Photochemical/thermal energy storage using organic cations

A prime need in developing reversible photo-latent heat storage systems is to find low molecular weight organic molecules which undergo highly specific photoreactions with visible wavelength light. A new approach of using an acid catalysed photoreaction is proposed. This approach has been tested by applying it to a methyl substituted benzenehomofulvene cycle. Such a storage system based on the isomerization of a benzenoid has a very high potential storage capacity of some 1100 J/g.