selenide, transparent solar cells, upconversion multicolor tuning, and lanthanide ion-doped quantum dots provide optimism in this respect. Our goal has been to harness as much of the solar flux as possible, and herein we report a wideband harvester with an emission profile tailored to the response of the silicon solar cell.…”

Improving the efficiency of copper indium gallium (Di-)selenide (CIGS) solar cells through integration of a moth-eye textured resist with a refractive index similar to aluminum doped zinc oxide

“…6). 10 For the CIGS cells with 1.00 µm and 0.85 µm absorber layer thickness, similar optical losses occur in the wavelength regime above 950 nm caused by incomplete absorption of the light in the thinner absorber layer. These optical losses are reflected in the EQE.…”

“…Nonetheless, through optical simulations we recently obtained strong indications that texturing of the surface of the transparent conductor would be optically advantageous. 10 Instead of direct texturing of the AZO layer, we applied a transparent UV curable resist with a refractive index sufficiently similar to AZO to avoid large optical losses at the resist-AZO interface (n resist = 1.792 v s. n AZO = 1.913 at 633 nm), which is suitable for texturing with UV nano-imprint lithography (NIL). In that way, the two-layered stack AZO-textured resist optically resembles textured AZO, and we can apply well-defined textures without performing tedious experimental studies on texturing of AZO, e.g.…”