Tuning emissive color of trivalent terbium ion through environmental factors: optoelectronic insights from theoretical, spectral and computational studies

RSC Adv. 2024 Dec 17;14(53):39569-39587. doi: 10.1039/d4ra05334f. eCollection 2024 Dec 10.

Abstract

The combination of 4,4,4-trifluoro-1-phenyl-1,3-butanedione (TFPB) and pyrazine (pyz) with Tb3+ ions forms two distinct types of complexes, represented by the formulas [Tb(TFPB)3(L)2], where L is either H2O or pyz, and [(Tb(TFPB)3)2pyz]. A detailed examination of the impact of the surrounding environment on the photophysical properties of these synthesized complexes was conducted. Photoluminescence (PL) analysis indicated that the magnetic dipole transition (5D47F5) is dominant in Tb(iii)-based systems. The prepared complexes exhibit visible luminescence in both solid and solution media. Remarkably, the luminescence intensity of the mononuclear complex is significantly higher than that of its dinuclear counterpart, highlighting the impact of efficient energy transfer on emission intensity. The CIE color coordinates of these complexes in solution closely align with NTSC standard values. Additionally, modulation of emissive color is evident when the surrounding media (from solid to solution) and solvent nature are altered. Density Functional Theory (DFT) calculations were performed to elucidate the electronic density distribution in the synthesized complexes. Additionally, a comprehensive analysis, including IR, UV, NMR, thermogravimetry and cyclic voltammetry, was conducted, along with theoretical calculations using Judd-Ofelt analysis.