Ca2latao6: Bi3+/Mn4+ Phosphors with High Brightness Far-Red Emitting and Luminescence Enhancement for Plant Growth Led Lights and Temperature Sensor

Herein, Bi3+/Mn4+ doped Ca2LaTaO6 phosphors with the double-perovskite structure have been successfully prepared by the high-temperature solid-state reaction. The phase structure and morphology of the samples were characterized by powder X-ray diffraction (XRD) and scanning electron microscopy (SEM). The photoluminescence (PL) properties were systematically studied. The blue emission band (~465 nm) of Bi3+ ion and the red emission (~686 nm) of Mn4+ ion were obtained under 313 nm excitation. Especially, the energy transfer (ET) process from Bi3+ to Mn4+ has enhanced the red emission intensity of Mn4+ ion in CLT: Bi3+/Mn4+ system. The PL mechanism of CLT: Bi3+/Mn4+ was analyzed through luminescence lifetimes and PL spectra. In addition, the emission bands of CLT: Bi3+/Mn4+ were well-matched with the absorption bands of chlorophylls b and phytochrome PFR for plant growth. So the phosphors are suitable for design plant growth light under the near ultraviolet (UV) to blue excitation. At last, the temperature sensing properties of the CLT: Bi3+/Mn4+ were investigated with the luminescence intensity ratio (LIR) technology. The sample has presented excellent temperature measuring relative sensitivity (SR=2.106% K−1). The result illustrated that the CLT: Bi3+/Mn4+ phosphor also can be used to develop optical temperature sensor.