Effective CdS/ZnO nanorod arrays as antireflection coatings for light trapping in c-Si solar cells

Abstract

Effective CdS/ZnO nanorod arrays (NRAs) as antireflection coatings for light trapping in c-Si solar cells were prepared by a chemical bath deposition method which is a mature technology suitable for mass production. Field emission scanning electron microscopy (FESEM) reveals that CdS nanoparticles with a diameter of ∼65 nm are deposited on the top of ZnO NRAs with an average length of 380 nm and a diameter of ∼40 nm. The cell with CdS/ZnO NRAs coatings exhibits lower reflectance and better light trapping ability than the cell with ZnO NRAs. PL spectra reveal that the formation of CdS nanoparticles can suppress the outward broad defect emission of ZnO NRAs peaking around 575 nm so that green-yellow light emission of ZnO NRAs can be transmitted into c-Si solar cells for photovoltaic conversion. The J–V curves obtained under the AM1.5G simulator illumination conditions further indicate the improved photovoltaic properties of c-Si solar cells due to CdS/ZnO NRA antireflection coatings.