Time-Resolved Temperature-Jump Measurements and Theoretical

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C: Plasmonics; Optical, Magnetic, and Hybrid Materials

Time-Resolved Temperature-Jump Measurements and Theoretical Simulations of Nanoscale Heat Transfer Using NaYF:Yb : Er Upconverting Nanoparticles 4

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Ali Rafiei Miandashti, Larousse Khosravi Khorashad, Alexander O. Govorov, Martin E. Kordesch, and Hugh H. Richardson J. Phys. Chem. C, Just Accepted Manuscript • DOI: 10.1021/acs.jpcc.8b11215 • Publication Date (Web): 18 Jan 2019 Downloaded from http://pubs.acs.org on January 21, 2019

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The Journal of Physical Chemistry

Time-Resolved Temperature-Jump Measurements and Theoretical Simulations of Nanoscale Heat Transfer Using NaYF4:Yb3+: Er3+ Upconverting Nanoparticles Ali Rafiei Miandashti,1 Larousse Khosravi Khorashad,2 Alexander O. Govorov,2,3 Martin E. Kordesch,2 and Hugh H. Richardson1* 1Department 2Department

of Chemistry and Biochemistry, Ohio University, Athens, Ohio 45701 of Physics and Astronomy, Ohio University, Athens, Ohio 45701

3Institute

of Fundamental and Frontier Sciences, University of Electronic Science and Technology of China, Chengdu 610054, China * Corresponding Author: [email protected]

Abstract We introduce for the first time a time-resolved temperature measurement technique which relies on temperature-jump luminescence thermometry using NaYF4:Yb3+: Er3+ upconverting nanocrystals. This new time-resolved technique is based on optical thermometry using upconverting nanoparticles (UCNPs) and does not have to infer temperature from changes in the optical properties of the heater or surrounding local environment. We have prepared gold decorated UCNPs that function as a dual single heater-thermometer system. We measure the timeresolved temperature-jump from nanocrystal clusters and compare our results to simulated thermal transfer data generated using finite element methods. The simulated data shows that temperature dissipation follows a power law where the temperature change is inversely related with time. This result agrees with a thermal diffusion model where a semi-infinite medium is exposed to a sudden temperature change at its surface, but the simulated results do not agree that the heat transfer process can be described by a single thermal diffusivity parameter. In contrast to the thermal diffusion model, our experimental and simulation data show that the heat generation and dissipation process is described by an energy balance model where the thermal conductivity for heat dissipation and heat capacity of the heated object are separated. The experimental data agrees with the prediction of the energy balance model where the temperature is expected to increase and decay with time as a single exponential.

Introduction The study of thermal transport from nanostructures and understanding of heat transfer into different dielectric mediums is essential for the advancement of electronic devices, solar energy conversion, and biological systems.1-12 Time-resolved measurement of temperature at the interface of nanostructures has been the focus of many recent scientific reports where pump-probe techniques such as transient-absorption, 8, 13-33and time-domain thermoreflectance,16, 34-59 or other techniques like time-resolved small-angle X-ray scattering,60-68 and time-resolved Fouriertransform spectroscopy 30, 69-73 have been used to measure nanoscale thermal transfer and heat

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dissipation into different environments. In pump-probe spectroscopy, the nanoheater generates heat by pump pulse absorption and causes a transient change in the optical properties of the system, which is detected by a probe pulse. These techniques provide fast measurements of cooling of nanostructures in different mediums and access information about the effect of size, shape, and environment on nanoscale thermal transfer and are able to characterize interfacial thermal transport effects such as Kapitza resistance at the nanostructure/environment interface.

Direct time-resolved measurement of temperature from a single nanostructure remains challenging without relying on the other secondary parameters such as change of optical properties of the medium. The assumption that there is a linear relationship between changes in the local temperature and system optical properties is not tenable as many environmental changes besides temperature can change the optical properties of the local environment.8 There have been some reports calling for a comprehensive thermo-optical model addressing an accurate analysis and measurement of time-resolved temperature measurements.8 Good tests of thermal transfer models are needed where a direct measure of time-resolved temperature is collected and compared to existing models. Unfortunately, there are few experimental techniques capable of measuring temperature directly and time-resolved direct temperature measurements on the nanoscale are virtually non-existent.

Here, we develop a new time-resolved direct temperature measurement technique where the time-resolved luminescence ratio from NaYF4:Yb3+: Er3+ upconverting nanocrystals is used to monitor the dynamic of heat dissipation. This technique is based on a well-proven optical thermometry using UCNPs and does not rely on the change in the optical properties of the medium. We measure the time-resolved temperature-jump from gold nanoparticle decorated upconverting nanocrystals and compare our results to numerical thermal transfer data calculated using finite element method and the software COMSOL Multiphysics. The simulated data shows that temperature dissipation follows a power law where the temperature change is inversely related with time. This result agrees with a thermal diffusion model where a semi-infinite medium is exposed to a sudden temperature change at its surface, but the simulated results do not agree that the heat transfer process can be described by a single thermal diffusivity parameter. A complementary and very convenient model is based on the energy balance principle. Our experimental and simulation data show that the heat generation and dissipation process is described by an energy balance model where the thermal conductivity for heat dissipation and heat capacity of the heated object are separated. The experimental data agrees with the prediction of the energy balance model where the temperature is expected to increase and decay with time as a single exponential. The dynamical photo-thermal methods that we develop in this study can be utilized to measure and control thermal and photo-chemical processes in nanostructures with complex shapes, such as Fano effects, strong temperature localization,74 chiral photo-thermal and photochemical responses.75-77

Methods Synthesis of NaYF4:Yb3+:Er3+ Upconverting Nanoparticles:


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All chemicals were purchased from Sigma-Aldrich and used without further purification. We synthesized NaYF4: 20%Yb,2%Er nanoparticles via thermal decomposition method. In this protocol, we decomposed rare-earth and sodiumtrifluoroacetate oleic acid (OA) and octadecene (ODE) as reported in the literature.78 In a typical protocol, we mixed 0.50 mmol of Ytterbium (III) Oxide (Yb2O3, 99.9%), 1.95 mmol of Yttrium (III) Oxide (Y2O3, 99.99%) and 0.050 mmol of Erbium (III) Oxide (Er2O3, 99.9%) in 10 ml trifluoroacetic acid (TFA, 99%) in a 200 ml threenecked flask. To remove water and excessive TFA, we heated the compounds to 80 ˚C with vigorous magnetic stirring under vacuum for 30 minutes. After drying the solvents, we added 5 mmol sodium trifluoroacetate (NaCOOCF3, 98%) to 15 mL of oleic acid (OA, 90%) and 15 ml of 1-octadecene (ODE, 90%) at 100 ˚C. Next, we increased the temperature to 330 ˚C with an increase rate of 30 ˚C per min and maintained at 330 ˚C for 60 minutes to complete the reaction. The nanoparticles were thoroughly washed and dispersed in toluene. Synthesis of Gold Nanoparticles In a typical procedure, we added 1 ml of aqueous solution of HAuCl4 trihydrate (0.01 M) and 1 ml of trisodium citrate (0.01 M) to 36 ml of deionized H2O and stirred for 1 minute. Next, we added 1 ml of ice-cold and freshly-prepared NaBH4 (0.1 M) to the solution and the color changed from colorless to orange. We continued the stirring stopped for 5 minutes and the solution was left undisturbed for 2 h. 79 Synthesis of Gold decorated Upconverting Nanoparticles The attachment of gold nanoparticles (GNPs) and the growth of larger GNPs on the surface of UCNPs are carried out in aqueous solution. To make the nanoparticles water soluble, we performed two surface-modification steps. Firstly, we removed the hydrophobic oleic acid from the surface of UCNPs by reducing the pH of environment to 4 as reported in the literature. 8081After removing the oleic acid from the surface, we used 5 ml of UCNP (1 wt %), 10 ml of polyacrylic acid (PAA) (1 wt %) and stirred it overnight. We then washed it 3 times with Ethanol before stirring it with 10 ml of Poly(allylamine hydrochloride) average Mw 50,000 Sigma-Aldrich in aqueous medium. We let the solution stir overnight before washing it again for 3 times. We centrifuged it at 10000 rpm for 10 min. We suspended the precipitate in deionized water. To 10 ml of UCNP (1 wt %), we added 2 ml of citrate stabilized GNPs and the solution was stirred for 2 hours. We separated the UCNPs decorated with gold nanoparticles from unattached particles through centrifuge. Due to the larger size of UCNP/GNPs, they are precipitated faster than GNPs and they are easily separable. Temperature Measurement To start, the decorated UCNPs are drop casted onto a plasma cleaned cover slip and is placed under Zeiss short working distance objective (NA 0.8) under WITech α-300 NSOM Microscope. The desired structure is imaged by raster scanning of a 20 x 20 µm area via a white light source (DH-2000 Mikropack Halogen Lamp) and then finding the coordinate of desired cluster through the ‘Listen’ function of the software. By setting a much smaller scan area of 5 x 5 µm, only the signal from a ~3 µm single cluster of UCNPs was collected. Upon illuminating the nanoparticles by 980 nm laser, the photoluminescence emission of UCNPs is collected through the



