Fabrication and characterization of ZnO nanowires/CdSe/CuSCN eta-solar cell

Abstract

ZnO/CdSe/CuSCN extremely thin absorber ( eta )-solar cells based on ZnO nanowires have been successfully realized using easily accessible electrochemical and solution deposition techniques. An n-type ZnO film consisting of free-standing single crystal nanowires several microns high and 100–200 nm in diameter was-deposited on a conducting glass (SnO 2 :F) substrate covered by a thin spray pyrolysis ZnO electronic blocking layer. A 30–40-nm-thin layer of CdSe absorber was electrodeposited, coating the ZnO nanowires. The voids between the ZnO/CdSe nanowires were filled with p-type CuSCN; the entire assembly formed a p–i–n junction. The ZnO/CdSe nanowire layer exhibited a high light-trapping effect, with an effective absorbance of ~89% and effective reflectance of ~8% in the 400–800 nm region of the solar spectrum (AM1.5). The effects of an annealing process on the CdSe grain size and on the energy conversion efficiency of the eta- solar cell have been analyzed. The obtained efficiencies, for cells with annealed CdSe (1.5–2.3%) show that the ZnO/CdSe/CuSCN nano-heterostructure is an interesting option for developing new solar cell devices. .