Photoluminescence studies, judd-ofelt analysis and biological activities of cool white-light emanating dysprosium(III) complexes with pipemidic acid

Synthesis of dysprosium (III) complexes was done using liquid-assisted green and eco-friendly grinding method with 8-Ethyl-5,8-dihydro-5-oxo-2-(1-piperazinyl) pyrido (2,3) pyrimidine-6-carboxylic acid also known as pipemidic acid (here abbreviated as EDOPP) as the primary ligand and four different N-donor heterocyclic secondary ligands to form ternary complexes. To characterize these complexes, several analytical methods were employed. The photoluminescence emission spectra comprised of intense bands for ⁴F_9/2 →⁶H_15/2 (482 nm), ⁴F_9/2 → ⁶H_13/2 (575 nm) and ⁴F_9/2 → ⁶H_11/2 (650 nm) transitions, recorded at 385 nm excitation wavelength. The diffuse reflectance spectra were utilized to determine the band gap values (1.9-2.9 eV) of the complexes. The result for color coordinates are in accordance with the values obtained from Commission Internationale de l'éclairage (CIE), which proves that the emission lies in white light region. CCT values >3200K establish the complexes as cool white light source. Nanoparticle grain size (22-39 nm) was determined through PXRD. Decay time ranging from 1.26 to 1.51 ms were calculated for the complexes. Detailed analysis using Judd-Ofelt theory, which utilized spectral absorption data recorded in the near-infrared region +(NIR), was conducted to ascertain the Judd-Ofelt parameters (Ω=2,4,6). Radiative and non-radiative transition rates, along with lasing parameters, were also assessed. Additionally, the antibacterial and antimicrobial properties of these complexes were evaluated. These synthesized complexes exhibit versatile applications in various sectors, including sensors, lasers, fluorescence labeling, and display devices.