Here, correlations between polymer structure and charge transport in solution-
processed indium oxide, In2O3:polymer blend flexible thin film transistors
(TFTs) are investigated using four polymers having electron-donating amine
functionalities (polyethyleneimine (PEI), poly(allylamine), polyethyleneimine
ethoxylated (PEIE), and PVP-NH2 (PVP; poly(4-vinylphenol)), and two PEIPEIE
mixtures) with varied atomic amine nitrogen content (N%) of 12.6, 9.1,
6.9, 2.6, respectively. These amino-polymers influence the semiconducting
oxide film TFT electron mobilities via a delicate interplay of electron transfer/
doping, charge generation/trap-filling, film morphological/microstructural
variations, which depend on the polymer structure, thermal stability, and N%,
as well as the polymer content of the In2O3 precursor and the carbon residue
content in In2O3. Thus, increasing the N% from 0.0% in the control PVP to
12.6% in PEI increases the electron doping capacity, the polymer content
of the blend formulation, and the blend TFT field-effect mobility. Optimal
polymer incorporation invariably enhances charge transport by as much as
≈2×, leading to a maximum carrier mobility of 8.47 ± 0.73 cm2 V?1 s?1 on rigid
Si/SiOx substrates and a remarkable 31.24 ± 0.41 cm2 V?1 s?1 on mechanically
flexible polyimide/Au/F:AlOx substrates with Al contacts. Furthermore, all of
the polymers equally enhance the mechanical durability of the corresponding
In2O3:polymer blend TFTs with respect to mechanical stress.