Highly efficient solar-thermal storage coating based on phosphorene encapsulated phase change materials

Solar-thermal energy storage using latent heat of phase change materials (PCMs) offers renewable penetration in wide range of smart applications. The limiting solar energy harvesting efficiency of existing photo-thermal dopant materials and their negative impact on thermal storage capacity have remained fundamental impediment to further advancement. Herein, we explore a phosphorene based bandgap engineered broadband photonic nanoheater for efficient thermal charging of solid-solid PCMs. In our devised composite system, we benefitted from the synergistic effect of highly efficient photonic energy harvesting characteristic of exfoliated phosphorene nanoflakes (PNF) and latent heat storage capability as well as encapsulating feature of PCM matrix. The solar-thermal energy storage efficiency of our developed materials exceeds 95% even at lower phosphorene doping level (1 wt. %) and under full solar spectrum with improved latent heat storage capacity (150 J g−1). The achieved efficiency is highest among all photo-thermal storage materials and attributed to the intense and broadband solar absorbance of PNF featured by wide thickness distribution. Further, coating of developed solar heat storage material on fabric substrate has shown promising results toward real world applications.