Photoactive Luminescence in a Silver Cluster Crystal.

Due to their atomically precise structures and tunable electronic properties, coinage metal clusters have emerged as a significant class of luminescent materials, demonstrating broad application potential in the development of optical sensors and light-emitting diodes. Recently, luminescent coinage metal clusters exhibiting novel photophysical properties, such as afterglow emission, circularly polarized luminescence, near-infrared luminescence, and x-ray excited luminescence, have been successively reported, attracting significant research attention. In this work, the first photo-responsive luminescent silver cluster (Ag8) was reported, whose phosphorescence can be activated through UV light irradiation in crystal state. Mechanism study revealed that the photo-response of Ag8 was attributed to the photo-induced oxygen scavenging by methanol within the lattice, which relieved the quenching of the phosphorescence of the metal cluster, leading to a "turn-on" response. Due to its reversible photoactive luminescent properties in the solid state and excellent stability, a specialized photo-responsive ink for three-dimensional printing was developed based on Ag8. This study expands the range of luminescent coinage metal clusters and offers a novel strategy for the development of coinage metal cluster-based stimuli-responsive materials.