Recently,the performance and fabrication of thin-film thermoelectric materials have been largely enhanced.Based on this enhancement,the thin-film thermoelectric cooler (TEC) is becoming a research hot topic,due to its high cooling flux and microchip level size.To fulfill a thin-film TEC,interfacial problems are unavoidable,as they may largely reduce the properties of a thin-film TEC.Moreover,the architecture of a thin-film TEC should also be properly designed.In this review,we introduced the enhancement of thermoelectric properties of (Bi,Sb)2(Te,Se)3 solid solution materials by chemical vapor deposition,physical vapor deposition and electrodeposition.Then,the interfacial problems,including contact resistance,interracial diffusion and thermal contact resistance,were discussed.Furthermore,the design,fabrication,as well as the performance of thin-film TECs were summarized.