Low-temperature synthesis of CuInSe2 nanotube array on conducting glass substrates for solar cell application.

Highly ordered arrays of Cu-rich and -deficient CuInSe(2) nanotubes as well as ZnO/CuInSe(2) core/sheath nanocables have been synthesized on glass substrates by using ZnO nanorod arrays as sacrificial templates via a low-cost solution method. Chemical conversions from hexagonal ZnO to cubic ZnSe, hexagonal CuSe and tetragonal CuInSe(2) are demonstrated as a novel means for synthesis of I-III-VI nanomaterials. Large differences in their solubility product constant (K(sp)) are crucial for direct exchange in the conversions. In solvothermal reaction of ZnO/CuSe core/shell nanocables with InCl(3), the triethylene glycol solvent serves as a reducing agent for the reduction of cupric (Cu(2+)) to cuprous (Cu(+)) ions and also as an agent for the dissolution of ZnO cores. The absorption coefficient of the CuInSe(2) nanotubes in the visible region is on the order of 10(4) cm(-1). Photoelectrochemical solar cells were fabricated with arrays of ZnO/Cu(1.57±0.10)In(0.68±0.10)Se(2) and ZnO/CuSe nanocables. It was found that power conversion efficiency of the ZnO/Cu(1.57±0.10)In(0.68±0.10)Se(2) cell is about two times higher than that based on ZnO/CuSe.