optical fiber of the microscope. The luminescence emission is recorded by a spectrometer. We calculate the temperature of the UCNPs by measuring the relative peak areas of the 2H11/2  4I15/2 and 4S3/2  4I15/2 bands from Er3+ ions. To monitor instant temperature changes from GNP decorated UCNPs, we used two lasers to optically and photothermally excite the nanostructures. Continuous 980 nm with a spot size of ~3 µm laser provides the constant and steady-state emission from Er3+ ions in the nanostructures. When the particles were under steady state 980 nm illumination, pulsed 532 nm with a spot size of ~3 µm was used to excite small gold nanoparticles. The luminescence emission of UCNPs excited by 532 nm laser excitation is not significant and is about one order of magnitude weaker than that of 980 nm excitation. Therefore, 980 nm laser with a good approximation is the only source of luminescence emission in our experiment. We used 980 nm (CW) excitation laser with an intensity of ~ 200 W/mm2 for steady state excitation of luminescent nanoparticles and excitation intensity of 8-280 W/mm2 (depending on the pulse widths) for 532 nm photothermal heating of gold nanoparticles. According to the study published in our group previously, irradiation by 980 nm increased the temperature of UCNPs up to 15 degree when the 980 nm laser intensity turned up from 1 to 9 × 102 W/mm2.82 In current experiment, the intensity of 980 nm laser is kept constant at 200 W/mm2. This intensity caused a few degrees change on the temperature of UCNPs. We collected the photoluminescence emission from H and S bands in two subsequent steps. First, a band pass filter of 520 nm was placed before the collection fiber to exclude emission bands and collect H band photoluminescence signal. Next, the photoluminescence signal from S band was selected by a 540 nm band pass filter for the same amount of time. Since the thermalization of H and S bands are stochastic processes and measurement of temperaturtre is based on ratio of peaks, the subsequent collection of bands and small variation of intensities does not affect the results. The emission from UCNPs was collected through a 50 µm optical fiber. Avalanche photodiode were used to count the photoluminescence signal from H and S emission bands. A time-to pulse height converter and a multichannel analyzer (ADC 8067) with a negative shut off pulse of 40 us (Stanford Research Instrument DG 535) was used for generation of final histogram. The data generated by the multichannel analyzer is a histogram of intensity versus channels. The time component of the x axis was defined by changing the collection windows built in time to pulse height converter (467 Ortec) instrument.

Results and Discussion We prepared NaYF4:Yb3+:Er3+ ~300 nm upconverting nanocrystals using thermal decomposition method as adopted from the literature.80 NaYF4:Yb3+:Er3+ nanocrystals are comprised of a nanocrystalline structure β-NaYF4 that makes up the 80 percent of the NaYF4:Yb3+:Er3+ nanocrystals. These nanoparticles are embedded with a sensitizer (Yb3+) that absorbs light at 980 nm and transfers electrons to Er3+ where a second photon is absorbed to promote the electron to the 2H11/2  4I15/2 and 4S3/2  4I15/2 levels.78, 80, 82-88 We further functionalized nanocrystals using gold nanostructures that are significantly smaller ~10 nm according to the previous report. 82 In our case it appears that the gold seed nanoparticles act as a sensitizer and a strong light absorber to promote extra electrons into the 2H11/2  4I15/2 and 4S3/2  4I15/2 energy levels.81-82, 84, 89-91 Figure 1a depicts a representative TEM image of a single hexagonal NaYF4:Yb3+:Er3+ nanocrystal decorated with spherical gold nanoparticles. Figure 1b


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shows a HRTEM image of spherical gold nanoparticle attached to the corner of the hexagonal shape NaYF4:Yb3+:Er3+ nanocrystal. Gold nanospheres are synthesized separately and attached to the nanocrystals with electrostatic interaction. Negatively charged seed gold nanoparticles (average size ~ 10 nm) are functionalized with citrate capping agent and upconverting nanocrystals are coated with polyallylamine hydrochloride (PAH).80, 83, 89 The decoration of UCNPs by gold seed nanoparticles is tuned by changing the ratio of gold seed nanoparticles to UCNPs. The elemental analysis of NaYF4:Yb3+:Er3+ nanocrystal decorated with gold nanospheres are shown in supporting information (See Figure S1)

Figure 1 a and b) TEM and HRTEM image of β-phase hexagonal NaYF4:Yb3+: Er3+ nanocrystals decorated with ~10 nm gold nanospheres c) photothermal response of UCNPs to the intensity of 532 nm laser under constant 980 nm illumination. d) photothermal response of UCNPs to the pulse width of 532 nm laser under constant 980 nm illumination. We used two lasers (980 nm and 532 nm) to optically and photothermally excite the nanostructures so that we can collect temperature jump data from gold decorated UCNPs. Upconverting nanoparticles emit a strong photoluminescence signal upon irradiation by 980 nm laser. The emission signal from UCNPs excited by 532 nm is an order of magnitude weaker than that of 980 nm laser. As a result, using two laser illumination does not affect the temperature measurement. As a result, using two laser illumination does not affect the temperature measurement. Continuous 980 nm laser provides the constant and steady-state emission from Er3+ ions in the nanostructures. When the particles were under steady state 980 nm illumination, continuous and pulsed 532 nm was used to excite small gold nanoparticles. When we used continuous 532 nm to excite the gold nanostructures, we observed a linear temperature increase of 60 degrees as the intensity of 532 nm CW laser increased for a ~3 µm cluster of gold decorated NaYF4:Yb3+:Er3+ nanocrystals (Figure 1c). We also looked at the photothermal property of the same cluster when we modulated 532 nm



and saw the effect of 532 nm pulse width for the same cluster. The graph in Figure 1d shows a linear relationship between the temperature of the cluster and laser power applied. Figure 1d shows the temperature increase as a function of pulsed 532 nm laser at 5 different pulse widths. The temperature increase is shown in figure 1c and d is calculated using luminescence ratio thermometry. The extinction spectrum of gold decorated UCNPs is shown in Figure S3. The strong absorption peak at around ~540 nm indicates the photothermal properties of decorated UCNPs. The long tail in both profiles is attributed to the scattering effect due to the large size of UCNPs.

