Role of nanocone and nanohemisphere arrays in improving light trapping of thin film solar cells

A new crystalline silicon solar cell with Si nanocone arrays on the top and Al nanohemisphere arrays on bottom surface were proposed. The light-trapping ability were systematically studied by COMSOL Multiphysics. The nanocone arrays benefit light-trapping by introducing gradient change of refractive index and coupling the incoming light into optical modes. The metallic nanohemisphere arrays affect the light-harvesting by surface plasmon polaritons (SPPs) and scattering effect. The numerical simulations show that the optimal parameters for the periodic nanocone arrays are 350 nm in diameter and 1.1 of the pitch/diameter ratio. The optimal parameters for the nanohemisphere arrays are 160 nm in diameter, 1.3 of the pitch/diameter ratio respectively. Eliminating the Ohmic Loss in metallic nanohemisphere, a 700 nm thick silicon solar cell with the combination of these two nanostructures will contribute an average absorption of 72.928% and a 33.311 mA/cm2 short circuit photocurrent density in the wavelength of 310-1127 nm.