Low-Voltage Organic Field Effect Transistors with a 2-Tridecyl[1]benzothieno[3,2-b][1]benzothiophene Semiconductor Layer

Abstract

An asymmetric n-alkyl substitution pattern was realized in 2-tridecyl[1]benzothieno[3,2-b][1]benzothiophene (C(13)-BTBT) in order to improve the charge transport properties in organic thin-film transistors. We obtained large hole mobilities up to 17.2 cm(2)/(V·s) in low-voltage operating devices. The large mobility is related to densely packed layers of the BTBT π-systems at the channel interface dedicated to the substitution motif and confirmed by X-ray reflectivity measurements. The devices exhibit promising stability in continuous operation for several hours in ambient air.

Recent advances in organic field effect transistors

“…The same trend was also demonstrated by theoretical modelling, for all the members of the acene series from naphthalene to hexacene, in which the mobility increases monotonically from 0.0511 to 1.461 cm 2 /Vs [71]. Unfortunately, the increased mobility with longer conjugation lengths is accompanied by reduced environmental stability and solubility of the longer acenes.…”

Improving the Performance of Organic Thin‐Film Transistors by Ion Doping of Ethylene‐Glycol‐Based Self‐Assembled Monolayer Hybrid Dielectrics

“…As semiconducting material the asymmetric 2-tridecyl [1]benzothieno [3,2-b][1]benzothiophene (C 13 -BTBT) was utilized, a small molecule which showed excellent mobilities in previous experiments. [ 16,17 ] Figure 3 b shows the changes in capacitance as direct effect of the doping of the SAM. In Table 2 the corresponding capacitance data of the layers at 1 V at 500 kHz can be seen.…”

“…We address the increased mobility to an increased charge carrier density induced by the local dipole fi eld. [ 18 ] The slightly reduced "overall performance" of transistors compared to devices with the same semiconductor but on other SAMs [ 16 ] can be attributed to the surface energy of the SAM which infl uences the semiconductor orientation and morphology at the interface which in turn directly infl uences the performance. [ 19,20 ] Additionally, the decrease of the absolute threshold voltage V th for the doped samples can be seen in Figure 3 c. V th of the reference sample is −2.91 V whereas the doping with potassium shifts it to −2.78 V, for lithium to −2.70 V, and for sodium to −2.68 V.…”

Versatile Organic Transistors by Solution Processing

“…[67,73] Another major impediment associated with these materials has been the elaborate synthesis steps, along which comes higher cost and lower yield; however, new synthetic techniques have been developed for both symmetric and asymmetric BTBT derivatives. [74,75] In parallel with the development of organic p-type materials, n-type OSCs are also necessary for integration in complementary architectures for application in logic devices. [76][77][78] Challenges faced during the development of n-channel materials have included low I on /I off ratios and large threshold voltages when characterized under ambient conditions.…”