A typical green emission spectrum of UCNPs is shown in SI (Figure S4). The temperature of UCNP nanostructures is determined using luminescence ratio thermometry as reported in the literature. 82, 86, 92 In brief, the photoluminescence emission of UCNPs is collected via the optical fiber of the microscope and the luminescence emission is recorded by a spectrometer. The temperature of the UCNPs is calculated by measuring the relative peak areas of the 2H11/2  4I15/2 and 4S3/2  4I15/2 bands from Er3+ ions. The temperature is determined from temperature dependent H E  A exp( ) , where ΔE is an energy difference states using the Boltzmann equation of states, S kT between the H band (2H11/2  4I15/2 transition) and the S-band (4S3/2  4I15/2 transition) and A is the pre-exponential factor. The pre-exponential factor A is determined by adjusting the parameter so that at very low laser intensity, the calculated temperature is the same as the room temperature.

In order to make time-resolved temperature measurement, we used the same protocol as luminescence ratio thermometry where we recorded the 2H11/2  4I15/2 and 4S3/2  4I15/2 photoluminescence signal through two narrow band filters and an avalanche photodiode. The photodiode signal is then converted to analog pulses via a time-to-amplitude converter. The pulses are then processed by a multichannel analyzer to obtain a timing spectrum.


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Figure 2. a) Schematic diagram of the technique used to obtain a time-resolved emission profiles for individual bands of gold decorated UCNP using 980 nm CW and modulated 532nm lasers. b) the change in the relative intensities of H and S bands indicated by dark and light green colors, under 25 W/mm2 532 nm laser irradiation. c) the 532 nm laser profile (black) and calculated temperature from luminescence ratio thermometry obtained from emission bands shown in 2b. The schematic diagram of our time-resolved measurement is shown in Figure 2a. A detailed description of the microscope set up and instruments are given in the methods section. In brief, we used two laser beams of modulated 532 nm and 980 nm CW to excite the UCNPs and generate optical heating via gold nanospheres. The photoluminescence emission from UCNPs is collected through the optical fiber of the microscope and is recorded using avalanche photodiode. The signal from avalanche photodiode is transformed to a histogram of intensity as a function of time using a time to pulse height converter and a multichannel analyzer. The time-resolved intensity plots are further processed to calculate the temperature using luminescence ratio thermometry. Figure 2b shows the H bands and S emission bands when a small cluster of ~3 µm gold decorated UCNP was irradiated with modulated 532 nm laser with an intensity of 250 W/mm2. Both H and S were selected by 520 nm and 540 nm bandpass filters in the filter set of the microscope. Since the system is under steady state illumination by CW 980 nm laser, the H and S bands show a flat line in the emission spectrum. When the modulated 532 nm laser is applied along with the CW 980 nm laser, the irradiation of 532 nm pulses creates a temperature spike in the gold nanoparticles. The heat generated in the gold nanoparticles is transformed to UCNPs and the relative population of H and S states as a result changes in the luminescence emission of Er3+ ions.



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The change in the relative intensities of H and S bands under 25 W/mm2 532 nm irradiation is shown in Figure 2b. H and S bands are shown in dark green and light green respectively. Figure 2c shows the 532 nm laser profile (black) and calculated temperature from the emission bands shown in 2c (also see Figure S4). The black laser profile corresponds to 10 µs 532 nm excitation laser.We monitored the temperature time traces from 5 different 532 nm pulse widths as shown in Figure 3a. The data was collected from a ~3 µm diameter cluster of UCNPs that has around 30 decorated UCNPs. We changed the pulse width from 2 µs to 25 µs and observed the change in the temperature profiles. The overall ΔT changed as the pulse width increased until steady-state is established even though the lifetime of the thermal decay after the laser pulse stayed relatively constant (see supporting information Figure S5). Figure 3b shows an exponential fit (red trace) to the 15 µs pulse length data (black) extracted from the thermal profile immediately after the laser pulse.

Figure 3. a) Thermal profiles for a ~ 3 µm cluster under 980 nm CW under 5 different 532 nm excitation pulse widths b) Energy balance model fitted to the experimental decay thermal profile under 15 µs pulse width Energy Balance Model The theoretical fit is obtained from the energy balance equation model. A detailed description of the model is in the supporting information. In brief, we start with a heat source of 532 nm laser to optically excite gold nanoparticles that are connected to a thermal reservoir. The rate of heat generation and heat dissipation can be described by energy balance model (equation 1) where energy is supplied by laser light absorption of gold nanoparticles attached to UCNPs (QI) and dissipation of heat to an external reservoir (Qdiss). 𝑛

∑ 𝑖

dT dT mi𝐶𝑝,𝑐,𝑖 = 𝑚𝑐𝐶𝑝,𝑐 = 𝑄 ― 𝑄𝑑𝑖𝑠𝑠 dt dt 𝐼

(1)

The temperature trace after the laser pulse is turned off (G = 0) is given by equation 2 where Tmax is the maximum temperature immediately after the laser pulse. Equation 2 is used to


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determine the heat dissipation rate constant and consequentially, the characteristic cooling time. 𝑇(𝑡) ― 𝑇𝑜 = (𝑇𝑚𝑎𝑥 ― 𝑇𝑜)𝑒 ―𝐷𝑡 𝑤ℎ𝑒𝑛 𝐺 = 0

(2)

where D is the characteristic cooling rate, 𝑇𝑚𝑎𝑥 is the maximum temperature and 𝑇0 the room temperature. The temperature profile during the laser pulse is given by equation 3. 𝐺 𝑇(𝑡) ― 𝑇𝑜 = (1 ― 𝑒 ―𝐷𝑡) 𝑤ℎ𝑒𝑛 𝐺 ≠ 0 𝐷

(3)

A simple model for the cooling rate starts with a hot spot (cluster) at temperature T with heat capacity Cp,c and density c connected to a thermal reservoir with a bridge that has a cross sectional area 𝑆 = 𝜋𝑟2𝑐 , length L, and thermal conductivity kc.93 At steady state, the heat flow equals the thermal loss rate, leading to a solution of 𝑇(𝑡) = 𝑇(0)exp ( ―𝐷𝑡) where D (the 𝑘𝑐𝐴𝑐

thermal loss rate) is 𝐿𝐶𝑝,𝑐𝑉𝑐 . Vc is the cluster volume and Ac is the cluster surface area. The length between the hot and cold reservoirs is proportional to the cluster radius (rc) and is given by 𝐿 = 𝑎 𝑟𝑐 where a is the proportionality constant. The temperature drops by a factor of 2 for every rc distance away from the cluster.94 A proportionality constant between 6 and 7, implies that the temperature has dropped by a factor of ~100 and at this distance, the temperature is nearly comparable to the temperature of the cold reservoir and heat flow stops. Equation 4 gives the steady-state temperature (Tss) during laser excitation if the UCNP cluster is modeled as a circular disk. Here c is the cluster density, AUCNP is the cluster area and NA is the surface concentration of gold nanoparticle within the laser area. 𝑑𝑇 ∗ 𝐺 𝐼𝑜𝜎𝑎𝑏𝑠𝑁𝑡𝑜𝑡𝐿 𝐼𝑜𝜎𝑎𝑏𝑠𝑁𝐴𝐿 = = 0; Δ𝑇𝑠𝑠 = 𝑇𝑠𝑠 ― 𝑇𝑜 = = 𝜌𝑐𝑘𝑐 𝑑𝑡 𝐷 𝜌𝑐𝑘𝑐𝐴𝑈𝐶𝑁𝑃

(4)

The ratio G/D gives the steady-state temperature. The steady-state temperature is achieved when the laser pulse is much longer than the dissipation rate. The steady-state temperature inside the cluster is assumed to be uniform and unchanging because of collective heating95-96 and is achieved when the rate of energy absorption is equal to the rate of heat loss. Outside the cluster the temperature drops, and its localization length depends on the size of the cluster (𝑟𝑐).74 The temperature when the system is not at steady-state (short pulse light excitation) is given by equation 5. Here, the approximation 𝑒 ―𝐷𝑡 ≈ 1 ― 𝐷𝑡 is used with substitution of the pulse width (p) for time.

