Modeling and design of non-fullerene organic solar cells using pyramidal lens arrays

Abstract

Addressing front-end reflection in solar cells poses a significant challenge for Organic Photovoltaic (OPV) technology. Ongoing research endeavors aim to mitigate this reflection loss, with the adoption of various light-trapping and reflection-reducing mechanisms emerging as a promising solution. In this work, periodical structures in the form of pyramidal lens arrays (PLAs) have been studied for efficient photon management in organic solar cells (OSCs) made of high dielectric constant non-fullerene-based acceptor (NFA) active layers. When stacked on top of OSCs, these arrays reduce the overall reflection and increase the incident flux to the active layer, boosting exciton generation and overall cell efficiency. This approach could potentially be adopted as a prospective strategy in the future solar cell industry. For the first time, an analytical model is proposed to investigate the effect of the geometrical parameters and packing design of the PLAs on the optical generation rate. The interaction of the lateral surface area with the incoming light has also been considered. The highest power conversion efficiency and short circuit density are obtained with a filling ratio of 1 and an apex angle of 90°, demonstrating a remarkable improvement of over 12 % and 11 %, respectively, for the textured device compared to the planar configuration. The mathematical results obtained are in excellent agreement with the simulation results, thus proving the model's validity.