Photopyroelectric Spectroscopy of Pure Fluids and Liquid Mixtures: Foundations and State-of-the-Art Applications

Since the mathematical foundations of photothermal effects in condensed phase materials were established in the middle 1970s, new photothermal methodologies have emerged based on the detection of heat generated from the absorption and non-radiative conversion of modulated radiation. Among them, photopyroelectric techniques have become very popular and widely used for a variety of studies ranging from calorimetry (photothermal calorimetry), phase transitions and the measurement of thermophysical (thermal diffusivity, effusivity and conductivity) and optical properties (photopyroelectric spectroscopy). More recently photopyroelectric detection has been used for the direct quantification of the optical absorption coefficient of condensed phase materials and has demonstrated its potential for quantitative analysis. In this work, a survey of various applications of photopyroelectric detection for the analysis of fluids and liquid mixtures is presented with special focus on theoretical and experimental progress in quantitative analytical measurements as new developments in this field.