Photothermal calorimetric techniques applied to condensed matter materials

Abstract

This paper is a review of new possibilities offered by two photothermal (PT) methods, a contact (photopyroelectric (PPE) calorimetry) and a non-contact one (photothermal radiometry (PTR)) for accurate measurements of dynamic thermal parameters of condensed matter samples. Concerning the PPE method, the possibilities offered by the two main detection configurations, “back” and “front”, are analyzed and the information contained in the amplitude and phase of the PPE signal are compared. The applications of the technique refer both to liquid and solid samples. Concerning liquids, high-resolution measurements of thermal diffusivity and effusivity of some “special liquid samples” (volatile liquids, nanofluids,) are described. Several particular PPE detection cases, used for thermal inspection (measurement of thermal parameters, detection of phase transitions, etc) of solids were also presented. The PTR technique was used in the back configuration, together with the thermal-wave-resonator cavity (TWRC) method. This configuration allows for coupled PPE-PTR experiments. A comparison of the two techniques is presented and future developments are analyzed.