TAILIEUCHUNG - Báo cáo " Sol-gel synthesis and particle size characterization of CdSe Quantum dots "

In this article, we report on the preparation of CdSe quantum dots (QDs) by sol-gel method and their optical properties. The average size of QDs is also estimated by using various ways, such as the Scherer’s formula, The Effros-Brus-Kayanuma’s theoretical expression, TEM etc. The TEM images of samples show that the mean sizes of QDs are 4 nm. The mean sizes of QDs are smaller than that of other methods and arranging from 2 to nm. | VNU Journal of Science Mathematics - Physics 25 2009 207-211 Sol-gel synthesis and particle size characterization of CdSe Quantum dots Khong Cat Cuong1 Trinh Duc Thien1 Pham Thu Nga2 Nguyen Van Minh1 Nguyen Van Hung2 1 Hanoi National University of Education 136 Xuan Thuy Road Cau Giay Hanoi Vietnam 2 Institute of Materials Science Hoang Quoc Viet Road Hanoi Vietnam Received 9 November 2009 received in revised form 24 November 2009 Abstract. In this article we report on the preparation of CdSe quantum dots QDs by sol-gel method and their optical properties. The average size of QDs is also estimated by using various ways such as the Scherer s formula The Effros-Brus-Kayanuma s theoretical expression TEM etc. The TEM images of samples show that the mean sizes of QDs are 4 nm. The mean sizes of QDs are smaller than that of other methods and arranging from 2 to nm. 1. Introduction Size-dependent optoelectronic properties of CdSe quantum dots QDs make them ideal candidates for tunable absorbers and emitters in application such as nanoscale electronics laser technology and biological fluorescent labeling. The properties of QDs are strongly influenced not only by the composition and structure of the matrix but also by the preparation technique. The band-edge emission of CdSe QDs in a strongly confined regime has been generally attributed to electron transitions from the highest occupied to the lowest non-occupied molecular orbital 1 . Therefore there exist many methods that have been applied to synthesize CdSe quantum dot. A variety of methods has been employed to synthesize semiconductor nanorods in recent years. These methods include the hot coordination solvents method using tri-n-octylphosphine oxide TOPO and trioctylphosphine TOP 2 the hydrothermal or solvothermal method 2 3 and the micelle or reverse micelle method 3 . The electrical and optical properties of nanoparticles are affected by the chemistry involved in their synthesis. Bottom-up approaches such as .

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