Luminescence of nanocrystalline ZnS : Pb2+

Nanocrystalline ZnS:Pb2+ is synthesised via a precipitation method. The inf luence of the particle size on the luminescence of nanocrystalline ZnS:Pb2 is studied. Depending on the excitation wavelength, nanocrystalline ZnS:Pb 2+ shows: a very broad white (lambda (exc) = 380 nm) or red emission (lambd a (exc) = 480 nm), The red and white emissions are assigned to charge trans fer transitions involving different Pb2+ centres, The decay kinetics of bot h emissions are typical for Pb2+ (low temperature: ms, high temperature: mu s) and are independent of the particle size. The quenching of luminescence with increasing temperature is explained by photoionization. The lower quen ching temperature for the luminescence of larger nanoparticles is explained by quantum size effects.