Change from La2Ti2O7 to LaTiO3 induced by Li2CO3 addition: Higher local symmetry and particle uniformity achieved an efficient Mn4+ activated far red phosphor for agricultural cultivation

In this paper, a synthesized material change from perovskite-layer-structured La 2 Ti 2 O 7 to perovskite type LaTiO 3 induced by Li 2 CO 3 addition was observed. The [TiO 6 ] octahedral site symmetry and particle uniformity showed an obvious variation with the change from La 2 Ti 2 O 7 to LaTiO 3 . A broadband far-red emission from 670 to 780 nm emerged when Mn 4+ , Li + ions were co-doped. Furthermore, (Mn 4+ , Li + ) co-doped LaTiO 3 phosphor can be effectively excited by near-UV and blue lights, which is suitable for combining with commercial InGaN LED chips. The LaTiO 3 :0.4%Mn 4+ , 150%Li + phosphor exhibited a high quantum efficiency of 71.1% and a good thermal stability with emission intensity retained 65% at 423 K. Finally, a LED device was fabricated with the LaTiO 3 :0.4%Mn 4+ , 150%Li + phosphor, which matches well with the absorption of photochrome of P FR and shows a good potential for use in agricultural cultivation fields.