Quantum Dot‐Based Fluorescent Antennas via Digital Light Processing 3D Printing: Toward High‐Performance and Environmentally Stable Optical Communication

Fluorescent antennas (FAs) based on quantum dots (QDs) are promising light‐converting structures for optical wireless communication (OWC) owing to their high photoluminescence efficiency and ultrawide field of view (FOV). However, their stability is limited by degradation from water and oxygen, hindering long‐term operation. Here, we present a strategy that combines a cross‐linked resin with digital light processing (DLP) 3D printing to fabricate structurally programmable and environmentally robust FAs. The approach enables uniform QDs dispersion, high‐resolution geometries, and tunable device architectures beyond conventional mold‐based methods. Guided by Monte Carlo simulations, we further developed an encapsulated fluorescent antenna (EFA), in which the emissive QDs layer is fully enclosed in a transparent resin shell. This design provides effective isolation from moisture and oxygen while functioning as a low‐loss optical waveguide. The optimized EFA achieved a side‐emission efficiency of 10.9% and a wide FOV of 150°. Importantly, the EFA retained over 70% of its emission intensity after 10 days in water. In the communication tests, the EFA demonstrated a 26 MHz modulation bandwidth and a 135 Mbps data rate. These results establish DLP‐printed EFA as a versatile and stable platform for next‐generation underwater photonic communication devices.