Enhanced triplet–triplet annihilation upconversion by photonic crystals and Au plasma resonance for efficient photocatalysis

Strong upconversion luminescence is significant for effective photocatalytic technology. In this work, photonic crystals and Au nanoparticles (AuNPs) were introduced together to enhance triplet–triplet annihilation upconversion (TTA-UC) luminescence intensity. Photonic crystal films have been fabricated by demolding a polydimethylsiloxane film containing platinum(II)-octaethylporphyrin & 9,10-diphenylanthracene and AuNPs from V-shape anodic aluminum oxide templates. The blue light intensity of the photonic crystal film with AuNPs has gained a 3.69-fold enhancement under green light excitation. After coupling the photonic crystal structure with AuNP plasma resonance, the green-to-blue TTA-UC intensity of the composite film has been enhanced 7.68 times compared with the planar upconversion film without AuNPs. The pseudo-first-order rate constant of the composite film system with g-C3N4@CdS has been increased 3.88 times compared with that of the planar upconversion film system without AuNPs under visible light. This work presents a new route to enhance the TTA-UC luminescence via a hybrid effect, which is useful for photocatalysis.