RESUMEN
Remote thermal sensing has emerged as a temperature detection technique for tasks in which standard contact thermometers cannot be used due to environment or dimension limitations. One of such challenging tasks is the measurement of temperature in microelectronics. Here, optical thermometry using co-doped and mixed dual-center Gd2O3:Tb3+/Eu3+samples were realized. Ratiometric approach based on monitoring emission intensities of Tb3+(5D4-7F5) and Eu3+(5D0-7F2) transition provided sensing in the range of 30 °C-80 °C. Dispersion system type only slightly affected relative sensitivity, accuracy and precision. The applicability of phosphors synthesized to be utilized as remote optical thermometers for microelectronics has been proved with an example on a surface mount resistor and microcontroller.
RESUMEN
When navigated by the available energy of a system, often provided in the form of heat, physical processes or chemical reactions fleet on a free-energy landscape, thus changing the structure. In in situ transmission electron microscopy (TEM), where material structures are measured and manipulated inside the microscope while being subjected to external stimuli such as electrical fields, laser irradiation, or mechanical stress, it is necessary to precisely determine the local temperature of the specimen to provide a comprehensive understanding of material behavior and to establish the relationship among energy, structure, and properties at the nanoscale. Here, we propose using cathodoluminescence (CL) spectroscopy in TEM for in situ measurement of the local temperature. Gadolinium oxide particles doped with emissive europium ions present an opportunity to utilize them as a temperature probe in CL measurements via a ratiometric approach. We show the thermometric performance of the probe and demonstrate a precision of ±5 K in the temperature range from 113 to 323 K with the spatial resolution limited by the size of the particles, which surpasses other methods for temperature determination. With the CL-based thermometry, we further demonstrate measuring local temperature under laser irradiation.
RESUMEN
In the last decade much attention has been paid to the development of novel approaches in luminescence thermometry, which could allow contactless and noninvasive temperature sensing when traditional thermometers are useless. Typically, an optical thermometer exploits a distinct luminescence parameter to define temperature. However, the use of multimode sensors can significantly broaden the working range and improve the reliability of the temperature measurements. In this work, a Eu3+-doped LaVO4 sample was successfully utilized as a thermal sensor within a wide temperature range of 98-723 K based on monitoring various temperature-sensitive luminescence features. Different thermal sensing strategies were assessed and compared in terms of thermal sensitivity and temperature resolution. The best thermometric performances of the Eu3+-doped LaVO4 sensor reached an Sr = 1.49% K-1 and a ΔT = 0.6 K at room temperature. All the studies performed showed that the LaVO4:Eu3+ phosphor is a prospective multimode optical thermometer.
RESUMEN
Single doped CaWO4:Er3+phosphors were synthesized and studied for application of optical thermal sensing within a wide range of 98-773 K. Ratiometric strategy utilizing two luminescence intensity ratios, one between host and Er3+band (LIR1) and second between different Er3+transitions (LIR2), results in self-referencing temperature readouts. The presence of two temperature-dependent parameters could improve thermometric characteristics and broaden the working temperature range compared to a usual single-parameter thermometer. Thermometric performances of prepared samples were evaluated in terms of thermal sensitivities, temperature resolution and repeatability. The highest sensitivity of 2.09% K-1@300 K was found for LIR1, whereas LIR2provided more accurate thermal sensing with a temperature resolution of 0.06-0.1 K. Effect of Er3+doping concentration on sensing properties were studied. The presented findings indicate that CaWO4:Er3+phosphors are perspective in dual-mode thermal sensing with high sensitivity and sub-degree resolution.
RESUMEN
Crystalline inorganic nanoparticles doped with rare earth ions are widely used in a variety of scientific and industry applications due to the unique spectroscopic properties. The temperature dependence of their luminescence parameters makes them promising candidates for self-referencing thermal sensing. Here we report single phase YVO4 nanoparticles doped with different pairs of rare earth ions (Nd3+/Er3+, Tm3+/Er3+ and Nd3+/Tm3+) for contactless ratiometric thermometry within a wide temperature range of 298-573 K. The presence of dual luminescence centers in the optical thermometer allows one to circumvent the fundamental limitation of sensitivity inherent to thermometers based on thermally coupled levels. Important parameters for temperature sensing, such as relative thermal sensitivity and temperature resolution, were calculated for all synthesized samples and compared with the literature data. The YVO4:Tm3+,Er3+ sample displayed a relative sensitivity of 0.28% K-1 at room temperature, and the YVO4:Nd3+,Er3+ phosphor exhibited a high sensitivity of 0.56% K-1 at 573 K, while YVO4:Nd3+,Tm3+ demonstrated sub-degree thermal resolution. These findings demonstrate the good potential of dual-center ratiometric YVO4 thermometers and open the way toward future enhancement of their thermometric performances through variation of the doping concentration.
