Effective mobility in amorphous organic transistors: Influence of the width of the density of states

•High mobility P3HT/PS OTFTs have been fabricated and measured between 130 and 350 K.•The mobility dependence on gate bias is found to be very sensitive to temperature.•An advanced numerical OTFT model was used to simulate the I–V characteristics.•Good agreement was obtained over the whole range with a unique parameter set.•The P3HT/PS (1:5) Gaussian DOS width was found close to 45 meV.

The temperature dependence of poly(3-hexylthiophene-2,5-diyl) (P3HT)/polystyrene (PS) blend organic transistor current/voltage (I–V) characteristics has been experimentally and theoretically studied. The planar transistors, realized by drop casting the P3HT/PS ink, exhibit high mobilities (over 5 × 10−3 cm2 V−1 s−1) and good overall characteristics. A transistor model accounting for transport mechanisms in disordered organic materials was used to fit the measured characteristics. Using a single set of parameters, the measured effective mobility versus gate bias, either increasing or decreasing with the gate bias depending on temperature, is well reproduced over a wide temperature range (130–343 K). A Gaussian density of states width of 0.045 eV was determined for this P3HT/PS blend. The transistor I–V characteristics are very well described considering disordered material properties within a self-consistent transistor model.

Graphical abstractFigure optionsDownload full-size imageDownload as PowerPoint slide