Deneme, IbrahimLiman, GorkemCan, AyseDemirel, GokhanUsta, Hakan2025-09-252025-09-2520212041-1723https://doi.org/10.1038/s41467-021-26385-7https://hdl.handle.net/20.500.12573/3743Deneme, Ibrahim/0000-0001-9415-0242; Demirel, Gokhan/0000-0002-9778-917X; Can, Ayse/0000-0003-3965-4151; Liman, Gorkem/0000-0002-0778-9783;Nanostructured films of organic semiconductors with low lying LUMO orbitals can enhance Raman signals via a chemical enhancement mechanism but currently the material choice is limited to fluorinated oligothiophenes. Here, the authors investigate the growth of a porous thienoacene film enabled by carbonyls and demonstrate molecular specific organic-SERS platforms. Molecular engineering via functionalization has been a great tool to tune noncovalent intermolecular interactions. Herein, we demonstrate three-dimensional highly crystalline nanostructured D(C7CO)-BTBT films via carbonyl-functionalization of a fused thienoacene pi-system, and strong Raman signal enhancements in Surface-Enhanced Raman Spectroscopy (SERS) are realized. The small molecule could be prepared on the gram scale with a facile synthesis-purification. In the engineered films, polar functionalization induces favorable out-of-plane crystal growth via zigzag motif of dipolar C = O center dot center dot center dot C = O interactions and hydrogen bonds, and strengthens pi-interactions. A unique two-stage film growth behavior is identified with an edge-on-to-face-on molecular orientation transition driven by hydrophobicity. The analysis of the electronic structures and the ratio of the anti-Stokes/Stokes SERS signals suggests that the pi-extended/stabilized LUMOs with varied crystalline face-on orientations provide the key properties in the chemical enhancement mechanism. A molecule-specific Raman signal enhancement is also demonstrated on a high-LUMO organic platform. Our results demonstrate a promising guidance towards realizing low-cost SERS-active semiconducting materials, increasing structural versatility of organic-SERS platforms, and advancing molecule-specific sensing via molecular engineering.eninfo:eu-repo/semantics/openAccessArticle10.1038/s41467-021-26385-72-s2.0-85117701722