Enhanced omnidirectional photon coupling via quasi-periodic patterning of indium-tin-oxide for organic thin-film solar cells

Abstract

Enhanced optical coupling via an indium tin oxide quasi-periodic structure (ITO-QPS) as the frontal electrode for organic thin film solar cells was demonstrated. The QPS was fabricated via scalable polystyrene colloidal lithography, which effectively coupled the incident light to the photo-active layer through antireflection and light-trapping mechanisms. The cell efficiency was boosted from 2.91% to 3.26%, corresponding to a 12% enhancement after ITO patterning. Moreover, the angle-resolved absorption spectroscopy also confirmed excellent light coupling at large angles of incidence to 45 degrees, particularly in the wavelength range between 540 and 670 nm. The ITO-QPS guarantees broadband and omnidirectional light harvesting and is widely applicable to a variety of thin film solar cells. (C) 2011 Elsevier B.V. All rights reserved.