Patent ID: 8197721

Claim:
A method of producing thermochromic vanadium (IV) oxide by atmospheric pressure chemical vapour deposition (APCVD) comprising the steps of: (i) mixing together (a) a vanadium precursor, (b) an oxygen precursor, and, optionally, (c) a transition metal dopant precursor in the presence of an inert gas to form a precursor mixture; (ii) reacting together the precursors of the precursor mixture in an atmospheric pressure chemical vapour deposition reactor; and (iii) depositing the thermochromic vanadium (IV) oxide, characterised in that the vanadium concentration in the precursor mixture is, before reaction, less than 1×10 −3 mol/dm 3 ; and wherein the oxygen concentration in the precursor mixture is, before reaction, less than 1×10 −2 mol/dm 3 .