Electrical conductivity properties of boron containing Langmuir-Blodgett thin films

Abstract

Electrical characterisations of Mesitylene-2-boronic acid (MBA), Phenylboronic acid (PBA) and 1-Naphthylboronic acid (NBA) are investigated using C-f and I-V measurements. All materials are used to fabricate Langmuir-Blodgett (LB) thin film by vertical dipping method. Metal/LB film/Metal sandwich structure is prepared to investigate electrical properties of boron containing LB films. For evaluation of electrical measurements, the theoretical thickness is determined using ChemDraw software and experimental thickness value is calculated from surface plasmon resonance (SPR) curves. Dielectric measurements are used to determine the dielectric constant (epsilon) and to compare refractive index value which is determined from SPR results. The values of epsilon are determined as 2.79, 2.70, 2.82 for MBA, PBA and NBA respectively. The refractive indexes of three materials are calculated to be around 1.6. I-V results are used to study the conduction mechanism of these LB films. The low voltage region shows an ohmic characteristic for each LB film and conductivity values are calculated as 0.55 x 10(-11) S m(-1), 0.42 x 10(-11) S m(-1) and 3.62 x 10(-11) S m(-1) for MBA, PBA and NBA respectively. In the high voltage region of I-V curves that show Schottky type conduction mechanisms with the barrier heights estimated for each LB film as 0.77, 0.79 and 0.76 eV respectively.