The Influence of Thermal Conditions on V₂O₅ Nanostructures Prepared by Sol‐Gel Method

Abstract

This work presents the result of structure investigations of V2O5nanorods grown from thin films and powders prepared by sol-gel method. To examine the best temperature of nanorods crystallization, thin films deposited by spin-coating method on quartz glass or silicon substrates and bulk xerogel powders were annealed at various temperatures ranging from 100°C to 600°C. The structure of the samples was characterized by X-ray diffraction method (XRD), scanning electron microscope (SEM), differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), and mass spectroscopy (MS). The rod-like structure of V2O5was obtained at 600°C on both quartz glass and silicon substrates and also from the bulk xerogel. The growth process and the effect of annealing treatment on the nanostructure are briefly discussed.

Role of Polyvinylpyrrolidone (PVP) on Controlling the Structural, Optical, and Electrical Properties of Vanadium Pentoxide (V2O5) Nanoparticles

“…X‐ray diffraction patterns of V 2 O 5 nanoparticles (different molar concentrations‐ 0.05, 0.1, 0.15, and 0.2) with and without PVP are shown in Figure (a and b). From Figure , it is clear that the diffraction peaks of samples match very well with the JCPDS Card number 41–1426, which corresponds to the orthorhombic structure of V 2 O 5 with a space group of Pmmn (number 59) . It is evident that α‐V 2 O 5 is the only crystalline phase present in the samples.…”

“…From Figure 3, it is clear that the diffraction peaks of samples match very well with the JCPDS Card number 41-1426, which corresponds to the orthorhombic structure of V 2 O 5 with a space group of Pmmn (number 59). [32] It is evident that α-V 2 O 5 is the only crystalline phase present in the samples. No other secondary peaks related to other phases and impurities within the detection limit of XRD were observed.…”

Electrochromic Behavior of Vanadium Pentoxide Thin Films Prepared by a Sol–Gel Spin Coating Process

“…[ 27 ] The spin‐coated V 2 O 5 films exhibited the β‐V 2 O 5 phase at 480 °C annealing temperature. [ 28 ] Furthermore, the annealing temperature‐induced increase in peak intensity revealed the enhancement in crystallization of the films.…”

“…Our observation is consistent with the literature reports. [26][27][28] For instance, Okimura et al have prepared V 2 O 3 film by reactive magnetron sputtering technique at the substrate temperature of 400 C and further annealing the films up to 650 C leads to the formation of different crystalline phases such as VO 2 , V 2 O 5 and V 3 O 7 , and pure V 2 O 5 . [26] In addition, Poelman et al have deposited V 2 O 5 film by direct current magnetron sputtering technique using V 2 O 3 as a sputtering target material and obtained the amorphous and polycrystalline forms of V 2 O 5 at the annealing temperatures of 200 and 500 C, respectively.…”

“…[6] The V─O system exhibits different polymorph structures such as α-V 2 O 5 (orthorhombic), β-V 2 O 5 (monoclinic or tetragonal), and γ-V 2 O 5 (orthorhombic). [7] It has the highest oxidation state of V and the most stable form in crystallization which influences the applications in Li-ion batteries, electrochromic devices, gas sensors, optoelectronic devices, and catalysts. [6] Generally, V 2 O 5 is being considered as a superior electrochromic material, which exhibits dual anodic and cathodic behavior (multielectrochromism), [8] but it cannot be classified either as an anodic or as a cathodic material, precisely.…”