Langmuir-Blodgett Films of Dinuclear Mercury(II)-Containing Diethynylcarbazole/Polyoxometalate Hybrids: Film Characterization Studies and Potential Optoelectronic Applications

Abstract

A new family of organometallic/inorganic hybrid Langmuir-Blodgett (LB) films, consisting of organometallic mercury acetylide (OMA) as the π-conjugated organometallic molecule and polyoxometallate (POM, POM = K5BW12O40 or Na5IMo6O24) of the Keggin and Anderson structures as the inorganic composite and docosanoic acid (DA) as the auxiliary film-forming agent, were prepared and well characterized by π–A isotherms, UV-vis absorption and photoluminescence spectra, atomic force microscopy imaging, scanning tunnelling microscopy, and low-angle X-ray diffraction. Our experimental results indicate that stable and well defined monolayer Langmuir and LB films are formed in pure water and POM subphases. There is a quenching effect in the luminescence intensity of the mercury complex when it is made into the LB films due to the enhanced aggregation phenomenon. These alkynylmercury(ii) based LB films exhibit interesting electrical conductivity behaviour, dependent of the characteristics of the POM used. They all reveal decent electrical conductivity, and the tunnelling current can reach ±100 nA when the voltage is set at –5 to +5 V.