Three-Dimensional Encrypted Printing of Carbon Dots via Meniscus-Guided Microprinting

Carbon dots (CDs) offer a promising alternative for optoelectronic applications, featuring multicolor emission, biocompatibility, and low-cost synthesis from abundant precursors. The integration of CDs into intricately designed structures via micro-scale three-dimensional (3D) printing holds great potential for enhancing their optical and mechanical functionalities. This study presents a novel micro-printing strategy for achieving CD fluorescence by utilizing a CD-filled polymer ink composed of CDs, hydroxypropyl cellulose, and N,N-dimethylformamide (DMF). The ink forms polymer composites with uniformly dispersed CDs through the rapid evaporation of DMF at the micro-meniscus. As a result, the printed structures exhibit stable fluorescence under 365 nm UV light and enable continuous stacking and encrypted patterning of various 3D architectures. The findings of this study are anticipated to contribute to the development of a versatile and scalable manufacturing approach for biocompatible, multicolor fluorescent 3D optoelectronic systems.