The single near-infrared upconversion luminescence of a novel KYb (MoO4)2: Er3+ phosphor for the temperature sensing

The rare earth doping upconversion luminescence (UCL) materials exhibit multimodal emission, which has huge potential applications. However, it is still a difficult problem to obtain a single emission by modulating UCL, especially the modulation of single red light and single near-infrared light. In this work, we report a novel UCL KYb (MoO4)2: Er3+ phosphor, which can achieve a single near-infrared emission (804 nm) under rare earth Er3+ doping. Its pure phase was successfully prepared by high-temperature solid-state method, and its optimal Er3+ doping concentration was found to be 0.1%. Excited at 980 nm laser, KYb (MoO4)2: Er3+ exhibit a single near-infrared UCL attributed to the 4I9/2 → 4I15/2 transition of Er3+ ions. To further explain its UCL mechanism, the power dependence, ultraviolet-visible-near-infrared absorption spectrum, excitation spectrum and emission spectrum of KYb (MoO4)2: Er3+ was measured. Due to the excellent near-infrared emission, the temperature-dependent UCL properties of the KYb (MoO4)2: Er3+ material is investigated in the temperature range from 298 K to 673 K. The linear relationship between the UCL and the temperature, And the sensitivity of KYb (MoO4)2: Er3+ phosphor reaches the maximum value at 673 K, which is 0.0078 K−1. The single near-infrared luminescence with good penetrability and large sensitivity makes KYb (MoO4)2: Er3+ have a promising application prospect in the fields of non-contact temperature sensing and bioimaging.