Understanding and exploring the structural design principles of the inorganic hosts are necessary for the discovery of novel phosphors for white LEDs. Our recent work focuses on the discovery of new phosphor materials based on the structural evolution and the crystallographci sites engineering. Firstly, photoluminescence tuning can be realized via the cation substitution on one site, and hereby we have discovered several types of M₂SiO₄-based and M₃(PO₄)₂-based phosphors with tunable emission for white LEDs.^1-2 Secondly, we have recently proposed the concept of “chemical unit cosubstitution” as one potential design scheme, and the chemical unit cosubstitution strategy is applied to the melilite structure class designing the Ca₂(Al_1−xMg_x)(Al_1−xSi_1+x)O₇:Eu²⁺ solid solution phosphor via the [Mg²⁺−Si⁴⁺] for [Al³⁺−Al³⁺] cosubstitution.³ We also design the La₅Si₃O₁₂N phase from La₅Si₂BO₁₃ via the [B³⁺−O²⁻] by the [Si⁴⁺−N³⁻] cosubstitution.⁴ Thirdly, we have proposed a new insight into the design of the isostructural phases via the filling of M⁺ in the void channels of the Mg₂Al₄Si₅O₁₈ phase, so that the charge balance can be kept while the chemical composition varied, and this strategy will be also efficient in other porous inorganic hosts.⁵ Finally, we have recently studied the NaScSi₂O₆-based phosphor from CaMgSi₂O₆-based phosphor via the chemical unit cosubstitution of [Na⁺–Sc³⁺] for [Ca²⁺-Mg²⁺] unit.⁶ Further studies show that the isostructural solid-solution of (CaMg)_x(NaSc)_1-xSi₂O₆ (0 < x < 1) can be formed, in which cation nanosegregation enables the presence of dilute Eu²⁺ at two centers and their intensities are linearly proportional to x, so that it represents a new cation nanosegregation tuning of photoluminescence for the exploration of color-tunable phosphor for white LEDs.^7-10

References:

[1] H. Ji, Z. Huang^*, Z. Xia^*, et. al., J. Phys. Chem. C, 2015, 119 2038.

[2] M. Chen, Z. Xia^* M. Molokeev, Q. Liu, Inorg. Chem., 2015, 54, 11369.

[3] Z. Xia^*, C. Ma^*, M. Molokeev, K. R. Poeppelmeier^*, et. al. J. Am. Chem. Soc., 2015, 137, 12494.

[4] Z. Xia^*, M. Molokeev, W. B. Im^*, S. Unithrattil, Q. Liu, J. Phys. Chem. C, 2015, 119, 9488.

[5] J. Zhou, Z. Xia^*, M. Chen, M. Molokeev, Q. Liu, Sci. Rep., 2015, 5, 12149.

[6] Z. Xia^*, Y. Zhang, M. Molokeev, V. Atuchin, Y. Luo, Sci. Rep., 2013, 3, 3310.

[7] Z. Xia^*, K. R. Poeppelmeier^*, Acc. Chem. Res., 2017, 50, 1222.

[8] Z. Xia^*, G. Liu^*, K. R. Poeppelmeier^*, et. al., J. Am. Chem. Soc., 2016, 138, 1158.

[9] Z. Xia^*, and Q. L. Liu, Prog. Mater. Sci., 2016, 84, 59-118.

[10] Z. Xia^*, and A. Meijerink^*, Chem. Soc. Rev., 2017, 46, 275-299.