American Chemical Society
ao0c06313_si_001.pdf (2.35 MB)

Polarization Raman Imaging of Organic Monolayer Islands for Crystal Orientation Analysis

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journal contribution
posted on 2021-04-01, 10:30 authored by Toki Moriyama, Takayuki Umakoshi, Yoshiaki Hattori, Koki Taguchi, Prabhat Verma, Masatoshi Kitamura
An organic semiconductor film made of diphenyl derivative dinaphtho­[2,3-b:2′,3′-f]­thieno­[3,2-b]­thiophene (DPh-DNTT) has high carrier mobility. However, this mobility may be greatly affected by the crystal orientation of the DPh-DNTT’s first layer. Polarization Raman microscopy is widely used to quantitatively analyze the molecular orientation, and thus holds great potential as a powerful tool to investigate the crystal orientation of monolayer DPh-DNTT with high spatial resolution. In this study, we demonstrate polarization Raman imaging of monolayer DPh-DNTT islands for crystal orientation analysis. We found that the DPh-DNTT sample indicated a strong dependence of the Raman intensity on the incident polarization direction. Based on the polarization dependence, we developed an analytical method of determining the crystal orientation of the monolayer DPh-DNTT islands and experimentally confirmed that our technique was highly effective at imaging the islands’ crystal orientation with a spatial resolution of a few hundred nanometers.