Impact of grain geometry on performance and heat dissipation of Sb2Se3 solar cells
摘要
A semi-classical model was developed to evaluate the impact of grain shape and dimensions on the performance of Sb2Se3 solar cells. Two grain geometries—rectangular and cylindrical—were analyzed to determine their influence on current–voltage characteristics and conversion efficiency of the cell giving insights for optimizing grain morphology during fabrication. The model incorporated key material and electrical properties, including surface recombination velocity at grain boundaries, carrier recombination lifetime, and diffusion length. Grain dimensions, such as width, thickness, and diameter, were optimized to achieve higher efficiency. The results reveal that solar cells with rectangular-shaped grains exhibit superior performance, achieving a 13.2% higher efficiency (14.2% compared to 11.5%) than those with cylindrical grains. The open-circuit voltage Voc increased by 11% (0.5 V vs. 0.45 V), while the short-circuit current density Jsc improved by 8% (32.5 mA/cm2 vs. 30 mA/cm2). The Fill Factor also showed a modest increase of 2% (87% vs. 85%). Nevertheless, the heat dissipation through radiative and convective cooling in cylindrical grains is better compared to rectangular grains likely due to more surface area retained between the cylindrical geometry. For example, the top side of cylindrical grains remains at 100 × 109 W/m3 while for rectangular grain it remains hot at 200 × 109 W/m3. These findings underscore the advantages of rectangular grains in enhancing solar cell performance and the cylindrical grain’s capability in thermal stability and heat dissipation.