Untangling heat transport dynamics using luminescence nanothermometry

doi:10.21203/rs.3.rs-2213198/v1

Download PDF

Article

Untangling heat transport dynamics using luminescence nanothermometry

https://doi.org/10.21203/rs.3.rs-2213198/v1

This work is licensed under a CC BY 4.0 License

Version 1

posted

You are reading this latest preprint version

Temperature touches all aspects of our daily life, including climate, production plants, food storage, transportation, metrology, microelectronics, and medicine, and is a major factor dictating performance of nanotechnologies.^1-4 However, while the heat transfer is well understood in bulk, neither experimental nor theoretical models provide a complete picture of the thermal dynamics at the nanoscale.^5-7 Here, in situ luminescence thermometry is used to probe the heat propagation taking place within lanthanide (Ln³⁺)-doped upconverting nanoparticles (UCNPs). We have designed UCNPs with Er³⁺ and Tm³⁺ thermometric layers positioned at different locations relative to their surface, varying the distance a heat wave travels before encountering the layers. Despite being separated only by a few tens of nanometers, the thermometric layer closer to the surface of UCNPs detects temperature increase much earlier than the one located at the center – yielding the heat propagation speed in UCNPs ~1.3 nm/s. The UCNPs featuring the two thermometric layers in a single nanostructure confirmed the above result and allowed us to uncover diffusive and non-diffusive (ballistic) heat transport regimes, as well as their interplay and complex heat exchange dynamics taking place in colloidal nanoparticles (nanofluids) at a room temperature.

Physical sciences/Nanoscience and technology/Nanoscale materials/Nanoparticles

Physical sciences/Optics and photonics/Optical materials and structures/Nanoparticles

Physical sciences/Materials science/Nanoscale materials/Nanoparticles

Thermal transport in non-metal materials is mediated by phonons and follows Fourier diffusion theory.⁷ However, when the physical size of the material approaches its phonon mean free path, the thermal gradient between regions at different temperatures disappears (Fig. 1) and phonons enter a ballistic movement regime, described by the non-diffusive Boltzmann transport equation.^6,7,5 Non-diffusive heat transport can lead to a substantial reduction of the phonon thermal conductivity of the material, resulting in erroneous absolute temperature and heat transport predictions when employing bulk thermal parameters.⁸ Although non-diffusive thermal transport has been observed in nanoparticles,^9,10 nanoparticle disordered films,¹¹ and nanowire arrays,¹² studying thermal dynamics and discriminating between heat propagation regimes remains a big challenge, especially for nanofluids. Current techniques including time-domain thermoreflectance,¹³ scanning thermal microscopy,¹⁴ transient thermal grating,¹⁵ and other microscale imaging techniques¹⁶ are relatively complex and limited only to surface probing. Meanwhile, the accuracy of theoretical approaches based on molecular dynamics simulations is contingent on the choice of empirical interatomic potentials, and ab initio simulations often examine phonons at 0 K rather than at finite temperatures.¹⁷

Luminescence thermometry is a powerful yet simple technique used to investigate the thermal behavior of nanofluids,^18,19 heat transfer across cellular barriers,^20,21 and the intracellular medium.^3,22−24 As a class of luminescent nanothermometers, UCNPs can report temperatures with high spatiotemporal and thermal accuracy, easily form colloidal solutions and are amenable to solution-processing.^25–27 Notably, the core/shell engineering of UCNPs affords rational placement of light upconverting Ln³⁺ dopants in distinct layers for purposefully-built heterostructures. To investigate heat propagation within the UCNPs themselves, here we exploit core/shell engineering and the temperature-sensitivity of different Ln³⁺ ions by creating luminescent nanothermometers with spatially-delayed thermal response to an external heating. Our UCNPs provide in situ transient thermal recordings that allow to estimate the heat propagation speed in the NaGdF₄ matrix and to discriminate between diffusive and non-diffusive heat transport regimes occurring in the nanoparticles.

