Implementing Defects for Ratiometric Luminescence Thermometry.

Joanna Drabik,Karolina Ledwa,Łukasz Marciniak

doi:10.3390/nano10071333

Abstract

In luminescence thermometry enabling temperature reading at a distance, an important challenge is to propose new solutions that open measuring and material possibilities. Responding to these needs, in the nanocrystalline phosphors of yttrium oxide Y2O3 and lutetium oxide Lu2O3, temperature-dependent emission of trivalent terbium Tb3+ dopant ions was recorded at the excitation wavelength 266 nm. The signal of intensity decreasing with temperature was monitored in the range corresponding to the 5D4 → 7F6 emission band. On the other hand, defect emission intensity obtained upon 543 nm excitation increases significantly at elevated temperatures. The opposite thermal monotonicity of these two signals in the same spectral range enabled development of the single band ratiometric luminescent thermometer of as high a relative sensitivity as 4.92%/°C and 2%/°C for Y2O3:Tb3+ and Lu2O3:Tb3+ nanocrystals, respectively. This study presents the first report on luminescent thermometry using defect emission in inorganic phosphors.

Highlights

A whole range of optically active emitters can be successfully used in luminescence thermometry due to the susceptibility of their optical properties to the temperature changes, like: organic dyes, quantum dots (QDs), metal–organic frameworks (MOFs), polymers, nanodiamonds (ND), inorganic nanoparticles doped with lanthanides (Ln3+ ) and transition metal ions (TM) etc
We show for the first time the exploitation of it is possible to note an increase in the intensity of defect emission, which is associated with satellite emission of oxygen defects, occurring in rare earth oxides, in excitation-ratiometric approach to phonons [25]
We show for the first time the exploitation of emission of oxygen defects, luminescence thermometry using Tb3+ ions emission as the luminescent reference

Summary

Introduction

A whole range of optically active emitters can be successfully used in luminescence thermometry due to the susceptibility of their optical properties to the temperature changes, like: organic dyes, quantum dots (QDs), metal–organic frameworks (MOFs), polymers, nanodiamonds (ND), inorganic nanoparticles doped with lanthanides (Ln3+ ) and transition metal ions (TM) etc. Usually emit in the visible range upon excitation with ultraviolet light Their emission is dependent on temperature, because it is affected by the electronic transitions between vibrational states responsible for luminescence. The luminescent properties of QDs, which result from the recombination of the electron–hole pair are strongly dependent both on the host material composition as well as their size [5,6,7]. In this case, the phonon-related depopulation processes and the energy gap are strongly temperature dependent. Luminescent thermometers (LTs) based on MOFs take advantage from the fact that probability of host-to-metal and metal-to-metal energy transfer probabilities are thermally induced, to enable noncontact temperature readout [10,11,12,13]

Methods

Results

Conclusion