Arrays of ZnO/CuInxGa1-xSe2 nanocables with tunable shell composition for efficient photovoltaics

摘要

Arrays of one-dimensional (1D) nanostructure are receiving much attention for their optoelectronic and photovoltaic applications due to their advantages in light absorption, charge separation, and transportation. In this work, arrays of ZnO/CuInxGa1-xSe2 core/shell nanocables with tunable shell compositions over the full range of 0 <= x <= 1 have been controllably synthesized. Chemical conversions of ZnO nanorods to a series of ZnO-based nanocables, including ZnO/ZnSe, ZnO/CuSe, ZnO/CuSe/InxGa1-x, ZnO/CuSe/(InxGa1-x)(2)Se-3, and ZnO/CuInxGa1-xSe2, are well designed and successfully achieved. Composition-dependent influences of the CuInxGa1-xSe2 shells on photovoltaic performance are investigated. It is found that the increase in indium content (x) leads to an increase in short-circuit current density (J(SC)) but a decrease in open-circuit voltage (V-OC) for the ZnO/CuInxGa1-xSe2 nanocable solar cells. An array of ZnO/CuIn0.67Ga0.33Se2 nanocables with a length of similar to 1 mu m and a shell thickness of similar to 10 nm exhibits a bandgap of 1.20 eV, and yields a maximum power conversion efficiency of 1.74 under AM 1.5G illumination at an intensity of 100 mW/cm(2). It dramatically surpasses that (0.22) of the ZnO/CuIn0.67Ga0.33Se2 planar thin-film device. Our work reveals that 1D nanoarray allows efficient photovoltaics without using toxic CdS buffer layer. (c) 2015 AIP Publishing LLC.