𝑇(𝜏) ― 𝑇𝑜 = 𝐺𝜏𝑝 =

𝐼𝑜𝜎𝑎𝑏𝑠𝑁𝑡𝑜𝑡𝜏𝑝 𝜌𝑐𝑉𝑐𝐶𝑐

Energy Balance Model Fit to the Experimental Data


(5)


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The rate of heat loss, D, was determined by plotting ln (𝑇 ― 𝑇𝑜) versus time. The resultant plot is linear with the slope equal to D. Such a plot is shown in the supporting information Figure S10 where D is determined to be 0.1582 ± 0.0009 μs-1. The characteristic heat dissipation time (τd) is 6.32 ± 0.03 μs. The temperature drops away from the cluster is expected to drop off with a 1/r dependence. This means that the temperature drops by a factor of 2 every cluster radius away from the cluster.94 The distance between the hot and cold behavior, L as the fitting parameter, is defined to be around 6R at which the system shows an adiabatic behavior and temperature drops by a factor of ~100 that gives 0.12 W/m-K for the thermal conductivity of the surrounding medium when a disk height of 100 nm and a cluster radius of 1200 nm is used. This small thermal conductivity agrees with the theoretical simulation and shows that the UCNP cluster is generally surrounded by air because the heat dissipation to the surrounding is extremely sluggish. The solid lines in Figure 3b is our fit to the data using equation 2 and D equal to 0.1582 μs-1. The rate of energy absorption (G) is determined using equation

𝐼0𝜎𝑎𝑏𝑠(𝜆) 𝑁𝑡𝑜𝑡 𝑚𝑐𝐶𝑝,𝑐

. The laser

intensity (Io) is measured as a function of pulse width. The absorption cross section is given by 𝜎𝑎𝑏𝑠 𝜀𝑒𝑓𝑓 3/2

[ ]

= 0.43(𝑛𝑚 ―1)𝑟3

𝜀𝑤

= 24 𝑛𝑚2 where εeff is effective dielectric constant of gold particles on

a UCNP in air and εw is the dielectric constant of water (εw = 1.8). The effective dielectric constant of a spherical particle on a substrate in air is given by 𝜀𝑒𝑓𝑓 =

1 ― 𝜂/16 1 + 𝜂/8

𝜀𝑏 ― 𝜀𝑠

where 𝜂 = 𝜀𝑏 + 𝜀𝑠 = ―0.27 and

εs is the dielectric constant of the substrate (UCNP) equal to ~1.8 and εb is the dielectric constant of air (εb = 1).97-98 The mass of the UCNP cluster (1.5 x 10-12 g) is given by UCNP density (4.8 g/cm3)99 and the cluster volume (30 UCNPs x 1 x 10-14 cm3/particle). The heat capacity of the UCNP is ~0.5 J/g-K (Cv = 3*6*R). The laser intensity is given by 𝐼𝑜 = 𝐼𝜏𝜏𝑝 where I is equal to

(

3.0 𝑥 106

𝑊

2

𝑚 ― 𝜇𝑠

) and τ

p

is the laser pulse width in s. The temperature change during and after

the laser pulse has been modeled using equations 2 and 3. The best fit, using the parameters above, yields a surface concentration of 1.75 x 1014 nanoparticles/m2 instead of the estimated surface concentration of 4 x 1015 nanoparticles/m2. This result suggests that there is some variation in the surface concentration of gold nanoparticles between UCNPs and that there is a significant air void between UCNPs particles in agreement with the slow cooling rate. We tested the hypothesis that there are significant air voids between the UCNPs by measuring and comparing the steady-state temperature when the sample is immersed in air and water. This data is shown in the supporting information (Figure S9). The ratio of steady-state temperatures is given by

Δ𝑇𝑎𝑖𝑟 Δ𝑇𝑤

=

𝑘𝑤 𝑘𝑎𝑖𝑟

where Δ𝑇𝑎𝑖𝑟 is the steady-state temperature with air

immersion, 𝑘𝑤 is the average thermal conductivity of the surroundings when immersed in water and 𝑘𝑎𝑖𝑟 is the average thermal conductivity of the surroundings when immersed in air. The weighted average in water (air) is given by 𝑘𝑤 = 𝑥1𝑘𝑤 + (1 ― 𝑥1)𝑘𝑔 and 𝑘𝑎𝑖𝑟 = 𝑥1𝑘𝑎𝑖𝑟 + (1 ― 𝑥1) 𝑘𝑔 respectively where 𝑘𝑤 is the thermal conductivity of water (0.6 W/m-K), 𝑘𝑔 is the thermal conductivity of glass (1.4 W/m-K) and 𝑘𝑎𝑖𝑟 is the thermal conductivity of air (0.024 W/m-K). The steady-state temperature ratio is ~10 (see Figure S9). This gives a value of 0.97 for 𝑥1 and an average thermal conductivity of the surroundings when immersed in air of 0.06. This low value for the thermal conductivity supports our hypothesis that there exist significant air voids between


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the UCNPs.

Theoretical Simulation In order to figure out the underlying theoretical considerations of the present work, we theoretically simulate the plasmonic effects along with time-resolved thermal dissipation of the system of gold decorated UCNPs using finite element method and the software COMSOL Multiphysics. To account for the time-resolved simulation, one needs to numerically solve the time-dependent heat equation: 𝜌(𝑟)𝑐(𝑟)

∂𝑇(𝑟,𝑡) ∂𝑡

= ∇ ∙ (𝑘(𝑟)∇𝑇(𝑟,𝑡)) + 𝑄ℎ𝑒𝑎𝑡𝑖𝑛𝑔(𝑟,𝑡) = 0

(6)

Independent variables 𝑟 and 𝑡 are position and time, respectively. Thermal parameters 𝑘, 𝜌, and 𝑐 are locally defined in the entire domain of the simulation. The thermal parameters used in our calculations are summarized in Table 1. In equation 6, 𝑄ℎ𝑒𝑎𝑡𝑖𝑛𝑔 is the time dependent volumetric heat. 𝑄ℎ𝑒𝑎𝑡𝑖𝑛𝑔, in general, is the sum of resistive and magnetic losses as a result of light-matter interaction. Magnetic losses are orders of magnitude less than resistive losses and can be conveniently ignored. Resistive losses are derived from plasmonic absorption of AuNPs because these NPs are the only material in the system with non-zero imaginary part of permittivity. We can define 𝑄ℎ𝑒𝑎𝑡𝑖𝑛𝑔(𝑟,𝑡) for ensemble of AuNPs as:100 𝑄ℎ𝑒𝑎𝑡𝑎𝑛 𝑖𝑛𝑔(𝑟) = 𝜌𝐴𝑢𝑁𝑃(𝑟) ∙ 𝜎𝑎𝑏𝑠 ― 𝐴𝑢𝑁𝑃 ∙ 𝐼𝑝𝑢𝑚𝑝(𝑟)

(7)

where 𝜎𝑎𝑏𝑠 ― 𝐴𝑢𝑁𝑃 is the plasmonic absorption cross section of one AuNP. This parameter can be determined according to Mie theory (See Figure S6). 𝐼𝑝𝑢𝑚𝑝(𝑟) is the pump laser intensity. In our simulation, we consider the gaussian distributed pump laser with a spot size of 2000 nm like in the experiment. 𝜌𝐴𝑢𝑁𝑃(𝑟) is the number density of nanoparticles determined by the TEM image which is approximately equal to 4.6 × 1023𝑚 ―3. AuNPs with diameter 10𝑛𝑚 are scattered around each UCNP. In the simulation, we take each UCNP surrounded by a 10𝑛𝑚 thick layer to account for the region where AuNPs are located. Equation 7 with 𝜌𝐴𝑢𝑁𝑃(𝑟) = 4.6 × 1023𝑚 ―3 is applied to the layer. UCNPs are spread on the glass substrate and exposed to air. The thermal conductivity of the system is considered to be a crucial factor in cooling rate of the system. We account for the thermal conductivity of glass substrate and surrounding air with the parameters given in Table 1. To calculate for the average thermal conductivity of system, one can start with equally weighted average of glass and air components. In our calculations, this equally weighted average gave a cooling rate that was much faster than the results in practice. Therefore, we used a weighted average of 0.12 W/m.k that gave relatively comparable decay rate from a large cluster of gold decorated UCNPs. We argue that this weighted average better describes our system since the UCNPs are not tightly close packed and they are randomly placed on the glass substrate. The weighted average accounts for the air that is trapped inside the cluster and surrounds each upconverting nanoparticle.



