Probing Local Electronic Transitions in Organic Semiconductors through Energy‐Loss Spectrum Imaging in the Transmission Electron Microscope

Guo, Changhe; Allen, Frances; Lee, Young-Min; Le, Thinh P.; Song, Chengyu; Ciston, Jim; Minor, Andrew M.; Gomez, Enrique D.

doi:10.1002/adfm.201502090

Cited by 25 publications

(46 citation statements)

References 55 publications

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“…17,36−38 Based on the low-loss EELS results presented in ref (17), a critical dose can be estimated which is similar to our diffraction results. This clearly illustrates the close relationship between diffraction intensities and energy levels in OPV materials with low-dose diffraction being somewhat simpler to carry out and more broadly available for critical dose measurements.…”

Section: Resultssupporting

confidence: 82%

Quantitative Analysis of Electron Beam Damage in Organic Thin Films

Leijten

Keizer²,

With³

et al. 2017

J. Phys. Chem. C

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In transmission electron microscopy (TEM) the interaction of an electron beam with polymers such as P3HT:PCBM photovoltaic nanocomposites results in electron beam damage, which is the most important factor limiting acquisition of structural or chemical data at high spatial resolution. Beam effects can vary depending on parameters such as electron dose rate, temperature during imaging, and the presence of water and oxygen in the sample. Furthermore, beam damage will occur at different length scales. To assess beam damage at the angstrom scale, we followed the intensity of P3HT and PCBM diffraction rings as a function of accumulated electron dose by acquiring dose series and varying the electron dose rate, sample preparation, and the temperature during acquisition. From this, we calculated a critical dose for diffraction experiments. In imaging mode, thin film deformation was assessed using the normalized cross-correlation coefficient, while mass loss was determined via changes in average intensity and standard deviation, also varying electron dose rate, sample preparation, and temperature during acquisition. The understanding of beam damage and the determination of critical electron doses provides a framework for future experiments to maximize the information content during the acquisition of images and diffraction patterns with (cryogenic) transmission electron microscopy.

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Section: Resultssupporting

confidence: 82%

Quantitative Analysis of Electron Beam Damage in Organic Thin Films

Leijten

Keizer²,

With³

et al. 2017

J. Phys. Chem. C

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show abstract

Section: Physical Origin and Behavior Of Electron Beam Damagementioning

confidence: 99%

“…The second strategy allows the direct quantitative measurement of mass loss arising from the surface sputtering and other beam damage mechanisms (e.g., ion emission or hole drilling). Because various chemical species exhibit quite different mass loss rate,99 the overall chemical composition may change upon beam irradiation. Energy‐dispersive X‐ray spectroscopy (EDS) and electron energy loss spectroscopy (EELS) core‐loss spectroscopy provide ideal tools for (semi)quantitative measurement of element‐specific mass loss associated with various beam damage behaviors 99–101.…”

Section: Physical Origin and Behavior Of Electron Beam Damagementioning

confidence: 99%

“…Because various chemical species exhibit quite different mass loss rate,99 the overall chemical composition may change upon beam irradiation. Energy‐dispersive X‐ray spectroscopy (EDS) and electron energy loss spectroscopy (EELS) core‐loss spectroscopy provide ideal tools for (semi)quantitative measurement of element‐specific mass loss associated with various beam damage behaviors 99–101. EDS generally has an accepted accuracy of around 5% relative error for major elements,101 while the relative accuracy of EELS quantification strongly depends on many factors such as thickness, chemical composition and energies of the ionization edges 102,103.…”

Section: Physical Origin and Behavior Of Electron Beam Damagementioning

confidence: 99%

“…The third strategy quantitatively measures the local and collective structural evolutions associated with chemical bonding, coordination environment and electronic structure upon electron beam irradiation,56,99,100,104–108 via either the fine structures of the ionization edge or the low‐loss regime in EELS spectroscopy 99,100,104–106. The former feature allows the monitoring of beam‐induced local structural destruction associated with chemical states,106 bond hybridizations108 and coordination environment,107 while the latter is related with the loss of collective structural properties such as plasmons and phonons 99. For example, to monitor the beam damage behaviors in a π‐conjugated sp 2 carbon network, the destruction of sp 2 carbon species can be tracked by the intensity evolutions of either the σ → π* peak in the carbon K‐edge fine structure or the π‐plasmon peak in the low‐loss regime of EELS spectroscopy 109.…”

Section: Physical Origin and Behavior Of Electron Beam Damagementioning

confidence: 99%

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Imaging Beam‐Sensitive Materials by Electron Microscopy

et al. 2020

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Electron microscopy allows the extraction of multidimensional spatiotemporally correlated structural information of diverse materials down to atomic resolution, which is essential for figuring out their structureproperty relationships. Unfortunately, the high-energy electrons that carry this important information can cause damage by modulating the structures of the materials. This has become a significant problem concerning the recent boost in materials science applications of a wide range of beam-sensitive materials, including metal-organic frameworks, covalent-organic frameworks, organicinorganic hybrid materials, 2D materials, and zeolites. To this end, developing electron microscopy techniques that minimize the electron beam damage for the extraction of intrinsic structural information turns out to be a compelling but challenging need. This article provides a comprehensive review on the revolutionary strategies toward the electron microscopic imaging of beamsensitive materials and associated materials science discoveries, based on the principles of electron-matter interaction and mechanisms of electron beam damage. Finally, perspectives and future trends in this field are put forward. he worked as a postdoctoral fellow and research scientist at King Abdullah University of Science and Technology. His research interests now focus on low-dose electron microscopy and structural elucidation of beam-sensitive materials for applications such as catalysis, gas separation, and energy conversion/storage.

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Nanoscale chemical analysis of beam‐sensitive polymeric materials by cryogenic electron microscopy

Wirix

Lazar

Verhoeven

et al. 2021

Journal of Polymer Science

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Nanoscale chemical analysis of functional polymer systems by electron microscopy, to gain access into degradation processes during the materials life cycle, is still a formidable challenge due to their beam sensitivity. Here a systematic study on the different stages of degradation in a P3HT‐PCBM organic photovoltaic (OPV) model system is presented. To this end pristine samples, samples with (reversibly) physisorbed oxygen and water and samples with (irreversibly) chemisorbed oxygen and water are imaged utilizing the full capabilities of cryogenic STEM‐EELS. It is found that oxygen and water are largely physisorbed in this system leading to significant effects on the band structure, especially for PCBM. Quantification proves that degradation concomitantly decreases the amount of CC bonds and increases the amount of COC bonds in the sample. Finally, it is shown that with a pulsed electron beam utilizing a microwave cavity, beam damage can be significantly reduced which likely extends the possibilities for such studies in future.

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Probing Local Electronic Transitions in Organic Semiconductors through Energy‐Loss Spectrum Imaging in the Transmission Electron Microscope

Cited by 25 publications

References 55 publications

Quantitative Analysis of Electron Beam Damage in Organic Thin Films

Quantitative Analysis of Electron Beam Damage in Organic Thin Films

Imaging Beam‐Sensitive Materials by Electron Microscopy

Nanoscale chemical analysis of beam‐sensitive polymeric materials by cryogenic electron microscopy

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