Development of renewable energy technologies has been a significant area of research amongst scientists with the aim of attaining a sustainable world society Solar thermal fuels that can capture, convert, store, and release solar energy in the form of heat through reversible photoisomerization of molecular photoswitches such as azobenzene derivatives are currently in the limelight of research Herein, we provide a state-of-the-art account on the recent advancements in solar thermal fuels based on azobenzene photoswitches We begin with an overview on the importance of azobenzene-based solar thermal fuels and their fundamentals Then, we highlight the recent advances in diverse azobenzene materials for solar thermal fuels such as pure azobenzene derivatives, nanocarbon-templated azobenzene, and polymer-templated azobenzene The basic design concepts of these advanced solar energy storage materials are discussed, and their promising applications are highlighted We then introduce the recent endeavors in the molecular design of azobenzene derivatives toward efficient solar thermal fuels, and conclude with new perspectives on the future scope, opportunities and challenges It is expected that continuous pioneering research involving scientists and engineers from diverse technological backgrounds could trigger the rapid advancement of this important interdisciplinary field, which embraces chemistry, physics, engineering, nanoscience, nanotechnology, materials science, polymer science, etc

Azobenzene-based solar thermal fuels: design, properties, and applications

Solar thermal fuels, which reversibly store solar energy in molecular bonds, are a tantalizing prospect for clean, renewable, and transportable energy conversion/storage. However, large-scale adoption requires enhanced energy storage capacity and thermal stability. Here we present a novel solar thermal fuel, composed of azobenzene-functionalized carbon nanotubes, with the volumetric energy density of Li-ion batteries. Our work also demonstrates that the inclusion of nanoscale templates is an effective strategy for design of highly cyclable, thermally stable, and energy-dense solar thermal fuels.

Azobenzene-Functionalized Carbon Nanotubes As High-Energy Density Solar Thermal Fuels

Review on synthesis and properties of high-energy-density liquid fuels: Hydrocarbons, nanofluids and energetic ionic liquids

A device for solar energy storage and release based on a reversible chemical reaction is demonstrated. A highly soluble derivative of a (fulvalene)diruthenium (FvRu2) system is synthesized, capable of storing solar energy (110 J g−1) in the form of chemical bonds and then releasing it “on demand”, when excited thermally or catalytically. A microfluidic device is designed and constructed for both the photo-harvesting and the heat-utilization steps, allowing for the recycling of material.

https://publications.lib.chalmers.se/records/fulltext/local_163614.pdf

Molecular solar thermal (MOST) energy storage and release system

The results of studies on intramolecular interconversions in systems of norbornadiene quadricyclane and their derivatives are classified and discussed. The mechanisms of the forward photoreaction and reverse thermal process in relation to the nature of the substituents and carbocycles, type of sensitiser and catalyst, and properties of the medium are discussed in detail and classified. An analysis is made of the influence of these factors on the spectroscopic, kinetic, and thermodynamic properties of this system as an accumulator and converter of light energy. Methods of improving its characteristics — light absorption, the quantum yield of the photoreaction, and stability of the photoproduct — have been established. The bibliography includes 188 references.

https://iopscience.iop.org/article/10.1070/RC1991v060n05ABEH001088/pdf

Norbornadiene-quadricyclane — an effective molecular system for the storage of solar energy

Presentation de donnees experimentales sur la conversion photochimique du norbornadiene en quadricyclane. Evaluation, a l'aide de ces donnees et de donnees sur le rayonnement solaire, d'un collecteur photochimique plan discontinu. Analyse economique previsionnelle de ce systeme de conversion et stockage de l'energie solaire

Constantine Philippopoulos

Papers

Norbornadiene-quadricyclane system in the photochemical conversion and storage of solar energy