Simulation-based roadmap for the integration of poly-silicon on oxide contacts into screen-printed crystalline silicon solar cells

We present a simulation-based study for identifying promising cell structures, which integrate poly-Si on oxide junctions into industrial crystalline silicon solar cells. The simulations use best-case measured input parameters to determine efficiency potentials. We also discuss the main challenges of industrially processing these structures. We find that structures based on p-type wafers in which the phosphorus diffusion is replaced by an n-type poly-Si on oxide junction (POLO) in combination with the conventional screen-printed and fired Al contacts show a high efficiency potential. The efficiency gains in comparsion to the 23.7% efficiency simulated for the PERC reference case are 1.0% for the POLO BJ (back junction) structure and 1.8% for the POLO IBC (interdigitated back contact) structure. The POLO BJ and the POLO IBC cells can be processed with lean process flows, which are built on major steps of the PERC process such as the screen-printed Al contacts and the Al2 O3 /SiN passivation. Cell concepts with contacts using poly-Si for both polarities (POLO2-concepts) show an even higher efficiency gain potential of 1.3% for a POLO2 BJ cell and 2.2% for a POLO2 IBC cell in comparison to PERC. For these structures further research on poly-Si structuring and screen-printing on p-type poly-Si is necessary.

Automated summary

The study demonstrates the high efficiency potential of incorporating n-type poly-Si on oxide junctions (POLO) into industrial crystalline silicon solar cells. Utilizing POLO structures on p-type wafers can achieve higher efficiency, while structures based on POLO2 concepts have even greater efficiency potential. Further research on poly-Si structuring and screen-printing on p-type poly-Si is needed for these structures.