Biodegradable film enabling visible light excitation of Hexanuclear Europium(Ⅲ) complex for various applications

Highlights: • Hexanuclear Eu-complex Eu₆(TTA)₁₈CTP-TPY have been successfully designed and synthesized. • Biodegradable Eu₆(TTA)₁₈CTP-TPY/PLA composite luminescent films were fabricated. • Eu₆(TTA)₁₈CTP-TPY and Eu₆(TTA)₁₈CTP-TPY/PLA films can be excited by visible light. • Acrylic acid and glacial acetic acid can be quickly detected by these fluorescent films. Developing novel multinuclear organic visible-light-excited europium complex is highly challenging. Herein, novel visible light excitation hexanuclear Eu³⁺ complex (Eu₆(TTA)₁₈CTP-TPY) and Eu³⁺ complex/polylactic acid (PLA) luminescent films have been successfully designed and prepared. Through proper molecular engineering, the hexanuclear Eu³⁺ complex, Eu³⁺ complex/PLA luminescent films both can be successfully excited by visible light. Similarly, it was interesting that the LEDs assembled with Eu₆(TTA)₁₈CTP-TPY/PLA can also achieve excellent photoluminescence under 400 nm excitation wavelength, the luminous efficiency can reach as high as 333.33 lm/W, and the 10%-Eu³⁺ complex/PLA LED kept superior photothermal stability within 50 °C. What's most surprising was that the Eu₆(TTA)₁₈CTP-TPY/PLA luminescent films showed prompt and effective recognition for glacial acetic acid and acrylic acid. This work presents a promising strategy to explore molecular engineering platforms for effectively fluorescence sensing and red LED device applications.