Theoretical Calculation And Thermoelectric Property Investigation For Bi₂S₃

With the development of society,we has faced the problems with the excessive consumption of energy and damaging of environmention.However,it has been found that the energy could not be utilized effectively,most of the energy is wasted in the form of waste heat.If we can use these waste heat fully,the energy crisis can be greatly alleviated.Thermoelectric material is a good project,which is a semiconduct material of converting heat.At present,metal chalcogenides has been widely concerned because of the good performance in the thermoelectric material.Bi₂S₃ is becoming the most attention thermoelectric material,which has a high Seebeck coefficient and low thermal conductivity,but its conductivity is very low,which affecting in its thermoelectric properties.In preparation,melting is the preparation methods currently,and then sintering with PAS,but the preparation process is too complex,and the grain is too large,which made a bad role in thermal conductivity.As the above metion,we do the following research:?1?In theory,we drawed a conclusion that conductivity increased by doping Sn⁴⁺,the better doping amount,the better the conductivity.?2?In the preparation,powders were prepared by solvothermal method,sintered by PAS and microwave.After PAS sintering,the grain was obtained 0.50?m-1?m.The maximum dimensionless figure of merit?ZT?of Bi1.975Sn0.025S3 is 0.52 at 673 K.But the ZT need to improve.?3?The Bi₂S₃ thermoelectric materials doped Sn⁴⁺were prepared by microwave sintering.The maximum dimensionless figure of merit?ZT?of Bi1.985Sn0.015S3 is 0.67 at 673 K,which was about 8 times higher than that of undoped Bi₂S₃ samples.The microwave sintering method is more suitable for the preparation of bulk Bi₂S₃ thermoelectric materials.