Effects of Metallic Ions on Photoluminescence Properties of CdSe/PAMAM Nanocomposites and their Application in Fingerprint Detection

Abstract:

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Uniform and well-dispersed photoluminescent semiconductor CdSe(Cadmium selenium) QDs(Quantum dots) were in-situ prepared stabilized by G4.0-NH2 PAMAM dendrimers in water and effects of metallic ions such as Zn2+, Cd2+, Cu2+, Ag+, Pb2+, K+, Na+ on the photoluminescence(PL) properties of CdSe QDs were studied using spectrophotometric titration. The results show that Zn2+ and Cd2+ ions enhance the PL intensity of CdSe QDs, Cu2+, Ag+ and Pb2+ ions quench the PL intensity, while K+ and Na+ ions have no obvious effects. Those are attributed to the surface modification of CdSe QDs. Excess Cd2+ ions can reduce the non-combination centers, increase the passivation of PAMAM on the surface of CdSe QDs, and form a Schottky-like barrier which enhanced the PL efficiency. Excess Zn2+ ions can also increase the PL intensity of CdSe QDs in the same way as Cd2+ ions because of the much similar lattice parameters of CdSe and ZnSe. However, a CuSe, Ag2Se or PbSe shell on CdSe QDs emerges due to the substitution of Cd2+ ions, which leads to the decrease of band-edge emmiting of CdSe QDs. And the quenching effect of Ag+ is stonger than Cu2+ and Pb2+ because of the lower solubility of Ag2Se formed on the surface of CdSe QDs. Oil latent fingerprints deposited on tinfoil surface treated with CdSe/dendrimer NCs(Nanocomposites)、Cd2+-CdSe/ PAMAM NCs and Zn2+-CdSe /PAMAM NCs emitted bright yellow photoluminescence under ultraviolet excitation of 365nm from an UV LED in the dark., among, fingerprint treated with Cd2+-CdSe/dendrimer NCs and Zn2+-CdSe /PAMAM NCs was detected with better resolving rate.

Info:

Periodical:

Advanced Materials Research (Volumes 295-297)

Edited by:

Pengcheng Wang, Liqun Ai, Yungang Li, Xiaoming Sang and Jinglong Bu

Pages:

900-906

DOI:

10.4028/www.scientific.net/AMR.295-297.900

Citation:

Y. J. Jin et al., "Effects of Metallic Ions on Photoluminescence Properties of CdSe/PAMAM Nanocomposites and their Application in Fingerprint Detection", Advanced Materials Research, Vols. 295-297, pp. 900-906, 2011

Online since:

July 2011

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Price:

$35.00

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