Green luminescence from copper doped zinc sulphide quantum particles

Abstract

Free-standing powder of zinc sulphide quantum particles has been synthesized using a chemical route. X-ray diffraction analysis shows that the diameter of the particles is ∼21±2 Å which is smaller than the Bohr exciton diameter for zinc sulphide. UV absorption shows an excitonic peak centered at ∼300 nm corresponding to an energy gap of 4.1±0.1 eV. These particles show a luminescence band at ∼424 nm. The quantum particles could be doped with copper during synthesis without altering the UV absorption or x-ray diffraction pattern. However, doping shifted the luminescence to 480 nm, green wavelength in the visible region.

Tuning luminescence of 3d transition- metal doped quantum particles: Ni+2: CdS and Fe+3: CdS

“…Doped CdS nanoparticles were carried out by a chemical precipitation method which is very similar to described by Khosravi et al [22]. Spherical particles with a very narrow size distribution can be obtained by controlling the synthesis parameters [22].…”

“…Spherical particles with a very narrow size distribution can be obtained by controlling the synthesis parameters [22]. In a typical procedure, amounts of CdCl 2 .4H 2 O, NiCl 2 .4H 2 O and FeCl 3 .3H 2 O stock solutions and distilled water were added together to bring the concentration of Cd +2 , Ni +2 and Fe +3 of 0.01 mol.L −1 .…”

Luminescence of nanocrystalline ZnS:Cu2+

“…For nanocrystalline ZnS:Cu only a green luminescence is reported [12][13][14][15][16], while for bulk ZnS:Cu also UV/blue, red and IR emissions are observed. The spectral position reported for the green emission in the papers on nanocrystalline ZnS:Cu varies from 425 nm [12] to 525 nm [14].…”

“…Recently, the luminescence of nanocrystalline ZnS:Cu has been investigated [12][13][14][15][16]. Due to the large surface to volume ratio of the nanoparticles, charge carriers can be injected efficiently into these materials.…”

“…The spectral position reported for the green emission in the papers on nanocrystalline ZnS:Cu varies from 425 nm [12] to 525 nm [14]. The measurements are limited to room temperature and the lifetime of the observed luminescence has not been investigated.…”