A green- emitting a- substituted a- diketonate Tb3+phosphor for ultraviolet LED- based solid- state

Abstract

The -substituted -diketonate [Ln(3Cl-acac)(3)(H2O)(2)] [Ln=Tb, Gd] complexes (with 3Cl-acac(-) being 3-chloro-2,4-pentanedionate) were characterized by elemental analysis, infrared, ultraviolet (UV)-visible and photoluminescence spectroscopies. For comparison purposes regarding photoluminescence, the well-known [Tb(acac)(3)(H2O)(2)] complex was also synthesized. By considering the phosphorescence spectra of [Gd(3Cl-acac)(3)(H2O)(2)], the effect of chloride replacement of hydrogen on the triplet state energy of the 3Cl-acac ligand was revealed. To support the interpretation and rationalization of the experimental results, Time-dependent DFT calculations were performed on Tb(3Cl-acac)(3)(H2O)(2). Additionally, the possibility of Tb(3Cl-acac)(3)(H2O)(2) to be used as potential green-emitting phosphor material for solid-sate light emitting diodes was evaluated. A prototype was successfully fabricated coating a near-UV LED (370nm) with the Tb(3Cl-acac)(3)(H2O)(2) complex.