Extended light scattering model incorporating coherence for thin-film silicon solar cells

Abstract

We present a comprehensive scalar light-scattering model for the optical simulation of silicon thin film solar cells. The model integrates coherent light propagation in thin layers with a direct, noniterative treatment of light scattered at rough layer interfaces. The direct solution approach ensures computational efficiency, which is a key advantage for extensive calculations in the context of evaluation of different cell designs and parameter extraction. We validate the model with experimental external quantum efficiency spectra of state-of-the-art microcrystalline silicon solar cells. The simulations agree very well with measurements for cells deposited on both rough and flat substrates. The model is then applied to study the influence of the absorber layer thickness on the maximum achievable photocurrent for the two cell types. This efficient numerical framework will enable a quantitative model-based assessment of the optimization potential for light trapping in textured thin film silicon solar cells.

Photonic light trapping and electrical transport in thin-film silicon solar cells

“…Another strategy to trap sunlight in a thin absorber layer is based on rough textures [29,[67][68][69]. The light-trapping mechanism in this approach is different from that corresponding to the ordered and semi-ordered photonic lattices described previously.…”

Light trapping in solar cells: numerical modeling with measured surface textures

“…We have extended our optical solar cell model [12] to directly account for textured layer interfaces that we tackle with non-paraxial scalar scattering theory. This ab initio approach is amenable to a purely experimental input without simplifying assumptions and allows for computationally efficient simulations compared to more brute force full-wave simulation methods.…”

“…Our earlier developed absorption model computes the spectral absorption profiles by means of non-iterative ray-tracing [12]. We integrate over all azimuth angles and thus represent the propagating radiation by the discretized polar angle only.…”

“…We extend our earlier model that integrates thin-film optics with non-iterative ray-tracing [12] with an interface model that relies on non-paraxial scalar scattering theory [13,14]. We demonstrate that this interface model correctly describes the scattering at nano-textured interfaces even for oblique incidence, which is a prerequisite for avoiding heuristic scattering intensity distributions.…”

Laminated fabric as top electrode for organic photovoltaics

“…Details on the optical model are given in the literature. 26 The EQE of the OPV cell was simulated with light incident through the AZO/Ag/AZO bottom electrode and with light incident through the fabric top electrode. Assuming 85% extraction efficiency, we obtained a good agreement between simulated and measured EQE for both illumination directions.…”