Influence of temperature on wetting properties of thin films in organic solar cells applications

Abstract

Printed electronics is a new branch of electronics that allows the development of unique devices and manufacturing methods regardless of the substrate used. Solution-processed organic solar cells are the best example of printed electronics, where the production yield can be significantly increased. While the interface between engineered ink and the substrate plays an important role in fabricating high-efficiency devices, manipulating the wetting properties of printed layers remains a challenge, as the wetting mechanism is complex and may be affected by a variety of factors. This study analyses the influence of temperature on the wettability of some popular thin-film layers used in the manufacture of organic solar cells. It tests and analyses interactions between polymer-based inks and various substrates using the contact angle measurement method. In this study, temperature was set to range between 0 and 120°C to allow compatibility with commonly used blends and flexible substrates. Our results show that ink-substrate interactions and the consequent printing process depend on three factors: substrate temperature during processing, substrate material composition and the materials used for ink formulation. The study also indicates stable solar cell performance when manufactured with substrate temperatures below 90°C.