Unraveling the effect of varying auxiliary antennas on the photo-physical and magnetic attributes of Eu3+ complexes

Abstract

This manuscript reports the preparation of heteroleptic europium complexes with formulation of [Eu (DHMB)₃L’], where L’ stands for neutral auxiliary antennas of different denticities by adopting liquid − assisted grinding approach. The detailed explanation of the bonding environment surrounding the Eu³⁺ ion were expounded using various spectroscopic methods such as FTIR, NMR (¹³C and ¹H), EDAX, FESEM, XRD, CV, and elemental analysis. The thermal stability of complexes was recorded up to 200–210 ˚C, which indicates the applicability of these complexes in the photovoltaic domain. LAS fitting was implemented to interpret some magnetic parameters which indicates that our synthesized complexes are soft − magnetic materials with paramagnetic characteristics, and possess a single domain structure with modified anisotropic nature (R < 0.5). The visualization of latent fingerprints was accomplished under UV- illumination at 370 nm. The average crystalline size of the prepared complexes was calculated to be in the range of 5.75 nm to 13.01 nm. The band − gap assessed through Tauc’s plot reveals the materiality of complexes in wide-gap semiconductors, which lie in the range of 2.470–2.577 eV and are in concordance with the calculated electrochemical band gap. The PL study, color co-ordinates in red region of CIE-chart and CCT metrics < 3000 K divulged that these luminescent materials could act as magnificent candidates for warm light sources emitting in the red spectrum. The calculated branching ratio of ∼ 72 % for the most intense peak (Δ J = 2) unveils this transition as a potential laser. Decay time (τ), luminescence efficiency (ϕ) and J-O intensity parameters (Ω₂, Ω₄) were also elucidated. The value of Ω₂ surpassed that of Ω₄ indicating the presence of Eu³⁺ in a ligand field with high polarizability.