The differential approach is based on the determination of dimensionless differential slope, for instance, of current–voltage characteristics (IVC), I = f(V). This slope (α) is given by formula α = d(lgI)/d(lgV). With such definition the ranges of constancy of the α(V) dependency correspond to the part of IVC characterized by the power behaviour (I ∼ Vα). The differential slope of α(V) dependency γ = d(lgα)/dlgV determines the exponent behaviour of curve (I ∼ exp{eVγ/kT}). Processing by the differential approach of the investigated theoretical or experimental characteristics permits us to determine the peculiarity of charge flow mechanisms, temperature behaviour of conductivity, etc. The theoretical base and some applications of differential approach to the investigation of the current–voltage, temperature and degradation characteristics of the polyaniline and poly(p-phenilenevinilene) based structures have been shown.

ABSTRACT The peculiarities of charge flow mechanism in polymer films on the PEPC base with organic dyes of various ionic ability were investigated. The electroconductivity was established to depend on dye nature, their ionic ability and content in polymer media. The approximation of the current-voltage characteristics as exponential function was presented and the activation mechanism of charge flow in investigated structures was established. The activation energy of various system was estimated end established to depend on the dye concentration in PEPC. The self-organization as penta- and hexagons and aggregation in investigated structures obtained.

The surface morphology of the polymer films based onpolyepoxypropylcarbazole and 3,6-di-Br-polyepoxypropylcarbazole with V2O5 was investigated by Atom Force Microscopy (AFM). The surface of composite has been found to be a chaotically intertwining of V2O5 fibres intermittent with inclusions of a corresponding polymer. Polymer inclusions are single ellipsoidal grains for PEPC composite and an aggregate of small grains for 3,6-di-Br-PEPC sample. Both V2O5 fibres and polymer inclusions have smaller size in 3,6-di-Br-PEPC. The mass spectra of compounds under investigation have been obtained. Both PEPC oligomer ions and those identified as complexes of M PEPC oligomers with V2O4 molecule and 3M PEPC oligomers with V2O5 molecule have been observed in mass spectrum of PEPC+V2O5 composite at the emitter temperature from 120degreesC up to 430degreesC. 2M, 3M and even 5M PEPC olygomers were observed in mass spectrum of 3,6-di-Br-PEPC+V2O5 composite at the emitter temperature from 20degreesC up to 600degreesC and 2M 3,6-di-Br-PEPC at the emitter temperature above 200degreesC. In this mass spectrum the ions which can be identified as PEPC oligomer complexes with V2O3 , V2O4 and V2O5 molecules and as 3,6-di-Br-PEPC monomer complexes with V2O3 , V2O4 molecules were also observed. Some observed ions can be also identified as Br-PEPC (with one atom of Bromine) monomer complexes with V2O4 and V2O5 molecules.

Abstract Charge flow in the polymer structures on the base of polyepoxypropilcarbazol (PEPC) and PEPC with substitutes doped by V2O5 and SbCl5 was studied. Two types of structures were used: gap and sandwich. Dark and light I-V characteristics were measured and treated by differential approach. The main peculiarities of investigated characteristics were: all characteristics had the regions I∼Vα with α=(1.15–1.25); conductivity was enhanced with the doping concentration up to 5 times; the dark to light ratio K was over 100.