Saturday, January 23, 2010

Searching for a unified description of charge transport in molecular materials

Chemical Reviews just released a special issue on Materials for Electronics. There is a helpful article by David Weiss and Martin Abkowitz, Advances in Organic Photoconductor Technology. They note:
The story of the development of electrophotography is an object lesson in the connections between technology development, product development, and scientific understanding.
I found Section 6.1: Charge transport models particularly useful. It contains a critical and succinct discussion of the challenge of coming up with a model which can describe the dependence of the charge mobility on intermolecular separation, temperature, and electric field of a wide class of materials.

The conclusion is "questions remain and a complete description of charge transport in (molecularly doped polymers) MDPs remains elusive"

1 comment:

  1. I agree completely w/ that conclusion (see, for example, our most recent paper on the arxiv, arxiv:1001.3160). There are many reasons why the situation has remained murky. Contact effects are complicated, often non-negligible, and sometimes ignored. Material quality remains a challenge. As we know from inorganic semiconductors, tiny amounts of impurities can have an enormous impact on transport properties, and the synthetic chemistry definition of "pure" typically means 99.9% at absolute best. Throw in the challege of controlling local order and morphology in polymers, and there you are.