journal article
Open Access
Feb 13, 2026
Analysis of photo-functional materials using momentum-resolved EELS
Abstract
Abstract
Momentum transfer (q)-resolved electron energy-loss spectroscopy (q-EELS) is a powerful tool for analyzing photo-functional materials. The technique’s application has been demonstrated in several recent studies. This study first investigated the anisotropic plasmon oscillations in Cs-doped hexagonal WO3, a near-infrared (NIR) shielding material, to understand the origin of its highly efficient light-scattering properties. This revealed how plasmon energies differ along different crystallographic directions, contributing to the broad NIR absorption capabilities of the material. Second, the study measured the q dispersion of carrier plasmons and thus quantified interactions (exchange–correlation effect) between carrier electrons in LaB6 crystals, another NIR shielding filter. This analysis provides critical insights into many-body effects not captured by the ideal free-electron gas model. Finally, the spatial spread sizes of excitons in anatase TiO2 were determined, establishing a correlation between the exciton size and the anisotropic photocatalytic activity of anatase TiO2. Collectively, this research demonstrates that q-EELS provides unique, q-dependent information on electronic excitations, deepening our understanding of the properties governing the performance of advanced materials.
Momentum transfer (q)-resolved electron energy-loss spectroscopy (q-EELS) is a powerful tool for analyzing photo-functional materials. The technique’s application has been demonstrated in several recent studies. This study first investigated the anisotropic plasmon oscillations in Cs-doped hexagonal WO3, a near-infrared (NIR) shielding material, to understand the origin of its highly efficient light-scattering properties. This revealed how plasmon energies differ along different crystallographic directions, contributing to the broad NIR absorption capabilities of the material. Second, the study measured the q dispersion of carrier plasmons and thus quantified interactions (exchange–correlation effect) between carrier electrons in LaB6 crystals, another NIR shielding filter. This analysis provides critical insights into many-body effects not captured by the ideal free-electron gas model. Finally, the spatial spread sizes of excitons in anatase TiO2 were determined, establishing a correlation between the exciton size and the anisotropic photocatalytic activity of anatase TiO2. Collectively, this research demonstrates that q-EELS provides unique, q-dependent information on electronic excitations, deepening our understanding of the properties governing the performance of advanced materials.
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References
90
[1]
Kimoto "Element-selective imaging of atomic columns in a crystal using STEM and EELS" Nature (2007) 10.1038/nature06352
[2]
Chu "Chemical mapping and quantification at the atomic scale by scanning transmission electron microscopy" ACS Nano. (2013) 10.1021/nn4023558
[3]
Haruta "Atomic-resolution two-dimensional mapping of holes in the cuprate superconductor La2−𝑥Sr𝑥CuO4±𝛿" Phys. Rev. B (2018) 10.1103/physrevb.97.205139
[4]
Miyata "Effect of inorganic material surface chemistry on structures and fracture behaviors of epoxy resin" Nat. Commun (2024) 10.1038/s41467-024-46138-6
[5]
Sato "TEM-EELS/EDS chemical analysis of solute clusters in a dilute mille-feuille-type Mg–Zn–Y alloy" Mater. Trans (2023) 10.2320/matertrans.mt-md2022023
[6]
