Dr Shubham Duttagupta, Group Head of Monocrystalline Silicon Wafer Solar Cells Group – SERIS | Topic: Pilot-scale Demonstration of >23 % monopoly TM Cell Technology
The introduction of passivated contacts to high-volume screen-printed solar cell manufacture is very appealing and at the same time challenging. It requires the passivated contact to be thermally stable when metallized with an industrial screen-printing process that includes commercially available fire-trough pastes. It also requires very high-throughput (>400wafers/hour) and low-cost deposition schemes for the passivated contacts preferably with minimal additional process steps, for example, with single-side deposition and multi-layer deposition within a single system. We present further improvement of SERIS’ monoPoly™ front-and-back contact (FAB) cell structure that features monofacial application of polysilicon (polySi) layer. Using industrial tools, low absorbing doped poly-Si layers are shown to provide extremely low recombination current densities of <3 fA/cm² and implied open-circuit voltage of >730 mV that are able to withstand the high-temperature firing process of screen-printed metal contacts. Currently our monoPoly™solar cells are at 22.8% efficiency on large-area (244.3 cm²) commercially available Czochralski grown n-type monocrystalline wafers with screen-printed and fire-trough metal contacts on both sides – demonstrated in pilot-scale. A roadmap towards 24% efficiency will be presented at the conference.