Comparative analysis of radiation-induced effects on the performance of p-type PERC and TOPCon solar cells for space applications

Abstract

This work presents a comprehensive numerical evaluation of PERC and TOPCon technologies, focusing on the impact of radiation-induced defects. This assessment is conducted for p-type silicon solar cells as they are intrinsically more resistant to radiation defects. By rigorously calibrating recombination parameters, radiation-induced defect profiles, and other pertinent details, a robust basis is established for an in-depth comparison of the performance characteristics displayed by both architectures under space conditions. The investigation reveals that when utilizing substrates with high doping levels, both PERC and TOPCon cells exhibit nearly identical beginning-of-life (BOL) and end-of-life (EOL) performance. However, with lower substrate doping concentrations, both technologies show improved BOL efficiency. Notably, this enhanced BOL efficiency does not translate into superior EOL efficiency. This distinction in EOL efficiency can be attributed to two primary factors triggered by radiation exposure. Firstly, the emergence of defects leads to a reduction in open-circuit voltage. Secondly, dopant compensation contributes to an increase in series resistance. Specifically, for PERC cells, the challenge of elevated series resistance is further exacerbated by the requirement for majority carriers to traverse both vertically and laterally to reach the rear metal contact. When a robust defect recovery mechanism or resilient cover glass is absent, substrates characterized by lower doping levels display increased susceptibility to the adverse effects of radiation-induced defects and the subsequent dopant compensation. Under these circumstances, the TOPCon technology demonstrates a significant advantage over PERC, particularly for high electron fluence due to its full area contacts for both minority and majority charge carriers.