Sato "High energy-resolution electron energy-loss spectroscopy study of the dielectric properties of bulk and nanoparticle LaB6 in the near-infrared region" Ultramicroscopy (2011) 10.1016/j.ultramic.2011.05.003
[7]
Sato "High energy-resolution electron energy-loss spectroscopy study on the near-infrared scattering mechanism of Cs0.33WO3 crystals and nanoparticles" J. Appl. Phys (2012) 10.1063/1.4752867
[8]
Tegg "A review of alkali tungsten bronze nanoparticles for applications in plasmonics" Plasmonics (2023) 10.1007/s11468-022-01749-x
[9]
Rossouw "Multipolar plasmonic resonances in silver nanowire antennas imaged with a subnanometer electron probe" Nano Lett. (2011) 10.1021/nl200634w
[10]
Miyata "Measurement of vibrational spectrum of liquid using monochromated scanning transmission electron microscopy–electron energy loss spectroscopy" Microscopy (2014) 10.1093/jmicro/dfu023
[11]
Krivanek "Vibrational spectroscopy in the electron microscope" Nature (2014) 10.1038/nature13870
[12]
Venkatraman "Vibrational spectroscopy at atomic resolution with electron impact scattering" Nat. Phys. (2019) 10.1038/s41567-019-0675-5
[13]
Senga "Position and momentum mapping of vibrations in graphene nanostructures" Nature (2019) 10.1038/s41586-019-1477-8
[14]
Hage "Phonon spectroscopy at atomic resolution" Phys. Rev. Lett (2019) 10.1103/physrevlett.122.016103
[15]
Kikkawa "Optical and acoustic phonon temperature measurements using electron nanoprobe and electron energy loss spectroscopy" Phys. Rev. B (2022) 10.1103/physrevb.106.195431
[16]
Maureen "Advances in ultrahigh-energy resolution EELS: phonons, infrared plasmons and strongly coupled modes" Microscopy (2022) 10.1093/jmicro/dfab050
[17]
Yang "Phonon modes and electron-phonon coupling at the FeSe/SrTiO3 interface" Nature (2024) 10.1038/s41586-024-08118-0
[18]
Senga "Nanoscale C–H/C–D mapping of organic materials using electron spectroscopy" Nat. Nanotechnol (2025) 10.1038/s41565-025-01893-5
[19]
Kepaptsoglou "Magnon spectroscopy in the electron microscope" Nature (2025) 10.1038/s41586-025-09318-y
[20]
Liou "π-plasmon dispersion in free-standing graphene by momentum-resolved electron energy-loss spectroscopy" Phys. Rev. B (2015) 10.1103/physrevb.91.045418
[21]
Hong "Layer-dependent anisotropic electronic structure of freestanding quasi-two-dimensional MoS2" Phys. Rev. B (2016) 10.1103/physrevb.93.075440
[22]
Nicotra "Anisotropic ultraviolet-plasmon dispersion in black phosphorus" Nanoscale (2018) 10.1039/c8nr05502e
[23]
Schoen "Probing complex reflection coefficients in one-dimensional surface plasmon polariton waveguides and cavities using STEM EELS" Nano Lett. (2015) 10.1021/nl503179j
[24]
Saito "Optical guided modes coupled with Cerenkov radiation excited in Si slab using angular-resolved electron energy-loss spectrum" J. Appl. Phys (2013) 10.1063/1.4796140
[25]
Sato "Anisotropic plasmons due to carrier electrons in Cs-doped hexagonal WO3 studied by momentum transfer resolved electron energy-loss spectroscopy" J. Appl. Phys (2019) 10.1063/1.5115068
[26]
Machida "Anisotropic dielectric properties and ensemble inhomogeneity of cesium-doped tungsten oxide nanoparticles studied by electron energy loss spectroscopy" J. Appl. Phys (2020) 10.1063/5.0003007
[27]
Sato "Evaluation of exchange-correlation effects on the heat-shielding performance of carrier electrons in LaB6 using momentum-transfer resolved electron energy-loss spectroscopy" J. Appl. Phys (2022) 10.1063/5.0076692
[28]
Saito "Examining the anisotropic behavior of the excitons in anatase TiO2 by angle-resolved electron energy-loss spectroscopy" J. Appl. Phys (2023) 10.1063/5.0140536
