Upconversion Luminescence and Temperature Sensing Properties of Layered BiOCl: Er³⁺ under 1550 nm Excitation

Abstract

The sensitivity of optical temperature sensing based on the conventional rare-earth ion doped upconversion (UC) materials is limited by the energy gap between thermally coupled levels (TCLs) of rare-earth ions. Therefore, it is of great theoretical and technical interest to explore UC luminescent materials for optical temperature sensing with ultra-sensitive temperature characteristic. In this work, the UC luminescence properties and temperature sensing characteristics were studied for Er 3+ single-doped BiOCl excited by 1550 nm laser. Under near-infrared (NIR) excitation, BiOCl:Er 3+ exhibits strong red emission at 670 nm, weak green emissions at 525 and 542 nm, extremely weak violet emission at 406 nm, and near-infrared emission at 983 nm. Red and green emissions of the UC system exhibit strong temperature dependence, and in the temperature range of 300-563 K, the maximum absolute sensitivity (S A) obtained by employing the non-thermally coupled levels (NTCLs, 4 F 9/2 / 4 S 3/2) is 95.3×10-3 K −1 , which is 21 times more than that obtained by employing the thermally coupled levels (TCLs, 2 H 11/2 / 4 S 3/2), and the maximum relative sensitivity (S R) is as high as 1.19% K −1. The results show that the intense red UC luminescence and temperature sensing with ultra-high 第 8 期 彭跃红, 等: 1550 nm 激发层状 BiOCl:Er 3+ 上转换发光及温度传感特性 903 sensitivity in BiOCl:Er 3+ under 1550 nm excitation may have potential application prospect in display and optical temperature sensing.

Upconversion luminescence and temperature sensing properties of Ho3+,Yb3+-codoped Bi2WO6

“…The intensity of the sample emission peaks gradually increases with increasing power. According to the literature, 16 the number n of excitation photons absorbed by an upconversion luminescent material to emit one visible photon can be obtained from I ∝ P n , where I is the upconversion emission intensity and P is the pump power.…”

Synthesis and Upconversion Luminescence Properties of BaBiO2Cl:Yb3+,Er3+ Phosphor

“…The upconversion luminescence of these materials involves an anti-Stokes photophysical process, that is, the sequential absorption of two or more low-energy NIR photons by the sensitizer and energy transfer to the activator leads to the emission of a high-energy photon [6][7][8]. Due to their fascinating optical features, such as narrow emission spectrum, long luminescence lifetime, larger Stokes shift and high luminescence stability, upconversion luminescence phosphors have demonstrated a broad range of technological applications, including solar energy utilization [9,10], anticounterfeiting [11][12][13], photocatalysis [14] and optical thermometry [15][16][17]. In particular, excitation with low-energy NIR light can greatly minimize the autofluorescence background when compared with high-energy ultraviolet light excitation and enable a high excitation penetration depth in biological tissues in consideration of the reduced light absorption and scattering; thus, upconversion luminescence nanoparticles have promising potential for bioanalytical and biomedical applications, including in vivo bioimaging, biosensing and photodynamic therapy [18][19][20].…”