Phthalocyanines thin film electrodes

Electrochemical and solid state studies of phthalocyanine thin film electrodes. J. Am. Chem. Soc., 100, 4379 385. 

Klofla, T Rieke, P., Unkous, C., Buttner, W.J., Nanthakumar, A., Mewbom, T.D., and Armstrong, N.R. (1985) Tri- and tetravalent phthalocyanine thin film electrodes comparison with other metal and demetaUated phthalocyanine systems. 

Klofta, T., P. Rieke, C. Linkous, W.J. Buttner, A. Nanthakumar, T.D. Mewborn, and N.R. Armstrong (1985). Tri- and tetravalent phthalocyanine thin film electrodes Comparison with other metal and demetallated phthalocyanine systems. J. Electrochem. Soc. 132, 2134-2143. 

Oekermann, T., D. Schlettwein, N.I. Jaeger, and D. Wohrle (1999). Infiuence of electronwithdrawing substituents on photoelectrochemical surface phenomena at phthalocyanine thin film electrodes. J. Porphyrins Phthalocyanin 3, 444-452. 

Figure 17. Effect of front side and back side illumination of semiconductor electrodes coated with phthalocyanine thin films. The direction of the photocurrent could be controlled by illumination direction and the redox couple in the solution.

Auger techniques have also proven useful in the characterization of electrochemically induced changes in thin-film electrodes. An example concerns films (500-2000 A thick) of magnesium phthalocyanine (MgPc) deposited over a gold contact layer on a glass substrate (106) ... 

B. A. (1993) Phthalocyanine aggregates on metal dichalcogenide surfeces dye sensitization on tin disulfide semiconductor electrodes by ordered and disordered diloroindium phthalocyanine thin films. J. Phys. Chem., 97, 2690 2698. 

The intermittent plasma-assisted vacuum deposition technique has been found to introduce the effective electrocatalytic activity and stability for CO2 reduction into metal phthalocyanine thin films formed on a glassy carbon. The films properties are significantly influenced by the chemical state of the Aim. It has been suggested that the electrode process is determined by the surface chemical reaction involving adsorbed H and/or H+ and a carbon containing intermediate ". ... 

A typical multilayer thin film OLED is made up of several active layers sandwiched between a cathode (often Mg/Ag) and an indium-doped tin oxide (ITO) glass anode. The cathode is covered by the electron transport layer which may be A1Q3. An emitting layer, doped with a fluorescent dye (which can be A1Q3 itself or some other coordination compound), is added, followed by the hole transport layer which is typically a-napthylphenylbiphenyl amine. An additional layer, copper phthalocyanine is often inserted between the hole transport layer and the ITO electrode to facilitate hole injection. 

The results illustrated above show that the CFT method is suitable for making chemical-sensor measurements using both bulk polymers and, in particular, thin film materials that are intrinsically weak conductors. Therefore, the CFT looks premising for such materials as poly(phenylacetylene) derivatives 24., for which carefully shielded electrometer measurements have been required in the past because of current levels at the threshold of detectability. Furthermore, the fact that the CFT always makes AC measurements reduces the problem of DC polarization of electrodes. In addition, the CFT approach should be suitable for other "chemiresistor" applications, such as the metal-substituted phthalocyanines proposed by Jarvis et. al. 2 and for Langmuir—Blodgett films 26. which, because they are so thin, may prove impossible to use in parallel-plate form, but which can be routinely used with the high-sensitivity interdigi-tated-electrode approach provided by the CFT. 

M = Tb, Lu) into organic thin-film transistors by LB technique and reported their field effect mobility, which represented the first report for p-type OFETs based on bis(phthalocyaninato) rare earth complexes prepared via LB method [88], Due to the highly ordered molecular arrangement of M(Pc)[Pc(OC8Hi7)g] (M = Tb, Lu) in LB films and the appropriate HOMO energy level of these double-deckers relative to the Au source-drain electrodes, the OFETs reported in that work exhibited higher hole transfer mobility of 1.7 x 10-3 cm2 V-1 s-1 in comparison with those fabricated from monomeric phthalocyanine LB films. 

As shown in this symposium, interest in chemical modification of electrode surfaces has been extended in many directions, including the study of light-assisted redox reactions, and the use of modified electrodes in electrochromic devices (1,2). Our own studies have centered on the study of metal and metal oxide electrodes modified with very thin films of phthalocyanines (PC) and on the electrochromic reaction of n-heptyl viologen on metal oxide electrodes, and on the effect on these reactions of changing substrate chemical and physical composition (A,5). 

Our attention has been directed to modifying Sn02 electrodes and later, metal electrodes with very thin films (10-100 molecular layers) of phthalocyanines which appear to aggregate when sublimed. The oriented phthalocyanine phase or phases sensitize the response of the Sn02 electrodes with efficiencies many times greater than monomolecular layers of covalently attached chromophores or randomly oriented multilayer dye films (9). Our initial studies have been conducted with phthalocya-nines which we expected would orient in a linear "pancake-stack," by virtue of the interaction between the central metal atoms — either a covalent bond or a strong electrostatic interaction. 

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