Solution-processable and photopolymerisable TiO2nanorods as dielectric layers for thin film transistors

Abstract

We report the fabrication of a solution-processed n-type Thin Film Transistor (TFT) with current on/off ratios of 104, a turn-on voltage (VON) of 1.2 V and a threshold voltage (VT) of 6.2 V. The TFT incorporates an insoluble and intractable dielectric layer (k = 7-9) prepared in situ from solution-processed and then photopolymerised ligand-stabilised, inorganic/organic TiO2 nanorods. A solution processed zinc oxide (ZnO) layer acts as the semiconductor. The new surface-modified TiO2 nanorods were synthesised using a ligand replacement process with a monolayer coating of photopolymerisable 10-undecynylphosphonic acid (10UCYPA) to render them both soluble in common organic solvents and be photopolymerisable using UV-illumination after having been deposited on substrate surfaces from solution and drying.