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

Abstract

TiO _2 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 TiO _2 thin films with an inverse opal-like structure from TiO _2 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 TiO _2 films can be further improved by the dip-coating process. In particular, dip-coated and untreated inverse opal-like TiO _2 films exhibit photocurrent densities of ∼66.5 μ A cm ^−2 and ∼40.9 μ A 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 TiO _2 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.

Keywords

• TiO2
• thin films
• inverse opal-like structure
• photoelectrochemical activity
• dip-coating