Use of Commercial DVDs as photoelectrochemical sensors

Cu2O nanoparticles have been grown by pulse-electrochemical deposition on a digital versatile disc (DVD) which acts as a nanostructured electrode. Prior to Cu2O deposition, the silver-coated rectangular-shaped grooves of the disassembled DVD were coated with a TiO2 thin film by a modified sol-gel method. As demonstrated by atomic force microscopy (AFM) measurements, the DVD grooves are filled by a 120-130 nm thick TiO2 film, while the thickness of the TiO2 deposit on the crests is only ca. 50 nm. This inhomogeneous thickness leads to an inhomogeneous electric field when the DVD is used as electrode for depositing Cu2O nanoparticles, which eventually leads to the growth of Cu2O nanoparticles only on the DVD crests. A highly regular and reproducible Cu2O/TiO2 stripe-like heterostructure is obtained where both semiconducting oxides are aside. This system has been characterized by scanning electron microscopy (SEM), X-ray photoemission spectroscopy (XPS), Raman and photocurrent measurements. A possible use of this easy&cheap electrode as a visible light responsive sensor to water soluble organics in basic solution is suggested.