Custom-built thermometry apparatus and luminescence intensity ratio thermometry of ZrO <inf>2</inf> :Eu ³⁺ and Nb <inf>2</inf> O <inf>5</inf> :Eu ³⁺

Abstract

A complete apparatus for luminescence thermometry has been built comprising a programmable hot-plate up to 400 °C, a hot/cold plate 0 °C-80 °C, a control circuit with thermocouple feedback, a platinum resistance thermometer and an oven for calibration. An original design allowed us to build the apparatus for under 100 $, considerably less than for the commercial equipment. The apparatus must be used with an optical fiber bundle attached to a spectrofluorometer. It is tested for stability and on ZrO 2 :Eu 3+ and Nb 2 O 5 :Eu 3+ samples prepared by a plasma electrolytic process. The tests showed the high stability of the temperature-controlled surfaces. The thermometric properties of the investigated material were tested by the luminescence intensity ratio method of 5 D 1 → 7 F 1 and 5 D 0 → 7 F 2 transitions. The calculated relative sensitivities of Nb 2 O 5 :Eu 3+ and ZrO 2 :Eu 3+ are 3.17% K -1 and 3.07% K -1 at 290 K, respectively, and 0.0012 K -1 at 453 K and 0.000 12 K -1 at 445 K are the calculated absolute sensitivity values, respectively. Nb 2 O 5 :Eu 3+ has shown good thermometric properties up to 180 °C, while ZrO 2 :Eu 3+ is a promising temperature sensor phosphor for higher temperature measurements.