Microstructures of Electrochromic MoO₃ Thin Films Colored by Injection of Different Cations

Abstract

Raman microscopy was used to investigate microstructural properties of amorphous MoO3 thin films that had been subjected to a photochromic (PC) or electrochromic (EC) process. The Raman spectra changed reversibly when the films went through PC or EC coloration and decoloration cycles. Different molybdenum bronzes were produced with PC and EC treatments, as indicated by the shifts in the Raman bands. The same observation was made in the surface photovoltage spectral experiments. Hence, it was concluded that the microstructure of molybdenum bronze was affected by the coloration means (PC or EC process); the injected cations in an EC process were bonded to the triply coordinated O atoms, whereas the injected H+ ions in a PC process were bonded to both the triply coordinated and doubly coordinated O atoms. The size of the injected cations via EC processes had little effect on the microstructure of the colored films.

Structure, photochromic, and electrochemical properties of dioctadecylamine/H3PMo12O40 Langmuir–Blodgett film

“…S4c, the Mo 2 -O band at 806 cm −1 shifts to 795 cm −1 , and the Mo=O band at 947 cm −1 shifts to 987 cm −1 , whereas the other two bands in the region of 800-1000 cm −1 remain almost unchanged. Such a red shift of the Mo 2 -O vibration band suggested the insertion and attachment of a hydrogen atom into the Mo 2 -O bond during photochromism, as previously reported [18,34]. Considering the fact that PMo 12 was organized in the middle of two DOA layers electrostatically, we believed that the hydrogen atom involved in the reduction of Mo 6+ most likely originated from the protonated amino headgroup of DOA due to its close contact with the PMo 12 polyanion.…”

Molybdenum trioxide nanostructures prepared by thermal oxidization of molybdenum

“…Interest in layered crystal MoO 3 has been growing in recent years for its multifaced functional properties. Its applications include catalyst in selective oxidation reactions [3], secondary batteries [4], information display systems [5], sensors [6,7], lubricants [8], photochromic and electrochromic systems [9][10][11]. For these applications, large surface area has been found to be the efficient parameter.…”

Synthesis of photochromic nanoparticles and determination of the mechanism of photochromism

“…[1][2][3][4][5][6][7] Hence, they are expected to be used in sensors and fast optical shutters. In order to construct flexible electronic structures, organic modifiers [8][9][10][11][12][13][14] or lanthanides, [15][16][17][18][19][20][21][22][23][24][25] which have a high principal quantum number, have been employed as photochromic resources until now. Recently, some electrochromic oxide semiconductors have been reported.…”

“…Recently, some electrochromic oxide semiconductors have been reported. [21][22][23][24][25][26][27][28][29][30][31] In these materials, the color change occurs when photons excite electrons into the conduction bands or trap levels, and these electron transitions induce color change. Therefore, some researchers speculated that these electrochromic materials could be used in energy-storable solar cells.…”