Wave-optical front structures on silicon and perovskite thin-film solar cells

Photonic structures allow reducing the thickness of photovoltaic (PV) devices while improving their photocurrent, thereby enabling high-efficient, low-cost, and mechanically flexible solar cells. Wave-optical front structures have shown to be promising for integration in various thin-film PV technologies, as those based on silicon or perovskite semiconductors, due to a combination of: (1) Broadband absorption amplification-wavelength-sized structures provide geometrical index-matching for the impinging light, strongly reducing reflection while boosting the photons’ path length within the absorber via scattering.(2) Improved electrical performance-their incorporation in the transparent contact can enable higher electrode volume, thereby improving the cells’ voltage and fill factor. Such a location can also prevent increasing the cells’ roughness, therefore not contributing to recombination.(3) Enhanced stability-particularly in perovskite cells, the front photonic structures block most of the harmful UV radiation that degrades such devices. Colloidal lithography methods have revealed to be highly cost-effective for the nanopatterning of such structures, allowing compatibility with industrial scalability and low-cost requirements.