Gram-scale selective synthesis of WO3−x nanorods and (NH4)xWO3 ammonium tungsten bronzes with tunable plasmonic properties

WO_3-x and (NH₄)_xWO₃ are prepared from ammonium metatungstate. Oleyl oleamide, formed from oleic acid and oleylamine at T > 250 °C, favors the formation of WO_3-x nanorods, fast heating rates and high precursor concentrations the formation of (NH₄)_xWO₃.