Atomic-Layer-Deposition-Free Monolithic Perovskite/Silicon Tandem Solar Cell Reaching 29.91% Power Conversion on Industrial PERX/TOPCon-like Silicon Bottom Cells

Typically, the perovskite top-cell processes of monolithically integrated perovskite/silicon tandem solar cells (PSTSCs) include a slow and expensive atomic layer deposition (ALD) to grow a tin oxide (SnOx) buffer layer protecting against sputter damage during the subsequent transparent top electrode deposition. We successfully replaced the ALD-SnOx buffer layer with industry-compatible thermal evaporation of bathocuproine (BCP). By applying soft-sputter deposition of indium zinc oxide (IZO), we circumvent the increased risk of sputter damage when replacing ALD-SnOx with organic BCP. In addition to technological advantages, this leads to a 20 mV gain in open-circuit voltage, similar charge extraction rates, and higher current densities due to less parasitic absorption, as confirmed by absolute and transient photoluminescence, current density–voltage, spectral responsivity, and transient surface photovoltage measurements. Integrating the BCP/IZO top contact into tandem solar cells enables a certified power conversion efficiency of 29.91% of our ALD-free PSTSC using industrial silicon bottom cells from Q CELLS' Q.ANTUM technology.