Judd-Ofelt, optical and photophysical analysis of β-ketocarboxylate Sm(III) complexes with N-donor aromatic system as secondary sensitizers

Abstract

Reddish orange, Sm(III) complexes were synthesised by means of environmentally sustainable grinding method with β-keto carboxylic acid and heterocyclic aromatic systems. The photoluminescent studies revealed that 4G5/2 → 6H7/2 transition (608 nm) is responsible for the reddish orange emission of complexes when irradiated with UV light. Judd-Ofelt theory was applied to NIR absorption spectra to obtain three intensity parameters (Ω2, Ω4, Ω6) from oscillator strength. The higher Ω2 values obtained in complexes indicate greater covalence character. To assess luminescence performance, the radiative, nonradiative transition probability, radiative life time and intrinsic quantum yield were also evaluated. High quantum yield obtained for complexes signalises the superior luminescent behaviour. Exquisite color purity (89.8–96.2%) and CCT <3200 K establish these complexes as warm orange light source. The experimental data of absorption coefficient was fitted nonlinearly with Tauc's relation to obtain band gap energy. Two band gaps were reported in each complex hence the synthesised complexes can have materiality in solar cell and photovoltaic devices. The Urbach band tail width was also obtained through fitting with a new empirical relation which affirms the semiconducting properties of complexes. The investigation of antimicrobial and antioxidant properties of complexes ascertained the complexes as potent antibacterial and antioxidant agents.