Bi-Sb-Te Flexible Thin Films Thermoelectric Generators

As energy shortage and environment pollution getting more serious,the thermoelectric generator(TEG)as the third green power generation technology,after the photovoltaic cell and wind turbine,can directly convert thermal energy into electrical energy.The thermoelectric generator is also environmentally friendly,lightweight and flexible,and has low noise,no late maintenance etc,which is getting more attention.For the limitation of the thermoelectric generator with commonly used structure,the thesis proposed a new structure TEG and studied its TE materials and structure parameters by experiments.The research includes:A new structure TEG was designed,whose TE legs were departed into two parts by metal films in the middle.We fabricated new structure Bi1.5Sb0.5Te3/Sb1.5Bi0.5Te3 flexible thin films TEGs with different length and width of the metal films.The results showed that the length and the width of the metal films got larger,the output voltage of whole TEGs became smaller while the first level TE legs' output voltage became greater.Compared with new structure TEGs,the performance of TEG without metal films was better.We studied the influence of different materials of the TE legs on the performance of TEGs.On Kapton thin films,Bi2Te3/Sb2Te3 flexible thin films TEG and Bi1.5Sb0.5Te3/Sb1.5Bi0.5Te3 flexible thin films TEG were fabricated by co-evaporation.It turned out that Bi1.5Sb0.5Te3/Sb1.5Bi0.5Te3 TEG had superior TE characteristics.We compared the influence of different substrates on the performance of the TEGs.On the polyimide substrate(flexible)and on the quartz substrate(anti-flexible),Bi1.5Sb0.5Te3/Sb1.5Bi0.5Te3 thin films TEGs were fabricated.Comparison results showed that the TEG on the flexible substrate had better thermoelectric properties.The contact resistance between semiconductor thin film legs and metal films of TEGs was explored.Research results showed that the contact resistance between semiconductor thin films and metal films could be neglected,the contact between them could be viewed as ohmic contact.