Substrate dependence in the formation of TiO₂nanophases by dense electronic excitation

Abstract

Irradiation by swift heavy ion (SHI) is an excellent tool for the nanostructuring of thin films. During SHI irradiation, the energy of the projectile is transferred to the target mainly via electronic energy loss (S e ). If the value of S e is more than a threshold value S eth, then latent tracks are formed in the target and a large amount of deposited energy gets confined in narrow dimensions. This leads the system to a non-equilibrium state and it then relaxes dynamically by inducing nucleation of nanocrystallites along the latent tracks. In the present investigation, amorphous thin films of TiO 2 are deposited on substrates of fused silica and that of single crystal sapphire. The films are then irradiated by a 100 MeV Au ion beam. Atomic force microscopy is employed for the surface study. The structural phase change induced by SHI irradiation is identified by glancing angle x-ray diffraction. Optical characterization is carried out by UV-vis absorption spectroscopy. Defects created during irradiation are studied by electron spin resonance spectroscopy studies. The role of a substrate in the SHI-induced nanocrystallization process is studied.

Efficient Performance of Electrostatic Spray-Deposited TiO2 Blocking Layers in Dye-Sensitized Solar Cells after Swift Heavy Ion Beam Irradiation

“…When the temperature is greater than the melting temperature of TiO 2 (~1,300 ° C), a liquid phase is formed in this specific region. This high temperature region cools down immediately due to very rapid heat transfer to the surroundings, resulting in solidification of the surface, specifically melted TiO 2 nanoparticles [ 23 ] that form a highly adhesive TiO 2 blocking layer with the FTO substrate. To best of our knowledge, this is the first report of its kind to apply the SHI irradiation technique for obtaining an efficient blocking layer in DSSCs.…”

Microstructural and plasmonic modifications in Ag–TiO2 and Au–TiO2 nanocomposites through ion beam irradiation

“…9 ). Several studies on SHI-induced crystallization of amorphous TiO 2 thin films have been performed and it has been reported that under SHI irradiation, the crystallization evolves through the formation of TiO 2 nanocrystals in rutile and anatase phases [ 37 , 45 ]. In a similar study an increase of the dielectric constant of the TiO 2 film after 100 MeV Ag 8+ ion irradiation has been reported.…”

“…Unlike silica, SHI irradiation might introduce several other types of structural changes in the TiO 2 matrix, which in turn affect the plasmonic properties of the nanocomposite system [ 17 ]. The detailed structural modifications and changes of optical properties of pure titania thin films under SHI irradiations have been already investigated [ 17 , 33 – 37 ]. Detailed understandings about the modification of metal–SiO 2 and metal–polymer nanocomposites under SHI irradiation have already been reported but such studies about metal–TiO 2 nanocomposites would be very interesting.…”

Localized thermal spike driven morphology and electronic structure transformation in swift heavy ion irradiated TiO2 nanorods

“…The TiO 2 nanorods grown on FTO coated glass substrate were irradiated at room temperature with 100 MeV Ag ions using the 15UD accelerator at Inter-University Accelerator Centre, New Delhi, India. 41 The fluences used for irradiation were 1×10 12 , 5×10 12 , 1×10 13 and 5×10 13 ions/cm 2 . The beam current was maintained at ~7 nA to avoid any joule heating.…”

“…Titanium dioxide (TiO 2 ) remains one of the most prominent members of the metal oxide family owing to its high chemical and thermal stability, excellent photoactivity, biocompatibility and availability in the form of three different polymorphs (anatase, brookite and rutile). 8,9 There are a few reports, which have discussed SHI irradiation-induced structural changes in TiO 2 , for example, from amorphous to anatase, 10 rutile, 11,12 and mixed-phase; 12 and anatase to amorphous, 13 rutile, 14 and mixed-phase 15 transformations. SHI irradiation induced effects have also been studied on doped TiO 2 .…”