Balancing light-trapping and defect minimization in ultrathin amorphous silicon solar cells using dual <i>p</i>-layer architecture

Ultrathin solar cell devices based on amorphous silicon offer significant advantages in terms of cost and stability, provided they are effectively integrated with light-trapping strategies. However, integrating these devices with photonic nanotextures is challenging due to the high defect concentrations that may result from the deposition of ultrathin material layers on textured substrates. This study utilizes a cost-effective, scalable approach using quasiperiodic nanowrinkles as textured substrates for ultrathin amorphous silicon solar cells fabricated in a<i>p-i-n</i>configuration, with a 100 nm absorber layer. To enhance the performance on the nanowrinkles, a dual<i>p</i>-layer architecture, comprising a thin hydrogenated amorphous silicon protective layer combined with a nanocrystalline<i>p</i>-type layer is employed. These nanowrinkle solar cell devices show significant improvements, up to ∼33%, in power conversion efficiency compared to their flat substrate counterparts. The dual<i>p</i>-layer approach is effective in mitigating the adverse effect of defects, demonstrating a maximum of ∼33% increase in short-circuit photocurrent densities compared to single-<i>p</i>-layer configuration in the highest efficiency device. Simulation studies are conducted to analyze the electrical characteristics and charge transport phenomenon of the device layers, and the improved performance of the final device.