Impurity effects on charge transport and magnetoconductance in a single layer poly(3-hexyl-thiophene) device

Abstract

We have used the introduction of shallow hole traps in poly(3-hexyl-thiophene) to test one of the predictions of the bipolaron theory of magnetoconductance (MC). The results show that the introduction of shallow traps effectively increases the degree of energetic disorder in the transport states whilst not affecting the position of the Fermi level and that this results in an increase in the MC response. These results are demonstrated to be in qualitative agreement with the theory and suggest one mechanism through which trap states may affect the MC response of organic semiconductors. This work presents a controllable way of chemical doping to engineer a change in absolute current at a given bias depending on the choice of anodes. It also allows for tuning the magnitude of negative MC response and electroluminescence efficiency under different driving conditions.