Phthalocyanine, effective contact

Shen X, Sun L, Benassi E et al (2010) Spin filter effect of manganese phthalocyanine contacted with single-walled carbon nanotube electrodes. J Chem Phys 132 054703/ 1-054703/6... 

The first report of a WF field-effect transistor with a gate material other than Pd apparently appeared in the late 1980s. A phthalocyanine film has been evaporated over the gate insulator and over the Al contacts (Burr et al., 1987). Since then, a variety of conducting polymers has been deposited over the transistor gate and evaluated as materials for gas sensing (Liess et al., 1996) (Fig. 6.31). The general... 

Quite pronounced photovoltaic effects have been observed in Mx 1150 nm -chlorophyll a M2 sandwich cells, where Mx = A1 or Cr and M2 = Hg or Au.7e>77 These are ascribed to a Schottky barrier at the junction with metal Mx which has a lower work function than M2. If the Mi junction is the front (illuminated) electrode then the photovoltaic action spectrum is identical with the absorption spectrum of the chlorophyll. If it is at the rear, the action spectrum shows an inner filter effect, because only light absorbed in the region of the barrier is effective. Figure 11 shows the performance of a typical cell, which has a power conversion efficiency of ca. 10-3% at 745 nm. The best efficiency, 5 x 10-a%, was achieved by a Cr chlorophyll a Hg cell. Photovoltaic properties have also been reported in the cell A11 Mg phthalocyanine Ag, which has a Schottky barrier of height ca. 0.6 eV at the A1 junction.78 At 690 nm, the power conversion efficiency was ca. 10-2%. It has been shown that oxidized A1 contacts to Cu phthalocyanine are blocking.79... 

Sevastyanov VI, Alferov GA, Asanov AN, Komissarov GG (1975) Photovoltaiv effect in the films of pigments contacting with electrolyte. Biofizika 20 1004-1009 Shumov YS, Heyrovsky M (1975) The relation between catalytic and photoelectro-chemical properties of phthalocyanine films. J Electroanal Chem 65 469-471... 

Anode contacts to hole transporting molecular layers were discussed briefly in Section 9.3.2. To reiterate, it is often found that metal phthalocyanine compounds effectively mediate the injection of holes from ITO into hole transport layers. (One could also say oxidation of carbocations in the HTL with net transfer of an electron from the HTL into the ITO.) Some experiments have suggested that multiple layers of phthalocyanines based on different metals, and hence having different HOMO state energies, can further reduce the injection barrier. The basic method in use in these cases is to provide a staircase of small barriers up which a hole can climb more easily than would be the case for a single large step. The low mobility of holes in the organic interlayers comes in handy here as it reduces the rate at which holes return to the contact. 

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