Luminescent thermometers with spatially-delayed temperature sensing were synthesized by hot-injection thermal decomposition which facilitates layer-by-layer growth of the UCNPs and allows to place Ln³⁺ dopants at the designated positions, henceforth thermometric layers (Supplementary Section I, Figs. 1–14). Er³⁺,Yb³⁺ and Tm³⁺,Yb³⁺ co-dopants were rationally introduced in the NaGdF₄ host (Fig. 1a), comprising three distinct architectures with: (i) a single thermometric layer ~ 28 nm away from the surface (Er1 and Tm1), (ii) ~ 5 nm from the surface (Er2 and Tm2), and (iii) two thermometric layers separated by ~ 28 nm (Er1-Tm2). Thin Ln³⁺-doped thermometric layers ensure more uniform heat wave detection, and non-overlapping upconversion emissions of Er³⁺ and Tm³⁺ allow for simultaneous temperature monitoring under near-infrared laser irradiation in our custom-built setup (Fig. 2a). To further simplify the analysis of the thermal recordings we studied ligand-free UCNPs as water-suspended nanofluids.

Under continuous 980 nm laser excitation, the Yb³⁺, Er³⁺-doped UCNPs display the characteristic upconversion emission of Er³⁺ with green (²H_11/2/⁴S_3/2→⁴I_15/2) and red (⁴F_9/2→⁴I_15/2) radiative transitions at around 525/545 and 660 nm, respectively (Fig. 2b). The emission intensity ratio from the thermally-coupled green (²H_11/2 and ⁴S_3/2) excited states is used to calibrate the Er1, Er2, and Er1-Tm2 luminescent thermometers (Supplementary Figs. 15–17). Their relative thermal sensitivity (S_r) and temperature uncertainty (δT) are .3 %·K^− 1 and 1.0 K, respectively (Supplementary Fig. 18).²⁷ UCNPs containing Tm³⁺, Yb³⁺-doped thermal layers upconvert 980 nm excitation to blue (¹D₂→³F₄, ¹G₄→³H₆) and red (¹G₄→³F₄) emissions. The intensity ratio of the blue emission bands from both ¹D₂ and ¹G₄ excited states is used to calibrate the Tm1, Tm2, and Er1-Tm2 luminescent thermometers (Supplementary Fig. 17), having S_r~0.14 %·K^− 1 and δT ~ 0.8 K for an acquisition time of 1250 ms (Supplementary Fig. 18). Details on the calibration and thermal uncertainty are presented in Supplementary Section II.

To study heat propagation dynamics in nanoparticles, a UCNP nanofluid was subjected to a temperature gradient induced by a heating contact. The experimental setup allows to set the magnitude of the temperature step and to record transient thermal curves with an adjustable integration time. Transient heating curves of Er1/Er2 (Figs. 3a, b) and Tm1/Tm2 (Figs. 3c, d) have a typical functional form of an external heating process in nanofluids.^18,28−30 We can observe that the temperature increase is not recorded immediately with the instantiation of heating, and the onset time t₀ at which the temperature change is registered depends on the spatial placement of the thermometric layer within the UCNP (Supplementary Section III). As expected, t₀ values are greater for core-adjacent thermometric layers of UCNP (Er1 and Tm1) than for the surface-proximal ones (Er2 and Tm2). However, the onset times between the two architectures differ by as much as ≈ 20 s. We note that the reported effects are fully reversible and independent of the setup, experimental variables, or temperature-sensitive Ln³⁺ ions (Er³⁺ or Tm³⁺) (Supplementary Figs. 19–21).

We can extract the effective heat transfer velocity (\({v}_{h}\)) as the slope of the t₀ vs. the location of the thermometric layers within the UCNPs (Fig. 4a). Regardless of the Ln³⁺ ion employed for luminescence thermometry we estimate \({v}_{h}=1.3\pm 0.1\) nm s⁻¹, four orders of magnitude slower than expected by Fourier law (Supplementary Section III). Note that t₀ does not depend on the employed Joule heating rate (Supplementary Fig. 21).

