We have investigated the channel-length dependence of responses to a vapor analyte with a series of α,ω-dihexylquarterthiophene (DHα4T) field-effect transistors (FETs). Single-crystalline DHα4T devices deposited by vacuum sublimation at substrate temperatures of 70°C are compared with polycrystalline DHα4T films deposited at room temperature. By changing the length of FET channels and/or the size of polymer grains, the number of grain boundaries per device is changed systematically. A larger response to vapor analyte is obtained by increasing the number of grain boundaries per device, showing that vapor sensing occurs mainly at grain boundaries.
All Science Journal Classification (ASJC) codes
- Physics and Astronomy (miscellaneous)