Thomas P. Vaid Assistant Professor  INORGANIC CHEMISTRY Inorganic and organic electronic materials, Solar energy conversion B.S. Chemistry,1992, University of Illinois; Ph.D. Chemistry, 1997,Cornell University; Postdoctoral Research Associate, 1997-2000, California Institute of Technology. office: 243D SHLB Telephone: 205-348-8454 fax (205) 348-9104

Research Interests Research in our group involves materials chemistry. Both inorganic and organic materials are synthesized and studied. Our main interest is in materials with novel electronic and magnetic properties. Organic molecules in unusual oxidation states. Our investigations of dopants for organic molecular semiconductors have led to the synthesis and isolation of number of unusual molecules. For example, we have isolated the first antiaromatic porphyrin complex, Si(TPP)(THF)2, shown to the right. New Semiconducting Materials. Inorganic. We have synthesized several members of a new class of materials, metal-sulfur-organic networks. Their crystal structures have been determined either by single-crystal X-ray diffraction or synchrotron X-ray powder diffraction. Some of these materials are semiconducting: an example is [Pb3(C6S6)]n, shown to the right.

Organic. While a large number of 1-dimesional conjugated polymers are known, 2-dimesional conjugated materials are essentially unknown. A graphene sheet is one example. We have synthesized new graphite-like 2-dimensional conjugated materials, and the physical properties of those materials are being studied. Composite Solar Cells with Ionic Polymer-Based Built-in Potentials. While solar cells with good energy-conversion efficiency are currently available, their price relative to other forms of energy production has limited their widespread application. Less expensive solar cells can be produced by using a direct-bandgap semiconductor such as CdTe (rather than indirect-bandgap Si) and solution-phase deposition of the active materials (rather than high-temperature crystal growth of Si). We are investigating a method that combines particles of a semiconductor such as CdTe with an organic ionic polymer to create a composite that will function as the active layer of inexpensive solar cells.

---

Representative Publications

“Semiconducting Lead-Sulfur-Organic Network Solids”, Turner, D. L.; Vaid, T. P.; Stephens, P. W.; Stone, K. H.; DiPasquale, A. G.; Rheingold, A. L., J. Am. Chem. Soc. 2008, 130, 14-15.

“Reversible Oxidation State Change in Germanium(tetraphenylporphyrin) Induced by a Dative Ligand: Aromatic Ge^II(TPP) and Antiaromatic Ge^IV(TPP)(pyridine)₂”, Cissell, J. A.; Vaid, T. P.; Yap, G. P. A., J. Am. Chem. Soc. 2007, 129, 7841-7847.

“An Antiaromatic Porphyrin Complex: Tetraphenylporphyrinato(Silicon)(L)₂ (L = THF or Pyridine)”, Cissell, J. A.; Vaid, T. P.; Rheingold, A. L., J. Am. Chem. Soc. 2005, 127, 12212-12213.

“Synthesis and Characterization of a Highly Reducing Neutral ‘Extended Viologen’ and the Isostructural Hydrocarbon, 4,4’’’’-Di-n-octyl-p-quaterphenyl”, Porter, W. W., III; Vaid, T. P.; Rheingold, A. L., J. Am. Chem. Soc. 2005, 127, 16559-16566.

The University of Alabama Department of Chemistry Faculty