Next, we recorded the transient heating curves from Er1-Tm2 UCNPs. The two thermometric layers placed away from each other in Er1-Tm2 UCNPs registered a temperature increase in the nanofluid at different onset times. The t₀ of the Tm³⁺ thermometric layer in Er1-Tm2 is similar to Er2 and Tm2, and lower than t₀ of the Er³⁺ one. The latter was also greater than Er1 and Tm1, due to the larger total size of the Er1-Tm2 UCNPs (Fig. 1a). The linear dependence of t₀ with the distance travelled across the Er1-Tm2 UCNP corroborates constant \({v}_{h}\) in NaGdF₄ UCNPs, no matter the Ln³⁺ doping (Fig. 4a).

Interestingly, while the core-adjacent Er³⁺ thermometric layer in Er1-Tm2 detects the transient heating profile similar to Er1 and Tm1, the Tm³⁺ thermometric layer manifests in a more complex behavior (Fig. 4b). After registering heating of the nanofluid (t₀ = 10 s), Tm³⁺ ions in the surface-proximal thermometric layer of Er1-Tm2 report a temperature increase for the first 5 s, followed by a 20 s plateau. Subsequently, the temperature increases again, until a steady-state is reached. We have calculated the diffusive heat propagation length, \({v}_{h}t\), and found a perfect match between the observed temperature changes and the dimensions of the distinct layers of Er1-Tm2 (Figs. 4c,d). Each discontinuity in the temperature increase, registered by the Tm³⁺ thermometric layer, corresponds to a unique compositional section of the Er1-Tm2 as the heat wave crosses UCNPs. This unequivocally validates that the effective heat wave velocity is constant and invariant to UCNPs composition or the interfaces of the core/shell structures.

We further analyze the transient heating profile measured in Er1-Tm2 as a thermal gradient \({\nabla }_{r}T=\frac{{T}_{1}-{T}_{2}}{L}\) (Supplementary Section IV); here, T₁ and T₂ are the temperatures respectively recorded by the Tm³⁺ and Er³⁺ thermometric layers, and L is the mean distance between them. Since the heat transfer regime is determined by the relationship between the size of a nanomaterial and its phonon mean free path, it is convenient to normalize the thermal gradient against r/L, where \(r={v}_{h}{t}_{h}={v}_{h}\left(t-{t}_{0}\right)\) is the distance travelled by the heat way (t being the heating elapse time). Thermal gradients in the diffusive regime are then considered within the framework of the lumped elements’ thermal circuit,³¹ in which the heat flow is a thermal current (i), while the heat transfer by diffusion maps onto the thermal resistance (R) and capacitances (C) of each layer. In the simplified thermal circuit of Er1-Tm2, R₁/C₁ and R₂/C₂ are used to describe the thermal gradients in the Tm³⁺ and Er³⁺ thermometric layers, respectively (Fig. 5a).

Four distinct regions were found in \({\nabla }_{r}T\) (Fig. 5b). In the \(r/L<1\) region, there is no thermal gradient within the UCNPs (Supplementary Fig. 22a), despite temperature increase registered in both thermometric layers, indicative of the non-diffusive heat transport between them. The non-diffusive regime is active until the heat wave reaches the core-adjacent Er³⁺ thermometric layer, since \(r<L\). In the second region, \(1<r/L<3\), a positive thermal gradient within the UCNP (Supplementary Fig. 22b) represents thermal loading of C₁. In \(1<r/L<2\) the thermal current flow in C₁ (denoted by i_1C) is greater than in R₁ (denoted by i_1R), thus the energy is transported by i₁ (heating from the surrounding water) and loaded into C₁. For \(2<r/L<3\), the \({\nabla }_{r}T\) approaches zero as C₁ is maximally loaded and the thermal current begins to flow in Er³⁺ thermometric layer. The null thermal gradient is reached at \(r/L=3\). The third region, \(3<r/L<7.5\), displays a negative thermal gradient (Supplementary Fig. 22c). Within \(3<r/L<4.5\) thermal current i₁ is used to load C₂ and when passing into \(4.5<r/L<7\) the thermal gradient tends to zero as C₂ reaches its maximum load. Finally, we observe a null thermal gradient for \(r/L>7.5\) (Supplementary Fig. 22d) when both thermometric layers are recording the same steady-state temperature, meaning that the system has reached a net-zero balance between the ingoing and outgoing heat fluxes. From the point-of-view of thermal capacitance, maximum thermal loading is attained in both C₁ and C₂, and the thermal current flows only through R₁ and R₂.

