Ca<sub>2</sub>LaTaO<sub>6</sub>:Bi<sup>3+</sup>/Mn<sup>4+</sup> Phosphors with High Brightness Far-Red Emitting and Luminescence Enhancement for Plant Growth LED Lights and Temperature Sensor
Hang Liu, Jian Liu, Bo Sun, Ziyi Zhang, Chongshan Jiao, Ding Sun, Lixin Zhang, Yuhong Zhang
Abstract
Herein, Bi 3+ /Mn 4+ doped Ca 2 LaTaO 6 phosphors with a double-perovskite structure were successfully synthesized with solid-state reaction at high temperature. The photoluminescence (PL) performances were investigated in detail. The blue radiation (∼465 nm) from the Bi 3+ ion and the red radiation (∼686 nm) originating from the Mn 4+ ion were obtained under 313 nm excitation. Especially, the pathway of energy transfer (Bi 3+ → Mn 4+ ) contributes to enhance the red emission intensity (Mn 4+: ∼686 nm) in Ca 2 LaTaO 6:Bi 3+ /Mn 4+ system. The PL mechanism of Ca 2 LaTaO 6:Bi 3+ /Mn 4+ was analyzed through luminescence lifetimes and PL spectra. Moreover, the emitting bands of Ca 2 LaTaO 6:Bi 3+ /Mn 4+ were primarily matched with the absorbing bands of carotenoids and phytochrome P FR on behalf of plant growth, so the phosphors were suitable for the design of a plant growth light under near-ultraviolet to blue excitation. At last, the optical temperature dependent performances of the Ca 2 LaTaO 6:Bi 3+ /Mn 4+ were analyzed with luminescence intensity ratio technology. The sample has presented excellent temperature measuring relative sensitivity ( S R = 2.106% K –1 ). The results illustrated that the Ca 2 LaTaO 6:Bi 3+ /Mn 4+ phosphor also can be used to develop an optical temperature sensor.