We propose an optimization algorithm to design multilayer antireflection (AR) structure, which has robustness against variations in layer thicknesses, for organic photovoltaic cells. When a set of available materials are given, the proposed method searches for the material and thickness of each AR layer to maximize the short-circuit current density (Jsc). This algorithm allows for obtaining a set of solutions, including optimal and quasi-optimal solutions, at the same time, so that we can clearly make comparison between them. In addition, the effects of deviations in the thicknesses of the AR layers are examined for the (quasi-)optimal solutions obtained. The expectation of the decrease in the AR performance is estimated by calculating the changes in Jsc when the thicknesses of all AR layers are varied independently. We show that some of quasi-optimal solutions may have simpler layer configuration and can be more robust against the deviations in film thicknesses, than the optimal solution. This method indicates the importance of actively searching valuable, nonoptimal solutions for practical design of AR films. We also discuss the optical conditions that lead to light absorption in the back metal contact and the effects of changing active layer thicknesses.

Date Published: 17 October 2013
PDF: 9 pages
Proc. SPIE 8830, Organic Photovoltaics XIV, 88301K (17 October 2013); doi: 10.1117/12.2022989

Published in SPIE Proceedings Vol. 8830:
Organic Photovoltaics XIV
Zakya H. Kafafi; Paul A. Lane, Editor(s)