Stable CdTe nanocrystals grown in situ in thiol-modified MCM-41 mesoporous silica: Control synthesis and electrochemical detection of Cu2+

• Stable CdTe nanocrystals in the pores of thiolated MCM-41.
• Emission properties of CdTe were changed by the silica proportion.
• Obtained CdTe emit at lower wavelengths in comparison to common aqueous routes.
• Materials were efficient in electrochemical detection of Cu2+.

Stable CdTe nanocrystals were grown in the mesoporous environment of thiol-functionalized MCM-41 mesoporous silica from an approach employing 3-mercaptopropionic acid, an efficient capping agent widely used in the aqueous route to semiconductor nanocrystals. The emission properties of CdTe were found to be dependent on the proportion of mesoporous matrix used in the synthesis, yielding CdTe nanocrystals emitting below the wavelength range usually obtained from aqueous synthesis. Electrochemical characterization of CdTe confirmed the higher band gap of nanocrystals obtained using this approach. Finally detection of Cu2+ ions using modified carbon paste electrodes by stripping cyclic voltammetry was only possible with silica samples containing CdTe nanocrystals, evidencing the role of the semiconductor as active phase, responding also to differences in Cu2+ concentration. The most active sample obtained here was exactly that containing the lowest CdTe loading, showing that it is possible to reduce the dosage of Cd-containing nanocrystals while improving their properties, which is crucial to concretize applications of Cd-containing nanocrystals.

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