Excitation power dependent optical temperature behaviors in Mn4+ doped oxyfluoride Na2WO2F4. Issue 3 (4th January 2018)

• Record Type: Journal Article
• Authors: Cai, Peiqing; Wang, Xiangfu; Seo, Hyo Jin
• Is Part Of: Physical chemistry chemical physics. Volume 20:Issue 3(2017)
• Page Start: 2028
• Page End: 2035
• Publication Date: 2018-01-04
• Subjects: Chemistry, Physical and theoretical -- Periodicals; 541.3
• DOI: 10.1039/c7cp07123j
• Languages: English
• ISSNs: 1463-9076

Abstract

Abstract : Optical temperature sensing behaviors of Na2 WO2 F4 :Mn 4+ under different excitation powers. Abstract : A Mn 4+ doped Na2 WO2 F4 phosphor was synthesized through a two-step wet chemical method. The relationship between crystal structure and luminescence properties is discussed and unusual strong intense zero phonon lines (ZPLs) have been found in a distorted octahedral environment. The power dependent luminescence spectra exhibit the existence of down conversion luminescence intensity saturation under a high pumping power limit. The fluorescence intensity ratios of anti-Stokes bands to the ZPL and Stokes bands reveal an obvious temperature dependent relationship based on thermal de-population from the low states to the upper states of an intrinsic Mn 4+ 2 Eg → 4 A2g transition. The temperature dependent emission intensity of Mn 4+ is investigated by changing the excitation power, and an optical temperature sensitivity as high as 0.00658 K −1 is achieved at 193 K with the intensity ratio of anti-Stokes bands to the ZPL under 488 nm excitation by a Xenon lamp. This work presents a new method to realize optical thermometry at low temperature by controlling the intensity ratio of the anti-Stokes bands to the ZPL.