Luminescence, energy transfer and optical thermometry of a novel narrow red emitting phosphor: CsWOF:Mn.

A novel red emitting CsWOF:Mn phosphor was successfully synthesized by a two-step wet chemical method. The crystal structure, morphology, and elemental composition were confirmed by powder X-ray diffraction (XRD), transmission electron microscopy (TEM) and energy-dispersive X-ray spectroscopy (EDS), respectively. The luminescence properties were investigated from emission, excitation and luminescence decay curves in the temperature region of 10-500 K. The application of non-contact optical thermometry of CsWOF:Mn based on the fluorescence intensity ratio (FIR) of the two coupled anti-Stokes and Stokes sidebands is discussed. The as-prepared CsWOF:Mn phosphor shows a bright narrow red emission at 632 nm under excitation by a blue lamp at 470 nm and it also presents a broad and yellow-white intrinsic tungstate emission (∼520 nm) under UV excitation. The mechanism of energy transfer from [WOF] (the sensitizer) to Mn (the activator) is discussed.