Enhanced photoluminescence of CoWO sub(4) in CoWO sub(4)/PbWO sub(4) nanocomposites

Abstract

CoWO sub(4)/PbWO sub(4) nanocomposites were successfully synthesized at room temperature (RT) by co-precipitation route without using any templates or surfactants and sintered at 600 degrees C for good crystallization. The sintered samples were characterized by X-ray diffraction, Fourier transform infrared spectroscopy, scanning electron microscopy (SEM), transmission electron microscopy and Zeta potential measurements. UV–Visible diffuse reflectance spectroscopy, photoluminescence (PL) and PL lifetime were studied at RT. The results indicate that the composites have two-phase composition: CoWO sub(4) and PbWO sub(4). SEM micrograph and zeta potential measurements reveal particle agglomeration. The intrinsic PL peak emission at 467 nm of CoWO4 nano sample was enhanced upto four times by optimizing the atomic ratio of Pb/Co concentration. The interconnected interface of CoWO sub(4)/PbWO sub(4) nanocomposites could have led to increase in number of recombination of electron hole pairs in CoWO sub(4) and enhanced its intrinsic PL emission intensity. The mechanism of enhanced PL emission for the CoWO sub(4)/PbWO sub(4) nanocomposites can be attributed to charge transfer between [WO sub(4)]sup(2-) and [WO sub(6)]sup(6-) complexes due to intra particle agglomeration leading to possible interface.