Development and Scaling of Slot-Die-Coated Perovskite/Silicon Tandem Two-Terminal Photovoltaic Cells

Two-terminal perovskite/silicon tandem solar cells have repeatedly been demonstrated with efficiencies exceeding 30%, but significant challenges remain to scaling to 5,000 wafer per hour throughput with high yield and ensuring reliability over a module’s lifetime. This talk will share Beyond Silicon and ASU’s progress in slot-die coating perovskite top cells on full-area M2 silicon heterojunction bottom cells. Both the microscopic and milliscopic texture of the silicon wafer—which result from the combination of the wafer sawing, saw-damage removal etching, and texturing—determine the morphology of the perovskite layer. We categorize the most common perovskite slot-die coating defects, many of which stem from the underlying silicon texture, and introduce techniques to eliminate them or mitigate their effects. With proper defect control, the tandem device performance across a wafer becomes spatially uniform and exceeds 26%.