Miscibility-Controlled Mechanical and Photovoltaic Properties in Double-Cable Conjugated Polymer/Insulating Polymer Composites

Abstract

Flexibility is one of the main characteristics of organic solar cells (OSCs), which enables them to possess potential applications in flexible electronics. The study of flexibility (such as mechanical and bending behaviors) of the photoactive layers and the strategy to enhance the flexibility are important research topics in this field. In this work, we have focused on studying the flexibility of a single photoactive layer via using a double-cable conjugated polymer instead of two-component bulk-heterojunction layers. This simplified system enabled us to add the insulating polymers into the double-cable polymer to generate a polymer/polymer mixtures. The results found that the miscibility between the double-cable conjugated polymer and insulating polymers was the key factor to influence the mechanical and photovoltaic properties. Good miscibility by using polystyrene as an additive can provide better crack-onset strains as well as high efficiency, while lower miscibility by using polydimethylsiloxane as an additive exhibited low efficiencies in single-component OSCs