Page 12 of 23

Table 1: Thermal parameters used in the simulation. UCNP Glass Air

𝜌 (𝑘𝑔/𝑚3 ) 4760 2700 1.205

𝐶 (𝐽/(𝑘𝑔 ∙ 𝐾)) 720 730 1005

𝑘 (𝑊/(𝑚 ∙ 𝐾)) 3.7 1.4 0.024

 (m2/s) x106 1.0 0.5 20

We first calculated the temperature map and profile of a single, a small circular cluster, a linear cluster and a large cluster of gold decorated UCNPs on a glass substrate exposed to air. Figure 4a-e shows the theoretical calculation of time-resolved temperature graphs for single UCNP. The single UCNP is assumed to be isolated and is located on a cover slip. Figure 4a and b show the schematic shape of a ~300 nm diameter and ~100 nm thick upconverting nanoparticle that is coated with ~10 nm gold nanoparticles from different angles. Figure 4c gives the calculated temperature as a function of distance in x and y-axis for a single UCNP under 532 nm pulsed laser irradiation. The temperature versus distance profile of a line passing through the center of nanostructure for a single gold decorated upconverting nanoparticle is shown in 4e. The steady state temperature increases where the temperature of UCNP reaches its maximum is ~8 K. For a small cluster of UCNPs on a glass substrate surrounded by air the profile and the maximum temperature is different. Figure 4f and g depict the schematic shape of a ~900 nm diameter and ~100 nm thick upconverting nanoparticle that is coated with gold nanoparticles. Figure 4h gives the thermal mapping of heat dissipation as a function of distance in x and y-axis for the cluster of UCNPs under 532 nm pulsed laser excitation. Figure 4i shows the time-resolved temperature profile of cluster of UCNPs under 532 nm pulsed laser. The temperature versus distance profile of a line passing through the center of the cluster shows a maximum temperature of 27 degrees and the thermal decay that scales with the radius of a cluster of UCNPs (Figure 4j). Due to the asymmetry of the linear cluster, two different thermal profiles along x and yaxis is observed. Figure 4k-o shows the calculated graphs for a linear cluster of UCNPs. The small linear cluster of UCNPs is ~2000 nm in length and ~300 nm in width (Figure 4k and l). Figure 4m gives the thermal mapping of heat dissipation as a function of distance in x and y-axis for the linear cluster of UCNPs under 532 nm modulated laser. The time-resolved temperature profile of the linear cluster under 532 nm pulsed laser is given in 4n. Figure 4o shows the temperature versus distance profile of a line passing through different x and y-axis with a maximum temperature of ~23 degrees and the thermal decay that is shown with two different colors in Figure 4o. For a large cluster of UCNP on a glass substrate, the maximum temperature and profile are a lot more similar to our experimental results than previous systems. Figure 4p-t shows the theoretical calculation for the ~3 µm cluster of UCNPs. The large cluster of UCNPs is assumed to be arranged tightly such that little empty space exists between the UCNPS as shown in Figure 4p and 4q. Figure 4r gives the thermal mapping of the cluster as a function of distance in x and y-axis at the steady state where the system reaches equilibrium. Figure 4s shows the time-resolved temperature profile of large cluster of UCNPs under 532 nm pulsed laser at the steady state. The temperature versus distance profile of a line passing through the center of the cluster shows a maximum temperature of ~80 degrees and the thermal decay that scales with the radius of a cluster of UCNPs and has an FWHM of ~ 4 µm (Figure 4t).


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Figure 4. Theoretical calculation of time-resolved temperature graphs for single, a small circular cluster, a linear cluster and a large cluster of gold decorated upconverting nanoparticle. a and b for a single UCNP, c, and g for a circular cluster, k and l for linear cluster and p and q for a large cluster of gold decorated UCNP from different angles. c, h, m, and r) Calculated temperature as a function of distance for a single, a small circular cluster, a linear cluster and a large cluster of gold decorated upconverting nanoparticle. d, I, n and s) time-resolved temperature profile of single, a small circular cluster, a linear cluster and a large cluster of gold decorated upconverting nanoparticle under 532 nm pulsed laser. e, j, o, and t) temperature versus distance profile of a line passing through the center of a single, a small circular cluster, a linear cluster and a large cluster of gold decorated upconverting nanoparticle. Thermal Diffusion Model The general solution for the thermal time constants in one dimension for a semi-infinite 𝑥 medium exposed to a sudden temperature change at its surface is 𝑇(𝑥,𝑡) = 𝑇1 + (𝑇𝑜 ― 𝑇1)erf (2 𝛼𝑡 𝑘

) where  is the thermal diffusivity of the semi-infinite medium and is given by 𝛼 = 𝜌𝐶.101 Here, k is the thermal conductivity,  is the density and C is the heat capacity (J/g-K). The specific solution satisfying boundary conditions in two-dimensions is a shrinking Gaussian and is given by equation 8.



1 ∆𝑇(𝑡) = 4𝜋𝛼𝑡

∬

∞

(

∆𝑇𝑠𝑠(exp ― ―∞

Page 14 of 23

𝑥2 + 𝑦2 4𝛼𝑡

)

(8)

𝑑𝑥𝑑𝑦

At the maximum temperature change (x,y equal to 0), this equation reduces to ∆𝑇(𝑡) = (𝐹𝑊𝐻𝑀)2

∆𝑇𝑠𝑠Κ Κ+𝑡

where

Κ = 2𝛼(2.3546)2 . The full width at half maximum (FWHM) of the two-dimensional Gaussian function is established at the steady-state temperature change of TSS. This solution gives a power law temperature decay that varies as 1/t after steady-state temperature is established and the laser is switched off and is inversely proportional to the thermal diffusivity of the semi-infinite medium. The solution for the maximum temperature change when the laser is first switched on is given by Κ ∆𝑇(𝑡) = ∆𝑇𝑠𝑠(1 ― Κ + 𝑡). The FWHM for the steady-state temperature is approximately 4R where 8𝑅2

R is the cluster radius.94 This gives a value for K of (2.3546)2𝛼 where K directly varies with the square of the cluster radius and inversely with the thermal diffusivity. Comparison between Experimental, Simulation, and Model Results Figure 5a shows the simulated results for the large cluster shown in figure 4r with the fit using the thermal diffusion model. The power law prediction from the thermal diffusion model fits the simulated results extremely well with a value for K of 3.8 s. This gives 0.4 x 10-6 m2/s for the thermal diffusivity using 4 m for the FWHM of the thermal profile (see Figure 4t). This value for the thermal diffusivity is slightly lower than the thermal diffusivity for glass (see Table 1) and a factor of ~50 smaller than the expected value of 20 x 10-6 m2/s for air (the largest thermal diffusivity should dominate). Figure 5b compares the thermal profile for different thermal diffusivities (air, shown in black, compared to the best fit to experimental data, shown in red). Our experimental and simulated results do not support a thermal diffusion model where the heat flow is dependent upon a single parameter (thermal diffusivity). The thermal diffusivity is a ratio of two parameters (thermal conductivity and heat capacity). The thermal conductivity is related to the heat dissipation process while the heat capacity is related to heat generation. Heat is stored in the vibrational modes of a material that has a certain heat capacity. The thermal transfer to the 𝑑𝑇 surroundings (cold reservoir) is described by Fourier’s law (𝑞 = ―𝑘𝐴𝑑𝑥 ) where the heat transfer through a cross section area A is dependent upon the thermal conductivity and the temperature gradient. In this case, the fitting parameter f of 0.4 x 10-6 m2/s for the thermal diffusivity is really 𝑘𝑠

equal to 𝛼𝑓 = 𝜌 𝐶 where 𝑘𝑠 is the average thermal conductivity of the surroundings and 𝜌𝑐𝐶𝑐 is the 𝑐 𝑐

average density and heat capacity of the heated object. Both the simulated data and the experimental data agree with the steady-state temperature as well as the linear dependence with cluster size shown in figure 5c. The black squares are the steady-state temperature predictions from the simulation superimposed on the model predictions using equation 4.