The thermal loading of Tm³⁺ and Er³⁺ thermometric layers of Er1-Tm2 can be further supported by an analogous analysis of a hypothetical nanoparticles with two Tm³⁺ layers as in Tm1-Tm2 or two Er³⁺ layers in Er2-Er1 (Supplementary Section IV). Experimental transient heating profiles independently recorded by Tm1, Tm2, Er1 and Er2 (Figs. 3a-d) were used to calculate the temperature gradients in the hypothetical Tm1-Tm2 and Er2-Er1 (Supplementary Fig. 23). For both simulated geometries, we observe a null thermal gradient in \(r/L<1\), clearly attesting to the non-diffusive heat transport in the nanoparticles and it being invariant to the composition of the thermometric layers. Individually, the thermal loading of the surface-proximal Tm³⁺ thermometric layer in Tm1-Tm2 (Supplementary Figs. 23a,b) occurs for \(1<r/L<2\), and that of the core-adjacent Er³⁺ thermometric layer in Er2-Er1 for \(1<r/L<2.5\) (Supplementary Figs. 23c,d). Although maximum values of \({\nabla }_{r}T\) between Tm³⁺ thermometric layers in Tm1-Tm2 and Er1-Tm2 differ due to the greater thermal capacity of the the latter structure (Supplementary Table 6), the \({\nabla }_{r}T\) vs \(r/L\) dynamics between the two nanoparticles are in near-perfect agreement. Comparing Er2-Er1 and Er1-Tm2, the minimum \({\nabla }_{r}T\) and thermal loading dynamics are very similar as the physical dimensions of the core-adjacent Er³⁺ thermometric layers are the same.

The thermal loading of each thermometric layer of Er1-Tm2 can be further described by the characteristic time \({\tau }_{j}={R}_{j}{C}_{j}\),³² where j = 1,2 correspond to Tm³⁺ and Er³⁺, respectively. The thermal loading times were determined by fitting the experimental data (solid lines in Fig. 5b) to a diffusive heat propagation model (Supplementary Eq. 9). We estimate τ₁ = 20 ± 4 s and τ₂ = 18 ± 3 s (Supplementary Table 5), which are comparable, within experimental error, to the characteristic times extracted from the simulated geometries, τ’₁=21±1 s (for Tm1-Tm2) and τ’₂=19±1 s (for Er2-Er1). The characteristic times are the same with (in Er1-Tm2) and without (in the hypothethical architectures) thermal exchange between the embedded thermometric layers as both thermal capacitances are being loaded simultaneously under a low heating rate (< 10 W·cm⁻²). To affirm that the diffusive heat transport explains thermal loading of the thermometric layers when \(r/L>1\), we determine the expected values of \({\tau }_{j}\) considering the dimensions and compositions of the the respective layers (Supplementary Table 6). The predicted values are τ₁ = 21±8 s, τ₂ = 21 ± 8 s, τ’₁=19±8 s, and τ’₂=22±9 s and within the uncertainty match the experimentally obtained ones. Thus, the existence of different thermometric layers exchanging energy as heat does not affect the diffusive heat exchange within the UCNPs and follows the classical Fourier law. However, the overall thermal gradient profile can be altered in complex heterostructures, as the additional layers accumulate and store the thermal energy.

