Theoretical Evaluation of Angle-Dependent Optical Properties of a Thin Film Solar Cell including One-Dimension Photonic Crystals

Abstract

The effective use of photonic-based integrated systems, whose optical properties can be tuned through light management engineering in optoelectronic devices, constitutes the backbone of today's technology. Especially in systems such as CdTe-based solar cells with well-known and high efficiency, one-dimensional photonic crystal designs emerge as an effective way to provide an electronic or optical improvement. With this intention, in this study, the optical spectra of the MgF2/MoO3 one-dimensional photonic crystal integrated into the CdTe solar cell to improve photon harvesting were investigated theoretically under both bottom and top illumination according to the incidence angle of the electromagnetic wave. The transfer matrix method was used to calculate the angle dependent optical spectra. Since the electromagnetic wave interacts directly with the photonic crystal, it has been observed that the optical properties are more dependent on the angle under the top illumination compared to the bottom one. For top illumination, up to 30°, there is no significant change in reflection in the photonic band gap, but reflection drops significantly at incidence angles greater than 30°. Also, increasing the angle indicates that the low wavelength tail of the photonic band gap shifts to shorter wavelengths and enters the visible region. In the photonic band gap, for angles greater than 45°, the probability of absorption increases significantly as more electromagnetic waves enter the structure. For the bottom illumination, there is no serious dependence on the angle of incidence. For 75°, there is an increase in reflection for all wavelengths and, therefore, a decrease in absorption.