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Photovoltaic and structural characteristics of Langmuir-Blodgett film photocells have been studied using asymmetrically substituted copper phthalocyanine (asy-CuPc). By polarized-light absorbance measurements, each phthalocyanine molecule was found to be arranged in the film with its ring facing towards the dipping direction. The polarity of photoelectric characteristics showed typical features expected for an organic p-type Schottky diode, while the dark characteristics exhibited a reversed polarity. The maximum short-circuit photocurrent was on the order of 10-8 A/cm2 for 100 µW/cm2 monochromatic light, indicating the superiority of asy-CuPc as a film-forming molecule for photovoltaic LB films.

The change in morphology of merocyanine-Cd arachidate mixed Langmuir-Blodgett (LB) films induced by hydrothermal treatment (HTT) has been studied using a polarized light photomicroscope and an X-ray diffractometer. By applying HTT of 100% humidity at 70 C for 60 min, the as-deposited J-band with an in-plane anisotropy is reorganized to an isotropic phase with a sharp peak, and the image, initially anisotropic in brightness, becomes isotropic and filled with round superstructures of 0.1 mm or larger in diameter with an average thickness of presumably less than three monolayers. The change in the X-ray diffraction pattern indicates that the Y-type LB lamellar structure remains intact with an enhanced degree of order of the Cdion alignment.

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We have studied the blue-shifted and the red-shifted bands formed in mixed Langmuir–Blodgett films of the merocyanine dye (MS)-arachidic acid (C20)-n-octadecane (AL18) ternary system with the molar mixing ratio [MS]:[C20]:[AL18]=1:2:x(0.5≦x≦5.0). The formation of the blue-shifted and the red-shifted bands depends on the AL18 content, and shows that the aggregation state can be modulated by changing the AL18 content. The observed overlapping spectra of the blue-shifted and the red-shifted bands are deconvoluted into two original bands. The extended dipole model has been applied to examine the aggregation state of MS referring to the deconvoluted spectra. Thus the estimated minimum aggregation number Nmin and the slip angle α between the long axis of the aggregate and the transition dipole moment are Nmin=40 and α=30° and Nmin=40 and α=50° for fully-developed J- and H-aggregates, respectively, seen for x≦1.5, and Nmin tends to decrease with increasing x.