Highly stable lanthanide cluster-based luminescent materials constructed from -diketone to 1,10-phenanthroline exhibiting ultrahigh photoluminescence and efficient pesticide detection

Simultaneously enhancing the photoluminescence quantum yield (PLQY) to reach a considerable value (>90%) and stability of lanthanide complexes holds tremendous significance for their practical applications. Here, we have successfully synthesized two series of luminescent lanthanide clusters: Ln(2b) (Ln = Eu for Eu-2b and Gd for Gd-2b) and Ln(2p) (Ln = Eu for Eu-2p and Gd for Gd-2p). Structural analysis revealed that compound Ln(2b) with a chromophore/metal ratio of 3 : 1 exhibited a weak intermolecular pi-pi interaction, while compound Ln(2p) with a higher ratio (4 : 1) of chromophore to metal exhibited strong intramolecular and intermolecular pi-pi interactions. Compound Eu2p had an ultrahigh PLQY of (96.6 +/- 0.3)%, surpassing the PLQY ((49.5 +/- 0.5)%) of compound Eu-2b, and exhibited high thermal and solvent stability. The temperature-dependent emission spectra showed that the emission intensity of compound Eu(2p )and Eu-2p-doped PMMA film did not decrease with increasing temperature. The Eu2p-doped white light emitter achieved an impressive PLQY of (75.5 +/- 0.5)%, outperforming commercial phosphors. Furthermore, the luminescent probe results showed the highly selective and sensitive nature of compound Eu-2p for DCN (2,6-dichloro-4-nitroaniline) detection, and the lowest detection limit of 0.12 mu M, meeting the detection requirements for environmental protection and food safety. In general, this study synthesized two multi-functional lanthanide cluster-based luminescent materials with ultrahigh quantum yield and high solvent stability. The increase in chromophore-metal ratio and the enhancement of intramolecular and intermolecular interactions have provided insight into the structure-function relationship and represent a promising strategy for fabricating luminescent devices based on lanthanide clusters.