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Figure 5. a) Numerical calculation and fitted power law model for rise and decay profiles of 3 m cluster of UCNPs for a pulse width of 25 s, b) numerical simulation of thermal profiles for 3 µm cluster under different thermal conductivities, c) maximum steady state temperature of clusters of different sizes and theoretical linear result obtained from energy balance equation model showing the linear relationship between T and radius of the cluster.

Conclusion We have developed a new time-resolved temperature measurement technique which relies on temperature-jump luminescence thermometry using NaYF4:Yb3+: Er3+ nanocrystals. This technique is based on optical thermometry using UCNPs and does not have the shortcomings related to changes in the optical properties of the surrounding dielectric environment. We have prepared gold decorated UCNPs that act as a single heater-thermometer system in both homogenous and heterogenous environments and does not require sampling the optical properties of the local environment to determine the local temperature. The results of time-resolved temperature-jump measurements from a cluster of decorated UCNPs are compared to simulated thermal transfer data generated using finite element methods. The simulated data shows that temperature dissipation follows a power law where the temperature change is inversely related with time. This result agrees with a thermal diffusion model where a semi-infinite medium is exposed to a sudden temperature change at its surface, but the simulated results do not agree that the heat transfer process can be described by a single thermal diffusivity parameter. In contrast to the thermal diffusion model, our experimental and simulation data show that the heat generation and dissipation process is described by an energy balance model where the thermal conductivity for heat dissipation and heat capacity of the heated object are separated. The experimental data agrees with the prediction of the energy balance model where the temperature is expected to increase and decay with time as a single exponential.

Supporting Information Photoluminescence and SEM images of UCNPs; Calibration curve of UCNPs decorated with gold nanoparticles; Extinction spectrum of UCNPs; Luminescence ratio thermometry protocol; Lifetime versus excitation pulse widths; Numerical calculation of temperature; Schematic



diagram of numerical calculation; Energy balance equation model; Effect of surrounding medium; Model fit to the experimental data for the rate of eat loss

Corresponding Author Email:[email protected] ORCID: Hugh Hill Richardson: 0000-0002-7338-4645

Notes Authors declare no competing financial interest Acknowledgement The authors acknowledge Ohio University Condensed Matter and Surface Science Program and Nanoscale Quantum phenomena Institute for financial support. Authors also thank Donald Carter and Dr. Eric Stinaff for their help with time-resolved instruments.

References (1) (2)

(3)

(4) (5) (6) (7)

Alaulamie, A. A.; Baral, S.; Johnson, S. C.; Richardson, H. H., Targeted Nanoparticle Thermometry: A Method to Measure Local Temperature at the Nanoscale Point Where Water Vapor Nucleation Occurs. Small 2017, 13, 1601989. Alper, J.; Schmidt, A.; Hamad-Schifferli, K., Thermal Transport from Gold Nanorod to Solvent, an Investigation of Ligand Effects by Ultrafast Laser Spectroscopy. ASME. ASME proceedings, 13: Nano-Manufacturing Technology; and Micro and Nano Systems, Parts A and B 2008, 1269-1271. Angadi, M. A.; Watanabe, T.; Bodapati, A.; Xiao, X. C.; Auciello, O.; Carlisle, J. A.; Eastman, J. A.; Keblinski, P.; Schelling, P. K.; Phillpot, S. R., Thermal Transport and Grain Boundary Conductance in Ultrananocrystalline Diamond Thin Films. J. Appl. Phys. 2006, 99, 114301. Bodapati, A.; Schelling, P. K.; Phillpot, S. R.; Keblinski, P., Vibrations and Thermal Transport in Nanocrystalline Silicon. Phys. Rev. B 2006, 74, 245207. Cahill, D. G.; Goodson, K.; Majumdar, A., Thermometry and Thermal Transport in Micro/Nanoscale Solid-State Devices and Structures. J. Heat Transfer 2002, 124, 223241. Cai, W.; Moore, A. L.; Zhu, Y.; Li, X.; Chen, S.; Shi, L.; Ruoff, R. S., Thermal Transport in Suspended and Supported Monolayer Graphene Grown by Chemical Vapor Deposition. Nano Lett. 2010, 10, 1645-1651. Eastman, J. A.; Phillpot, S. R.; Choi, S. U. S.; Keblinski, P., Thermal Transport in Nanofluids. Annu. Rev. Mater. Res. 2004, 34, 219-246.


Page 16 of 23

Page 17 of 23 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60


(8) (9) (10) (11) (12) (13) (14) (15)

(16) (17) (18)

(19) (20) (21) (22)

Gandolfi, M.; Crut, A.; Medeghini, F.; Stoll, T.; Maioli, P.; Vallee, F.; Banfi, F.; Del Fatti, N., Ultrafast Thermo-Optical Dynamics of Plasmonic Nanoparticles. J. Phys. Chem. C 2018, 122, 8655-8666. Ganser, A.; Benner, D.; Waitz, R.; Boneberg, J.; Scheer, E.; Leiderer, P., Time-Resolved Optical Measurement of Thermal Transport by Surface Plasmon Polaritons in Thin Metal Stripes. Appl. Phys. Lett. 2014, 105, 191119. Ge, Z., Nanoscale Thermal Transport at Solid-Liquid Interfaces, University of Illinois at Urbana-Champain, 2006. Harata, A.; Taura, J.; Sugiyama, T., Heat Transport in Nano-Environments Adjacent to Metal-Liquid Interfaces: Ultrafast Photothermal Study. Anal. Sci. 2001, 17, 197-200. Hu, L.; Desai, T.; Keblinski, P., Thermal Transport in Graphene-Based Nanocomposite. J. Appl. Phys. 2011, 110, 033517. Chen, C.; Vasudevan, I.; Du, Z. D.; Xu, X. F.; Pan, L., Ultrafast Time-Resolved Measurement of Energy Transport at the Metal-Liquid Interface. Appl. Phys. Lett. 2018, 112, 253105. Girard, A.; Gehan, H.; Mermet, A.; Bonnet, C.; Lerme, J.; Berthelot, A.; Cottancin, E.; Crut, A.; Margueritat, J., Acoustic Mode Hybridization in a Single Dimer of Gold Nanoparticles. Nano Lett. 2018, 18, 3800-3806. Khan, T. Z.; Donfack, P.; Namboodiri, M.; Kazemi, M. M.; Born, S.; Wagner, V.; Materny, A., Femtosecond Time-Resolved Transient Absorption Spectroscopy with SubDiffraction-Limited Spatial Resolution Reveals Accelerated Exciton Loss at GoldPoly(3-Hexylthiophene) Interface. J. Phys. Chem. C 2018, 122, 3454-3462. Zhu, J.; Wu, X. W.; Lattery, D. M.; Zheng, W.; Wang, X. J., The Ultrafast Laser PumpProbe Technique for Thermal Characterization of Materials with Micro/Nanostructures. Nanosc. Micros. Therm. 2017, 21, 177-198. Valley, D. T.; Ferry, V. E.; Flannigan, D. J., Imaging Intra- and Interparticle AcoustoPlasmonic Vibrational Dynamics with Ultrafast Electron Microscopy. Nano Lett. 2016, 16, 7302-7308. Chen, J.; Zhang, Y.; Kohler, B., Excited States in DNA Strands Investigated by Ultrafast Laser Spectroscopy. Photoinduced Phenomena in Nucleic Acids II: DNA Fragments and Phenomenological Aspects, Barbatti, M.; Borin, A. C.; Ullrich, S., Eds. Springer International Publishing: Cham, 2015, 39-87. Major, T. A.; Lo, S. S.; Yu, K.; Hartland, G. V., Time-Resolved Studies of the Acoustic Vibrational Modes of Metal and Semiconductor Nano-Objects. J. Phys. Chem. Lett. 2014, 5, 866-874. Knappenberger, K. L.; Dowgiallo, A. M.; Chandra, M.; Jarrett, J. W., Probing the Structure-Property Interplay of Plasmonic Nanoparticle Transducers Using Femtosecond Laser Spectroscopy. J. Phys. Chem. Lett. 2013, 4, 1109-1119. Siems, A.; Weber, S. A. L.; Boneberg, J.; Plech, A., Thermodynamics of Nanosecond Nanobubble Formation at Laser-Excited Metal Nanoparticles. New J. Phys. 2011, 13, 043018. Tang, J.; Yu, P.; Tai, P. T.; Lin, S. H., Photoinduced Ultrafast Structural Dynamics of Nanomaterials. Proc. SPIE 7214, Ultrafast Phenomena in Semiconductors and Nanostructure Materials XIII, 2009, 72140F.



