Multi-Lattice Cascade Architecture with Dual-Stage Electron Extraction for Reducing Voltage Deficits in Kesterite Photovoltaics

We propose a multi-lattice cascade architecture for kesterite (CZTSSe) solar cells that dramatically reduces the persistent 200–300 mV Voc deficit. By combining a low-Urbach ordered corridor, dual-stage TiO₂/ZnSe electron extraction with a +0.20 eV CBO spike, and NiO back-surface field, the design delivers analytically derived Voc gains of 42–71 mV. SCAPS-1D simulations predict perovskite/kesterite tandem efficiencies of 29.5% (2T) and 31.2% (4T), offering a compelling earth-abundant pathway for high-efficiency, sustainable tandem photovoltaics. Key features: First-principles recombination suppression model + full Python code included.