Photoluminescence and electroluminescence from copper doped zinc sulphide nanocrystals/polymer composite

Abstract

Cu-doped ZnS nanocrystals were prepared in an inverse microemulsion at room temperature as well as under a hydrothermal condition. X-ray diffraction analysis showed that the diameter of the Cu-doped ZnS nanocrystals particles was about 9 nm. These particles showed a strong photoluminescence intensity and a broad emission band from 490 to 530 nm. The half-width of emission was about 60 nm. Cu-doped ZnS nanocrystals/polymethylmethacrylate composite as a light-emitting layer was used to fabricate a single layer structure electroluminescent device which had low turn on voltage (less than 5 V). The green light of electroluminescence was observed at room temperature. The electroluminescence and photoluminescence spectra were nearly identical at room temperature.

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.…”

Luminescent properties of fine-dispersed self-propagating high-temperature synthesized ZnS:Cu,Mg

“…The nature of the luminescent centers responsible for the blue and green lines is ZnS was studied in sufficient detail in [11][12][13][14][15][16][17][18]. Authors [11][12][13][14][15][16][17] showed that the center responsible for the appearance of Cu green line was insulated copper ion that replaced the zinc one in the lattice of ZnS. It was determined that symmetry of this center is not less than that of the regular lattice point in cubic or hexagonal lattice of ZnS.…”

Synthesis, Structural and Optical Characterization of Copper and Rare Earth doped CdS Nanoparticles

“…[11][12][13][14][15] The doped nanostructures are known to have unusual physical and chemical properties in comparison with the corresponding bulk materials. [16][17][18] Among chalcogenides, special photoelectrical and chemical properties of CdS (band gap 2.42 eV at 300 K for bulk CdS and 3.25 eV for nanosized CdS 19 ) have generated much interest because of its relatively large nonlinear response, 20 photocatalytic activity 21 and luminescence. 22 Both size and surface effects are important in nanosized materials.…”