Optimization of the Pechini-derived synthesis of rare-earth free aluminum borate phosphors presenting tunable white emission

Abstract

The present study is dedicated to the development of aluminum borate luminescent powders which appear as promising and more environmental-friendly than conventional phosphors. The different steps of the luminescent powder synthesis, in particular the precursors (inorganic and organic) ratios and calcination conditions, are adjusted by studying the resulting optical features to get a broader and warmer white emission. As shown in previous works, the photoluminescence emission originates from polycyclic aromatic hydrocarbons (PAH) trapped in the inorganic aluminum borate matrix. Morphological and structural properties of the particles remain otherwise identical for every optimized parameter. The aluminum borate powder synthesized in these optimized conditions exhibits a wide and intense emission band under near-UV excitation. These structural and optical properties combined with time-resolved photoluminescence measurements demonstrate that the adjustments of the synthetic process allow the formation and trapping of more and different emitting centers. The modulation of the excitation wavelength (from 305 to 405 nm) leads to a tunable photoluminescence emission characterized by a large band lying between 400 and 700 nm. This feature, associated with the use of secure and abundant precursors makes aluminum borate powders very interesting phosphors for optical applications.