Open AccessHigh efficiency and nearly cubic power dependence of below-band-edge photoluminescence in water-soluble, copperdoped ZnSe/ZnS Quantum dots
Author(s) -
Guichuan Xing,
Wei Ji,
Yuangang Zheng,
Jackie Y. Ying
Publication year - 2008
Publication title -
optics express
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.394
H-Index - 271
ISSN - 1094-4087
DOI - 10.1364/oe.16.005715
Subject(s) - photoluminescence , quantum dot , materials science , absorption edge , optoelectronics , copper , absorption (acoustics) , excited state , doping , optics , excitation , laser , band gap , molecular physics , atomic physics , physics , quantum mechanics , metallurgy , composite material
Three-photon absorption (3PA) and three-photon-excited photoluminescence (3PE-PL) of ZnSe/ZnS and copper-doped ZnSe/ZnS core-shell quantum dots (QDs) in aqueous solutions have been unambiguously determined by Z-scan and 3PE-PL measurements with 200-fs laser pulses at 1000 nm. The 3PA cross-section is as high as 3.5 x 10(-77) cm6 s2 photon(-2) for 4.1 nm-sized, copper-doped ZnSe/ZnS QDs, while their below-band-edge PL is found to be nearly cubic dependent on the excitation intensity, with efficiency enhanced by approximately 20 fold compared to the undoped ZnSe/ZnS QDs.