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The effect of p-type doping of the donor layer with 2,3,5,6-tetrafluoro-7,7,8,8-tetracyanoquinodimethane (F 4 TCNQ) on the performance of planar pn-heterojunction organic photovoltaic devices using 4,4 ,4-tris[3-methylphenyl(phenyl)amino]triphenylamine (m-MTDATA) or 4,4 ,4-tris[2-naphthyl(phenyl)amino]triphenylamine (2-TNATA) as an electron donor and C 60 as an electron acceptor was studied. It was found that doping of the donor layer with F 4 TCNQ increases both the short-circuit photocurrent and the fill factor by 1.7 to 2.0 times and 1.5 to 1.6 times, respectively, but reduces the open-circuit voltage, resulting in the enhancement of power conversion efficiency by 1.6 to 1.7 times. These features caused by the doping are attributed to the decrease in the bulk resistance of the electron donor layer as a result of the p-type doping. The decrease in the open-circuit voltage was partly compensated by incorporation of a thin layer of undoped m-MTDATA on the ITO electrode, and hence, the power conversion efficiency was further enhanced.

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AC field-stabilization phenomena of ferroelectric LC cells have been studied. The amplitude E h of an AC electric field which is necessary for stabilizing an LC cell under a DC electric field with reverse polarity, has been obtained by theoretical discussions. E h is expressed by the following equation: E h 2=E ho 2+R·\frac{P_{\text{s}}{\cdot}E_{\text{b}}}{|\Delta\epsilon| \sin^{2}\theta_{t}} where E ho is the AC electric field which is necessary for stabilizing an LC cell without an electric field, P s is the spontaneous polarization, E b is the DC electric field, Δε is the dielectric anisotropy, θt is the tilt angle and R is a constant. This equation represents the experimental results well.

We report the fabrication and characterization of a dye-sensitized solar cell containing a carboxymethyl-β-cyclodextrin sodium salt (CM-β-CD) layer and a noncarboxylated dye compound (tris(2,2′-bipyridyl)ruthenium(II)dichloride hexahydrate (Ru-dye)). The values of the incident photon-to-current conversion efficiency (IPCE) of the Ru-dye/CM-β-CD-containing device measured under 450 and 490 nm light irradiation were, respectively, 2.35% and 3.33%. The IPCE was due to the absorption of Ru-dye in ethanol solution. In contrast, the IPCE of the device that was prepared without the CM-β-CD layer measured under 450 nm irradiation was approximately three times smaller. Accordingly, the current findings demonstrate the application of a noncarboxylated dye compound in DSSCs incorporating a CM-β-CD layer.