Impact of Surface Texturization on Overall Performance of Mono-Crystalline Silicon Solar Cells

Abstract

Solar photovoltaics are amongst the foremost and most extensively studied sustainable energy systems. Silicon solar cells dominate commercial systems and hence bringing them ever closer to the theoretical efficiency is of vital importance. Technologists are continuously refining the manufacturing process to improve the efficiency of the cell while bringing down the cost. The Silicon solar cell manufacturing is a complex process with many vital steps. Studies have shown the importance of steps like surface texturization[1], diffusion[2], antireflective coatings[3], making contacts[4] and metallization[5]. Amongst these the maximum impact on the final efficiency of the solar cell was found to come from the surface texturization[7]. This step creates surface features that improve light harvesting by the multi bounce approach. While heuristically it is understandable that the reduction in reflectivity would impact the cell performance, the present study aims to quantify this improvement. To that end, two different processes were used to texture the mono-crystalline silicon wafers, the difference being the bath additives used. The studies were carried out on 125x125 mm mono-crystalline silicon (C-Si) wafers. The wafer reflectivity and texture uniformity were studied using a full spectrum colourimeter. The wafers were then processed into finished cells and the I-V characteristics of these cells were evaluated. The various performances characteristics of the cell were statistically analyzed to study there correlation to the reflectivity.