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This paper introduces a cohesive experimental-computational framework for assessing natural dye thin films and dye-nanomaterial hybrid films as active layers in photothermal sensor applications. The study integrates Quantitative Infrared Thermography (QIRT) with sophisticated thermal response modeling to examine the enhancement of photothermal sensitivity and thermal kinetics in natural dye systems by the incorporation of nanomaterials such as reduced graphene oxide (rGO), zinc oxide (ZnO), and titanium dioxide (TiO₂). We got natural dyes, cleaned them up, and put them down as uniform thin films. We also made hybrid films by adding regulated amounts of rGO, ZnO, or TiO₂ to change how light is absorbed and how heat moves through them.
A fully calibrated QIRT system was used to measure both steady-state and transient temperature fields while a regulated monochromatic laser was used to excite the system. Calibration processes included optimizing the emissivity for each film composition, using a blackbody as a reference, and filtering out noise over time to provide precise heat measurements. We looked at the extracted temperature–time profiles to find sensor-relevant metrics such the photothermal rise rate, the thermal time constant, the steady-state temperature sensitivity, and the response repeatability when the laser pulses were repeated. Hybrid films with rGO showed quicker thermal rise because they absorbed light better and conducted heat better. ZnO and TiO₂ composites, on the other hand, showed wavelength-selective heating and better thermal stability.
A finite-element thermal model was created to simulate how heat is made and spreads in both pure dye films and dye-nanomaterial composites. This was done to add to the experimental results. The model included absorption coefficients that changed with wavelength, anisotropic thermal diffusivity from rGO networks, scattering effects from ZnO and TiO₂ nanoparticles, and realistic boundary conditions that matched the shape of the laser point. The comparison of simulated and observed thermal profiles revealed a great match, which confirmed the modeling method and gave us more information on how to keep heat in, how to move it laterally, and how nanomaterials may make things better.
The findings underscore substantial enhancements in photothermal efficacy with the incorporation of nanomaterials with natural colors. Films with rGO in them have quick thermal transients and high responsivity, which made them good for quick photothermal sensing. ZnO- and TiO₂-based hybrids exhibited stable plateau temperatures and high repeatability, facilitating applications that need reliable steady-state detection.
Our combined QIRT–modeling study shows that natural dye–nanomaterial hybrid films have adjustable and improved photothermal properties. our makes them good candidates for eco-friendly, low-power photothermal sensors and sophisticated optothermal monitoring systems. The study lays the groundwork for additional enhancements via nanomaterial engineering, spectrum customization, and device-level integration.
