Molecular Dynamics Study of the Nematic-Isotropic Interface

We present large-scale molecular dynamics simulations of a nematic-isotropic interface in a system of repulsive ellipsoidal molecules, focusing in particular on the capillary wave fluctuations of the interfacial position. The interface anchors the nematic phase in a planar way, i.e., the director aligns parallel to the interface. Capillary waves in the direction parallel and perpendicular to the director are considered separately. We find that the spectrum is anisotropic, the amplitudes of capillary waves being larger in the direction perpendicular to the director. In the long wavelength limit, however, the spectrum becomes isotropic and compares well with the predictions of a simple capillary wave theory.Comment: to appear in Phys. Rev.

Yellow Phosphorescent Electrogenerated Chemiluminescence Cell Based on a Cyclometalated Iridium Complex with a Redox Mediator

We demonstrated a bright yellow phosphorescent electrogenerated chemiluminescence (ECL) cell with a maximum luminance of over 100 cd m−2 and a maximum current efficiency of 2.84 cd A−1 by adding a redox mediator to the iridium complex solution, which are both among the highest values ever reported for the iridium complex-based ECL cells. Here, bis(2-phenylbenzothiazolato)(acetylacetonate)iridium(III) (Ir(BT)2(acac)) was used as a luminescent material, while 4,5-bis(carbazol-9-yl)-1,2-dicyanobenzene (2CzPN) was used as the mediator. The working mechanism for the developed cell was discussed based on the electrochemical and photophysical properties of the employed materials