Enhanced green and orange photoluminescence of nanostructured CdS in glass nanocomposites by energy transfer From Ho3+ and Eu3+ ions

We report enhanced photoluminescence (PL) of both band edge and trap state emissions in Ho3+ or Eu3+ ion doped CdS (II-VI semiconductor) nanoparticles (NPs) containing glass nanocomposites. These glass nanocomposites were synthesized by the conventional melt-quench technique. The sizes of CdS NPs are found to increase from 5-15 nm to 40-80 nm with the increase in thermal treatment. Band edge emission (green emission, peak around 495 nm) of CdS NPs is controlled by their size and enhanced about three to nine-fold by Ho3+ ions on excitation at 446 nm by a diode laser. Under the same excitation, twelve to fifty-fold enhanced trap state emission (orange and red emissions about 550-900 nm) of CdS NPs is obtained by Eu3+-doping compared to undoped CdS NPs containing glass nanocomposites. The predominant mechanism of PL enhancement is the energy transfer from rare earth ions to CdS NPs. Enhanced PL of these nanocomposites enables their applications in efficient solar concentrators, green and red light emitting component for white light emission devices