Method for high sensitivity and wide range temperature detection based on fluorescence intensity ratio of Er<3+> and Nd<3+> up-conversion luminescence

Abstract

The invention discloses a method for high sensitivity and wide range temperature detection based on a fluorescence intensity ratio of Er<3+> and Nd<3+> up-conversion luminescence. The temperature quenching effect of the up-conversion luminescence is avoided by the energy transfer between the rare earth Er<3+> and Nd<3+> ions. A method for performing wide range temperature detection by adopting therare earth Er<3+> and Nd<3+> ions co-doped up-conversion luminescent materials and having a high temperature sensitivity is realized based on the fluorescence intensity ratio of self-coupling energylevel of the Er<3+> and Nd<3+> ions to the up-conversion luminescence, and the fluorescence intensity ratio of the up-conversion luminescence between the Er<3+> and Nd<3+> ions.

Description

technical field [0001] The invention relates to a method for temperature detection, specifically based on Er 3+ and Nd 3+ Fluorescence Intensity Ratio of Upconversion Luminescence Method for High Sensitivity Wide Range Temperature Detection. Background technique [0002] Temperature is one of the most important parameters in the fields of physics, chemistry, biomedicine and engineering technology. It is extremely important to accurately control and measure temperature with fast response, high sensitivity and high spatial resolution. Therefore, anti-interference, high sensitivity, high Temperature sensing with spatial resolution and fast response is of great scientific significance and application value. Temperature is the statistical average performance that reflects the thermal motion of object molecules, and the indirect measurement of temperature can be realized by measuring the stable quantitative dependence of the properties of the temperature on the temperature. Acc...

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Problems solved by technology

And if the energy difference ΔE of thermally coupled energy levels is too large, the absolute sensitivity S of temperature detection will be reduced a

And if the energy difference ΔE of thermally coupled energy levels is too small, although it helps to improve the absolute sensitivity S a , but based on two thermally coupled energy levels E 1 and E 2 The luminous peaks of the transitions overlap again, resulting in a decrease in the accuracy of the luminous intensity measurement

At room temperature or lower, even if two energy levels with a large energy difference ΔE can achieve thermal coupling, the fluorescence intensity ratio R usually deviates in magnitude because of its exponential dependence on the energy difference ΔE, making Absolute Sensitivity S a Greatly reduced

Another factor that restricts the accuracy of temperature detection is the fluorescence quenching effect during the temperature detection process. Generally, as the temperature rises, the luminescence of rare earth ions gradually decreases until it is quenched, which makes it difficult to measure the luminescence intensity at high temperatures and the fluorescence intensity ratio. The calculation error increases, and even the fluorescence intensity ratio cannot be obtained

Therefore, temperature sensing using the fluorescence intensity ratio of a single rare-earth ion-coupled energy level pair has significant limitations.

[0004] At present, temperature sensing is based on the relationship between the fluorescence intensity ratio and temperature of two different rare earth ions, and there is also an obvious temperature quenching effect, such as the rare earth ion Eu 3+ ( 5 D. 0 → 7 f 2 ) and Tb 3+ ( 5 D. 4 → 7 f 5 ) The intensity of the two luminescence peaks is quenched with the increase of temperature, which will also lead to an increase in the error of the calculation of the fluorescence intensity ratio

On the other hand, the temperature sensor based on the fluorescence intensity ratio of two different rare earth ions still has a limited temperature measurement range, and the sensitivity is not high (about 1% / K)

In short, whether it is the existing fluorescence intensity ratio temperature measurement based on the thermal coupling energy level of a single rare earth ion or the temperature measurement based on the fluorescence intensity ratio of two different rare earth ions, on the one hand, there will be an increase in the measurement error caused by the temperature quenching effect. On the other hand, the temperature detection range and temperature detection sensitivity are often very low and cannot be balanced

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