Optical properties of Cu2S nano-hollow cactus arrays with different morphologies

In this study, a series of Cu2S nano-hollow cactus arrays (CNHC) with varying morphologies is prepared by a two-step process including electrodeposition and the solid-gas reaction method. The structure of the arrays is characterized by scanning electron microscopy, X-ray diffraction, transmission electron microscopy, X-ray photoelectron spectroscopy, and Raman spectroscopy; while, their light absorption performance is investigated by diffuse reflectance and photoluminescence spectroscopy. The thorns of the CNHC are single-crystal Cu2S semiconductors, and the band gap of the CNHC can be adjusted by changing their morphology, where the light absorption ability of the array is enhanced from 82% to 93% as the thorn diameter decreases from 1500 to 163 nm. All of the different CNHC morphologies exhibit little sensitivity to the incident angle of the light. For example, the light absorption of the CNHC with a thorn diameter of 430 nm only decreases by 5% as the incident angle increases from 0 degrees to 45 degrees. This shows the potential of the CNHC for use in solar energy applications, where its insensitivity to the angle of the incident light will reduce the necessity of adjusting the angle of solar cell panels using CNHC in the photovoltaics. (C) 2015 Elsevier B.V. All rights reserved.