Nanoscale additive manufacturing with perovskite quantum dots

Abstract

This thesis presents the development of an electrohydrodynamic (EHD) printing technique for nanoscale additive manufacturing using CsPbBr₃ perovskite quantum dots (QDs). Perovskite QDs have attracted significant attention due to their outstanding photoluminescence properties, tunability, and solution-processability, making them promising candidates for advanced photonic applications, particularly in lasers and sensors. However, conventional fabrication techniques face challenges of complexity, cost, and limited flexibility in pattern design. To address these, we designed and implemented a custom-built EHD printing platform with hardware and software capable of high-resolution programmable printing of perovskite QD micro- and nanostructures. We systematically investigated key printing parameters – including electric field, solution concentration, printing speed, and number of stacked layers – and analyzed their effects on printability and structural dimensions. Also using this custom system, we successfully fabricated diverse morphologies from nano-pillars (with an average width of 276.8 nm and aspect ratio of 29.70) to micro-ring arrays (with a minimum radius of 2 µm), as well as customized patterns (the HKU logo and a triangular fractal pattern). Photoluminescence characterization confirmed that the printed structures retain the excellent optical properties of the original quantum dots, demonstrating a narrow emission peak (with an FWHM of 19.55 nm) and good uniformity in terms of emission intensity. This work thus provides a robust engineering foundation and clear optimization guidelines for leveraging EHD printing to fabricate perovskite QD-based photonic devices, paving the way forward toward scalable, flexible, cost-effective, and repeatable manufacturing of next-generation optoelectronic and photonic circuits.