Realization of plant growth lighting and temperature detecting based on novel Bi3+, Sm3+ and Mn4+ doped Ca2GdNbO6 double perovskite phosphors

The Bi3+ or Sm3+ ions are introduced into Mn4+-activated Ca2GdNbO6 (CGN) double perovskite phosphors to achieve highly efficient plant growth lighting and temperature measurement. Here, the energy band and density of states for CGN are computed using density functional theory (DFT) in detail. The emission bands of CGN: Bi3+/Mn4+ consist of both the blue-light band (3P1→1S0 transition of Bi3+ ions) and red-light band (2E→4A2 transition of Mn4+ ions), which solves the issue of the lack of blue light in Mn4+-activated phosphors used in plant-growth LEDs. The electroluminescence emission spectrum of the LEDs assembled with CGN: Sm3+/Mn4+ shows a wide emission band (550–800 nm), which coincides perfectly with the absorption (550–825 nm) of Phytochrome (PR and PFR). Moreover, non-contact thermometers are designed by luminescence intensity ratio technique (LIRMn/Bi or LIRMn/Sm) with excellent absolute (Sa = 0.074 K-1@448 K or 0.036 K-1@373 K) and relative sensitivity (Sr = 2.13 %K−1@498 K or 1.11 %K−1@448 K). The results reveal that as-prepared phosphors have great potential in promoting indoor plant cultivate and optical temperature sensing.