Measuring heat transport within polymer nanocomposites via fluorescence thermometry

Measuring heat transport within complex polymeric systems with several different components is important for applications ranging from electronics to solar cells. Previously we reported a scheme whereby spot heating with a laser combined with measurement of the resultant temperature profile within a polymer thin film could be utilized to measure heat loss from film surfaces. An extension of this technique is presented to alternatively measure heat transport within a polymeric film laminated to a sensing layer. Such a scheme might be useful for testing materials intended for heat management applications. The sensing layer contains embedded metal nanoparticles, which will generate heat when irradiated with light resonant with their localized surface plasmon resonance, and molecular fluorophores that can be utilized to make a spatial map of the temperature versus position in the plane of the sensing layer. Because this radial temperature distribution depends on heat loss from the lateral surfaces, a simple fit of this profile provides information about heat transport in the attached film. We present experimental data and a theoretical analysis.