Optical downconversion in rare earth (Tb3+ and Yb3+) doped CdS nanocrystals

CdS host nanocrystals (4.2-5.5 nm in diameter) have been prepared by a low-cost synthetic chemical route using air stable precursors and doped with rare earth (RE) ions, terbium (Tb3+) and ytterbium (Yb3+). The resulting RE3+-doped nanocrystals show a complete broadband absorption below their band edge (400-460 nm) to the deep UV region. CdS host nanocrystals act as an energy receptor and sensitizer for the RE3+-Lions. A broadband emission in the visible region is observed for the RE3+-doped CdS nanocrystals by room temperature photoluminescence (PL) measurements. Our results show that these novel RE3+-doped nanocrystals can be used as an optical down-conversion material for solar spectral matching in solar cells or as a wavelength shifting down-converter for nanoscale optoelectronic applications. (C) 2011 Elsevier B.V. All rights reserved.