The third-order optical nonlinearity and upconversion luminescence of CdTe quantum dots under femtosecond laser excitation
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- 作者：Qinhan Jin ; Wenzhi Wu ; Zhiren Zheng ; Yuxi Yan ; Weilong Liu ; Aihua Li ; Yanqiang Yang and Wenhui Su
- 关键词：CdTe ; Quantum dots ; Optical nonlinearity ; Time ; resolved luminescence dynamics ; Nanomaterials
- 刊名：Journal of Nanoparticle Research
- 出版年：2009
- 出版时间：April, 2009
- 年：2009
- 卷：11
- 期：3
- 页码：665-670
- 全文大小：1.4 MB
文摘
The aqueous CdTe quantum dots (QDs) were synthesized by the electrostatic reaction method. The optical properties of CdTe QDs were investigated by femtosecond Z-scan and time-resolved luminescence technique in nonresonant spectral region. The nonlinear absorption and refraction are ascribed to two-photon absorption, and time-resolved upconversion photoluminescence produces biexponential decay pattern at infrared femtosecond laser excitation. Upconversion luminescence is composed of a band-edge excitonic state and a photoinduced trapping state. The short-lived band-edge excitonic emission is independent of the detection wavelengths, and long-lived species becomes even longer with the increase of detection wavelengths, which indicates the size dependence of surface excitonic emission.