Strongly Enhanced Long-Lived Persistent Room Temperature Phosphorescence Based on the Formation of Metal-Organic Hybrids

Molecule-based solid-state materials with room temperature phosphorescence (RTP) are playing an increasingly important role in developing optical sensors, security systems, and biological imaging. However, molecular systems involving long-lived persistent RTP are still rare to date, which has limited the efficiently luminescent recognition and identification. Herein, it is illustrated that the RTP properties of molecular phosphors can be highly enhanced based on coordination interaction with common metal (such as Zn2+). These molecule-metal hybrids present tunable afterglow phosphorescence by adjusting metal species and stacking fashions of molecular units, with the longest RTP lifetime of 1.3 s. Such long-lived persistent emission decay is higher than most of currently reported molecule-based and molecule-metal solid-state RTP systems. Moreover, the reversible phosphorescence transformation under different pH and heat conditions can be further switched and recycled. This work therefore offers a cost-effective and facile way to achieve high-performance RTP metal-organic hybrid materials, which could serve as promising candidates for noble-metal-free and rare-earth-free phosphors in illumination and sensor applications.