Abstract
The resolution capability of the scanning electron microscope has increased immensely in recent years, and is now within the sub-nanometre range, at least for inorganic materials. An equivalent advance has not yet been achieved for imaging the morphologies of nanostructured organic materials, such as organic photovoltaic blends. Here we show that energy-selective secondary electron detection can be used to obtain high-contrast, material-specific images of an organic photovoltaic blend. We also find that we can differentiate mixed phases from pure material phases in our data. The lateral resolution demonstrated is twice that previously reported from secondary electron imaging. Our results suggest that our energy-filtered scanning electron microscopy approach will be able to make major inroads into the understanding of complex, nano-structured organic materials.
Highlights
The resolution capability of the scanning electron microscope has increased immensely in recent years, and is within the sub-nanometre range, at least for inorganic materials
The P3HT:PCBM blend was chosen as our test system because of it being a popular and well-studied active layer for organic photovoltaic (OPV) purposes, providing an excellent sample on which to demonstrate and validate a new imaging technique
It has admittedly been long surpassed in terms of OPV performance[5], the energyfiltered scanning electron microscopy (EFSEM) technique may be applied to other materials systems with similar results
Summary
The resolution capability of the scanning electron microscope has increased immensely in recent years, and is within the sub-nanometre range, at least for inorganic materials. At present, acquiring chemical composition data in a SEM relies primarily on backscattered electron imaging or X-ray spectroscopy Both these techniques have low spatial resolution in comparison to SE images, and struggle to distinguish between materials with similar elemental composition. An alternative technique showing recent potential is energyfiltered scanning electron microscopy (EFSEM), based upon the energy spectroscopy of detected SE. Such SE spectra are not widely known for exhibiting clear features related to sample chemistry, Joy et al[14] have shown that they can be used for fingerprint identification of inorganic materials. The electrode bias can be linked to a SE detection cutoff energy EC by detector efficiency calculations, examples of which can be found in work published by Rodenburg et al.[15] and Young et al.[18]
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
