Quantum dots to probe temperature and pressure in highly confined liquids

• Published in: RSC advances Vol. 8; no. 41; pp. 22897 - 2298
• Main Authors: Albahrani, Sayed M. B, Seoudi, Tarek, Philippon, David, Lafarge, Lionel, Reiss, Peter, Hajjaji, Hamza, Guillot, Gérard, Querry, Michel, Bluet, Jean-Marie, Vergne, Philippe
• Format: Journal Article
• Language: English
• Published: England Royal Society of Chemistry 21-06-2018; The Royal Society of Chemistry
• Subjects: Cadmium sulfide; Calibration; Chemistry; Contact pressure; Diamonds; Emission; Engineering Sciences; Fluorescence; Liquids; Other; Parallel plates; Point contact; Pressure dependence; Pressure measurement; Quantum dots; Sensitivity; Temperature dependence; Thin films
• ISSN: 2046-2069; 2046-2069
• DOI: 10.1039/c8ra03652g

A new
in situ
technique for temperature and pressure measurement within dynamic thin-film flows of liquids is presented. The technique is based on the fluorescence emission sensitivity of CdSe/CdS/ZnS quantum dots to temperature and pressure variations. In this respect, the quantum dots were dispersed in squalane, and their emission energy dependence on temperature and pressure was calibrated under static conditions. Temperature calibration was established between 295 K and 393 K showing a temperature sensitivity of 0.32 meV K
−1
. Pressure calibration was, in turn, conducted up to 1.1 GPa using a diamond anvil cell, yielding a pressure sensitivity of 33.2 meV GPa
−1
. The potential of CdSe/CdS/ZnS quantum dots as sensors to probe temperature and pressure was proven by applying the
in situ
technique to thin films of liquids undergoing dynamic conditions. Namely, temperature rises have been measured in liquid films subjected to shear heating between two parallel plates in an optical rheometer. In addition, pressure rises have been measured in a lubricated point contact under pure rolling and isothermal conditions. In both cases, the measured values have been successfully compared with theoretical or numerical predictions. These comparisons allowed the validation of the new
in situ
technique and demonstrated the potential of the quantum dots for further mapping application in more complex and/or severe conditions.
A new
in situ
technique using CdSe/CdS/ZnS quantum dots fluorescence to probe pressure and temperature within highly confined flows of liquids.