Luminescence and energy-transfer mechanism of a praseodymium material

Abstract

A praseodymium (Pr) material, [Pr(isonicotinic acid)2(H2O)4] n nNO3 (1), was synthesized through a solvothermal reaction and was characterized by single-crystal X-ray diffraction. It is characterized by a one-dimensional chain-like structure. The [Pr(isonicotinic acid)2(H2O)4] n n+ cationic chains and isolated nitrate (NO3 −) anions are interlinked by hydrogen (H)-bonding interactions, yielding a three-dimensional supramolecular network. Solid-state photoluminescence measurements revealed that it exhibits a yellow-light emission. The photoluminescence emission bands originate from the characteristic emission of the 4f electron intrashell transitions of 3 P 1 → 3 H 5 and 3 P 0 → 3 H 6 of the praseodymium ion (Pr3+). The energy-transfer mechanism is explained by the energy-level diagram of the praseodymium ion and the isonicotinic acid (C6H5NO2) ligand. The praseodymium material has remarkable Commission Internationale de l’Éclairage chromaticity coordinates of (0·4251, 0·4646). Therefore, it is a promising color converter for lighting and displays. It is found that isonicotinic acid is not an ideal ligand to excite Pr3+ ions, i.e. not a good “antenna”. The purity of the bulky sample was confirmed by PXRD. The FT-IR bands of the title complex were assigned. The title complex is thermally stable at about 90°C