Exploring Photothermal Pathways via in Situ Laser Heating in the Transmission Electron Microscope: Recrystallization, Grain Growth, Phase Separation, and Dewetting in Ag0.5Ni0.5 Thin Films

Wu, Yegang; Liu, Chenze; Moore, Terrence J.; Magel, Gregory A.; Garfinkel, David A.; Camden, Jon P.; Stanford, Michael G.; Duscher, Gerd; Rack, Philip D.

doi:10.1017/s1431927618015465

Cited by 24 publications

(32 citation statements)

References 42 publications

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“…S13). The above results show that such a process provided a green chemical separation for flavonoids with fewer steps and lower energy consumption than the traditional organic solvent extraction method, preparation liquid chromatography and capillary electrophoresis (Pyo et al, 2009;Liu et al, 2014;Wu et al, 2018b).…”

Section: Discussionmentioning

confidence: 76%

Competitive cocrystallization and its application in the separation of flavonoids

Xia

Wei

Chen

et al. 2021

Int Union Crystallogr J

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Recently, cocrystallization has been widely employed to tailor physicochemical properties of drugs in the pharmaceutical field. In this study, cocrystallization was applied to separate natural compounds with similar structures. Three flavonoids [baicalein (BAI), quercetin (QUE) and myricetin (MYR)] were used as model compounds. The coformer caffeine (CAF) could form cocrystals with all three flavonoids, namely BAI–CAF (cocrystal 1), QUE–CAF (cocrystal 2) and MYR–CAF (cocrystal 3). After adding CAF to methanol solution containing MYR and QUE (or QUE and BAI), cocrystal 3 (or cocrystal 2) preferentially formed rather than cocrystal 2 (or cocrystal 1), indicating that flavonoid separation could be achieved by competitive cocrystallization. After co-mixing the slurry of two flavonoids with CAF followed by centrifugation, the resolution ratio that could be achieved was 70–80% with purity >90%. Among the three cocrystals, cocrystal 3 showed the lowest formation constant with a negative Gibbs free energy of nucleation and the highest energy gap. Hirshfeld surface analysis and density of states analysis found that cocrystal 3 had the highest strong interaction contribution and the closest electronic density, respectively, followed by cocrystal 2 and cocrystal 1, suggesting CAF could competitively form a cocrystal with MYR much more easily than QUE and BAI. Cocrystallization is a promising approach for green and effective separation of natural products with similar chemical structures.

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Section: Discussionmentioning

confidence: 76%

Competitive cocrystallization and its application in the separation of flavonoids

Xia

Wei

Chen

et al. 2021

Int Union Crystallogr J

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“…The sample is irradiated with a fiber-coupled 1.58 eV laser diode with tunable optical power up to 215 mW focused to ~ 5 µm diameter. The sample is tilted at 30° and the unpolarized Gaussian laser spot is aligned and focused to the coincident (S)TEM electron point (see 58 for system details). The laser is operated in cw mode at 1.01 × 10 9 W/m 2 for all laser-on results presented here.…”

Section: Eel and Eeg Measurementsmentioning

confidence: 99%

“…Pulsed and continuous wave (cw) photothermal heating and excitation can both be achieved. In particular, we have studied the recrystallization, grain growth, phase separation, and dewetting of an Ag 0.5 Ni 0.5 film 58 , and resonant cw sEEG and sEEL in nanostructures resulting from a dewet silver film 59 .…”

mentioning

confidence: 99%

Near field excited state imaging via stimulated electron energy gain spectroscopy of localized surface plasmon resonances in plasmonic nanorod antennas

Collette

Garfinkel

et al. 2020

Sci Rep

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Continuous wave (cw) photon stimulated electron energy loss and gain spectroscopy (sEELS and sEEGS) is used to image the near field of optically stimulated localized surface plasmon resonance (LSPR) modes in nanorod antennas. An optical delivery system equipped with a nanomanipulator and a fiber-coupled laser diode is used to simultaneously irradiate plasmonic nanostructures in a (scanning) transmission electron microscope. The nanorod length is varied such that the m = 1, 2, and 3 LSPR modes are resonant with the laser energy and the optically stimulated near field spectra and images of these modes are measured. Various nanorod orientations are also investigated to explore retardation effects. Optical and electron beam simulations are used to rationalize the observed patterns. As expected, the odd modes are optically bright and result in observed sEEG responses. The m = 2 dark mode does not produce a sEEG response, however, when tilted such that retardation effects are operative, the sEEG signal emerges. Thus, we demonstrate that cw sEEGS is an effective tool in imaging the near field of the full set of nanorod plasmon modes of either parity. The localized surface plasmon resonances (LSPR) sustained in noble metal nanostructures have inspired many new concepts in fields such as photovoltaics 1-3 , photocatalysis 4-6 , biosensing 7-9 , readout strategies for quantum computing 10,11 , and terahertz optical 12-14 and magnetic meta atoms/materials 15-18. While standard far field optical scattering techniques are used to probe the resonance conditions of individual nanostructures as well as nanostructure ensembles, probing the resultant near field is often more challenging. Several techniques such as scanning near field optical microscopy (SNOM) 19-23 , photoemission electron microscopy (PEEM) 24,25 , and electron energy loss spectroscopy (EELS) 26-29 have been used to probe the near field distribution of LSPRs. Of the near field techniques, EELS is unique in that the swift electron acts like a white (spectrally broad) evanescent field and thus can excite the full plasmonic spectrum of both bright and dark modes with atomic scale resolution. To this end, EELS has been utilized to characterize individual nanoparticle LSPRs as well as surface plasmon polaritons (SPP) and in particular the LSPR modes in nanorods 30-41. Beyond standard EELS, photoinduced near field electron microscopy (PINEM) is used to image the near field of optically excited nanostructures 42-47. In PINEM, a pulsed laser photo-ejects electron beamlets or single electrons from the cathode, which are accelerated and arrive at the specimen synchronously to a second laser pulse that interacts with the sample. Thus PINEM enables the study of photoinduced near field phenomena at the nanoscale and the intense sample laser pulse (~ 1 × 10 15 W/m 2) induces photon stimulated electron energy loss (sEEL) and gain (sEEG) peaks. In addition to experimental demonstrations, several theoretical papers have described the sEEG and sEEL processes 48-51. Additionally, by...

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“…Using a 215 mW 785 nm single-mode fiber coupled laser diode producing an ~8 µm diameter Gaussian spot, Liu et al reported sEELS and EEGS responses of individual plasmonic nanoparticles [3]. By linearly varying the laser irradiance in the range of 0.5-4×10 8 W/m 2 , Liu et al were able to observe equivalent sEELS and EEGS probabilities without excessive heating.…”

Section: Statesmentioning

confidence: 99%

New Advances in Stimulated Electron Energy Gain and Loss Spectroscopy

Wolf¹,

Moore²,

Collette

et al. 2020

Microsc Microanal

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Exploring Photothermal Pathways via in Situ Laser Heating in the Transmission Electron Microscope: Recrystallization, Grain Growth, Phase Separation, and Dewetting in Ag_0.5Ni_0.5 Thin Films

Cited by 24 publications

References 42 publications

Competitive cocrystallization and its application in the separation of flavonoids

Competitive cocrystallization and its application in the separation of flavonoids

Near field excited state imaging via stimulated electron energy gain spectroscopy of localized surface plasmon resonances in plasmonic nanorod antennas

New Advances in Stimulated Electron Energy Gain and Loss Spectroscopy

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