Abstract
Weblike aggregates of coalesced MoO3 and WO3 nanoparticles have been prepared by a laser vaporization-controlled condensation technique. The nanoparticles show a very strong photochromic effect: the color change is one order of magnitude faster than that observed for the corresponding bulk material. The photochromic effect is also observed upon exposure of the MoO3 nanoparticles to normal room light. (C) 1999 Acta Metallurgica Inc.