Seminaire Buyun ZHENG 3/11/2026

PhD student, Buyun ZHENG

LMGP, Université Grenoble Alpes, CNRS, Grenoble INP, France

Physical properties and structure–property relationships in silver nanowire networks for low-emissivity applications

Resume

The increasing demand for energy-efficient windows has stimulated the development of transparent low-emissivity (low-E) coatings capable of reducing radiative heat transfer while maintaining high visible transparency. Conventional low-E technologies, such as metal-based multilayer structures and transparent conductive oxides, provide high optical and infrared performance but may involve limitations related to flexibility, processing, or manufacturing complexity. Silver nanowire (AgNW) networks have emerged as a promising alternative owing to their low infrared emissivity, high optical transparency, mechanical flexibility, and compatibility with scalable deposition processes.

This thesis investigates the physical properties of AgNW networks and their potential integration into low-E coatings, with particular emphasis on structure–property relationships. The influence of key structural parameters, including nanowire diameter, length, density, and alignment, is investigated through experimental characterization and physical analysis. In particular, an optical percolation transition is identified at a network density well above the electrical percolation threshold, accompanied by a transition in infrared angular emissivity from dielectric-like to metallic-like behavior. Furthermore, dense AgNW networks are further shown to follow a generalized Hagen–Rubens relationship, enabling infrared emissivity to be directly related to the electrical properties of the network. The impact of nanowire dimensions and network topology on low-E performance is further investigated to identify the structural parameters governing the trade-off between visible transparency and infrared emissivity. The stability of AgNW networks is also addressed through the deposition of oxide layers by spatial atomic layer deposition (SALD), with the aim of improving environmental and thermal stability while assessing their influence on the optical and emissive properties of the resulting coatings. Overall, this work contributes to a more comprehensive understanding of the structure–property relationships in AgNW networks and provides physical insights into their use as transparent low-E coatings for energy-efficient applications.

Short Bio/CV

Buyun Zheng is a PhD student at the Laboratoire des Matériaux et du Génie Physique (LMGP).  His research focuses on the physical properties of silver nanowire (AgNW) networks and their integration into low-emissivity (low-E) coatings for energy-efficient windows. His work investigates how network structure influences the electrical, optical, and infrared properties of AgNW networks, with particular interest in percolation phenomena and network topology.