Charge transport and trapping in organic field effect transistors exposed to polar analytes

Pentacene based organic thin-film transistors were used to study the effects of polar analytes on charge transport and trapping behavior during vapor sensing. Three sets of devices with differing morphology and mobility (0.001−0.5 cm2/V s) were employed. All devices show enhanced trapping upon exposure to analyte molecules. The organic field effect transistors with different mobilities also provide evidence for morphology dependent partition coefficients. This study helps provide a physical basis for many reports on organic transistor based sensor response.