NOVEL, MICROWAVE ASSISTED ROUTE OF SYNTHESIS OF BINARY OXIDE SEMICONDUCTING PHASES - PbMoO_4 AND PbWO_4

摘要

Highly crystalline powders of lead molybdate and tungstate were synthesized by a microwave assisted hydrothermal process in a microwave heated high pressure autoclave. Application of this novel and environmentally friendly technique in the synthesis of these compounds has never been reported before. The influence of a time of synthesis on a crystal structure, morphology and a value of a band gap for both PbMoO_4 and PbWO_4 was examined. The value of the band gap was determined using diffuse reflectance spectroscopy. For lead molybdate the medium value of the band gap equals to ca. 3.2 eV whereas for lead tungstate it oscillates around 4 eV and does not depend on the duration time of the synthesis.