Photoresponsive conductive polymer network based on azobenzene bridging crosslinked polycarbazole for boosting solar thermal storage

Abstract

Azobenzene is one of the most extensively researched multifunctional chromophores and azobenzene including materials has a wide variety of applications due to their photoisomerization behavior. In this study, electroactive and light-harvesting carbazole and photoresponsive azobenzene units have been combined with a special macromolecular design. In this design the azo groups can be effectively isomerized in solid state, and free-standing films can be obtained by the electrochemical method. Thermal characterizations of both monomer and polymer have been performed and isomerization kinetics and solar-thermal properties have been investigated. The half-life at 60 °C and the gravimetric energy storage density of polymer was calculated as 103 min and 179.9 j g⁻¹, respectively. Cross-linked polycarbazole structure causes dramatically increased solar thermal storage and half-life compared to respective monomer and brought unexpected mechanical and solvatochromic properties.