(23) (24)

(25) (26) (27)

(28) (29) (30) (31) (32) (33) (34) (35)

(36) (37)

Petrova, H., et al., Time-Resolved Spectroscopy of Silver Nanocubes: Observation and Assignment of Coherently Excited Vibrational Modes. J. Chem. Phys. 2007, 126, 094709. McNeill, C. R.; Westenhoff, S.; Groves, C.; Friend, R. H.; Greenham, N. C., Influence of Nanoscale Phase Separation on the Charge Generation Dynamics and Photovoltaic Performance of Conjugated Polymer Blends: Balancing Charge Generation and Separation. J. Phys. Chem. C 2007, 111, 19153-19160. Hartland, G. V., Coherent Excitation of Vibrational Modes in Metallic Nanoparticles. Annu. Rev. Phys. Chem. 2006, 57, 403-430. Sanii, L. S.; Schill, A. W.; Moran, C. E.; El-Sayed, M. A., The ProtonationDeprotonation Kinetics of the Protonated Schiff Base in Bicelle Bacteriorhodopsin Crystals. Biophys. J. 2005, 89, 444-451. Wraback, M.; Garrett, G. A.; Sampath, A. V.; Collins, C. J.; Rudin, S.; Shen, H., Fundamental Studies of Nanoscale Phenomena in Ultraviolet Photonic Materials and Devices. Quantum Sensing and Nanophotonic Devices Ii, Razeghi, M.; Brown, G. J., Eds. Spie-Int Soc Optical Engineering: Bellingham, 2005; 5732, 205-216. Hartland, G. V.; Hu, M.; Hillyard, P.; Pertova, H.; Wang, X., Coherent Excitation of Vibrational Modes in Nanospheres and Nanorods. Phys. Chem. Interfaces. Nanomat. 2004,. 5513, 48-55. Wang, J. P.; El-Sayed, M. A., Time-Resolved Fourier Transform Infrared Spectroscopy of the Polarizable Proton Continua and the Proton Pump Mechanism of Bacteriorhodopsin. Biophys. J. 2001, 80, 961-971. Wang, J. P.; Song, L.; Zou, B. S.; El-Sayed, M. A., Time-Resolved Fourier-Transform Infrared and Visible Luminescence Spectroscopy of Photoexcited Porous Silicon. Phys. Rev. B 1999, 59, 5026-5031. Logunov, S.; Green, T.; Marguet, S.; El-Sayed, M. A., Interfacial Carriers Dynamics of Cds Nanoparticles. J. Phys. Chem. A 1998, 102, 5652-5658. Martini, I.; Hodak, J. H.; Hartland, G. V., Probing Photo-Induced Electron Transfer Reactions at Semiconductor-Liquid Interfaces. Laser Techniques for Condensed-Phase and Biological Systems, 1998, 3273, 24-33. Nguyen, S. C.; Zhang, Q.; Manthiram, K.; Ye, X.; Lomont, J. P.; Harris, C. B.; Weller, H.; Alivisatos, A. P., Study of Heat Transfer Dynamics from Gold Nanorods to the Environment Via Time-Resolved Infrared Spectroscopy. ACS Nano 2016, 10, 2144-2151. Kimling, J.; Philippi-Kobs, A.; Jacobsohn, J.; Oepen, H. P.; Cahill, D. G., Thermal Conductance of Interfaces with Amorphous SiO2 Measured by Time-Resolved MagnetoOptic Kerr-Effect Thermometry. Phys. Rev. B 2017, 95, 10, 184305. Belliard, L.; Fretigny, C.; Charron, E.; Vincent, S.; Perrin, B.; Fournier, D., Determination of the Thermal Diffusivity of Bulk and Layered Samples by Time Domain Thermoreflectance: Interest of Lateral Heat Diffusion Investigation in Nanoscale Time Range. J. Appl. Phys. 2015, 117, 9, 065306. Cahill, D. G.; Braun, P. V.; Chen, G.; Clarke, D. R.; Fan, S.; Goodson, K. E.; Keblinski, P.; King, W. P.; Mahan, G. D.; Majumdar et al, A., Nanoscale Thermal Transport. II. 2003–2012. Appl. phys. rev. 2014, 1, 011305. Harikrishna, H.; Ducker, W. A.; Huxtable, S. T., The Influence of Interface Bonding on Thermal Transport through Solid-Liquid Interfaces. Appl. Phys. Lett. 2013, 102, 251606.


Page 18 of 23

Page 19 of 23 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60


(38) (39) (40) (41) (42) (43) (44) (45) (46) (47) (48) (49) (50)

(51) (52) (53) (54) (55)

