Manipulating the distribution of rare-earth activators in multiple cation lattices can achieve versatile color output for single-phased phosphor-converted white light-emitting diodes (LEDs). However, successful cases are barely reported, owing to the uncertain distribution of rare-earth activators and the special combination of three primary colors for white LEDs. Herein, we took whitlockite β-Ca(PO) as a multiple cation lattice host to manipulate the redistribution of Eu activators, and the surprising Mg-guided redistribution of Eu activators among different Ca sites is reported for the first time to regulate the photoluminescence (PL) behavior in series CaMg (PO):Eu phosphors. The preferential neighboring substitution of smaller Mg cations in Ca(5) and Ca(4) sites triggers a discontinuous evolution of local structure along c axis and induces covalent variable Ca(1), Ca(2), and Ca(3) cation sites for the accommodation of Eu activators. The unique optical feature enables the single-phased CaMg(PO):Eu phosphor-converted white LED to exhibit quite high color-rendering index R (85) and R (91) values. The preferential neighboring-cation substitution reported here can not only manipulate the migration of Eu activators among different cation sites for tunable PL properties, but also carve out a new way for next-generation high-quality solid-state lighting.

Mn2+ ion doped 2D (PEA)2PbBr4 perovskite nanocrystals with a high PLQY of 54% were synthesized using a crystallization method at room temperature, and efficient energy transfer from excitons to the Mn2+ dopant was proven.

Figure 4. a) FTIR spectra and b) Raman spectra (taken under excitation at 633 nm) of the pristine (black), the "2 s OxA" (red), and the "10 min OxA" (blue) CsPb(Cl/Br) 3 perovskite NCs.