A Flexible Antireflection Layer of ZnO Nanowires Embedded in PDMS

Abstract

The antireflection layer (ARL) plays an important role for improving the conversion efficiency of solar cells by enhancing incident light harvesting at the interface between the air and the top of the cells. Although a SiNx layer prepared via a plasma enhanced chemical vapor deposition method may be applied as an ARL in Si-based solar cells, it exhibits a gradual increase of reflectance effects in a narrow band of wavelengths around 600 nm and limit application to flexible solar cell due to their rigidity. Here, we implement the fabrication of ordered hybrid structures made up of ZnO nanowires and a polymeric matrix with polymer precursor infiltrated into the nanowire arrays. The antireflective properties of the resulting ZnO nanowire-embedded polydimethylsiloxane composite (ZPC) were investigated at various ZnO nanowire lengths and ZPC bending angles. Interestingly, the antireflective properties showed a strong correlation with the length of the embedded ZnO nanowires. As the length of the ZnO nanowires was increased up to 6 ?m, the reflectance of the ZPC films on the silicon ribbon patterns decreased to about 3.3%. However, ZnO nanowire-free polydimethylsiloxane showed lower antireflection efficiency with a reflectance of about 10% with an interference fringe. Interestingly, the ZPC did not lose its antireflective properties by bending and its reflectance value was less than that of the flat ZPC film at a maximum bending angle of 45o.