Optical thermometry based on near-infrared luminescence from phosphors mixture

Luminescence ratiometric thermometry based on rare earth(RE)ions has attracted great interest for the potential applications in many fields.But the improvement of the measurement sensitivity and accuracy is significantly restricted due to the small energy gap between thermally coupled levels(TCL).Here,a strategy striving for good thermometric properties of luminescent materials was designed by using the phosphors mixture composed of NaY(WO_(4))_(2):Nd^(3+)-Yb^(3+)and NaY(WO_(4))_(2):Er^(3+),which were prepared by secondary sintering method.Under the excitation of 980 nm lase r,the near-infrared(NIR)emissions(710-920 nm)from Nd^(3+)ions are effectively strengthened when the temperature increases from 304 to773 K,whereas Er^(3+)NIR luminescence centered at around 1536 nm is thermally quenched.The remarkably different response of NIR emissions to the thermal variation allows us to map temperature through the ratiometric method.By optimizing the dopant concentration of rare earth(RE)ions,a maximum sensitivity of 5.14%/K together with a measurement uncertainty of about 0.1 K is acquired at304 K,which is superior to the previously reported RE luminescence-based temperature sensors,indicating that the approach developed here can pave the way for achieving optical thermometry with desired properties.

Dual-excitation decoding multiparameter-based ratiometric luminescence thermometry:a new strategy toward reliable and accurate thermal sensing

Luminescence thermometry can perform noninvasive thermal sensing with high spatial resolution and fast response,emerging as an exciting field of research due to its promising applications in biomedicine.Nevertheless,because of the interaction between light and complex tissues,the reliability and the accuracy of this technique suffer serious interference,which significantly restricts its practical utilization.Here,a strategy to implement effective luminescence nanothermometry is preliminarily proposed by employing the different thermal responses between Yb^(3+)→Nd^(3+)and Nd^(3+)→Yb^(3+)energy transfer processes.Different from the traditional ratiometric sensing method,where two luminescence intensities are used as the thermal response parameters,we use two intensity ratios between Yb^(3+)and Nd^(3+)near-IR emissions that are obtained under dual excitation as the detecting and reference signals to perform temperature measurement.This multiparameter-based,self-reference thermometry technique,as we define it,exhibits excellent immunity to the influences arising from the fluctuation and loss of pumping sources as well as the luminescence attenuation in media.High thermal sensitivity(~2.2%K^(-1))and good resolution(~0.35°C)are successfully achieved here,accompanied by a measurement error of~1.1°C in a biological environment test,while large errors are observed based on the traditional ratiometric approach(~8.9°C,~23.2°C).We believe the viewpoint in this work could boost luminescence thermometry and provide an ingenious route toward high-performance thermal sensing for biological systems.