Measurement of the in-plane thermal conductivity by steady-state infrared thermography

TL;DR

This paper presents a rapid, non-contact method using steady-state infrared thermography to measure the in-plane thermal conductivity of thin films, validated with materials like PEDOT:PSS and polyimide.

Contribution

The authors introduce a simple, quick technique for in-plane thermal conductivity measurement of thin films using IR thermography and analytical modeling, validated against literature values.

Findings

Measured conductivities of PEDOT:PSS and polyimide films match literature.

The method provides accurate results with a straightforward setup.

It enables rapid assessment of thin film thermal properties.

Abstract

We demonstrate a simple and quick method for the measurement of the in-plane thermal conductance of thin films via steady-state IR thermography. The films are suspended above a hole in an opaque substrate and heated by a homogeneous visible light source. The temperature distribution of the thin films is captured via infrared microscopy and fitted to the analytical expression obtained for the specific hole geometry in order to obtain the in-plane thermal conductivity. For thin films of poly(3,4-ethylenedioxythiophene):polystyrene sulfonate post-treated with ethylene glycol and of polyimide we find conductivities of 1.0 W/mK and 0.4 W/mK at room temperature, respectively. These results are in very good agreement with literature values, validating the method developed.