In brief, we have accurately quantified the heat transport taking place in UCNPs unveiling the presence of non-diffusive and diffusive regimes inside the nanoparticles. We have measured the relatively slow propagation of the heat wave within the nanoparticles at the speed of around 1.3 nm∙s^− 1 which is, remarkably, four orders of magnitude slower than the value predicted by Fourier’s law. Moreover, the heat propagation between the distinctly placed thermometric layers is primarily non-diffusive before a thermal gradient is established. Furthermore, depending on the structure of the nanoparticles, the diffusive heat transport assumes different normalized heat propagation lengths and shows differential thermal loading in the same nanoparticle. Our results pave the way to extract phenomenological heat propagation parameters at the nanoscale through a generalized use of luminescence nanothermometry, which will become instrumental in the nanotechnological development of optoelectronics,³³ catalysis,³⁴ thermal biology,²³ and precision medicines.³⁵

Synthesis of UCNPs

Core-adjacent nanothermometers (Er1 and Tm1)

Core/shell1/shell2 UCNPs: a) NaGdF₄/NaGdF₄: 20 mol% Yb³⁺, 2 mol% Er³⁺/NaGdF₄ and b) NaGdF₄/NaGdF₄: 20 mol% Yb³⁺, 0.5 mol% Tm³⁺/NaGdF₄; featuring a small core and a thick outer shell2, with optically active shell1 placed deep within the UCNPs’ volume, were synthesized via previously reported thermal decomposition method,³⁶ with minor modifications to the synthesis procedure.

Surface-proximal nanothermometers (Er2 and Tm2)

Core/shell1/shell2 UCNPs: a) NaGdF₄/NaGdF₄: 20 mol% Yb³⁺, 2 mol% Er³⁺/NaGdF₄ and b) NaGdF₄/NaGdF₄: 20 mol% Yb³⁺, 0.5 mol% Tm³⁺/NaGdF₄; featuring a large core and a thin outer shell2, with optically active shell1 positioned close to the UCNPs’ surface, were made following the same synthesis protocol with modifications to the procedure.

Core-adjacent and surface-proximal nanothermometer (Er1-Tm2)

Core/shell1/shell2/shell3/shell4 UCNPs: NaGdF₄/NaGdF₄: 20 mol% Yb³⁺, 2 mol% Er³⁺/NaGdF₄/NaGdF₄: 20 mol% Yb³⁺, 0.5 mol% Tm³⁺/NaGdF₄; featuring a small core, a thick intermediate shell2, and a thin outer shell4, with optically active shell1 placed deep within the volume of the UCNP and optically active shell3 positioned close to its surface, were synthesized via additional shelling of the core-adjacent Er³⁺-doped nanothermometers (Er1).

Structural characterization

The morphology and size distribution of final UCNPs, as well as of intermediate synthesis steps, were further investigated by transmission electron microscopy (TEM, Philips Tecnai 12). The particle size was determined from TEM images using ImageJ software with a minimum set size of 200 individual NPs per sample. The crystallinity and phase of all the NPs were determined via X-ray powder diffraction (XRD) analysis with a Diffractometer (D8 Advance, Bruker) using Cu K_α radiation.

Optical characterization of the as-prepared UCNPs

Upconversion (UC) emission spectra of hexane dispersions of the synthesized UCNPs were obtained at room temperature under 960 nm continuous-wave (CW) laser diode excitation (BWT). UC emission was collected using a lens at a 90º angle from the excitation beam and recorded with a portable spectrometer (Avaspec-ULS2048L, Avantes). Acquired data were spectrally corrected using black body emission approximation. Stray light from the excitation source was removed with a short-pass 825 nm filter (Newport Corp).

Transient heating curves processing and determination of the onset time

The transient heating curves were recorded using the same experimental setup described for calibration (Supplementary Section II). To generate a temperature gradient within the cuvette a temperature step was set in the temperature controller and the emission spectra of the suspension were recorded over time. The 980 nm excitation laser beam was positioned in the center of the cuvette (5.0 mm from the cuvette surface in contact with the Cu holder). The instant t = 0 s was set to the time in which the heater was turned on. The functional form of the transient heating curve depends on the external joule heating power per unit of area (heating flow) most probably due to the combined Soret and Dufour effects.³⁷ Therefore, we limit here the discussion of the transient heating curves acquired for heating power values lower than 10 W·cm^− 2 (Supplementary Fig. 21).

