A Dual Luminescent Sensor Material for Simultaneous Imaging of Pressure and Temperature on Surfaces

Abstract

A novel kind of composite material for simultaneous luminescent determination of air pressure and temperature is presented. The dual sensor consists of a fluorinated platinum porphyrin complex (PtTFPP) as an oxygen‐sensitive probe, and of the highly temperature‐sensitive europium complex Eu(tta)3(dpbt) as temperature probe. Both are incorporated into different polymer microparticles to control response characteristics and to avoid interferences. Encapsulation of PtTFPP in poly(styrene‐co‐acrylonitrile) (PSAN) results in a broad dynamic range from 0.05 to 2.00 bar for pressure measurements. The europium complex was incorporated into poly(vinyl chloride) to reduce the cross sensitivity towards oxygen. This system represents a new class of luminescent sensor system, where the signals are separated via the different luminescence lifetimes of the indicators. It is possible to monitor the emission of the temperature‐sensitive probe by means of time‐resolved fluorescence imaging without interferences, because the luminescence lifetime of the temperature indicator is tenfold longer than that of the oxygen indicator. The temperature image can then be used to compensate cross sensitivity of the pressure indicator towards temperature. In combination with an appropriate time‐resolved measurement technique, this material enables simultaneous imaging of pressure (or oxygen partial pressure) and temperature distributions on surfaces. It is distinguished from other approaches of dual pressure and temperature sensitive paints because it avoids the need of signal separation by application of different cameras or by use of different optical filters or light sources.

Exceptional Oxygen Sensing Properties of New Blue Light‐Excitable Highly Luminescent Europium(III) and Gadolinium(III) Complexes

“…[22] These complexes are widely applied as labels in various luminescence assays both as free dyes bearing a functional group for conjugation and in the form of dye-doped nanoparticles, [22,23] but application in optical sensors and analyte-sensitive probes is comparably rare. [24][25][26][27] For example, luminescent Eu(III) complexes were applied as optical temperature probes, [27][28][29][30][31] pH indicators, [32][33][34][35][36] fluoroionophores for bicarbonate, [37,38] citrate [39] and lactate [40] and as hydrogen peroxide [41] and nitrogen monooxide probes. [42] Several Eu(III) complexes were applied as luminescent oxygen indicators.…”

Luminescent Europium(III) Nanoparticles for Sensing and Imaging of Temperature in the Physiological Range

“…[10] The Eu(III) chelates used so far for sensing temperature have been designed for much wider temperature ranges and have been immobilized into matrix polymers to form thin films as sensor paints. [8] In order to overcome interferences due to quenching of luminescence by oxygen, [11] the probes were incorporated into microbeads ($3-10 mm), which also exerts a beneficial effect on the stability of the Eu(III) complex.…”

Evaluation of rare earth doped silica sub-micrometric spheres as optically controlled temperature sensors

“…Mainly, the red emission centered at around 615 nm is expected to be temperature dependent due to its large sensitivity to environmental effects in the vicinity of the Eu 3þ ions. 32,33 This fact is shown in Figure 3(b), where the luminescence spectra for the Eu 3þ :…”

“…32,33 The different techniques used to obtain the ion sensitivity have the advantage that are unaffected by local intensity changes (concentration of RE 3þ or laser fluctuations) and so require simple experimental instrumentation and so require simple experimental instrumentation when compared to previously proposed approaches for luminescence thermal sensing at the sub-micrometric scale. 4 These results together with the possibility of trapping and handling the sub-micrometric spheres without perturbation of the medium make these spheres highly suitable as a thermal sensor in microfluidic.…”