Phonon transport properties in silicon nanoparticles and polymer nanocomposite thin films

• Main Authors: Juangsa, Firman Bagja, Muroya, Yoshiki, Ryu, Meguya, Morikawa, Junko, Nozaki, Tomohiro
• Format: Conference Proceeding
• Language: English
• Subjects: Amorphous materials; Amorphous silicon; Differential scanning calorimetry; Electrical properties; Electrical resistivity; Heat conductivity; Heat transfer; Nanocomposites; Nanoparticles; Nanostructured materials; Optical properties; Optoelectronic devices; Particle size distribution; Polymer films; Polystyrene resins; Silicon; Thermal conductivity; Thermal diffusivity; Thermal resistance; Thermodynamic properties; Thin films; Transport properties; Wave dispersion
• ISSN: 0094-243X; 1551-7616
• DOI: 10.1063/1.5046594

Silicon nanocrystals (SiNCs) have been observed to have size dependent thermal properties, other than well-known optical and electrical properties, which has been widely studied and applied to the various application of optoelectronic devices. However, the effect of nano scale particles in nanostructured materials remains unclear with unspecified determining factors of thermal transport. In this work, well crystalline SiNCs and amorphous silicon nanoparticles (a-SiNPs) with a mean diameter of 6 nm and narrow particle size distribution were synthesized and dispersed in polystyrene (PS) matrix by solution procession to produce nanocomposite material. The thermal conductivity of SiNCs/PS nanocomposite sample were measured base on thermal diffusivity, specific heat, and density that were measured by Temperature Wave Analysis (TWA), Differential Scanning Calorimeter (DSC), and Hydrostatic Densimeter, respectively. Thermal conductivity measurement result of SiNCs/PS shown decreasing value when particle fraction increased, although SiNCs has higher thermal conductivity than PS. Furthermore, the comparison with amorphous filler (a-SiNPs) shown insignificant discrepancy, indicating the phonon scattering at material’s interface boundary played a dominant factor in determining the thermal transport in nanocomposite materials. Also, thermal conductivity models that include thermal boundary resistance (TBR) were calculated and compared with the measurement result. Thermal conductivity models showed good agreement, and minimum deviation with estimated TBR of ca. 4×10−7 m2K/W. Moreover, the fabrication and measurement processes were carried out at low temperature, which allows preservation of unique size dependent properties of nano scale particles and silicon ink utilization that opens the possibility of a broad range of inexpensive application.