Organic phosphor and lead fluoride based luminescent hybrids

Abstract

Powder hybrid materials based on the organic phosphor 8-hydroxyquinolate lithium and the inorganic matrix PbF2 have been synthesized. Powder hybrid materials were obtained by co-precipitation from aqueous-alcoholic solutions with ammonium fluoride under various conditions – different concentrations of the organic component, precursor solutions, the order of mixing the reagents: direct precipitation and reverse precipitation, providing a local excess of nitrate or fluorinating agent during the synthesis. Hybrid materials are single-phase powders, whose crystal structure corresponds to the rhombic phase of α-PbF2. All obtained hybrid materials showed effective broadband luminescence in the region of 390–700 nm. The shift of the photoluminescence bands to longer wavelengths relative to the initial Liq is observed, which is characteristic of lead luminescent complexes, which suggests the formation of new optical cents associated with Pbq2 or [PbqF]2, for all obtained hybrid materials. The formation of optical centers occurs as a result of an exchange reaction and the formation of new bonds between lead and organic ligands. Moreover, an increase in the concentration of the initial Pb(NO3)2 solution promotes a more complete course of the exchange reaction (up to 88%). During reverse deposition, a large fraction of Liq is captured by the crystallizing lead fluoride molecularly, and the completeness of the exchange reaction is generally lower than during direct deposition. The photoluminescence intensity during reverse deposition is 3 to 10 times higher than during direct deposition for different concentrations of reagents. The most intense luminescence is provided by the conditions of reverse precipitation with ammonium fluoride of a solution of lead nitrate with a concentration of 0.8 M and a Liq content of 1 wt.%.This research was funded by the Russian Science Foundation, Grant No. 19-79-10003.