Abstract:
Fluid lubrication is widely present in the engineering field, and the measurement of local pressure at various points in the lubrication contact area plays an important role in studying the lubrication status of machinery and ensuring the smooth operation of the system. Based on their excellent properties, nanomaterials have been widely used in many fields such as temperature sensing, material detection, optical imaging, medical diagnosis and therapy. Among them, quantum dot nanomaterials have excellent chemical and photoluminescence stability, as well as excellent optical properties, making them the favorites in the field of optoelectronics, and their sensitivity to pressure makes it possible to apply them for pressure monitoring in the field of fluid lubrication. To this end, the pressure-sensitive quantum dot materials commonly used in research and their common preparation methods were summarized, and the commonly used quantum dot materials for pressure sensitivity were introduced from CdSe based quantum dots, chalcogenide quantum dots, and PbSe based quantum dots, respectively. From the perspective of quantum dot morphology, quantum dot morphology is mainly solution-based, but there are also studies for quantum dot composites, nanosheets, etc. In this paper, for pressure sensing based on quantum dot nanocrystals under fluid, the preparation methods of quantum dots were described from two routes: organic phase preparation and aqueous phase preparation, the advantages and disadvantages of the two methods of preparing quantum dots were analyzed, and other forms of pressure sensing materials were also briefly introduced. The advantages and disadvantages of both methods were analyzed, and other forms of pressure sensing materials were also briefly introduced. The pressure-dependent principle of quantum dots was introduced for the pressure measurement principle based on quantum dot unfolding. The relationship between the photoluminescence properties of quantum dots and the pressure variation was the basic of pressure sensing measurement using quantum dots, and the common research methods for pressure dependence of quantum dots were summarized from in-situ pressure experiments and first-principle calculations, and the diamond anvil technique commonly used in in-situ pressure experiments was described. The existing analytical procedures for the study of quantum dot properties under pressure and the work done by researchers were presented separately. Finally, the potential applications of quantum dots were analyzed from the perspective of engineering applications, and the problems and challenges that still existed. The development of new quantum dot spectral decoupling methods to extract temperature and pressure from the spectral information of quantum dots accurately and separately was of great significance to realize the application of quantum dot pressure sensitive materials and solve the problem of fluid lubrication pressure monitoring. In summary, this paper reviewed the progress of research on pressure-sensitive quantum dot sensor materials for fluid lubrication in recent years, including quantum dot material types, preparation methods, pressure-dependent properties research methods, pressure-related optical properties research and engineering applications. The purpose of this paper was to provide a reference for researchers to synthesize stable and efficient pressure-sensitive quantum dot nanomaterials and to develop more effective and sensitive pressure detection methods for fluid lubrication based on quantum dot sensors.