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Photo-Assisted Photoluminescent Enhancement Of Water-Soluble CdTe Nanocrystals

Posted on:2011-05-06Degree:MasterType:Thesis
Country:ChinaCandidate:Y LiuFull Text:PDF
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CdTe nanocrystals have attracted much attention due to their narrow band gap, quantum size effect and special photoluminescence (PL) properties. Various methods have been developed to obtain CdTe nanocrystals with controlled particle size and shape, in which the aqueous route is the most attractive way. However, the as prepared CdTe nanocrystals (NCs) via an aqueous route always show low photoluminescence (PL), and thus limited its further applications. In the thesis, we have proceeded investigations on enhancing the PL of CdTe nanocrystals obtained via aqueous route. These include:1. Preparation of CdTe nanocrystals:An aqueous route was used to prepare CdTe nanocrystals, where the particle size and crystallity of CdTe crystal were simply controlled by adjusting the reflux time. UV-Vis, PL confirmed that both the size and crystallity of CdTe crystals is increased while prolong the reflux time.2. PL enhancement of CdTe nanocrystals:detail investigations were performed on enhancing the PL of CdTe nanocrystals.①Increase of PL was obtained by "reacting" of pyridine with CdTe NCs, but no obvious PL increase was observed in absent of pyridine, indicating the importance of pyridine on enhancing the PL of CdTe.②Investigations on the incident light indicate that appropriate light intensity is benefit for increasing the PL of CdTe, where high light intensity always result in the fast photocorrosion.③Lowered PL increase was found when the post-treating was performed in N2 as compared with that of in air, indicating O2 should be a favorable factor for the PL enhancing in our case.④A possible competive surface reaction was suggested to be responsible for the PL enhancement of CdTe nanocrystals in our case.
Keywords/Search Tags:CdTe nanocrystal, PL enhancement, Photo-assist, blue shift
PDF Full Text Request
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