Fascinating morphologies of lead tungstate nanostructures by chimie douce approach

Abstract

Lead tungstate occurs in nature as tetragonal stolzite of scheelite (CaWO4) type and monoclinic raspite. In this work, we report, the typical growth of snowflake-like tetragonal stolzite and bamboo-leaf-like monoclinic raspite nanocrystals of PbWO4 via a simple aqueous precipitation method and a polyol (polyethylene glycol-200) mediated precipitation method at room temperature (27C). The synthesised PbWO4 nanocrystals were characterised by XRD, SEM, EDAX and TGA-DTA. The UV-Vis absorption and photoluminescence studies of PbWO4 nanocrystals in the two morphologies were performed. The nuclei of PbWO4 nanocrystals in aqueous medium self-assemble in a tetragonal manner to form the snowflake-like crystals. In polyol medium, PbWO4 nuclei preferentially grow by oriented attachment process to form the bamboo-leaf-like morphology. The specific morphology of the regularly assembled PbWO4 nanocrystals in the two phases finds applications in nanoelectronics and photonics. Compared to other well-known scintillators, PbWO4 is most attractive for high-energy physics applications, because of its high density, short decay time and high irradiation damage resistance.