The electrical characterization of solar cells is essential to evaluate their performance and understand their behavior under different environmental conditions, including temperature. Charge carriers, under the influence of temperature, diffuse into the cell, a phenomenon quantified by the diffusion capacitance. These generated carriers do not contribute to the electric current; some recombine in specific areas, either on the surface or in the bulk. Bulk recombination mechanisms include Shockley-Read-Hall (SRH) recombination, radiative recombination, and Auger recombination. We analyzed the variation of diffusion capacitance as a function of temperature, neglecting surface recombinations to focus on bulk recombination mechanisms. Calculations, performed for three different bias voltages, show that diffusion capacitance due to Auger recombination predominates, followed by that associated with radiative recombination, while SRH recombination contributes the least. The study reveals that, although the open-circuit voltage decreases with increasing temperature, the diffusion capacitance increases, mainly due to carrier thermogeneration and the exponential variation of the diode current. These results demonstrate a lack of direct causal relationship between the decrease in open-circuit voltage and the increase in diffusion capacitance.
