1

Molecular Conductors

By: Adam Krause4/17/07

Physics 672

2

Molecular Conductor Quick Intro.

Two types of molecules: carbon nanotubes and polyphenylene-based molecules

Multiple approaches to conductance experiments

Molecular conductors as applied to molecular electronics

3

Polyphenylene-based molecules

Figure adapted from: Ellenbogen, J. C. and J. C. Love, Proceedings of the IEEE, Vol. 88 No. 3, (2000) 386

4

Mechanically Controlled Break-Junction Method

Figures from: Reed, M. A., et al., Science 278, (1997) 252

Benzene-1,4-dithiolate

5

Mechanically Controlled Break-Junction Method

Benzene-1,4-dithiolate

Figures from: Reed, M. A., et al., Science 278, (1997) 252

6

Crossed-Wire Method

Oligo(phenylene ethynylene)

Figure from: Kushmerick, J. G., et al., Phys. Rev. Lett 89, (2002) 086802

7

Crossed-Wire Method

Oligo(phenylene ethynylene)

Figure from: Kushmerick, J. G., et al., Phys. Rev. Lett 89, (2002) 086802

8

STM Break-Junction Method

Many Thiolated Molecules Used

Figure from: Xiao, X., et al., Nano. Lett. 4, (2004) 267

9

STM Break-Junction Method

Figure from: Xu, B. Q.and N. J. Tao, Science 307, (2003) 1221

Many Thiolated Molecules Used

10

Conductance Summary

The various polyphenylene-based molecules shown here exhibit conductive properties.

These properties can change based on the electrode-molecule bond.

There are several approaches to measuring the conductance and current of a molecule

11

Applications

Figure from: Ellenbogen, J. C. and J. C. Love, Proceedings of the IEEE, Vol. 88 No. 3, (2000) 386

Diode

12

Applications

Logic Gates

Figure from: Ellenbogen, J. C. and J. C. Love, Proceedings of the IEEE, Vol. 88 No. 3, (2000) 386

13

Applications

Memory

Figures from: Chen, J., et al., Ann. N.Y. Acad. Sci. 960, (2002) 69

14

Summary

The conductance of functionalized polyphenylene-based molecules can be tailored to behave in a desired manner.

In theory, diode molecules are possible. These diodes can be used to build more

complex molecular electronic devices. The persistent conductance states of some

molecules can be utilized for molecular memory applications.

15

References

1. Ellenbogen, J. C. and J. C. Love, Proceedings of the IEEE, Vol. 88 No. 3, (2000) 386

2. Reed, M. A., et al., Science 278, (1997) 252

3. Kushmerick, J. G., et al., Phys. Rev. Lett 89, (2002) 086802

4. Xiao, X., et al., Nano. Lett. 4, (2004) 267

5. Xu, B. Q.and N. J. Tao, Science 307, (2003) 1221

6. Chen, J., et al., Ann. N.Y. Acad. Sci. 960, (2002) 69