[29]
Inelastic Collisions of Fast Charged Particles with Atoms and Molecules—The Bethe Theory Revisited
Mitio Inokuti
Reviews of Modern Physics
1971
10.1103/revmodphys.43.297
[30]
Fink "Recent developments in energy-loss spectroscopy" Adv. Electron. Electron Phys (1989)
[31]
Lindhard "On the properties of a gas of charged particles" Danske Vidensk. Selsk. Mat.-Fys. Medd (1954)
[32]
Dietz "Inelastic electron scattering by intra- and interband plasmons in rhenium trioxide, tungsten trioxide, and some tungsten bronzes" Phys. Rev. B (1978) 10.1103/physrevb.17.3790
[33]
Takeda "Near infrared absorption of tungsten oxide nanoparticle dispersions" J. Am. Ceram. Soc (2007) 10.1111/j.1551-2916.2007.02065.x
[34]
Adachi "Activation of plasmons and polarons in solar control cesium tungsten bronze and reduced tungsten oxide nanoparticles" J. Mater. Res. (2012) 10.1557/jmr.2012.25
[35]
Machida "Ensemble inhomogeneity of dielectric functions in Cs-doped tungsten oxide nanoparticles" J. Phys. Chem. C (2016) 10.1021/acs.jpcc.6b02936
[36]
Mamak "Thermal plasma synthesis of tungsten bronze nanoparticles for near infra-red absorption applications" J. Mater. Chem. (2010) 10.1039/c0jm02169e
[37]
Tegg "Bulk scale fabrication of sodium tungsten bronze nanoparticles for applications in plasmonics" Nanotechnology (2018) 10.1088/1361-6528/aad34b
[38]
Chowdhury "Plasmonic enhancement of aqueous processed organic photovoltaics" RSC Adv. (2021) 10.1039/d1ra02328d
[39]
Tegg "Plasmon responses in the sodium tungsten bronzes" Plasmonics (2018) 10.1007/s11468-017-0528-y
[40]
Kielwein "High-energy electron-energy-loss study of sodium-tungsten bronzes" Phys. Rev. B 10.1103/physrevb.51.10320
[41]
Born (1999) 10.1017/cbo9781139644181
[42]
Hussain "Crystal growth of alkali metal tungsten bronzesMxWO3 (M=K, Rb, Cs), and their optical properties" J. Alloy Compd (1997) 10.1016/s0925-8388(96)02470-x
[43]
Kim "The interplay of shape and crystalline anisotropies in plasmonic semiconductor nanocrystals" Nano Lett (2016) 10.1021/acs.nanolett.6b01390
[44]
Lee "Electronic band structure study of the anomalous electrical and superconducting properties of hexagonal alkali tungsten bronzes AxWO3 (a = K, Rb, Cs)" J. Am. Chem. Soc. (1997) 10.1021/ja964455t
[45]
Batson "Surface plasmon coupling in clusters of small spheres" Phys. Rev. Lett. (1982) 10.1103/physrevlett.49.936
[46]
Koh "Electron energy-loss spectroscopy (EELS) of surface plasmons in single silver nanoparticles and dimers: influence of beam damage and mapping of dark modes" ACS Nano (2009) 10.1021/nn900922z
[47]
Nelayah Nat. Phys
[48]
Horak "Influence of experimental conditions on localized surface plasmon resonances measurement by electron energy loss spectroscopy" Ultramicroscopy (2020) 10.1016/j.ultramic.2020.113044
[49]
Chu "Probing bright and dark surface-plasmon modes in individual and coupled nobel metal nanoparticles using an electron beam" Nano Lett. (2009) 10.1021/nl803270x
[50]
Yoshio "Destabilization of psedo-Jahn-Teller distortion in cesium-doped hexagonal tungsten bronzes" J. Appl. Phys (2018) 10.1063/1.5045156
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Details
- Published
- Feb 13, 2026
- Vol/Issue
- 75(2)
- Pages
- 116-128
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Funding
Grant-in-Aid for Scientific Research for Young Scientists
Award: 17K14075
Cite This Article
Yohei K Sato (2026). Analysis of photo-functional materials using momentum-resolved EELS. Microscopy, 75(2), 116-128. https://doi.org/10.1093/jmicro/dfag006
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