Effects of frequency upconversion layer and two-dimensional arrays of inverted nanocone hole on the performance of ultrathin crystalline silicon solar cells

Abstract

We report the design and optimization of photonic crystal (PhC) structures within the crystalline silicon absorption layer in ultrathin solar cells with a frequency upconversion layer. In the PhC structure, inverted nanocone hole (ICH) arrays with different diameters and inclination angles are used, and the light-trapping performances of air and Si3N4 filled ICH arrays are systematically studied by COMSOL Multiphysics, respectively. The simulation results indicate that the average optical absorption of the solar cells and the local electric field intensity in the upconversion layer can be greatly improved by using PhC structures within the absorption layer. For ICH in height of 1.6 μm, the maximum absorptivity of the solar cells with air filled ICH arrays is 90.75%, while the maximum absorptivity of solar cells with Si3N4 filled ICH arrays is 85.62%. In addition, the upconversion effects of β-NaYF4:Er3+/Yb3+ nanomaterials on the power conversion efficiency of the solar cells were also investigated. The presented model will be the basis for further preparations of high-efficiency ultrathin crystalline silicon solar cells.