Hybrid TiO₂–ZnO–CNT–PVA anti-reflection coatings for silicon solar cells: A simulation and experimental study

This study presents a simulation-guided and experimentally supported comparison of CNT–PVA and TiO₂–ZnO–CNT–PVA antireflection coatings for silicon solar cells, with the aim of improving optical coupling while avoiding exaggerated performance claims. Under standard test conditions using a QuickSun solar simulator, the uncoated reference cell exhibited an efficiency of 16.07% and a short-circuit current density of 35.88 mA/cm². The fabricated CNT–PVA and Hybrid 1 L coated cells were experimentally measured and achieved efficiencies of 20.45% and 22.22%, respectively, confirming the same performance ranking predicted by the model. The improvement is attributed mainly to reduced front-surface reflection, improved refractive-index matching, and current-driven photovoltaic enhancement, while the nearly unchanged fill factor indicates that the primary coating benefit is optical rather than electrical. Because wavelength-resolved EQE was not measured in the present work, this optical-current interpretation is supported by reflectance and I–V evidence but remains to be confirmed by future EQE characterization. A calibrated optical–electrical framework based on hierarchical effective-medium modeling and the transfer-matrix method was used to project thickness-dependent behavior over the 50–114 nm range. Within this framework, hybrid designs outperformed CNT–PVA, and the best projected Hybrid 2 L case reached 23.13% near 114 nm; however, this two-layer architecture remains a model-guided candidate pending direct coated-cell validation. A substrate-aware hardness model was used only for comparative mechanical screening and not as a substitute for nanoindentation. Overall, the contribution lies in the calibrated comparative framework and direct device-level evaluation of selected hybrid architectures rather than in claiming a wholly new ARC class.