Photoinjection of hydrogen and the nature of a giant shift of the fundamental absorption edge in highly disordered V2O5 films

Abstract

Production of atomic photochemical hydrogen under the action of light and its subsequent injection into transition metal oxides has yielded numerous interesting results. Here we report on the mechanism of the photo-induced hydrogen transfer between adsorbed organic molecules and the surface of highly disordered V(2)O(5) films. We have managed to carry out the photoinjection of hydrogen into the V(2)O(5) films at very low temperatures, which is very important both for investigations of the reaction mechanism and for the optical properties of the V(2)O(5) films. The photochemical reaction exhibits all features of proton-coupled electron transfer which is a basic mechanism for bioenergetics conversion. Second, the new possibility to carry out experiments at very low temperatures has yielded a new approach in investigations of the nature of color centers and of the giant "blue" shift of the fundamental absorption edge in the V(2)O(5) films both arising due to injection of hydrogen atoms.

Vanadium Oxide Compounds: Structure, Properties, and Growth from the Gas Phase

“…Beta-diketonates, essentially V(acac) 3 and VO(acac) 2 , were intensively investigated for CVD processes under atmospheric and reduced pressures. Both precursors were used in aerosol-assisted (AA)CVD with various solvents.…”

“…Vanadium alkoxides have been reported as efficient single-source precursors. [168][169][170] Mathur et al have reported on the grown phases starting from the thermal decomposition of vanadium oxo-tri-isopropoxide (VO(O i Pr) 3 ) under reduced pressure. [168] The authors reported the formation of a single-phase coating of V 2 13 was obtained at 600°C, while VO 2 was grown at 700°C.…”

“…[1] The photochromism of V 2 O 5 was attributed to the photo-reduction of V 5þ with a visible laser light that turns the yellow V 2 O 5 into blue-black. [2,3] Thermally induced chromism was also observed for V 2 O 5 , [4] and intensively investigated along the structural transition in VO 2 . [5][6][7] Electrochromism was reported for VO 2 [8] and V 2 O 5 -based coatings.…”

“…V 2 O 5 and VO 2 are well‐established chromogenic materials, able to respond to various external stimuli such as electromagnetic radiation, temperature, and electrical charge . The photochromism of V 2 O 5 was attributed to the photo‐reduction of V 5+ with a visible laser light that turns the yellow V 2 O 5 into blue‐black . Thermally induced chromism was also observed for V 2 O 5 , and intensively investigated along the structural transition in VO 2 .…”

Smart Window Technologies: Electrochromics and Nanocellulose thin film Membranes and Devices

“…Resulting in deeper coloration due to increased charge transfer; while also, the device may degrade especially due to formation of excess polymeric components for consistent resonant tunneling effects [14][15][16][17][18][19][20]. The EC devices have open circuit memory, and can function without energy for long periods; optical absorption can be tuned between states, but the optical change is slow depending on device size varying from seconds to tens of minutes [3].…”