Fabrication and optical characterization of trivalent-rare-earth doped CdS nanocrystals

摘要

US nanocrystals doped with trivalent rare earth ions have been fabricated, and their photoluminescence (PL) properties have been studied at 10 K using excitation light chopped at 750 Hz. In Eu3+-doped CdS nanocrystals, sharp intra-4f emissions of Eu3+ are superposed on a broad defect-related PL band of US nanocrystals in the PL spectrum in phase with the excitation light. In the out-of-phase PL spectrum, on the other hand, only the intra-4f emissions of Eu3+ are observed. However, the excitation spectrum for the out-of-phase D-5(0)-F-7(2) PL of Eu3+ shows a peak due to CdS nanocrystals in addition to the peaks due to the intra-4f transitions of Eu3+. Further, PL properties of Eu3+-doped CdS nanocrystals are much different from those Of Eu(CH3COO)(3), a raw material of the sample. These observations indicate that Eu3+ ions are effectively doped into CdS nanocrystals and the energy transfer occurs from CdS nanocrystals to Eu3+ ions. [References: 11]