Enhanced hydrothermal crystallization and color tailorable photoluminescence of hexagonal structured YPO4:Sm/Tb nanorods?

CrystEngComm Pub Date: 2018-02-27 DOI: 10.1039/C8CE00183A

Abstract

Hexagonal structured YPO4:Tb/Sm (h-YPO4:Tb/Sm) nanorods with significantly large aspect ratios of up to ～32 have been successfully fabricated via hydrothermal crystallization in the presence of sodium malate (Mal2?) and superfluous PO43?. The combined techniques of XRD, SEM, TEM, and PLE/PL were employed to characterize the products, and the formation mechanism of the nanorods was discussed in detail. It was found that Mal2? and superfluous PO43? jointly ensured the crystallization of the metastable hexagonal phase, and the latter promoted the 1D growth of the crystals. The h-(Y0.99?xTb0.01Smx)PO4 ternary phosphors simultaneously displayed the green emission of Tb3+ at 545 nm and the red emission of Sm3+ at 601 nm under 221 nm UV excitation, with which the emission color was finely tuned from green to yellow by increasing the Sm3+ content. The Tb3+ → Sm3+ energy transfer in h-(Y0.99?xTb0.01Smx)PO4 was revealed to occur via an electric dipole–dipole interaction mechanism. The fluorescence lifetime of Tb3+ was found to steadily decrease with increasing Sm3+ concentration, and the efficiency of energy transfer was determined to be ～31.2% at the optimal Sm3+ content of 4 at% (x = 0.04).

Graphical abstract: Enhanced hydrothermal crystallization and color tailorable photoluminescence of hexagonal structured YPO4:Sm/Tb nanorods
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