Perovskite/Silicon Tandem Solar Cells: A Scalable Manufacturing Process Using Slot-Die Coating for Enhanced Photovoltaic Efficiency

Abstract

The photovoltaic (PV) industry, dominated by single-junction crystalline silicon (c-Si) technology, is approaching its practical efficiency limit. To push beyond the Shockley-Queisser limit and further reduce the levelized cost of electricity (LCOE), perovskite/silicon tandem solar cells have emerged as a transformative technology. These devices leverage the complementary bandgaps of silicon (~1.1 eV) and perovskite (~1.6-1.8 eV) to more efficiently harvest the solar spectrum, with lab-scale devices now exceeding 33% efficiency. However, a critical bottleneck preventing their commercialization is the transfer of these high-performance devices from spin-coated, small-area lab curiosities to large scale, industrially viable modules. This work addresses this challenge by 
presenting a comprehensive manufacturing process centered on slot-die coating, a pre-industrial deposition technique, for the fabrication of the perovskite top cell. We detail the optimization of the ink formulation, coating parameters (meniscus stability, temperature, speed), and drying conditions for depositing high-quality, pin-hole free perovskite and charge transport layers over large areas. Furthermore, we integrate this process with a commercially textured silicon heterojunction (SHJ) bottom cell, addressing the critical challenge of coating conformally on rough surfaces. The resulting tandem devices, fabricated on 6-inch substrates, achieved a stabilized champion efficiency of 28.5% with minimal performance dispersion (<3% relative standard deviation) across the substrate, demonstrating exceptional uniformity. This performance represents one of the highest reported for a slot-die coated perovskite/silicon tandem cell. A techno-economic analysis indicates that this slot-die-based manufacturing flow can significantly reduce material waste and manufacturing costs compared to spin-coating and vacuum-based alternatives. This study provides a critical pathway for bridging the gap between lab-scale innovation and the gigawatt scale manufacturing of high-efficiency, low-cost tandem photovoltaics, marking a significant step toward their sustainable commercialization.