Nanoimprint patterning for tunable light trapping in large-area silicon solar cells

We demonstrate the flexibility of UV nanoimprint lithography for effective light trapping in p–i–n a-Si:H/μc-Si:H tandem solar cells. A textured polymeric layer covered with pyramidal transparent conductive oxide structures is shown as an ideal system to promote front light scattering and thus enhanced photocurrent. The double structure incorporated into micromorph tandem thin film silicon solar cells is systematically investigated in order to find a relationship between interface morphology, optical properties and photovoltaic characteristics. To prevent the formation of defects during cell growth, a controllable smoothing of the imprinted texture is developed. Modules grown on polymer structures smoothed via multi-replication show excellent performance reaching a photocurrent of 12.6 mA/cm2 and an efficiency of 12.8%.

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► Large area a-Si:H/μc-Si:H tandem solar cells with incorporated imprint structures for effective light scattering.
► Gain in the photocurrent and efficiency is observed due to double texturing.
► Texture smoothing achieved via multi-replication increases the FF facilitating enhanced solar cell performance.