Microwave-assisted synthesis and photoluminescence properties of ZnS:Pb2+ nanophosphor for solid-state lighting

Abstract

Nanocrystalline ZnS:Pb2+ phosphor was synthesized by microwave-assisted co-precipitation method. The phase purity and surface morphology of prepared material were investigated using an X-ray diffractometer (XRD) and a scanning electron microscope. The photoluminescence property was studied by near-UV (nUV) excitation. The XRD pattern of prepared phosphor matches well with that of an ICDD (International Center for Diffraction Data) file. Surface morphology of prepared phosphor was found to be in submicron range. As-prepared ZnS:Pb2+ phosphor shows a green emission under nUV excitation. As Pb2+ ions are located on a regular Zn2+ site they produce a green emission band in the range of 400–650 nm, centred at 500 nm, under excitation wavelength of 357 nm, exhibiting luminescence properties typically observed for Pb2+. Effect of concentration of Pb2+ ions on emission intensity was studied. The colour co-ordinates of prepared phosphor were calculated and found to lie in the green region of Commission Internationale de l’Eclairage diagram.