研究目的
Investigating the thermal properties of ZnO quantum dots (QDs) synthesized by sol-gel method and their concentration-dependent thermo-optic properties.
研究成果
Stable yellow emissive ZnO quantum dots (QDs) have been synthesized by a typical sol-gel method using ethanol as solvent. The thermal diffusivity of the nano?uid can be tuned with respect to the concentration of ZnO. Hence the ZnO QDs nano?uids can be used for coolant as well as insulating applications in various thermoelectric devices.
研究不足
The study is limited to the concentration range from 20 mg l?1 to 200 mg l?1 due to the loss of transparency of the liquid above this concentration. The dispersion stability of the nano?uid and the increase in cluster size with the increase in concentration of the nanoparticles are factors affecting the concentration-dependent thermal diffusivity.
1：Experimental Design and Method Selection:
The study employed a sol-gel method for the synthesis of ZnO QDs without the use of any capping agents. The thermal properties were measured using a dual beam mode matched thermal lens technique.
2：Sample Selection and Data Sources:
Zinc acetate dihydrate and Potassium hydroxide were used as the zinc and oxygen sources for the synthesis. Ethanol was used as a solvent.
3：List of Experimental Equipment and Materials:
Bruker AXS D8 Advances x-ray diffraction (XRD) technique, JEOL JEM -2100 Transmission electron microscopy (TEM), JASCO V-570 UV–vis-NIR spectrophotometer, Carry Eclipe Varian spectrophotometer, 403 nm DPSS laser, 632.8 nm He-Ne laser.
4：8 nm He-Ne laser.
Experimental Procedures and Operational Workflow:
4. Experimental Procedures and Operational Workflow: The mixed solution was stirred for 15 min at 60 °C, cooled down to room temperature, centrifuged, washed several times using ethanol, and dried at 60 °C for 2 h.
5：Data Analysis Methods:
The thermal diffusivity was calculated using the time dependent variation of probe beam intensity.
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