Micro-/Nanostructured Highly Crystalline Organic Semiconductor Films for Surface-Enhanced Raman Spectroscopy Applications

The utilization of inorganic semiconductors for surface-enhanced Raman spectroscopy (SERS) has attracted enormous interest. However, despite the technological relevance of organic semiconductors for enabling inexpensive, large-area, and fl exible devices via solution processing techniques, these π-conjugated systems have never been investigated for SERS applications. Here for the fi rst time, a simple and versatile approach is demonstrated for the fabrication of novel SERS platforms based on micro-/nanostructured 2,7-dioctyl[1]benzothieno[3,2-b][1]benzothiophene (C8-BTBT) thin fi lms via an oblique-angle vapor deposition. The morphology of C8-BTBT thin fi lms is manipulated by varying the deposition angle, thus achieving highly favorable 3D vertically aligned ribbon-like micro-/nanostructures for a 90° deposition angle. By combining C8-BTBT semiconductor fi lms with a nanoscopic thin Au layer, remarkable SERS responses are achieved in terms of enhancement (≈10 8 ), stability (>90 d), and reproducibility (RSD < 0.14), indicating the great promise of Au/C8-BTBT fi lms as SERS platforms. Our results demonstrate the fi rst example of an organic semiconductor-based SERS platform with excellent detection characteristics, indicating that π-conjugated organic semiconductors have a great potential for SERS applications.