Surface-Modified Substrates for Quantum Dot Inks inPrinted Electronics

摘要

Printed electronics fill the niches for low-cost, flexible devices in electronics. Developing substrates suitable for various printable electronic inks becomes an important topic in both academia and industry. Because of their extraordinary properties like solution processability, colloidal quantum dots (QDs) are gradually emerging in this field as promising candidates for electronic inks. In recent years, researchers have successfully produced high quality PbS QD inks in polar solvents. However, the incorporation of electronic inks onto a well-passivated substrate remains challenging due to the processing incompatibility between polar solvents and hydrophobic substrates. Here, we propose a surface modification strategy by using chlorine to achieve both trap-site suppression and a hydrophilic surface. The chlorine can effectively passivate the surface dangling bonds and charged hydroxyls while creating a hydrophilic surface. On this modified substrate, the contact angle between the water droplet and the SiO2 substrate can be as small as 20° and this strategy is also feasible for other polymer and inorganic substrates. For a proof-of-conceptdemonstration, we fabricated a PbS QD ink-based field-effect transistoron a Cl-passivated substrate, and the device showed a mobility ashigh as 4.36 × 10^–3 cm²/V s, whichindicates effective trap-site suppression. This device also enablesthe potential of the Cl-passivated substrates for QD inks with wateror other polar solvents.