Overview

Come and celebrate ARC SEAM HDR Nan Zheng’s PhD candidacy completion.

Abstract:

Highly emissive micro- and nano-structured surfaces are of great interest for a variety of studies and research, particularly in areas such as antireflective surfaces and radiative cooling designs. This thesis investigates emissive metasurfaces made from metals, anisotropic crystals, and polymers, primarily fabricated through laser machining techniques.

The emissivity of these metasurfaces was designed in the infrared range, specifically engineered within the atmospheric transmission windows (7–14 µm and 16–26 µm), enabling an effective radiative cooling effect in high-temperature thermal emission environments. Additionally, a full solar band radiative cooling film was developed for daytime outdoor applications, efficiently emitting heat through the atmospheric transparent window to outer space without any external energy input.

The metasurfaces demonstrated exceptional infrared emissivity, with comprehensive investigations into their design principles, structural features, and surface chemistry. These characteristics were correlated with spectral analysis and radiative cooling performance, providing valuable insights into the development of advanced metamaterials for energy-efficient thermal management.

About the speaker:

Nan began his career as an environmental consultant before earning a Master of Engineering degree at the University of Melbourne. Following his master’s completion, he applied his skills as a lab technician specialising in physical and chemical analysis. Currently, Nan is completing his Ph.D. in laser physics and photonics, sponsored by the Australian Research Council – Surface Engineering for Advanced Materials (ARC SEAM), focusing on cutting-edge research into highly emissive metamaterials and their applications in radiative cooling.

Nan’s research emphasises the design and fabrication of radiative cooling metasurfaces using metals, anisotropic crystals, and polymers. His work involves advanced processes such as laser modification, etching, annealing, plasma vapor deposition, and photolithography.

Beyond academia, Nan is dedicated to bridging the gap between research and industrial applications. During his Ph.D., he contributed to three collaborative projects. Leveraging his engineering expertise, Nan conceptualized and developed a portable cooler using a full solar band radiative cooling film with phase-changing materials. He also enhanced a portable solar-driven water purification device with a graphene-based solar steam film. These innovations earned him the Innovation Excellence Award in the 16th Chunhui Cup Global Talent Innovation & Entrepreneurship Competition in 2021. His pitch also earned third prize in the 2021 Nexus Future City Competition, reflecting his interest in turning research into practical, real-world solutions.