Positive charge transport in an alternating oligo-p-phenylenevinylene-derivative/aliphatic-segment block copolymer

A.R.V Benvenho,I.A Hümmelgen

doi:10.1590/s1516-14392001000200016

A.R.V Benvenho, I.A Hümmelgen

Open Access

https://doi.org/10.1590/s1516-14392001000200016

Copy DOI

Journal: Materials Research	Publication Date: Jan 1, 2001
Citations: 2	License type: cc-by

Affiliation: Federal University of Paraná

Abstract

An effective positive charge carrier mobility of 4.4 x 10 -9 cm2/V.s was directly determined using analytical expressions for space-charge-limited current in poly(1,10-decanedioxy-2-methoxy-1,4-phenylene-1,2-ethenylene-3,6-dimethoxy- 1,4-phenylene-1,2-ethenylene-3-methoxy-1,4-phenylene), OPPVDBC, which is a soluble electroluminescent alternating block copolymer. Current vs. voltage measurements have been made using single carrier injection and transport in metal/OPPVDBC/metal structures. The experimental results demonstrate that the positive charge transport in these devices is space-charge-limited and temperature dependent. Additionally, there is evidence that the evaporation of the aluminum electrode induces an increase in the charge density near the Al/OPPVDBC interface.

Highlights

IntroductionConjugated oligomers have well defined optical emission and absorption characteristics, which make them natural candidates for organic optoelectronic applications[1]
Conjugated oligomers have well defined optical emission and absorption characteristics, which make them natural candidates for organic optoelectronic applications[1]. In spite of their interesting optical properties, these organic semiconductors commonly present difficulties when used in the form of thin films, due to their low molecular weight
A strategy that permits to combine the advantages of both classes of materials is to build an alternating block copolymer, constituted by conjugated segments and aliphatic segments

Summary

Introduction

Conjugated oligomers have well defined optical emission and absorption characteristics, which make them natural candidates for organic optoelectronic applications[1] In spite of their interesting optical properties, these organic semiconductors commonly present difficulties when used in the form of thin films, due to their low molecular weight. The chromophores determine the optical characteristics of the polymer, whereas the spacers may improve mechanical properties, e.g. flexibility, and enhance polymer solubility in common organic solvents In this case, the spectral absorption/emission characteristics are controlled in a way similar to the variation of oligomer length[2,3], controlling the length of the conjugated segment. At higher voltages and increased injection levels charge accumulates near the injecting electrode redistributing the electric field intensity, controlling charge transport through the polymer bulk and determining the I(V) dependence. The mobility value determined in this work is the field-independent mobility

Experimental

Results and Discussion

Conclusion