This paper reports the synthesis of ternary ZnCdTe quantum dots (QD) system with highly luminescent in the red region.
The ternary QD system was prepared by quick injection of trioctylphosphine telluride (TOPTe) into a reactor that
contains a hot mixed cadmium and zinc precursors, trioctylphosphine oxide and oleic acid at temperature of as low as
300°C. After the injection of TOPTe, the reaction was left undisturbed for a period of time to facilitate the growth of
QDs and then quenched the reaction at a certain period of time. Photoluminescence analysis found that the ZnCdTe QDs
exhibited highly luminescent properties with the quantum yield was calculated as high as ca. 60%. The emission
wavelength was found to be in the range of 640 to 675 nm. It was also found that the QDs showed a relatively narrow
spectral width, namely ca. 28 nm, reflecting a narrow quantum dots size distribution. Owing to their interesting
photoluminescence properties, the ternary ZnCdTe QDs should find an extensive used in light-emitting diode, solar cell,
laser and biolabelling.
This paper reports the fabrication of an optical receptor for cyclohexane vapour using self-assembly monolayer (SAM) of 1-amino, 9-fluorenone compound. The SAM was built up on quartz substrate and quartz substrate-coated monolayer Langmuir-Blodgett (LB) film of arachidic acid. The UV-VIS spectroscopy technique was used to characterize the self-assembled film. It was found that the SAM on the quartz-coated LB film indicated a clearer optical absorption profile than the SAM on the quartz surface. The optical sensing characteristic of the SAM to the presence of the saturated vapour of cyclohexane indicated that the thin film features a good sensing sensitivity.
A gas sensor system using the assembled molecular layer of poly amino acid derivative, poly-L-proline has been developed. The thin layer was prepared using self assembly technique which was deposited onto a quartz crystal microbalance (QCM) substrate. The QCM coated self-assembly monolayer (SAM) was used to detect the presence of two vapor samples; saturated vapor of acetone and 2-propanol. The sensing sensitivity was based on the change in the fundamental frequency of the QCM upon exposure towards gas sample. It was found that the SAM-coated QCM sensor system was sensitive towards the vapor samples by reducing its fundamental frequency. It was also found that the SAM exhibited a good stability and reproducibility behaviors.