the past decade, a number of photoresponsive materials have been reported as STF candidates, such as anthracene, [7] norbornadiene, [8,9] fulvalene diruthenium, [10,11] stilbene, [12] and azobenzene. [13] As we all know, azobenzene and its derivatives have been explored to broad applications for optical data storage, [14-16] molecular motors, [17-20] artificial mechanical actuator, [21-24] and STFs, [25-28] due to these unique photoresponsive character and extraordinary cycling stability. However, azobenzene derivatives still have challenges to meet the requirements of STFs, such as a short storage half-life (determined by the barrier of photoinduced isomerization process, Ea) and low energy density (determined by internal energy difference between cis and trans isomers, ΔH). [13] Recently, some functionalized azobenzene derivatives or azobenzene hybrid materials have been reported to improve the energy density and storage half-life. [29-33] Grossman and co-workers synthesized hybrid materials containing carbon nanotube (CNT)-templated and azobenzene with covalent bonds, which demonstrated that the energy density and storage half-life were both improved due to the generation of intermolecular steric strain. [5] They also introduced layer-by-layer cross-linked approach, bulky aromatic molecular design, and engineering concept to obtain high energy storage density. Feng and co-workers prepared series of graphene oxide or CNT-templated azobenzene hybrids via covalent functionalization, which demonstrated that the intermolecular hydrogen bonds between the grafted azobenzenes significantly improved the energy density and storage half-life. [31-33] Wu and co-workers prepared a four-layer STF cell for visible light charging to improve the conversion efficiency of solar energy due to the wider absorption spectral overlap. [4] Although nanohybrid Azo-STFs achieved a higher energy density and improved the storage half-life, the charging process with solvent pretreatment was inevitable before application due to the close-packed structure and the poor penetration of UV light. This inconvenient solvent-assistant process potentially aggravated the environmental pollution and increased the costs, which limited their practical applications. [6] By contrast, the solid-state film STF was more practical and convenient due to ready-to-use charging and discharging process. However, few literatures reported pristine azobenzene derivatives prepared for the solid-state film STFs application. [34,35] Azobenzene and its derivatives are proposed as promising solar thermal fuel (STF) candidates due to the unique photoinduced trans-cis isomerization. However, the routinely processed azobenzene/inorganic-nonmetal nanocomposite-based STF usually encounters the problems of close-packed structure and the poor penetration of UV light, which need a solvent pretreatment charging process before STF application. Electrochemical deposition (ED) is widely used in the preparation of photoelectric functional devices because of its unique polymerization a...
