Improved LDSE processing for the avoidance of overplating yielding 19.2% efficiency on commercial grade crystalline Si solar cell

A record in laser doped selective emitter (LDSE) solar cells with an efficiency η=19.2% is reported. In this study, we investigate the effect of SiNx films for laser doped selective emitter solar cells with plated front contacts. It is observed that the condition of processes such as silicon nitride and laser doping (LD) is of critical importance prior to light induced plating. If these processes are not performed optimally, localized shunts may form during the light induced plating (LIP) process that then inhibit plating in the surrounding areas. In the previous work an efficiency of 18.3% has been achieved, even though the fill factor was only 74.2% and the cell suffered from additional shunting and shading losses due to overplating. However, in this work, we demonstrate that with the optimization of the PECVD SiNx and metallization processes, cells have reached efficiencies of more than 19% on commercial grade p-type CZ Si substrates.

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► Effect of SiNx films for Si solar cells with plated contacts investigated.
► New condition of SiNx layer studied to minimize the overplating.
► New SiNx film has denser structure than conventional SiNx.
► Use of the new SiNx layer minimizes overplating.
► As a result higher FF of 78.3% and efficiency of 19.24% achieved.