High-efficiency silicon solar cells with boron local back surface fields formed by laser chemical processing

The successful implementation of industrially feasible local boron dopings as local back surface field (LBSF) for high-efficiency silicon solar cells processed with laser chemical processing (LCP) is demonstrated for the first time. The processed passivated-emitter rear locally diffused solar cells with LCP LBSFs show cell efficiencies of up to 20.9% with a cell efficiency benefit of up to 0.3-0.4%abs. in comparison to the reference passivated emitter and rear cells processed with a doping-free LCP opening. The results show the potential of LCP to create boron dopings in order to decrease the contact resistance and reduce the minority carrier recombination at the local metal contacts in order to improve the fill factor and the open-circuit voltage, respectively.