Placing Conducting Polymers onto a H-Terminated Si(100) Surface via a Pulse Valve

Abstract

We used a pulse-injection method to fix π-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.

Scanning tunneling microscopy studies of pulse deposition of dinuclear organometallic molecules on Au(111)

“…26,28 Our Ru2-toluene/Au͑111͒ sample was heated under vacuum at 470 K for 20 min, and the heated sample is shown in Fig. 26,28 Our Ru2-toluene/Au͑111͒ sample was heated under vacuum at 470 K for 20 min, and the heated sample is shown in Fig.…”

“…2 was annealed under a hydrogen flame for 10 min; the Au substrates used in Figs. 26,28 Grill et al used temperature programed desorption to show that with diethyl ether as solvent, molecules remain on a Cu͑111͒ surface at room temperature. The clean Au͑111͒ was transferred to a sample preparation chamber with a pulsed valve ͑Parker Instrumentation 9-Series, 0.5 mm nozzle diameter, IOTA One driver͒ installed.…”

“…26 In our laboratory, we have used pulsed deposition to prepare samples of Ru2 on Au͑111͒ for imaging with STM. 26,28 Terada et al report that thermal annealing after pulse injection results in substantial improvement in STM image quality, and attribute this to the removal of solvent molecules. Several studies have reported that immediately after pulse deposition, STM images are noisy and of lower quality, and it is speculated that this is caused by a significant number of solvent molecules remaining on the surface.…”

“…27 In pulse deposition, the most likely source of contamination is the solvent. 26 In that study, hexane solvent was pulse injected onto a hydrogen-terminated Si͑100͒ surface at room temperature. 26,28 Terada et al report that thermal annealing after pulse injection results in substantial improvement in STM image quality, and attribute this to the removal of solvent molecules.…”

Investigating the motion of molecular machines on surfaces by STM: The nanocar and beyond

“…The sample preparation and data collection for the STM investigation were performed as follows: These molecules were suspended in toluene or ethanol depending on the solubility, and initially spun-cast on Au(111) on mica and imaged in an ambient, home-built STM. Following initial investigations in air, the solutions were deposited in high vacuum using a fast-actuating, small orifice solenoid dosing valve [4,5] onto argon-sputtered and annealed Au(111) on mica substrates and imaged using an RHK variable temperature UHV-STM [6]. The dosing technique was chosen over sublimation in vacuum because it appeared in thermal decomposition studies using a thermogravimetric analyzer on related oligo(phenylene ethynylene) (OPE) alkynyl-fullerenes that the fullerene-based wheels began to cleave from the alkynyl-axles at ca.…”