Monte Carlo simulations were used to study the effects of charge traps on charge transport in monolayer organic field effect transistors. The results show that the source drain current decreases as the trap/barrier concentration increases, reaches a minimum, and increases as the concentration reaches 100%, regardless of the trap/barrier distribution. More current is predicted for heterogeneous trap distributions than for homogeneous trap distributions due to wider conduction pathways that allow for more charge carriers to reach the drain electrode. Also, the distributions of distances and potential energy between charge carriers and trap sites were shown to depend on the heterogeneity of the traps and device geometry and, in many cases, are non-Gaussian in shape. We also found exponential tails for some ranges of heterogeneity. These results suggest that more experimental work is needed to gain more insight into the energetic density of states in electronic devices made from mixed films of organic semiconductors.

Professor Hutchison will also be giving several talks.

Congratulations! More details on the talks will be posted when available later this summer.

This award is meant to recognize exceptional ability and drive to integrate teaching with research among professors at major research universities. Along with the receipt of a grant, Dr. Hutchison has been accepted into the Cottrell Scholars Collaborative, a group with over 250 like-minded professors focused on the necessity for continued improvements in the teaching of science in an increasingly competitive global arena.

Congratulations Dr. Hutchison!

This is an outstanding achievement- congratulations Terry!

Chris comes to us from South Carolina and will be working on the piezoelectric project.  Ilana has lived in Pittsburgh for awhile with her husband and four children and will work on computational projects in the group.

Welcome Ilana and Chris!

Background

A frequent problem in computational modeling is the interconversion of chemical structures between different formats. While standard interchange formats exist (for example, Chemical Markup Language) and de facto standards have arisen (for example, SMILES format), the need to interconvert formats is a continuing problem due to the multitude of different application areas for chemistry data, differences in the data stored by different formats (0D versus 3D, for example), and competition between software along with a lack of vendor-neutral formats.

Results

We discuss, for the first time, Open Babel, an open-source chemical toolbox that speaks the many languages of chemical data. Open Babel version 2.3 interconverts over 110 formats. The need to represent such a wide variety of chemical and molecular data requires a library that implements a wide range of cheminformatics algorithms, from partial charge assignment and aromaticity detection, to bond order perception and canonicalization. We detail the implementation of Open Babel, describe key advances in the 2.3 release, and outline a variety of uses both in terms of software products and scientific research, including applications far beyond simple format interconversion.

Conclusions

Open Babel presents a solution to the proliferation of multiple chemical file formats. In addition, it provides a variety of useful utilities from conformer searching and 2D depiction, to filtering, batch conversion, and substructure and similarity searching. For developers, it can be used as a programming library to handle chemical data in areas such as organic chemistry, drug design, materials science, and computational chemistry. It is freely available under an open-source license from http://openbabel.org.

Welcome Valerie and Terry!