Thermal Stability, Optical and Electrical Properties of Substoichiometric Molybdenum Oxide

Abstract

Substoichiometric molybdenum oxide ceramics have aroused widespread interest owing to their promising optical and electrical performance. In this work, the thermal stability and decomposition mechanism of Mo9O26 and Mo4O11 at 700–1000 °C and 700–1100 °C were investigated, respectively. Based on this information, MoOx (2 < x < 3) bulk ceramics were prepared by spark plasma sintering (SPS). The results show that Mo9O26 is stable up to 790 °C in an argon atmosphere. As the temperature rises, it decomposes into Mo4O11. Mo4O11 can exist stably at 830 °C, beyond which it will convert to MoO2. The MoOx ceramic bulks with four different components (MoO2.9, MoO2.8, MoO2.7 and MoO2.6) were successfully sintered by SPS, and their relative density was greater than 96.4% as measured by the Archimedes principle. The reflectivity of MoOx ceramic bulk is low and only 6.3% when the composition is MoO2.8. The resistivity increases from 10−3 to 10−1 Ωcm with the increase in the O/Mo atomic ratio x. In general, the thermal stability information provides a theoretical basis for the processing of MoOx materials, such as the sintering of the MoOx target. The optical and electrical properties show that MoOx is a low-reflective conductive oxide material with great photoelectric application value.

K3Mo2O5.6F3.4 and K3V2O3.3F5.7 – exploring transition metal cation valence and anion distribution in oxyfluorides

“…With MAPLE calculations predicting a perfectly stable structure for K 3 Mo 2 O 6 F 3 without the presence of any Mo 4+ or occupancy of the M2 site, we do not believe the reduction of Mo 6+ to play a major role in the formation of the new compound. Instead, we suspect that a small but varying amount of MoO 3 naturally decomposes to MoO 2 and O 2 at high temperatures, 42 leading to the incorporation of Mo 4+ into the M2 octahedral void, which happens to be perfectly sized to host a cation of this nature.…”