Engineering the MoOx/CIGS Interface for Enhanced Performance and Suppressed Recombination in Industrial Modules

This study investigates how molybdenum oxide (MoO<i>_x</i>) rear interface passivation-specifically its thickness and deposition conditions-affects CIGS thin-film solar cells. The MoO<i>_x</i> layer effectively suppresses selenium/sulfur diffusion into the molybdenum back contact during high-temperature processing, while improving the absorber's microstructure by reducing interfacial voids. These modifications enhance electrical properties, yielding lower series resistance, higher shunt resistance, and improved fill factor and current density. Although recombination increases slightly, the reduction in voltage-related fill factor loss ultimately boosts hole extraction and suppresses electron recombination at the back contact. Consequently, MoO<i>_x</i>-passivated cells achieve superior performance, with industrial-scale modules (1650 mm × 658 mm) reaching 152.41 W output power and 14.0% efficiency. This work provides valuable insights for optimizing MoO<i>_x</i>-based interface engineering to improve CIGS solar cell efficiency and manufacturability.