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

• Published in: Progress in photovoltaics 2014-12, Vol.22 (12), p.1237-1245
• Main Authors: Bozzola, Angelo, Liscidini, Marco, Andreani, Lucio Claudio
• Format: Article
• Language: English
• Subjects: Applied sciences; Disorders; Energy; Exact sciences and technology; light trapping; Mathematical models; Natural energy; Optimization; Photonics; Photovoltaic cells; Photovoltaic conversion; Silicon; Solar cells; Solar cells. Photoelectrochemical cells; Solar energy; Thin films; thin-film silicon solar cells; Trapping
• ISSN: 1062-7995; 1099-159X
• DOI: 10.1002/pip.2385

ABSTRACTWe 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. We theoretically investigate light trapping in thin‐film crystalline silicon solar cells with photonic structures combining order and disorder. We find that the richer Fourier spectrum of disordered patterns is responsible for increased coupling of incident sunlight inside the solar cell. We derive guidelines for disorder optimization, and we prove that partially disordered photonic structures represent a valid way to approach the Lambertian limit to light trapping.