Broadband light trapping with disordered photonic structures in thin‐film silicon solar cells

Abstract

We theoretically investigate light trapping with disordered 1D photonic structures in thin‐film crystalline silicon solar cells. The disorder is modelled in a finite‐size supercell, which allows the use of rigorous coupled‐wave analysis to calculate the optical properties of the devices and the short‐circuit current density Jsc. The role of the Fourier transform of the photonic pattern in the light trapping is investigated, and the optimal correlation between size and position disorder is found. This result is used to optimize the disorder in a more effective way, using a single parameter. We find that a Gaussian disorder always enhances the device performance with respect to the best ordered configuration. To properly quantify this improvement, we calculate the Lambertian limit to the absorption enhancement for 1D photonic structures in crystalline silicon, following the previous work for the 2D case [M.A. Green, Progr. Photovolt: Res. Appl. 2002; 10(4), pp. 235–241]. We find that disorder optimization can give a relevant contribution to approach this limit. Finally, we propose an optimal disordered 2D configuration and estimate the maximum short‐circuit current that can be achieved, potentially leading to efficiencies that are comparable with the values of other thin‐film solar cell technologies. Copyright © 2013 John Wiley & Sons, Ltd.

Nano-cones for broadband light coupling to high index substrates

“…A few studies support this operating principle. It has been shown that in disordered 1D structures, the reflection losses decrease with the degree of disorder of the groove width at low degree of disorder of the period44. Similar results have been reported for 2D structures4546, like the one studied here.…”

A fair comparison between ultrathin crystalline-silicon solar cells with either periodic or correlated disorder inverted pyramid textures

“…The major difference between periodic and random structures is that the former excite a well-defined Fourier spectrum, coupling light only at specific wavelengths. On the contrary, disordered structures have a richer Fourier spectrum, increasing the number of accessible diffraction orders and therefore the density of photonic states [18][19][20]. This property improves the coupling of the incident radiation into a broad spectral range thanks to scattering in various directions [14,[19][20][21][22].…”

Deterministic composite nanophotonic lattices in large area for broadband applications

“…In order to analyze the geometrical features of the studied nanostructured thin film and its impact on the optical performance of the structured thin films, we neither used any antireflection coating nor any back reflectors in the present study. The use of such material layers for a given application naturally improves further the absorption in the Si thin films1723. For a quantitative analysis, we also estimated the maximum achievable short circuit current density j sc,max ( see Methods ) as summarized in Table 1.…”

“…panels, slow light integrated chips, structured thin film photovoltaics, novel surface-enhanced Raman scattering nanoplasmonic building blocks, artificially engineered tailorable photonic bandgap materials and efficient nanophotonic test beds for nonlinear light-matter interactions like Anderson localization, and multiple wavelength higher harmonic generation23481112131415161718192021.…”