Highly soluble tetrasubstituted lanthanide bis-phthalocyanines; synthesis, characterization, electrical properties and aggregation studies

Abstract

We report the synthesis, characterization and electrical properties of lanthanide metal based bis-phthalocyanines, {M[Pc-(β-HHT)4]2} (HHT:1-hydroxyhexane-3-ylthio){ M [Formula: see text] Lu[Formula: see text] (2), Eu[Formula: see text] (3), and Yb[Formula: see text] (4)}. The interaction of bis-phthalocyanines with Ag[Formula: see text] and Pd[Formula: see text] metal ions were investigated by UV-vis spectroscopy and atomic force microscopy. Thin films of bis-phthalocyanine molecules were prepared by spin-coating method. The surface morphology of thin films were performed with Atomic Force Microscopy as further investigate. The electrical transport properties of ITO/Pc/Al devices were investigated. At low voltages all the films showed an ohmic conduction, whereas at higher voltage levels the conduction is dominated by space charged limited conduction with exponential distribution of trapping levels. Measurements of current density as a function of inverse temperature at constant applied voltage yielded a hole mobility values, μp[Formula: see text], [Formula: see text] and [Formula: see text] m2.sn[Formula: see text].V[Formula: see text] for lanthanium phthalocyanines. From the analysis of frequency, ω, dependence of electrical conductivity, σac. it was found that the [Formula: see text] obeys the power law given by σac = Aωs, in which the frequency exponent “s” decreases with temperature.

Newly synthesised gadolinium bis-phthalocyanine sandwich complex: ambipolar organic semiconductor

“…Spin-coated films, ∼40 nm thick, of alkyl-substituted dysprosium phthalocyanine molecules showed an increase in rt Ohmic conductivity by two orders of magnitude from 6.57×10 −8 to 6.42×10 −6 S m −1 as the sample was annealed at the liquid crystalline temperature of 350 K, implying the formation of thermally induced ordered film [13]. Values of 2.12×10 −7 m 2 V −1 s −1 , 6.72×10 −7 m 2 V −1 s −1 and 21.58×10 −6 m 2 V −1 s −1 were estimated for hole mobility of spin-coated tetrasubstituted Lu, Eu, Yb thin films, respectively [14]. The Ohmic conductivity of 5 nm thick thermally deposited TbPc 2 under high vacuum conditions is found to be 0.032 S m −1 at 303 K with the value of 0.158 eV for the temperature independent activation energy, implying the thermal excitation of carriers from a continuous density of deep trap states [15].…”