Effect the Technique of Light Trapping on the Performance of Simple Junction n-p Solar Cells Based on GaAs and Si

Abstract

Light trapping enhances the absorption of active materials in photovoltaic cells. The use of light trapping results in a thinner active region in a solar cell, which lowers the production cost by reducing the amount of material used, and increases the energy conversion efficiency by facilitating carrier collection and enhancing the open circuit voltage. There are many light trapping techniques have been introduced in order to enhance absorption of the active layer in the thin film solar cell. Antireflective layers reduce reflection losses at interfaces, Light Trap: force the light to stay longer in the layer by changing the structure of interfaces. In the present work we proposed a technique based on closed-form analytical calculation to analyse the effect of light trapping on the performance of simple Si and GaAs np junction solar cells. Particular importance is paid to light reflection. A comparison is carried out between three types of cells, with antireflection coating, with texturing on the front of the cell, and with a lambertinne reflector. The conversion efficiency increased from 23.00 % in a cell with GaAs texturing on the front and a rear reflector (incoherent reflection) to 23.90 % and for Si it passes from 15.05 % to 16.00 %. GaAs solar cell exhibits a maximum efficiency around 28.68 % with a Lambertian reflector. An efficiency of 19.37 % is obtained with Si when a Lambertian reflector is inserted.