Nanoimaging of Orientational Defects in Semiconducting Organic Films
| Authors | |
|---|---|
| Year of publication | 2021 |
| Type | Article in Periodical |
| Magazine / Source | Journal of Physical Chemistry C |
| MU Faculty or unit | |
| Citation | |
| Web | https://pubs.acs.org/doi/10.1021/acs.jpcc.1c00059 |
| Doi | http://dx.doi.org/10.1021/acs.jpcc.1c00059 |
| Keywords | Molecular properties; Defects; Layers; Molecules; Oscillation |
| Description | The development of defect analysis for inorganic semiconductors in the past century paved the way for the success story of today's electronics. By analogy, defect analysis plays a critical role in developing and improving devices based on organic molecular semiconductors. However, because of weak molecular interactions, absent in inorganic semiconductors, device-relevant thin organic films are susceptible to the formation of defects in the molecular orientation, which in turn have a profound impact on the performance in the optoelectronic applications. To address this problem, we broaden the applicability of scattering-type scanning near-field optical microscopy (s-SNOM) and utilize the light-induced anisotropic response of vibrational modes to reveal the defects in molecular orientation. We show that in the case of molecular islands with steep crystal facets only the scattered s-SNOM optical amplitude can be exploited to describe the molecular arrangement reliably, while the phase-based analysis leads to artifacts. The presented s-SNOM analysis of molecular defects can be universally applied to diverse topographies, even at the nanoscale. |
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