Feser, J. P.; Cahill, D. G., Probing Anisotropic Heat Transport Using Time-Domain Thermoreflectance with Offset Laser Spots. Rev. Sci. Instrum. 2012, 83, 104901. Hsieh, W.-P.; Cahill, D. G., Ta and Au(Pd) Alloy Metal Film Transducers for TimeDomain Thermoreflectance at High Pressures. J. Appl. Phys. 2011, 109, 113520. Hsieh, W.-P.; Lyons, A. S.; Pop, E.; Keblinski, P.; Cahill, D. G., Pressure Tuning of the Thermal Conductance of Weak Interfaces. Phys. Rev. B 2011, 84, 184107. Hsieh, W.-P.; Losego, M. D.; Braun, P. V.; Shenogin, S.; Keblinski, P.; Cahill, D. G., Testing the Minimum Thermal Conductivity Model for Amorphous Polymers Using High Pressure. Phys. Rev. B 2011, 83, 174205. Losego, M. D.; Moh, L.; Arpin, K. A.; Cahill, D. G.; Braun, P. V., Interfacial Thermal Conductance in Spun-Cast Polymer Films and Polymer Brushes. Appl. Phys. Lett. 2010, 97, 011908. Oh, D. W.; Ko, C.; Ramanathan, S.; Cahill, D. G., Thermal Conductivity and Dynamic Heat Capacity across the Metal-Insulator Transition in Thin Film VO2. Appl. Phys. Lett. 2010, 96, 151906. Yang, H. S.; Cahill, D. G.; Liu, X.; Feldman, J. L.; Crandall, R. S.; Sperling, B. A.; Abelson, J. R., Anomalously High Thermal Conductivity of Amorphous Si Deposited by Hot-Wire Chemical Vapor Deposition. Phys. Rev. B 2010, 81, 104203. Cahill, D. G.; Melville, A.; Schlom, D. G.; Zurbuchen, M. A., Low Thermal Conductivity of Csbinb2o7 Epitaxial Layers. Appl. Phys. Lett. 2010, 96, 121903. Wang, Y.; Park, J. Y.; Koh, Y. K.; Cahill, D. G., Thermoreflectance of Metal Transducers for Time-Domain Thermoreflectance. J. Appl. Phys. 2010, 108, 043507. Hsieh, W. P.; Chen, B.; Li, J.; Keblinski, P.; Cahill, D. G., Pressure Tuning of the Thermal Conductivity of the Layered Muscovite Crystal. Phys. Rev. B 2009, 80, 180302. Persson, A. I.; Koh, Y. K.; Cahill, D. G.; Samuelson, L.; Linke, H., Thermal Conductance of Inas Nanowire Composites. Nano Lett. 2009, 9, 4484-4488. Chiritescu, C.; Mortensen, C.; Cahill, D. G.; Johnson, D.; Zschack, P., Lower Limit to the Lattice Thermal Conductivity of Nanostructured Bi2te3-Based Materials. J. Appl. Phys. 2009, 106, 073503. Koh, Y. K.; Singer, S. L.; Kim, W.; Zide, J. M. O.; Lu, H.; Cahill, D. G.; Majumdar, A.; Gossard, A. C., Comparison of the 3 Omega Method and Time-Domain Thermoreflectance for Measurements of the Cross-Plane Thermal Conductivity of Epitaxial Semiconductors. J. Appl. Phys. 2009, 105, 054303. Koh, Y. K.; Cao, Y.; Cahill, D. G.; Jena, D., Heat-Transport Mechanisms in Superlattices. Adv. Funct. Mater. 2009, 19, 610-615. Rawat, V.; Koh, Y. K.; Cahill, D. G.; Sands, T. D., Thermal Conductivity of (Zr,W)N/Scn Metal/Semiconductor Multilayers and Superlattices. J. Appl. Phys. 2009, 105, 024909. Liu, X.; Feldman, J. L.; Cahill, D. G.; Crandall, R. S.; Bernstein, N.; Photiadis, D. M.; Mehl, M. J.; Papaconstantopoulos, D. A., High Thermal Conductivity of a Hydrogenated Amorphous Silicon Film. Phys. Rev. Lett. 2009, 102, 035901. Hsieh, W.-P.; Chen, B.; Li, J.; Keblinski, P.; Cahill, D. G., Pressure Tuning of the Thermal Conductivity of the Layered Muscovite Crystal. Phys. Rev. B 2009, 80, 180302. Kang, K.; Koh, Y. K.; Chiritescu, C.; Zheng, X.; Cahill, D. G., Two-Tint Pump-Probe Measurements Using a Femtosecond Laser Oscillator and Sharp-Edged Optical Filters. Rev. Sci. Instrum. 2008, 79, 114901.



(56)

(57) (58) (59) (60) (61)

(62)

(63) (64)

(65) (66) (67) (68)

(69)

Lopez-Honorato, E.; Chiritescu, C.; Xiao, P.; Cahill, D. G.; Marsh, G.; Abram, T. J., Thermal Conductivity Mapping of Pyrolytic Carbon and Silicon Carbide Coatings on Simulated Fuel Particles by Time-Domain Thermoreflectance. J. Nucl. Mater. 2008, 378, 35-39. Highland, M.; Gundrum, B. C.; Koh, Y. K.; Averback, R. S.; Cahill, D. G., BallisticPhonon Heat Conduction at the Nanoscale as Revealed by Time-Resolved X-Ray Diffraction and Time-Domain Thermoreflectance. Phys. Rev. B 2007, 76, 075337. Cahill, D. G., Analysis of Heat Flow in Layered Structures for Time-Domain Thermoreflectance. Rev. Sci. Instrum. 2004, 75, 5119-5122. Bruetzel, L. K.; Walker, P. U.; Gerling, T.; Dietz, H.; Lipfert, J., Time-Resolved SmallAngle X-Ray Scattering Reveals Millisecond Transitions of a DNA Origami Switch. Nano Lett. 2018, 18, 2672-2676. Michelsen, H. A.; Schulz, C.; Smallwood, G. J.; Will, S., Laser-Induced Incandescence: Particulate Diagnostics for Combustion, Atmospheric, and Industrial Applications. Prog. Energy Combust. Sci. 2015, 51, 2-48. Caetano, B. L.; Meneau, F.; Santilli, C. V.; Pulcinelli, S. H.; Magnani, M.; Briois, V., Mechanisms of Sno2 Nanoparticles Formation and Growth in Acid Ethanol Solution Derived from Saxs and Combined Raman-Xas Time-Resolved Studies. Chem. Mater. 2014, 26, 6777-6785. Krishna, K. S.; Navin, C. V.; Biswas, S.; Singh, V.; Ham, K.; Bovenkamp, G. L.; Theegala, C. S.; Miller, J. T.; Spivey, J. J.; Kumar, C., Millifluidics for Time-Resolved Mapping of the Growth of Gold Nanostructures. J. Am. Chem. Soc. 2013, 135, 54505456. St John, S.; Nan, Z. P.; Hu, N. P.; Schaefer, D. W.; Angelopoulos, A. P., A NanoscaleModified Lamer Model for Particle Synthesis from Inorganic Tin-Platinum Complexes. J. Mat. Chem. A 2013, 1, 8903-8916. Ibrahimkutty, S.; Wagener, P.; Menzel, A.; Plech, A.; Barcikowski, S., Nanoparticle Formation in a Cavitation Bubble after Pulsed Laser Ablation in Liquid Studied with High Time Resolution Small Angle X-Ray Scattering. Appl. Phys. Lett. 2012, 101, 103104. Plech, A.; Ihee, H.; Cammarata, M.; Siems, A.; Kotaidis, V.; Ciesa, F.; Kim, J.; Kim, K. H.; Lee, J. H., Structural Kinetics in Protein-Coated Gold Nanoparticles Probed by TimeResolved X-Ray Scattering. Ultrafast Phenomena XVI, 2009; 92, 134-136. Plech, A.; Kotaidis, V.; Istomin, K.; Wulff, M., Small-Angle Pump-Probe Studies of Photoexcited Nanoparticles. J. Synchrotron Radiation 2007, 14, 288-294. Kagan, C. R.; Murray, C. B.; Bawendi, M. G., Long-Range Resonance Transfer of Electronic Excitations in Close-Packed Cdse Quantum-Dot Solids. Phys. Rev. B 1996, 54, 8633-8643. Wang, J. P.; Li, Y.; Hong, X. Y.; El-Sayed, M. A., Direct Observation of ChargeTransfer Dynamics in a Conjugated Conducting Polymer Poly (3-Octylthiophene)Fullerene Composite by Time-Resolved Infrared Spectroscopy. Phys. Rev. B 2001, 64, 235413. Wang, J. P.; El-Sayed, M. A., The Effect of Protein Conformation Change from Alpha(Ii) to Alpha(I) on the Bacteriorhodopsin Photocycle. Biophys. J. 2000, 78, 2031-2036.


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(70) (71) (72) (73)

(74) (75) (76) (77) (78) (79) (80)

(81) (82) (83)

(84) (85)

Hartland, G. V.; Qin, D.; Dai, H. L., Collisional Deactivation of Highly Vibrationally Excited No2 Monitored by Time-Resolved Fourier-Transform Infrared-Emission Spectroscopy. J. Chem. Phys. 1994, 100, 7832-7835. Hartland, G. V.; Qin, D.; Dai, H. L., State-to-State Rotational Energy-Transfer and Reaction with Ketene of Highly Vibrationally Excited b᷉1 B1 CH2 by Time-Resolved Fourier-Transform Emission-Spectroscopy. J. Chem. Phys. 1993, 98, 6906-6916. Hartland, G. V.; Xie, W.; Dai, H. L.; Simon, A.; Anderson, M. J., Time-Resolved Fourier-Transform Spectroscopy with 0.25 cm-1 Spectral and

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