Photoluminescence thermometry with alkyl‐terminated silicon nanoparticles dispersed in low‐polar liquids

Abstract

Steady‐state and time‐resolved photoluminescence of silicon nanoparticles dispersed in low‐polar liquids at above room temperature is studied. The roles of low‐polar liquids as well as mechanisms responsible for their temperature‐dependent photoluminescence are discussed. The thermal sensitivity of the photoluminescence is estimated and application of the nanoparticles as nanothermometers is proposed. (© 2013 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)

A New Generation of Primary Luminescent Thermometers Based on Silicon Nanoparticles and Operating in Different Media

“…Δ S r calculated using Equation yields a relative error (Δ S r / S r ) of ≈1%. Despite the existence of previous reports on the temperature dependence of the peak emission position of SiNPs, only a small number of works addressed the use of SiNPs as nanothermometers and only for SiNPs in solution . The S r values for the thermometers based on surface‐oxidized SiNPs‐C12 are similar to those reported for surface‐functionalized SiNPs in a squalane solution (0.052% K −1 ) in the interval 303–390 K .…”

“…SiNPs are an attractive choice for nanothermometry as they combine tunable emission from the near‐infrared to visible spectral range with properties such as the material abundance, compatibility with the current microelectronic technology, and biocompatibility . Despite this great potential, few have report the use of SiNPs as nanothermometers, and the research has been limited to SiNPs dispersed in a liquid medium . Using a hyperspectral camera (pixel field‐of‐view of 1.3 × 1.3 μm 2 ), we show that the film's surface emission is homogenous, at least, at the microscale.…”

“…Within the diverse approaches to nanothermometry, luminescent probes are one of the most attractive as they are noninvasive, contactless, and easy to use, unlike conventional tools, such as thermocouple and fiber optic probes or volumetric methods (e.g., ultrasound, computed tomography, and magnetic resonance thermometry) . Additionally, luminescent probes can combine competitive spatial (<10 −4 m) and temporal (<10 −3 s) resolutions, allowing down to sub‐micrometric resolution with a measurement based on the temperature dependence of the photophysical properties (also known as thermometric parameter) of the materials, such as the steady‐state emission intensity of one or two transitions, and the lifetime (or risetime) of an excited state. Several luminescent materials such as organic dyes, polymers, layered double hydroxides, quantum dots (QDs), and trivalent lanthanide ions (Ln 3+ ) have been used as nanothermometers, as reviewed elsewhere …”

“…Regarding the calibration process, the thermometric systems can be classified in two categories: (i) primary or semi‐primary thermometers that are characterized by well‐established equations of state, directly relating the measured parameter to temperature, or (ii) secondary thermometers that require calibration . While for non‐self‐calibrated secondary thermometers, the calibration curve must be determined prior to each measurement, for self‐calibrated secondary thermometers, the calibration curve is obtained by fitting the thermometric parameter values measured in a given temperature range to an arbitrary function . If other variables besides temperature, e.g., the ionic strength, pH, pressure, or atmosphere composition, impact the thermometric parameter value, a recalibration procedure must be performed as the empirical functions are not supported by theoretical or phenomenological model.…”

Formation and properties of SiC and C particle nano‐colloids in non‐polar liquids

“…The final aim is to use these NPs as luminescent temperature nano-probes in lubricants as it was proposed for Si NPs [19,20]. Toward this nano-thermometer application in non-polar liquids, two main issues have to be addressed: (i) surface functionalization for efficient dispersion in NPLs; (ii) selection of small size nanoparticle (diameter < 10 nm) in order to minimize perturbations of the lubricant rheological properties.…”