Enhancement of Photoelectrochemical Performance of AACVD‐produced TiO₂ Electrodes by Microwave Irradiation while Preserving the Nanostructure

Abstract

TiO 2 electrodes are deposited on FTO-glass substrates at 350 and 400 8C by aerosol-assisted chemical vapour deposition (AACVD) and the deposited TiO 2 electrodes are irradiated with microwave radiation (2.45 GHz) at various percentages (10, 25, 50, and 100%). X-ray diffraction (XRD) pattern shows that the deposited electrodes have anatase phase TiO 2 oriented in the (101) direction, and the crystallinity of these electrodes increases after microwave treatment. Field emission gun scanning electron microscopy (FEG-SEM) surface topography analysis proves the preservation of the nanostructure after exposure to various percentages of microwave radiation. The photoelectrochemical (PEC) studies prove a threefold enhancement of photocurrent density of AACVD-produced TiO 2 electrodes after 100% microwave irradiation. This improved performance of PEC properties is attributed to improvements in the crystallinity and the particle-necking properties. The results presented demonstrate that microwave processing is a promising alternative method to conventional sintering for TiO 2 photoanodes.

Aerosol-assisted chemical vapor deposition of metal oxide thin films for photoelectrochemical water splitting

“…The effect of microwave radiation on the PEC properties of a TiO 2 thin film deposited using the AACVD approach was evaluated by Tahir et al [100]. In their work, the TiO 2 films deposited by AACVD have two different morphologies, a compact film deposited at 350 C and a relatively porous film with cauliflower-like feature deposited at 400 C. They were subsequently exposed to different amounts of microwave radiation.…”

Microwave-assisted low temperature fabrication of ZnO thin film electrodes for solar energy harvesting

“…Post-annealing under air also helps to oxidize remaining metallic Zn or Zn containing precursors present in the film [13]. At the same time, post-annealing steps can cause collapse of the specifically engineered nanostructure, reducing the porosity and surface area of the film, which in turn affects the final device performance [3,4]. This effect is more pronounced when using conventional radiant annealing as the method for post-annealing, due to non-uniform heat distribution.…”

“…Recent trends have been to process semiconductor thin films under microwave radiation as it provides new approaches for enhancing the physical, chemical, and photoelectrochemical (PEC) properties of materials as well as providing economic benefits through significant energy savings [2]. It has also been proven that microwave annealing is a promising alternative method to conventional radiant annealing, as it opens up a new research strategy for engineering semiconductor material properties while keeping the specifically engineered texture and nanostructure unaltered for use in a range of applications such as solar energy harvesting and energy storage devices (PEC cells, solar cells, batteries, supercapacitors) [3,4].…”

Dispersion and microwave processing of nano-sized ITO powder for the fabrication of transparent conductive oxides

“…Irradiation with microwaves as an alternative heat-treatment technique has received a great deal of interest and has been reported to improve the particle necking and crystallinity with minimal thermal stress in the substrate [14,15]. This is due to the generation of an entirely different heating profile by microwave irradiation in comparison with that of conventional heating.…”

“…Microwaves interact with lossy materials (materials with medium-range electrical conductivity) and can generate rapid and uniform heating throughout the material, which leads to minimisation of the thermal gradient and the processing time [16,17]. In addition, it has been reported that some ceramic materials, such as TiO 2 , synthesised using low temperature methods can be partially amorphous; this can be solved by microwave irradiation of the film without affecting its micro-or nano-sized structure [15].…”