Effect of capping agent concentration on thermoluminescence and photoluminescence of copper-doped zinc sulfide nanoparticles.
Copper-doped zinc sulfide (ZnS:Cu) nanoparticles with varying concentrations of capping agent were prepared using a chemical route technique. These particles were characterized by scanning electron microscopy (SEM), transmission electron microscopy and X-ray diffraction (XRD). Optical absorption studies showed that the absorption edge shifted towards the blue region as the concentration of the capping agent increased. Using effective mass approximation, calculation of the nanoparticle size indicated that effective band gap energy increases with decreasing particle size. The thermoluminescence (TL) properties of sodium hexameta phosphate (SHMP)-passivated ZnS:Cu nanoparticles were investigated after UV irradiation at room temperature. The TL glow curve of capped ZnS:Cu showed variations in TL peak position and intensity with the change in capping agent concentration. The photoluminescence (PL) spectra of ZnS:Cu nanoparticles excited at 254 nm exhibited a broad green emission band peaking around 510 nm, which confirmed the characteristic feature of Zn(2+) as well as Cu(2+) ions as the luminescent centres in the lattice. The PL spectra of ZnS:Cu nanoparticles with increasing capping agent concentrations revealed that the emission becomes more intense and shifted towards shorter wavelengths as the sizes of the samples were reduced.
SOS Physics & Astrophysics, Pt. Ravishanker Shukla University, Raipur C.G., India.
Lata
L
Wanjari
SOS Physics & Astrophysics, Pt. Ravishanker Shukla University, Raipur C.G., India.
D P
DP
Bisen
SOS Physics & Astrophysics, Pt. Ravishanker Shukla University, Raipur C.G., India.
Namita
N
Brahme
SOS Physics & Astrophysics, Pt. Ravishanker Shukla University, Raipur C.G., India.
Ishwar Prasad
IP
Sahu
Govt. Arts and Commerce Girls College, Devendranagar, Raipur C.G., India.
Ravi
R
Sharma
D003300:Copper / Q000737:chemistry*; D049449:Luminescence; D049408:Luminescent Agents / Q000737:chemistry; D053768:Metal Nanoparticles / Q000737:chemistry*; D008855:Microscopy, Electron, Scanning; D046529:Microscopy, Electron, Transmission; D010316:Particle Size; D010710:Phosphates / Q000737:chemistry; D013056:Spectrophotometry, Ultraviolet; D013440:Sulfides / Q000737:chemistry*; D014961:X-Ray Diffraction; D017967:Zinc Compounds / Q000737:chemistry*
D049408:Luminescent Agents; D010710:Phosphates; D013440:Sulfides; D017967:Zinc Compounds; D003300:Copper; C031238:zinc sulfide; C009285:sodium polymetaphosphate
XRD; ZnS:Cu nanoparticles; absorption spectra; photoluminescence; thermoluminescence