Luminescence of er doped ZnS quantum dots excited by infrared lasers.
ZnS:Er quantum dots were prepared in aqueous medium from readily available precursors. The construction, morphology and luminescence properties of the ZnS:Er quantum dots were evaluated by X-ray diffraction (XRD), transmission electron microscopy (TEM), and photoluminescence spectra. The average particle size was calculated using the Scherrer formula to be 4 nm, which is also observed from high resolution transmission electron microscopy (HRTEM) image. Different laser wavelengths at 976 +/- 2 nm and 1480 nm were utilized as the excitation source. ZnS:Er quantum dots had a fluorescence spectrum in 1550 nm region through the 4I13/2 --> 4I15/2 transition. Furthermore, intensity increased with increasing excitation intensity and dopant concentration. The reason for the photoluminescence spectra broadening is discussed. It is because the energy levels of Er3+ are split by a coulombic interaction between electrons, including spin correction and spin-orbit coupling, and eventually by the Stark effect due to ZnS QDs crystal field and local coordination.
Institute of Material Physics, Tianjin University of Technology, Tianjin 300191, People's Republic of China.
Xiaosong
X
Zhang
Lan
L
Li
Qingsong
Q
Huang
Zhongpeng
Z
Zhang
Qun
Q
Xi
Xiaoyi
X
Dong
Yange
Y
Liu
Ting
T
Ji