Di-functional nanocomposite films for efficient conversion and storage of solar energy

•Rapid and efficient solar-to-heat conversion and storage.•Low loading concentration of gold nanoparticles.•Film interior reversible phase change process.•Enhanced thermal storage efficiency.•High cycling behavior and form-stable performance of the di-functional nanocomposite film.

There is no doubt that renewable sources, such as solar energy, have played an important role in the future renewable energy system. And solar heat has great potential and a high contribution towards the future energy supply. How to directly collect, fast convert and efficiently store solar heat is still a problem to be solved in solar energy application. Herein, the di-functional nanocomposite film was designed and fabricated toward efficient conversion and storage of solar thermal energy. The di-functional nanocomposite film was feasibly prepared by uniformly imbedding phase change materials (PCMs) and Au nanoparticles into PVA matrix uniformly through the hydrogen-bonding interactions. The Au nanoparticles, as photothermal nanoabsorbers, with a low concentration (~0.23% m/m), can instantly and intensely realize solar-to-heat conversion by utilizing surface plasmon resonance. Subsequently, efficiently conversion heat could be stored into the PCMs through film-interior reversible phase transformation. Meanwhile, no leakage and evaporation of the PCMs is observed due to the strong hydrogen-bonding confinement at interface between PCMs and the film matrix. This kind of di-functional nanocomposite films is of great importance and wide usage in the fields of solar thermal energy conversion and storage, thermal interface materials, protective layers and sensing, etc.