Phase change composites enhanced by gold nanorods decorated MXene for efficient photothermal conversion and storage

Gold nanorods (AuNRs)-doped phase change materials (PCMs) hold great promise for alleviating the instability and imbalance of solar energy due to their exceptional energy storage density and adaptability. However, their poor full-spectrum light absorption and inferior stability lead to insufficient photothermal conversion efficiency. Herein, we devise functional PCMs with synergistic reinforcement of light absorption and photothermal conversion through the in-situ growth of AuNRs on the MXene surface. The results indicate that the bimodal resonance effect of AuNRs and broad-spectrum absorption of MXene synergistically endow a 29.7 % increase in light absorption efficiencies over the pristine composites, which is superior to the sum of the two individually doped phase change composites (PCCs). Similarly, the photothermal storage and conversion efficiencies of the AuNRs/MXene-doped PCC are significantly enhanced by 36.6 % and 78.4 %, respectively. Furthermore, the fluorescence analysis reveals a prolonged fluorescence lifetime of 1.91 ns and a low quantum yield of 0.27 %, demonstrating efficient separation and migration of light-induced carriers and thermal dissipation via non-radiative relaxation, which is because the AuNRs and MXene synergistically enhance the localized surface plasmon resonance effect and the spectral absorption bands. This work offers fresh perspectives on the development of advanced photothermal PCMs for efficient solar thermal applications.