Light-thermal conversion organic shape-stabilized phase-change materials with broadband harvesting for visible light of solar radiation

To achieve highly efficient utilization of sunlight, organic shape-stabilized phase change materials (OSPCMs) with light-thermal conversion and visible light (solar radiation) harvesting abilities were designed and synthesized through color matching (yellow, red, and blue) according to the solar irradiation energy density. These materials exhibited excellent rapid and broadband visible light-harvesting, light-thermal conversion, thermal energy storage, and form-stable (remained in the same state upon transition) effects. The chemical structures of OSPCMs were verified using Fourier transform infrared and proton nuclear magnetic resonance techniques. Differential scanning calorimetry results indicated that the melting temperatures and latent heats of the synthesized OSPCMs ranged from 48 degrees C to 64 degrees C and from 107.1 J g(-1) to 138.5 J g(-1), respectively. The novel materials show a reversible (more than 200 cycles) phase transition (crystalline state change) via ON/OFF switching of visible light irradiation. Colour matching showed that the light-to-heat conversion and thermal energy storage efficiency (eta) of the OSPCMs significantly improved upon solar irradiation.