Anisotropic and temperature-dependent thermal conductivity of PbI2

The temperature-dependent components of the anisotropic thermal diffusivity of lead iodide (PbI2) have been measured by Laser Flash Analysis (LFA). The temperature range used was −100 °C to +350 °C. The temperature-dependent specific heat capacity cp was determined independently by Differential Scanning Calorimetry (DSC) to calculate the thermal conductivities for PbI2 from the thermal diffusivity data. At 27 °C, the thermal conductivity in the c-axis-direction, k33, is 0.315 W m−1 K−1, whereas the component perpendicular to the c-axis, k11, is 0.681 W m−1 K−1. The anisotropy ratio k33/k11 changes from 1:2 at −100 °C to 1:2.4 at +350 °C. The temperature dependencies of both k33 and k11 in this range can be very well fitted with 3rd order polynomials.