High-precision temperature sensors to assist in industrial and research applications
Head of Multi-Functional Nanostructures Lab Maxim Pudovkin has co-authored a new paper in Journal of Luminescence.
His project ‘Study of the physical foundations of the functioning of luminescent temperature sensors based on nano- and microparticles of fluorides activated by rare-earth ions (Tm3+/Yb3+, Eu3+/Tb3+, Pr3+/Yb3+, Nd3+/Yb3+) in order to obtain sensors with maximum characteristics’ was supported by a grant from the Russian Science Foundation.
“For a wide class of tasks, such as temperature control of engines, industrial installations, as well as for many medical purposes, it is sufficient to use traditional methods of temperature measurement using mercury or alcohol thermometers, thermocouples and thermal imagers. However, in science and industry there are a number of complex problems associated with measuring temperature, for example, very small objects. Also relevant are the tasks of non-invasive temperature measurement and visualization of temperature fields with high spatial resolution. For such purposes, the use of luminescent temperature sensors is relevant,” says Pudovkin.
According to the scientist, highly sensitive temperature sensors are very necessary for the electronics industry, primarily for visualizing the temperature fields of microcircuits.
“The fact is that modern microcircuits consist of a large number of nanoelements that are very close to each other. If these elements are not optimally located or one of them fails, then the area of the microcircuit begins to heat up. It is impossible to detect such small heating regions (linear size 200-500 nanometers) by traditional methods. However, if a special dielectric coating containing nanoparticles is applied to the microcircuit, the luminescence parameter of which depends on temperature, then it will be much easier to find the location of the problematic parts of the circuit,” continues the interviewee.
Another very important application is cancer treatment.
“With hyperthermia of cancerous tumors, it is necessary to control the heating temperature of the tumor in the depth of the tissue. This must be done contactlessly and remotely. For hyperthermia, fairly powerful infrared lasers are used. Penetrating deep into the tissue, infrared radiation heats it up. The heating temperature should be 41-42 degrees Celsius. Underheating leads to low efficiency of therapy, and overheating leads to tissue necrosis. For such purposes, it is proposed to use nanoparticles capable of converting the absorbed laser radiation into heat and at the same time luminesce in the infrared region, informing us about the temperature. There is no need to introduce nanoparticles into the patient’s body. There are phantom tissues that can be changed taking into account the characteristics of the skin of a particular patient. Nanoparticles are introduced into these phantom tissues and the radiation mode is worked out, effective for hyperthermia,” explains the researcher.
As it appears, the project has also provided some new fundamental knowledge in materials, according to Pudovkin, “We all know that as the temperature rises, bodies expand. However, in the study of most luminescent materials, this feature is rightly not taken into account, since the smallest shift between ions does not play a special role. But we seem to have found a material (YF3 nanoparticles) for which this shift is significant. This feature can be used when creating sensors, and it must also be taken into account when creating lasers. As part of the project, it is planned to study this phenomenon in more detail and create a line of sensors based on it.”