Understanding polymer orientation at the interface by SERS

Abstract

In the organic electronic research field, it is well known that the largest contribution to charge transport occurs within the first few nanometers of the semiconductor near the dielectric interface. Surface Enhanced Raman spectroscopy (SERS) appears as an easy and straightforward technique to analyze this buried interface and to provide useful information on molecular orientation at the device active layer. Here we present the study of the molecular orientation of the widely studied P(NDI2OD-T2) polymer at the semiconductor/dielectric and semiconductor/metal interfaces using SERS and DFT calculations. Our first SERS results show a relative intensification of selected normal modes, which indicates that the orientation of the polymer changes from a face-on (before annealing treatment) to and edge-on disposition after melt annealing, being this in good agreement with the previous results gathered from other techniques (Figure 1).