Surface Modification of Paper Substrates by A Printed UV Curing Varnish Layer and A Transferred Transparent PEDOT:PSS Electrode for Paper-based Perovskite Light-Emitting Devices in Ambient Air

Abstract

Abstract Paper, a low-cost and eco-friendly substrate, can be used to prepare flexible electronic devices by resorting to surface modification technology. In this study, we investigated the surface modification of paper substrates, including those that were uncoated or coated with traditional mineral coatings, to analyze the enhancements to surface flatness and water resistance using a UV curing varnish layer. Furthermore, we explored the formation of perovskite films on the surface-modified paper substrates utilizing a PEO-doped perovskite precursor solution in ambient air, and the surface morphology, crystallinity, photoluminescence properties, and absorption properties of the prepared perovskite films were discussed accordingly. Considering the nontransparent feature of paper-based substrates, the inverted perovskite light-emitting device was finally assembled by transfer printing a transparent PEDOT:PSS layer as a top electrode. The conductive and optical properties of the electrode layer were thus analyzed as well. It is found that the surface modification of paper substrates via printing the UV curing varnish can illustrate significant improvements, such as pore-filling on the surface, a more than 10-fold reduction in roughness, and downward penetration. Moreover, prepared perovskite films on the surface-modified coated paper exhibit superior enhancements, including photoluminescence, higher crystallinity, and surface roughness and porosity. Devices fabricated on the surface-modified substrates are less susceptible to short-circuiting. The electroluminescence improved on the surface-modified coated paper substrate is 2.16 times higher than the prepared device on the surface-modified base paper substrate and even 3.23 times higher than on the PET substrate. Therefore, it is quite feasible to fabricate a perovskite light-emitting device on the modified surface of a paper substrate by using a printed UV curing varnish layer, which is expected to be a promising coating to polish the paper surface in the preparation of electroluminescent devices.