Near IR light sensitization modulated to self-assembled CuO-CuxS nanorods thin films

An assembled CuO-CuxS nanorods heterostructure has been produced by liquid chemical conversion and wet etching of the Cu thin film. The chemical etching and anionic exchange modify and convert the Cu thin film to self-assembled CuO/CuxS random nanorods. The enhanced near infrared (NIR) light absorption capability and the effective separation of electron-hole pairs generated by the conjugated CuO-CuxS nanorods complement high visible (especially red) light driven photocatalytic activities as well as NIR photodetecting performances. The surface morphology, chemical content, crystalline analysis and structural vibrations of the CuO/CuxS nanorods were characterized using field emission scanning electron microscopy (FESEM), energy dispersive Xray spectroscopy (EDX), X-ray diffraction (XRD) and Raman scattering, respectively. Diffuse reflectance spectroscopy was utilized to evaluate optical properties of the CuO-CuxS nanorods. The assembled CuO-CuxS nanorods thin film exhibits good crystallinity with superior reproducibility and high selectivity for NIR absorption. The CuxS coupling into CuO is also responsible to surface enhanced Raman scattering. The static and high frequency dielectric constant, Urbach tail, optical carrier density and nonlinear refractive index have been estimated. The bandgap energy and optical carrier density are estimated around 1.22 eV and 1027 m(-3), respectively. The photoharvesting performance was characterized using under sunlight illumination, and green, red and NIR laser irradiation. The CuO-CuxS hetero-interface manipulate charge transferring of the photoinduced carriers, which promotes the photodegradation efficiency of Methylene blue (MB) and NIR photosensitization.