Silica-Silicon Composites for Near-Infrared Reflection: A Comprehensive Computational and Experimental Study

TL;DR

This study combines computational modeling and experimental validation to develop silica-silicon composites with high near-infrared reflectance, suitable for heat management in high-temperature devices.

Contribution

It provides a comprehensive analysis of silica-silicon composites' near-infrared reflectance, integrating multiscale Monte Carlo modeling with experimental synthesis and characterization.

Findings

Composite reflectance reaches up to 72% in near-infrared region.

Porous microstructure influences scattering and reflectance.

Decreasing particle size enhances reflectance.

Abstract

Compact layers containing embedded semiconductor particles consolidated using pulsed electric current sintering exhibit intense, broadband near-infrared reflectance. The composites consolidated from nano- or micro-silica powder have a different porous microstructure which causes scattering at the air-matrix interface and larger reflectance primarily in the visible region. The 3 mm thick composite compacts reflect up to 72% of the incident radiation in the near-infrared region with a semiconductor microinclusion volume fraction of 1% which closely matches predictions from multiscale Monte Carlo modeling and Kubelka-Munk theory. Further, the calculated spectra predict an improvement of the reflectance by decreasing the average particle size or broadening the standard deviation. The high reflectance is achieved with minimal dissipative losses and facile manufacturing, and the composites described herein are well-suited to control the radiative transfer of heat in devices at high temperature and under harsh conditions.