Thermal transformations in In-MoO3 nanofilms

Abstract

Transformations in In-MoO 3 nanosystems have been studied by optical spectroscopy, micros copy, and gravimetry in relation to the thickness of the In and MoO 3 layers and heat treatment temperature and time. We have measured the contact potential difference across the In and MoO 3 films and the photo voltage in the In-MoO 3 system and constructed the energy band diagram of the In-MoO 3 system. A model has been proposed for the thermal transformation of the MoO 3 films in In-MoO 3 bilayers, which involves a redistribution of equilibrium charge carriers at the contact, the formation of a [(V a ) ++ e] center during the preparation of the MoO 3 film, transformation of the center into a [e(V a ) ++ e] center during the fabrication of the In-MoO 3 bilayer, and thermal ionization of the [e(V a ) ++ e] center.

Structure and physicochemical properties of nanostructured metal oxide films for use as the sensitive layer in gas sensors

“…According to [22], when an In 2 O 3 film is heated to 473-573 K, adsorbed oxygen desorbs and an In 2 O 3 -In heterosystem forms, which leads to a depletion in oxygen of the starting material. Because of this pro cess, the electronic structure of the investigated film rearranges, which leads to an increase in conductance, as observed in experiment.…”

“…During the first passage of electric current through the indium oxide film, its resistance first decreases and then increases. According to the hypothesis put for ward by the authors of [22], the observed effects can be explained by the fact that, during a long term storage, indium oxide loses a significant portion of the oxygen; it can only be restored at a temperature above 200°C. This manifests itself through an increase in the resis tance.…”

Reversible Chemochromic MoO3 Nanoribbons through Zerovalent Metal Intercalation

“…Both photochromism and electrochromism of MoO 3 are dictated by intercalation of hydrogen radicals, through photoreduction of water with UV light, or by electrochemical intercalation of lithium ions into the interlayer van der Waals gaps. Intercalated ions distort the lattice and add interband states into the wide band gap of MoO 3 (3.1 eV), enabling lower energy transitions and resulting in a light blue color. , The ionic nature of these intercalants, however, limits the amount of species uptake, either destabilizing the host structure or resulting in a reaction of the host + guest forming molybdenum bronze (A x MoO 3 , A = H or Li, Na, K) with an associated intervalence charge transfer between Mo (5+) and Mo (6+) ultimately limiting the color response of MoO 3 . , Despite significant amounts of work, the chromic performance of MoO 3 is still largely limited by the destructiveness of ionic intercalation combined with subtle and slow coloration. ,− …”