Time-of-flight measurement of poly(3-hexylthiophene) thin films

Abstract

Poly(3-hexylthiophene) (P3HT) is one of the most studied conjugated polymer for molecular electronics especially for organic field effect transistors (OFETs) and organic light-emitting devices (OLEDs). This is mainly due to the fact that P3HT provides excellent electrical properties and showed high carrier mobility. In this research we studied the photo generated charge carrier transport of P3HT film by the time-of-flight (TOF) method. For device fabrication, P3HT was dissolved in chloroform with concentration of 8 mg/ml then the solution was spun directly onto an ITO pattern coated on glass substrate. Then the aluminum electrode was prepared on film by thermal evaporation. In TOF measurement, the constant voltage was applied to electrode of sample and the film were photo-excited by irradiation of a short pulsed laser light (λ=650 nm). This caused charge separation within the film. The generated charge carrier was used to calculate the mobility of the film. The TOF mobility was determined as a function of applied voltage and light condition. © 2008 Trans Tech Publications, Switzerland.