Understanding and Advancing Bifacial Thin Film Solar Cells Under Dual Illumination

Bifacial thin film (BTF) solar cells are starting to receive more attention in the literature. However, deleterious band bending and high interface recombination velocities are often a problem for thin film devices. These issues may affect how BTF devices operate under bifacial illumination compared to monofacial illumination. Using numerical modeling we investigate a BTF device with bifaciality of 0.76 for varying illumination conditions. We show that the power generated from a BTF device is not simply the sum of powers generated by a front illuminated and back illuminated device and use the band diagram to explain the difference. In addition we investigate how the angle of the light incident on the backside of the device affects the device performance.