Building-block-selective deposition of self-assembled monolayers for enhancing interface polarity in solution-processed thin film transistors

Abstract

A frequently adopted approach in solution-processed electronics involves device engineering with self-assembled monolayers (SAMs). However, in some cases, such engineering occurs non-specifically, not only affecting the intended building blocks but also other parts of the device, deteriorating its performance. To this end, we propose and demonstrate a procedure for the selective deposition of functional SAMs onto a glass substrate of top-gate-bottom-contact transistors with indium tin oxide electrodes. The respective SAMs, carrying electron-donating and electron-withdrawing tail groups, were able to positively affect the charge carrier density in the adjacent active layer, with a clear correlation between the character of the groups and semiconductor type, resulting in improved device performance. This approach was demonstrated for both organic and inorganic semiconductors of different types (p-type, n-type, and ambipolar), which underlines its general character and suggests that it can be adapted to other kinds of solution-processed devices.