Efficient Broadband Light Absorption in a Bioinspired Silicon Photonic Structure

Inspired by the near-perfect light-harvesting mechanism in the phycobilisome complex of cyanobacterial cells, a hemicylindrical antenna-shaped photonic structure is proposed and analyzed in the present work for photovoltaic, photonic, and photochemistry applications. Results from finite difference time domain method-based analysis reveal that a cSi-based photonic structure with identical dimensions of the phycobilisome has a very low absorption efficiency in the peak solar wavelength regime. However, by scaling up and optimizing the geometric parameters of the antenna-like photonic structure, a light absorption efficiency of 90.5% can be achieved within a broad wavelength range of 400 to 900 nm. Besides being polarization-insensitive in terms of absorption, the optimized structure exhibits extraordinary dichroism property at a 45° angle of incidence. In addition, calculated electrical performance of the optimized structure is highly promising with a 21.05% photoconversion efficiency as a single-junction solar cell. Such encouraging polarization-insensitive broadband absorption properties and photoconversion efficiency on the silicon platform make the proposed bioinspired photonic structure an excellent candidate for a plethora of applications in photochemistry, optical detection, photovoltaics, and other photonic applications.