Thermoelectric Properties And Device Integration Based On The Flexible Carbon Nanotube Films With Structure Modified

Energy is very important for the development to our society.Thermoelectric materials can convert waste heat from the environment into electrical power.And the flexibility becomes more important for thermoelectric materials when the heat comes from curved surface,such as human body.In this dissertation,we investigate the thermoelectric performances of the modified carbon nanotube films（CNTF）prepared by chemical vapor deposition（CVD）as thermoelectric materials.In addition,the wearable thermoelectric devices also have been explored for their practical applications.The major conclusions are as follows:（1）The P-type thermoelectric material of bismuth telluride(Bi_0.5Sb_1.5Te₃)with high thermoelectric performance was nanocrystallized by electrochemical and ultrasonic approach.The obtained dispersion of Bi_0.5Sb_1.5Te₃ nanosheet can be easily adsorbed on the CNTF by soaking process.Due to the high performance of Bi_0.5Sb_1.5Te₃ nanosheet,the power factor of the modified thermoelectric material would be increased from 58.08μW m^-1 K^-2to 82.8μW m^-1 K^-2 with an increase of about 50%;（2）The carbon-coated iron particles attached on the CNTF were removed using calcination step-by-step and hydrochloric acid reaction processes.After the treatment,the carriers in purified CNTF could be transferred more easily.As a result,the electrical conductivity of the CNTF increases from 195 S cm^-1 to 1196 S cm^-1,and the power factor increases from 58.08μW m^-1 k^-2 to 311μW m^-1 k^-2.In addition,the purified CNTF indicates excellent tensile strength and flexibility.It can be stretched more than 10000 cycles with a resistance change less than 5%.The results further demonstrate the stable carrier transport property of the thermoelectric material duing the deformation processes.（3）The modified CNTF were then cut into thousands of pieces.And the pieces were further assembled into thermoelectric devices on the substrate,such as A4 paper or non-woven fabric,according to the method of"electric series,heat parallel".The thermoelectric device can work with a temperature differences of 20～60 K.Thermoelectric devices also can be integrated into clothing for wearable thermoelectric clothing.The electronic watch would be powered by the thermoelectric devices with a temperature difference of 48 K.Moreover,the powered watch works stably for more than two weeks.In addition,a thermoelectric curtain also has been fabricated with the thermoelectric materials on curtain.Therefore,standardized thermoelectric devices may be produced with mass production method.And the devices also can be usied in different conditions with high thermoelectric performances.