Effective thermal conductivity of silicone/phosphor composites

Abstract

The effective thermal conductivity of silicone/phosphor composites is studied experimentally and numerically. Thermal conductivity measurements are conducted from 30°C to 150°C for the composites with phosphor volume fraction up to 40%. In the numerical study, a finite element model with empirical particle size distribution and random particle position is constructed using a probability density function and the Monte Carlo method, and the interfacial thermal resistance layer between phases also introduced in the model. The results indicate that when phosphor concentration is below 25 vol.%, the conductivity of the composite increases slightly with either phosphor volume fraction or temperature, and the Kapitza radius of the composite is 0.8 µm. When phosphor concentration is above 25 vol.%, the increase of conductivity correlates positively with phosphor volume fraction significantly but negatively with the temperature, and the Kapitza radius is 0.032 µm.