Internal Quantum Efficiency of Hydrogenated Amorphous Silicon Based Plasmonic Thin Film Solar Cells Using Photonic Crystal Back Reflectors

Abstract

Of various light-trapping schemes commonly employed in the plasmonic solar cells, the photonic crystal back reflectors are proved in the literature to enhance the absorption of photons in the near infra-red wavelength region significantly. In these cells, the photonic crystal back reflectors are usually placed at the bottom of the cell along with diffracting Brag’s reflector (DBR). These reflectors block and reflect back the long wavelength light to the absorbing region. Therefore, the absorption of photons in the near infrared region has been significantly increased and the internal quantum efficiency in this wavelength region has been improved resulting in increased power conversion efficiency. In this work an analytical derivation of internal quantum efficiency has been developed to model such effects of photonic crystal back reflector on the internal quantum efficiency of a plasmonic solar cell based on hydrogenated amorphous silicon (a-Si: H) based absorber. The model results show the significant
improvement in the internal quantum efficiency in the near infrared region, as expected.