Preparation, structural and its enhanced green upconversion luminescence in rare-earth doped CdMnS nanopowders

Pure, Mn and rare-earth doped CdS nanopowders were prepared by simple chemical method and the synthesized powders were calcinied at 650 °C for 1 h 30 min in air environment. Their structural, vibrational and electronic properties were studied by XRD, SAED, FT-IR, UV–Visible absorption, DRS and luminescence studies. SAED and XRD data shows that as calcinied powders contain multi phase like CdS and CdSO4. Heat treatment in air environment leads to oxidization of the powders. FTIR spectra were recorded to analyze chemical groups in calcinied powders. FE-SEM and EDAX studies were performed to arrive at the morphological and elemental analysis. Upconversion studies were performed with 100 fs, 798 nm laser pulses. Square dependency of the upconverted signal on the input power indicated two photon absorption processes leading to the upconversion. We observed that with rare-earth doping in CdMnS, the upconverted signals were much larger than in the pure CdS. These results strongly suggest that doped CdS, especially transition metal and rare-earth elements, are useful in the field of two photon imaging.

Graphical abstractFigure optionsDownload full-size imageDownload as PowerPoint slideHighlights► Rare-earth and Mn doped CdS nanopowders were prepared by simple chemical method. ► XRD, FTIR and EDAX analysis shows that oxygen diffuses into the CdS crystal lattice. ► Enhanced upconversion luminescence was observed in rare-earth doped CdMnS powders. ► Observed upconversion luminescence is nonlinear (two photon absorption) process.