Light localization at randomly textured surfaces for solar-cell applications

Abstract

By using a rigorous diffraction theory, the localization of light near textured zinc oxide (ZnO) surfaces is theoretically investigated and compared with experimental data obtained from scanning-near-field-optical microscopy. Although random by nature, these surfaces show well-defined geometrical features, which cause the formation of localized light patterns near the surface. Particularly, photon jets are observed to emerge from conical surface structures. Because these structures are of primary importance for applications in photovoltaics, we analyze the “real” surface topography of textured ZnO used in silicon solar cells. With this work, valuable insight is provided into the mechanism of light coupling through randomly textured interfaces.

Maximizing omnidirectional light harvesting in metal oxide hyperbranched array architectures

“…Specifically, both the total and diffuse transmittances ( Supplementary Fig. 4a,b) are reduced in the order of TNW4TNW-NS4TNW-NS-NR, while an increased portion of diffuse component in TNW-NS and TNW-NS-NR has been witnessed after the step-by-step branched modification, which could increase the overall characteristic size of the samples that can serve as the effective scattering elements 29,40 . Further evidence can be shown in the haze factor, which is plotted as a function of wavelength from 400 to 800 nm ( Supplementary Fig.…”

Efficiency limits of Si/SiO2 quantum well solar cells from first-principles calculations

“…A very rough surface acting as a diffuser for the light will usually enhance the optical absorption by increasing the number of oblique paths through the absorber, thereby increasing the pathlength and the probability of total internal reflection. [58][59][60] A reasonable ideal case for the absorptance is the one where the light is scattered isotropically, thereby creating a Lambertian light distribution inside the absorber. 61 The absorptance for Lambertian scattering is the perfect case for isotropic illumination; only for tracked systems, where the light comes always from the same solid angle, better light trapping and higher absorptances are possible.…”

Diffraction and absorption enhancement from textured back reflectors of thin film solar cells

“…[6][7][8][9][10][11][12][13] From a modelling point of view, periodic structures pose fewer difficulties than random ones; consequently, many reports on rigorous calculations appeared. [14][15][16][17][18][19] While increasing computing power made the modelling faster and more accurate over the years, the understanding of the actual mechanisms of light trapping is still limited.…”