The Research On Rare Earth Ions Doped Inorganic Phosphors Powder For Temperature Sensing

Temperature is significant for micro and macro features of objects.The measured values scale usually obtained indirectly.Vast contact-type temperature measurement devices were employed traditionally,such as gas,liquid thermometer,using electric potential difference of the thermocouple thermoelectric effect,etc.The temperature measuring device are limited in coal-fired power plants,that strong electromagnetic environment such as high power,transformer,strong corrosion,high temperature and high pressure for harsh environment.Except Infrared measurement technology,the mode f-f transition of rare earth ions are irreplaceable.Optical temperature measurement can achieve precise response and high spatial resolution at fast moving objects.Special wavelength of light can implement goal by lifetime of excited state,charge transfer spectrum and fluorescence spectra of changed temperature.Using these methods,Nd³⁺ions,Ho³⁺ions and Dy³⁺ions doped CaWO₄ and Lanthanum aluminum garnet measure the temperature.The first part include Nd³⁺ions,Ho³⁺ions doped CaWO₄.The ⁴F_3/2 to ⁴I_9/2 and ⁴I_11/2transition of Nd³⁺ions obtained fitted temperature value from room temperature to 573K,temperature sensing value were 1.13×10^-3 K^-1 and 1.09×10^-3 K^-1.Charge transfer of W-O temperature sensing was 3.24×10^-2 K^-1,fluorescence decay lifetime was 7.4×10^-3K^-1 from ⁵F₄ to ⁵I₈ transition under 449 nm excitation.The transition of Ho³⁺ions from⁵I₆ to ⁵I₈ fluorescence intensity temperature sensing value was 1.3×10^-3 K^-1.The temperature control accessory emitted near infrared ray from 1400 nm to 1700 nm when temperature was about 460 K,fluorescence intensity would strengthen with the increasing temperature,which belongs to thermoluminescence.Garnet samples introduced physicochemical property of La₃Al₅O₁₂:1%Dy,Lu₃Al₅O₁₂:1%Dy and La_1.5Lu_1.5Al₅O₁₂:1%Dy.The transition from ⁴F_9/2 to ⁶H_13/2 of Dy³⁺ions emitted yellow light under the excited wavelength about 350 nm.The fitted value about temperature sensing were 0.24%K^-1 and 0.11%K^-1 from La₃Al₅O₁₂:1%Dy and Lu₃Al₅O₁₂:1%Dy samples.