Thermoelectrical properties of polithiophene (P3HT) thin film polymers

Abstract

Conducting and semiconducting polymers show very interesting thermoelectric characteristics by having relatively high electrical but low thermal conductivity. This suggests that they can be used in thermoelectric patterning, which is achieved by forming localized and con ned heated areas on the material by passing electric current through it. This thesis examines the usage of polymeric semiconductor of poly (3-hexyl thiophene)(P3HT) in thermoelectric applications. An experimental setup is build to measure the lateral thermal conductivity of P3HT thin lm polymer to be 3.7 W/mK, which is not close to the reported real value of 0.2 W/mK. The analysis of measurement setup and results show signi cant error induced by considerable amounts of thermal paths between measurement thermal probes alternative to the thermal path through the sample. Some suggestions are made to improve the experimental setup. E ect of doping on electrical conductivity and Seebeck coe cient of P3HT is discussed to increase the thermoelectric gure of merit, ZT. ZT of P3HT is calculated with thermal conductivity value of 0.2 W/mK and found to be 2.5 x 10-4.