Vapor-induced marangoni coating for organic functional films

Abstract

The meniscus-guided coating (MGC) is an efficient solution-processing method for preparing organic functional films. However, the uniform shear stress and mass transfer in the liquid meniscus is still challenging for large-area fabrication of organic functional films. Herein, we report a vapor-induced coating approach to fabricate highly conductive and transparent PEDOT:PSS thin films. The mechanism and morphology regulation rule for film fabrication via vapor-induced coating have been systematically studied. The vapor-induced coating is an intrinsically contactless and spontaneous meniscus-guided method, in which the vapor molecules not only induce the spontaneous dewetting of the liquid film but also behave as a direct dopant for PEDOT:PSS thin films to improve electrical conductivity. The resulting PEDOT:PSS thin films reach a conductivity up to 4227 S cm⁻¹ when combined with H₂SO₄ post-treatment and excellent transparency of 90%, exhibiting a much better performance as electrodes for perovskite solar cells (PSCs) than the films obtained by conventional meniscus-guided methods. Besides, the patterning PEDOT:PSS films can be successfully constructed using pre-patterned substrates and used as electrodes for organic field-effect transistors (OFETs). The results are of significance for the development of efficient and simplified solution-processing methods of organic functional films.