Disclosed are methods for making ultrafine particles. These methods include (a) introducing a plurality of precursors to a high temperature chamber, the precursors including a first precursor and a second precursor different from the first precursor and comprising an alkali metal dopant; (b) heating the plurality of precursors in the high temperature chamber, yielding a gaseous product stream; (c) quenching the gaseous product stream, thereby producing ultrafine particles; and (d) collecting the ultrafine particles. Also disclosed are apparatus for the production of ultrafine particles, ultrafine particles produced from a plurality of precursors and coating compositions and coated substrates that include ultrafine particles.