Insights into Wavelength-Dependent Photothermal Behavior of Plasmonic Nanomaterials: A Systematic Study across Metallic Au, Ag and Au–Ag Alloys Systems

The photothermal effect of plasmonic nanomaterials has attracted significant interest in recent research. While the light-to-heat effect induced by plasmonic materials has been extensively explored across various nanostructures (size and shape) under different irradiation conditions, such as infrared lights or broadband xenon lamp lights, the precise wavelength dependence of intrinsic photothermal efficiency remains insufficiently understood. In this work, we unveiled new insights into the photothermal conversion efficiency of plasmonic Au, Ag, and Au–Ag alloy systems under the irradiation of different wavelengths. We identified a wavelength-dependent external photothermal efficiency that peaks at the plasmon resonance band. Surprisingly, we observed a consistent near-unity internal photothermal efficiency across different wavelengths, significantly expanding our understanding of plasmonic photothermal behaviors. Additionally, our analysis across metallic systems indicates universally unreported photothermal conversion behavior for plasmonic systems. These findings have implications for efficient heat energy conversion in various applications.