Electroless Deposition of Conducting Polymers Using the Scanning Electrochemical Microscope

Abstract

a monolayer of amphiphilic polythiophene on a LB trough. The wires exhibit a room temperature conductivity of 40 S/cm, which is higher than any previously reported conductivity from a single component LB-film derived sample. [14] X-ray diffraction experiments showed that the wires were less ordered than the monolayer from which they were formed and the conductivity of 40 S/cm can hence be regarded as being a lower estimate of the conductivity in the highly ordered local domains of the LB films of 1. The intrinsic conductivity of these domains is presently under investigation. [15] Experimental Samples of polymer 1 were obtained from synthesis as described earlier [4]. A Lauda LB-trough was used to fabricate Langmuir films on a pure water subphase (Milli-Q filtered) [4]. Polarized optical microscopy pictures of the wires were obtained with a Nikon Optiphot microscope equipped with crossed polarizers. The dichroic ratio was derived from the absorption spectra obtained in a Perkin Elmer UV/VIS/NIR lambda 9 spectrometer equipped with polarizers. Images and cross-sections of the wires were recorded with a Nanoscope IIIa AFM from Digital Instruments working in contact mode. Analysis of the cross section of the wires including deconvo-lution of tip and thread structure using a tip radius of curvature of approximately 30 nm, show that the threads shown in Fig. 2D are approx. 60 nm wide and 10±15 nm high. The cross section of the bundles of wires used for conductivity measurements was obtained by analyzing the data from the AFM. The four probe technique was used for the D.C. conductivity measurements. The electrical contacts were fabricated on the substrate prior to nano-wire transfer, by evaporating gold on the substrate through a mask.