Microwave-assisted Synthesis Of Bi₂Te₃and Bi₂Se₃Thermoelectric Materials

Thermoelectric materials can directly convert energy between electrical andthermal. Application of thermoelectric materials is of great significance for alternativethe hydraulic cooling mode based on the destruction of the ozone layer as well as theuse of non-renewable energy resources.As the the thermoelectric materials preparation technology advances, especiallynanotechnology for thermoelectric materials, performance greatly enhanced. The use ofmicrowave heating is a unique way of heating methods: fast, uniform heating, highefficiency; made it combined with a bottom-up wet chemical method of preparation ofthermoelectric nanomaterials very practical.In this paper, a bottom-up wet chemical method to prepare nano thermoelectricmaterials, combined with microwave heating, preparation speed greatly enhanced,andeasy to control size and morphology of the nanocrystals.Using single factor methodto explorer preparation of Bi₂Te₃, Bi₂Se₃nano-materials, studies have shown that300Wheating for60seconds is insufficient to preparation of the Bi₂Se₃nano-particles, almostall product are Bi; heated for90seconds at300W, the final product are Bi₄Te₅and Biand Te impurities;300W heating to180seconds, the final product are Bi₂Te₃nanoplates and Bi and Te impurity. The nano-size plate can be controlled by controllingthe microwave dose,60seconds microwave dose to obtain size of approximately100nm,90seconds for approximately200nm,180seconds for approximately300-400nm.The dose of thioglycolic acid （TGA） is key to control morphology and size, increasing itcan directly increase the size of the final product; and sufficient heating time can obtainatomic percentage of approximately15.82%of the sulfur doping. Finally, the possiblerole of the reaction mechanism and thioglycolic acid dose were analyzed andsummarized.And through zone melt method, prepared p type thermoelectric bulkmaterial of Bi₂Te₃, By doping with different Tecontents, investigated it’s influences onvarious thermoelectric properties, and whe doping with0.09wt.%Te, Bi_0.5Sb_1.5Te₃reachesZT value at1.36.