Vanadium oxide thin films and fibers obtained by acetylacetonate sol–gel method

Abstract

Vanadium oxide films and fibers have been fabricated by the acetylacetonate sol-gel method followed by annealing in wet nitrogen. The samples are characterized by X-ray diffraction and electrical conductivity measurements. The effects of a sol aging, the precursor decomposition and the gas atmosphere composition on the annealing process, structure and properties of the films are discussed. The two-stage temperature regime of annealing of amorphous films in wet nitrogen for formation of the well crystallized VO2 phase is chosen: 1) 25-550°C and 2) 550-600°C. The obtained films demonstrate the metal-insulator transition and electrical switching. Also, the effect of the polyvinylpyrrolidone additive concentration and electrospinning parameters on qualitative (absence of defects and gel drops) and quantitative (length and diameter) characteristics of vanadium oxide fibers is studied.

Sol-gel approaches to thermochromic vanadium dioxide coating for smart glazing application

“…The deposited films demonstrated an electrical resistance transition of two orders of magnitude, confirming the presence of VO 2 . As proposed by previous studies [95,96], experiments by Berezina et al [93] also proved that stable formation of VO 2 is highly influenced by the temperature and the oxygen partial pressure (P O2 ). For instance, VO 2 is oxidized to higher valances (e.g.…”

“…Like all solution phase deposition methods, synthesis condition can modify the film properties. In this regard, the impact of processing parameters has been examined repeatedly, including the reducing atmosphere, drying and annealing temperature and aging of the precursor sol [92][93][94].…”

“…Well-crystallized VO 2 films were fabricated in wet N 2 ambient with flow rate of 4-9 ml/min, which reduced the sublimation of VO(acac) 2 as much as possible [93]. A two-step annealing system was adopted to obtain VO 2 crystals, consisting a warming up step at 550°C for 35 min followed by another heating step up to 600°C.…”

Поверхностная И Объемная Проводимость Диоксида Ванадия

“…В работе [14] представлены результаты отдельного исследования влияния хемосорбции донорных и акцеп-торных газов на параметры фазового перехода в плен-ках смешанного оксида ванадия, полученных золь-гель методом [22].…”

The electrochromic performances of single phase VO2 nanoparticled films

“…Among the transition metal oxides, vanadium oxide is exceptional due to both its anodic and cathodic behaviors. Furthermore, vanadium oxide (VO x ) coatings can be used as a counter electrode for electrochromic devices, thermochromic displays, lithium ion batteries (cathode materials), thin-film transistors, energy efficient windows, optical and electrical switching devices, gas sensors, and thermal detectors [1][2][3][4][5][6][7][8][9][10]. Electrochromic materials should be low-cost, easily applicable and fast responding on large areas for device applications.…”