Maximal Relative Sensitivity Research Articles

Luminescence thermometry with Eu3+ doped GdAlO3

Eu3+ doped GdAlO3 powder synthesized by solid state reaction was investigated for аpplication in luminescence thermometry. Phase composition of material was confirmed by X-ray powder diffraction analysis. The photoluminescence emission spectra were collected under excitation of 399nm, while elevating the temperature of the sample from the room temperature to 793K. Emissions from 5D1→7F1 and 5D0→7F2 characteristic transitions of Eu3+ ions are selected for the temperature-dependence study using the fluorescence intensity ratio method. Emission decay curves measured at the strongest emission peak centered at 614nm were recorded in a same temperature range. Data analysis showed that thermometry by fluorescence intensity ratio method can be used over the temperature region 293–793K with the maximal relative sensitivity of 2.96%K−1 (at 293K). Temporal dependence of emission (lifetime) provides temperature sensing from 620 to 793K with the maximal relative sensitivity of 2.28%K−1.

Luminescent properties of chromium(III)-doped lithium aluminate for temperature sensing

A series of novel temperature-sensitive phosphors LiAl5(1−x)O8: xCr3+ (x=0.001–0.012) are synthesized by combustion method. The phosphors can be efficiently excited by the whole wavelength range of the visible light, producing strong deepred emission, which can be assigned to the 2E→4A2 transition. The intensity, peak wavelength and decay lifetime of the emission are measured to vary strongly with temperature for all the samples. Especially, the decay lifetime change dramatically from 4.31ms to 0.38ms from 200K to 600K for the sample with x=0.002, which give a highest temperature sensitivity of −0.015msK−1 at 400K and a maximal relative sensitivity of 0.83% K−1 at 447K. These results show that LiAl5O8:Cr3+ is promising for optical thermometry.