Photo-to-heat conversion of broadband metamaterial absorbers based on TiN nanoparticles under laser and solar illumination

We theoretically investigate photothermal heating of ultra-flexible metamaterials, which are obtained by randomly mixing TiN nanoparticles in polydimethylsiloxane (PDMS). Due to the plasmonic properties of TiN nanoparticles, incident light is perfectly absorbed in a broadband range (300-3000 nm) to generate heat within these metamaterials. Under irradiation of an 808 nm near-infrared laser with different intensities, our predicted temperature rises as a function of time agree well with recent experimental data. For a given laser intensity, the temperature rise varies non-monotonically with concentration of TiN nanoparticles because the enhancement of thermal conductivity and absorbed energy as adding plasmonic nanostructures leads to opposite effects on the heating process. When the model is extended to solar heating, photothermal behaviors are qualitatively similar but the temperature increase is less than 13 K. Our studies would provide good guidance for future experimental studies on the photo-to-heat conversion of broadband perfect absorbers.

Automated summary

We theoretically investigate the photothermal heating of ultra-flexible metamaterials consisting of TiN nanoparticles randomly mixed in polydimethylsiloxane (PDMS). Due to the plasmonic properties of TiN nanoparticles, incident light is fully absorbed in the broadband range of 300-3000 nm, generating heat within the metamaterials. Our predicted temperature rise as a function of time under irradiation of an 808 nm near-infrared laser agrees well with recent experimental data. The temperature rise varies non-monotonically with the concentration of TiN nanoparticles due to the opposing effects of enhanced thermal conductivity and absorbed energy on the heating process.