Deposition of inverse opal-like TiO2 thin film with enhanced photoelectrochemical activity by a spin-coating combined with a dip-coating method

Abstract

Abstract TiO2 thin films with an inverse opal-like structure have attracted considerable attention recently owing to their high potential for a range of applications. In this study, we demonstrated the possibility to deposit TiO2 thin films with an inverse opal-like structure from TiO2 nanoparticle-based slurry paste using a conventional spin-coating process. In addition, we also showed that the photoelectrochemical (PEC) performance of as-fabricated inverse opal-like TiO2 films can be further improved by the dip-coating process. In particular, dip-coated and untreated inverse opal-like TiO2 films exhibit photocurrent densities of ∼66.5 μA cm−2 and ∼40.9 μA cm−2 at 1.23 V versus RHE, respectively. A detailed physicochemical analysis revealed that photocurrent density enhancement (∼38.5%) in dip-coated inverse opal-like films can be attributed to a variety of factors including improved interconnection between TiO2 nanoparticles, higher crystallinity, decreased light reflection, and reduced charge carriers recombination. We strongly believe that these findings will be useful in the development of highly efficient third-generation solar cells, photocatalytic systems, electrochromic devices, and gas sensors.