Structural colors use nanostructured building blocks or thin films to resonantly reflect or scatter light to generate colors and can exhibit higher resolution, saturation, and durability than pigment-based colors. To create structural color based paintings, it is essential to develop a capability of spatially varying the dimensions of these nanosized structures. Recently we reported a high-throughput and wafer-scale nanopatterning method by combining interference lithography and grayscale-patterned secondary exposure (IL-GPSE) to spatially modulate nanostructure feature sizes on large scale while maintaining sufficiently high resolution. Here, we employ the IL-GPSE method in the fabrication of wafer-scale structural color paintings, which can improve the patterning efficiency by orders of magnitude when compared with e-beam lithography. The fabrication techniques developed in this work have unique potentials for broader applications in biomedical sensing, spectral filtering, anti-counterfeiting or encryption, etc.
Professor Wendi Li is currently an Associate Professor in the Department of Mechanical Engineering, leading the Nanofabrication and Nanodevice Laboratory. Before joining HKU, he received his bachelor’s and PhD degrees from Tsinghua University and Princeton University, respectively, and conducted post-doctoral research on advanced lithography for next-generation nanoelectronics at Hewlett-Packard Labs. His research interests mainly focus on scalable lithographic micro/nanofabrication techniques, such as nanoimprint lithography, laser interference lithography, charged-particle-beam lithography, etc., from their fundamental mechanisms, process and instrumentation development, to practical applications in functional devices. The innovations from his team have been awarded three gold and silver medals at the Geneva International Exhibition of Inventions and licensed to spin-off companies, to commercialize flexible electronic devices and nanopatterning equipment.
Clean water and clean air are vital for public health. This project focuses on developing high-efficiency and environmentally sustainable filters for removing harmful air/water pollutants. The team has developed novel architectures and functionalities for the filters to achieve high permeance, high removal efficiency, and excellent reusability.
