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The high level of molecular control makes the Langmuir-Blodgett (LB) technique an appealing method of film deposition. The uniform nature of the films produced allows convenient investigation of intermolecular interactions and provides information pertaining to the orientation of molecules within films. LB films of two amphiphilic materials with contrasting molecular structures have been deposited. AmPc5 (a metal-free phthalocyanine (pc)) is a two-dimensional, cyclic molecule, whereas AmAzl (a resorcinol calixarene) possesses a three-dimensional basket-type structure. The amphiphilic nature of both molecules is as a result of functional side-chains. The AmPc5 spreading solution was prepared by dissolving in trichloroethane to a concentration of 0.1 mg/ml. After spreading 500-600 ul, the resulting Langmuir film was found to have a critical pressure of 28 mN/m and an area per molecule of 1.61 nm2 on the water surface. Monolayer deposition onto glass substrates enabled spectroscopic examination of the films and comparison to solution spectra. The solution spectrum shows the split Q-band absorption peaks at 700 nm and 733 nm characteristic of metal-free pc's. The LB film spectrum shows a broadening of both peaks and a red shift of the 733 nm peak, and a blue shift of the 700 nm peak. The 700 nm peak is suppressed as a result of the stack-like packing structure of AmPc5. Absorption spectra of floating AmPc5 monolayers imply that the material does not assume the monomer state at any stage of compression. This is characteristic of rigid molecules that induce order within the floating monolayer. The refractive indices (n) and extinction coefficients (k) were determined across the visible wavelength range. Both the n and k values are shown to increase with monolayer thickness, although the n value tends towards a steady value of 2.1. Deposition onto gold coated glass substrates enabled surface plasmon resonance analysis and determination of n and k at specific film thickness'. The n was found to increase with film thickness, tending towards a steady state value of 2.0. This is in excellent agreement with spectroscopic analysis. Absorption spectra measured using polarised light show AmPc5 exhibits dichroism. The calculations indicate that the pc ring lies almost perpendicular to the substrate. AmAzl was dissolved in chloroform to a concentration of 0.5 mg/ml with 10% ethanol to aid solubility. The optimum solution spreading quantity required to form a floating monolayer was found to be between 50 and 100 ul. The film was shown to have a critical pressure of 30 mN/m and an area per molecule of 1.86 nm2 on the water surface. Both LB film and solution spectra show a single absorbance peak at 454 nm which is due to transitions in the azo functional side chains. Calculation of n and k shows that they tend towards steady values of 1.5 and 2.0, respectively. The n obtained via surface plasmon resonance analysis shows a steady state value of 1.43 on silver coated glass and 1.35 on gold coated glass. This suggests a different type of packing structure on all three substrates. The lack of dichroism exhibited by AmAzl indicates the formation of in-plane amorphous films. AmAzl was deposited in alternating layers with tricosenoic acid. The structure was confirmed by X-ray diffraction studies and investigated using second harmonic generation. The second harmonic signal was shown to be proportional to the square of the number of bilayers.

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The method of the deposition of films of small molecules for use in electronic applications is just as important as the molecule design itself as the film’s morphology and continuity influence the performance of the devices that they are incorporated in. The purpose of the work in this thesis was to develop a method of electrochemically depositing films of small molecules for potential use in electronic applications. A method of electrochemically depositing films of chemically reduced low solubility dye molecules was successfully pioneered. The process was developed using N,N dibutyl-3,4,9,10-perylene-bis(dicarboxime), a simplified version of 3,4,9,10-perylene-tetracarboxylic bisbenzimidalzole. Both of these dyes have been used in electronic applications, but low solubility makes them difficult to deposit by traditional solution techniques. A series of films was electrochemically deposited onto FTO coated glass and field effect transistors using coulometry. These films were characterised by absorption spectroscopy, photoluminescence, scanning electron microscopy, X-ray diffraction and photo-electrochemistry. The same deposition method was applied to copper phthalocyanine. These films were characterised by absorption spectroscopy, photoluminescence, scanning electron microscopy and X-ray diffraction. The developed method was used to deposit films of bilayers of dyes and to investigate the dye penetration during the deposition of copper phthalocyanine onto porous titanium dioxide. Films of neutral copper and nickel dithiolenes were electrodeposited from air-stable TMA salts to investigate the absorbance of the near infrared species formed, as well as to investigate the conductivity of both complexes and the magnetoresponse of the neutral copper dithiolene which is air unstable when formed chemically.

This dissertation explores cathodic electrodeposition mechanisms that describe the synthesis of redox-active electrode materials. Several interesting elements are known to deposit at negative potentials (e.g., Mo, Re, Se), and by extending this work, we can tailor the growth of new binary systems (e.g., MoxRe₁₋xOy, MoxSe₁₋xOy) that have enhanced optical and electronic properties. To grasp the subtleties of deposition and understand how the growth of a particular phase is influenced by other species in solution, several analytical methodologies are used to thoroughly characterize film deposition, including chronocoulometry, voltammetry, nanogravimetry, UV-Visible spectroelectrochemistry, X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), and inductively coupled plasma mass spectrometry (ICPMS). Chapter 1 is a general introduction that discusses the growth of redox-active metal oxides and alloys with an emphasis on tuning the composition to enhance material performance. Chapter 2 proposes a mechanistic pathway for the deposition of rhenium films from an acidic perrhenate (ReVIIO₄⁻) solution containing both metallic and oxide components. Unlike many other metal anions, it was observed that ReVIIO₄⁻ adsorbs to the electrode surface prior to reduction. As such, ReVIIO₄⁻ is ideally situated to be a redox-active mediator for other electrochemical reactions, and in Chapter 3, this dissertation explores how ReVIIO₄⁻ increases the deposition efficiency of Mo oxide deposition. Depth profiling XPS supported by electrochemical studies demonstrated that Mo and Re deposit separately to form an inhomogeneous material, MoxRe₁₋xOy (0.6 < x ≤ 1.0). Over a limited potential range from –0.3 V to –0.7 V (vs Ag/AgCl) the rhenium mole fraction increases linearly with the applied voltage. Chapter 4 explores the deposition of MoxSe₁₋xOy, and in this case, the incorporation of Mo species in solution shifts the deposition of Se⁰ to more positive potentials. Depending on the applied potential used, voltammetry experiments suggest that a small amount of Mo (<5%) reduces to the zero-valent phase to yield the photosensitive alloy, MoxSey. Chapter 5 discusses future work and presents preliminary data describing the deposition of Se⁰ on ITO using adsorbed ReVIIO₄⁻ as a redox mediator. / text