Direct Photolithography of Fluorescent Copper (I) Iodide Cluster Microarrays

clusters. This approach allows the creation of micro- and nanoscale patterns with a resolution of 6 µm within just 15 min, eliminating the developing step required in conventional photolithography. The resulting patterns exhibit distinct fluorescence under dual-wavelength excitation (310 and 365 nm). Exploiting this characteristic for high-density information encoding, we demonstrate applications in anti-counterfeiting labels and chip encryption. This work provides an efficient and controllable strategy for patterning functional metal-halide clusters, expanding their potential for use in advanced optoelectronic devices.