Presentation Title

Analysis of the Relationship Between Valence and Conduction Band Dispersion and the Transfer Integral Property

Faculty Mentor

Bohdan Schatschneider

Start Date

17-11-2018 1:45 PM

End Date

17-11-2018 2:00 PM

Location

C335

Session

Oral 3

Type of Presentation

Oral Talk

Subject Area

physical_mathematical_sciences

Abstract

Due to increased expenses of inorganic materials in electronic devices, organic substitutes are being studied to replace them. However, the great variety of candidates available necessitates that processes to screen these candidates be created. While there are many physical and chemical properties that would make the crystalline form of an organic compound useful in an electronic device, high charge carrier mobility is one of the most desired traits, and is tied to high valence and/or conduction band dispersion. By using computational chemistry software, it is possible to examine trends between the band dispersion and other properties of the crystal to find suitable candidates. In this study, organic molecules were separated into groups according to the types of heteroatoms present, and both their valence and conduction band dispersions were calculated. The relationship between the dispersion values and the transfer integral property (Hab) was then investigated. It was found that several groups exhibited linear relationships between the two properties. Thus, this method shows promise in discovering organic substitutes in electronic devices if it is expanded to include a larger sample size.

Summary of research results to be presented

The molecules under study were gathered from the Cambridge Structural Database using the program ConQuest. To obtain values for the valence and conduction band dispersions for each molecule, their structures were imported into the Material Studios program where these values were calculated. All transfer integral values of each molecule were obtained in collaboration with Dr. Harald Oberhofer and the sum and average of these values were calculated. After all data was collected and the molecules were separated into groups according to the types of heteroatoms present, graphs of the valence or conduction band dispersion against the sum or average transfer integral value were created. Lines of best fit for each heteroatom group used in each graph were generated. A second set of the graphs was also generated that eliminated statistical outliers in each heteroatom group to increase linearity as indicated by the R² values. From these graphs, it was determined that certain heteroatom groups had consistently high linearity as indicated by the R² values for all or some of the relationships studied. These results show that this method may also successfully be applied to data sets divided into groups according to functional groups present or data sets of only hydrocarbons.

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Nov 17th, 1:45 PM Nov 17th, 2:00 PM

Analysis of the Relationship Between Valence and Conduction Band Dispersion and the Transfer Integral Property

C335

Due to increased expenses of inorganic materials in electronic devices, organic substitutes are being studied to replace them. However, the great variety of candidates available necessitates that processes to screen these candidates be created. While there are many physical and chemical properties that would make the crystalline form of an organic compound useful in an electronic device, high charge carrier mobility is one of the most desired traits, and is tied to high valence and/or conduction band dispersion. By using computational chemistry software, it is possible to examine trends between the band dispersion and other properties of the crystal to find suitable candidates. In this study, organic molecules were separated into groups according to the types of heteroatoms present, and both their valence and conduction band dispersions were calculated. The relationship between the dispersion values and the transfer integral property (Hab) was then investigated. It was found that several groups exhibited linear relationships between the two properties. Thus, this method shows promise in discovering organic substitutes in electronic devices if it is expanded to include a larger sample size.