Novel rare earth free phosphors CsMg <sub>2</sub> P <sub>3</sub> O <sub>10</sub> : Mn <sup>2+</sup> with efficient and ultra‐broadband red emission for plant growth LEDs
Heng Dai, Shanshan Li, Zhuowei Li, Jiankun Li, Shuangyu Xin, Chuang Wang, Ge Zhu, Bin Dong
Abstract
Abstract An efficient and ultra‐broadband red phosphor CsMg 2 P 3 O 10 : Mn 2+ (CMPO: Mn 2+ ) is first synthesized toward indoor plant growth LEDs. The phase purity, element composition, crystal, and local electronic structure are explored to discuss the structure and photoluminescence properties. Structure refinement and series X‐ray diffractometer (XRD) results show that CMPO: Mn 2+ is well crystallized in an orthogonal crystal system. The diffuse reflection and excitation spectra show that CMPO: Mn 2+ has strong absorption around near ultraviolet region, assigned to the [ 6 A 1 → 4 E( 4 D), 4 T 2 ( 4 D), [ 4 A 1 ( 4 G), 4 E( 4 G)], and 4 T 1 ( 4 G)] transitions of Mn 2+ , respectively. Upon 415 nm excitation, an efficient red emission centered at 647 nm with ultra‐broad full width at half‐maximum (FWHM ∼ 100 nm) and high quantum efficiency (IQE ∼ 44.3 %) is observed, and because of the ultra‐broad FWHM, the red emission is well accordant with the absorption spectra band of phytochrome P R and P FR . The optimal doping contents, lifetime as well as interaction mechanism of CMPO: Mn 2+ are discussed in detail. Finally, the excellent thermal stability (84.5% @ 140°C) and related thermal quenching mechanism of CMPO: Mn 2+ are discussed. The above results indicate that CMPO: Mn 2+ phosphors have great potential for application in plant growth LEDs.