Issue 12, 2017

Charge carrier trapping controlled by polymer blend phase dynamics


It has recently been shown that diluting a semiconducting polymer with an insulating or large band gap host material can lead to elimination of charge trapping in the former. In this work we systematically study the role of the phase thermodynamics of such blends via tuning the miscibility between the semiconductor (here: MEH-PPV) and host (here: polystyrene or polyvinyl carbazole), by varying the molecular weight of the latter. We show that calculation of the ternary phase diagram of semiconductor, insulator and solvent can predict whether charge transport in the dry blend film will be trap-free or not. Blending MEH-PPV with 35 kg mol−1 polystyrene does not lead to alleviation of the trap-limited nature of the electron current due to strong segregation of the polymers and the formation of pure coexisting phases. In contrast, the electron current in miscible (1 kg mol−1 polystyrene) or partially miscible (30 kg mol−1 polyvinyl carbazole) blends increases by up to four orders of magnitude compared to the pristine semiconductor, together with a doubling in luminous efficiency of the corresponding light-emitting diode.

Graphical abstract: Charge carrier trapping controlled by polymer blend phase dynamics

Article information

Article type
21 Nov 2016
21 Feb 2017
First published
21 Feb 2017
This article is Open Access
Creative Commons BY license

J. Mater. Chem. C, 2017,5, 3042-3048

Charge carrier trapping controlled by polymer blend phase dynamics

A. Kunz, P. W. M. Blom and J. J. Michels, J. Mater. Chem. C, 2017, 5, 3042 DOI: 10.1039/C6TC05065D

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