The recorded emission during the transient heating curves was processed by binning the emission spectra (to a binned time step of 2.5 s) in order to decrease the fluctuations resulting from fast acquisitions. Besides the fluctuation in the thermometric parameters, no further differences were noticed between the individual curves and the binned ones in what concerns the onset time and temporal dynamics of the temperature readouts. The thermometric parameters (intensity ratio) were converted to temperature using the corresponding thermal calibration relations (Supplementary Fig. 17).

The onset time of each transient heating curve was determined as the time-instant correspondent to a temperature change consistently above the temperature measurement uncertainty (see Supplementary Section III). The corresponding uncertainty is the maximum deviation found for 3 independent measurements.

Mecklenburg, M. et al. Nanoscale temperature mapping in operating microelectronic devices. Science 347, 629–632 (2015).
Ziabari, A. et al. Full-field thermal imaging of quasiballistic crosstalk reduction in nanoscale devices. Nat. Commun. 9, 255 (2018).
Zhou, J. J., del Rosal, B., Jaque, D., Uchiyama, S. & Jin, D. Y. Advances and challenges for fluorescence nanothermometry. Nat. Methods 17, 967–980 (2020).
Waissman, J. et al. Electronic thermal transport measurement in low-dimensional materials with graphene non-local noise thermometry. Nat. Nanotechnol. 17, 166–173 (2022).
Hoogeboom-Pot, K. M. et al. A new regime of nanoscale thermal transport: Collective diffusion increases dissipation efficiency. Proc. Natl. Acad. Sci. USA 112, 4846–4851 (2015).
Cunha, J. et al. Controlling light, heat, and vibrations in plasmonics and phononics. Adv. Opt. Mater. 8, 2001225 (2020).
Chen, G. Non-fourier phonon heat conduction at the microscale and nanoscale. Nat. Rev. Phys. 3, 555–569 (2021).
Alajlouni, S. et al. Geometrical quasi-ballistic effects on thermal transport in nanostructured devices. Nano Res. 14, 945–952 (2021).
Lin, X. et al. Measurement of temperature distribution at the nanoscale with luminescent probes based on lanthanide nanoparticles and quantum dots. ACS Appl. Mater. Inter. 12, 52393–52401 (2020).
Espinosa, A. et al. Photoactivated nanoscale temperature gradient detection using X-ray absorption spectroscopy as a direct nanothermometry method. Nano Lett. 21, 769–777 (2021).
Utterback, J. K. et al. Nanoscale disorder generates subdiffusive heat transport in self-assembled nanocrystal films. Nano Lett. 21, 3540–3547 (2021).
Siemens, M. E. et al. Quasi-ballistic thermal transport from nanoscale interfaces observed using ultrafast coherent soft x-ray beams. Nat. Mater. 9, 26–30 (2010).
Cahill, D. G. et al. Nanoscale thermal transport. J. Appl. Phys. 93, 793–818 (2003).
Spiece, J. et al. Quantifying thermal transport in buried semiconductor nanostructures via cross-sectional scanning thermal microscopy. Nanoscale 13, 10829–10836 (2021).
Huberman, S. et al. Observation of second sound in graphite at temperatures above 100 K. Science 364, 375–379 (2019).
Hu, S. et al. Quantifying surface temperature of thermoplasmonic nanostructures. J. Am. Chem. Soc. 140, 13680–13686 (2018).
Reig, D. S. et al. Unraveling heat transport and dissipation in suspended MoSe₂ from bulk to monolayer. Adv. Mater., 10.1002/adma.202108352 (2022).
Brites, C. D. et al. Instantaneous ballistic velocity of suspended brownian nanocrystals measured by upconversion nanothermometry. Nat. Nanotechnol. 11, 851–856 (2016).
