Placing conducting polymers onto a H-terminated Si(100) surface via a pulse valve

We used a pulse-injection method to fix x-conjugated poly(3-hexylthiophene) (P3HT) molecules onto H-terminated Si(100) surfaces. Isolated molecules of P3HT were observed by scanning tunneling microscopy. The P3HT molecules comprised an almost all-trans conformation, reflecting the rigid feature of molecular chains. By quenching the substrate at 135 K, residual solvent molecules were observed. We could control the surface density of fixed P3HT molecules by changing both or either the volume or concentration of the injected P3HT solution.