Handel, B. et al. Investigation of the concentration- and temperature-dependent motion of colloidal nanoparticles. Nanoscale 12, 12561–12567 (2020).
Bastos, A. R. N. et al. Thermal properties of lipid bilayers determined using upconversion nanothermometry. Adv. Funct. Mater. 29, 1905474 (2019).
Song, P. et al. Heat transfer and thermoregulation within single cells revealed by transient plasmonic imaging. Chem. 7, 1569–1587 (2021).
Piñol, R. et al. Real-time intracellular temperature imaging using lanthanide bearing polymeric micelles. Nano Lett. 20, 6466–6472 (2020).
Okabe, K. & Uchiyama, S. Intracellular thermometry uncovers spontaneous thermogenesis and associated thermal signaling. Commun. Biol. 4 (2021).
Di, X. et al. Quantitatively monitoring in situ mitochondrial thermal dynamics by upconversion nanoparticles. Nano Lett. 21, 1651–1658 (2021).
Vetrone, F. et al. Temperature sensing using fluorescent nanothermometers. ACS Nano 4, 3254–3258 (2010).
Jaque, D. & Vetrone, F. Luminescence nanothermometry. Nanoscale 4, 4301–4326 (2012).
Brites, C. D. S., Balabhadra, S. & Carlos, L. D. Lanthanide-based thermometers: At the cutting-edge of luminescence thermometry. Adv. Opt. Mater. 7, 1801239 (2019).
Savchuk, O. A. et al. Upconversion thermometry: A new tool to measure the thermal resistance of nanoparticles. Nanoscale 10, 6602–6610 (2018).
Wu, X. Y. & Yeow, E. K. L. Tuning the NIR downconversion luminescence and photothermal conversion efficiencies of MNd_xY_1-xF₄ (M = Na and Li) nanocrystals for use in anti-counterfeiting labels with opposite displays. Nanoscale 11, 15259–15269 (2019).
Paściak, A., Pilch-Wróbel, A., Marciniak, Ł., Schuck, P. J. & Bednarkiewicz, A. Standardization of methodology of light-to-heat conversion efficiency determination for colloidal nanoheaters. ACS Appl. Mater. Interfaces 13, 44556–44567 (2021).
Incropera, F. P., DeWitt, D. P., Bergman, T. L. & Lavine, A. S. Introduction to heat transfer. 5 Edn. (Wiley, 2006).
Bergman, T. L., Lavine, A. S., Incropera, F. P. & DeWitt, D. P. Fundamentals of heat and mass transfer. 7 Edn. 281 (Wiley, 2011).
Martínez, E. D. et al. Electrochromic switch devices mixing small- and large-sized upconverting nanocrystals. Adv. Funct. Mater. 29, 1807758 (2019).
Hartman, T., Geitenbeek, R. G., Whiting, G. T. & Weckhuysen, B. M. Operando monitoring of temperature and active species at the single catalyst particle level. Nat. Catal. 2, 986–996 (2019).
Dou, R. et al. Precision nanomedicines: Targeting hot mitochondria in cancer cells. ACS Appl. Bio Mater. 5, 4103–4117 (2022).
Boyer, J. C., Vetrone, F., Cuccia, L. A. & Capobianco, J. A. Synthesis of colloidal upconverting NaYF₄ nanocrystals doped with Er³⁺, Yb³⁺ and Tm³⁺, Yb³⁺ via thermal decomposition of lanthanide trifluoroacetate precursors. J. Am. Chem. Soc. 128, 7444–7445 (2006).
Bastos, A. R. N. et al. Thermal properties of lipid bilayers derived from the transient heating regime of upconverting nanoparticles. Nanoscale 12, 24169–24176 (2020).

There is NO Competing Interest.

HeatatNanoscaleSILDCarlos.docx
Supplementary Materials

Download PDF

Version 1

posted

You are reading this latest preprint version

Untangling heat transport dynamics using luminescence nanothermometry

Status:

Version 1

Abstract

Figures

Full Text

Methods

References

Additional Declarations

Supplementary Files

Status:

Version 1