Scientists for the first time have demonstrated the alignment of the energy levels in a group of advanced materials.
This research is done by MSE PhD Candidate Mark T. Greiner and Professor Zheng-Hong Lu, Canada Research Chair (Tier I) in Organic Optoelectronics and published in the recent journal of Nature Materials.
This research can open new horizons in the development of sustainable technologies like Organic light emitting diodes (OLEDs) and dye sensitized solar cells.
In this case, the uses of transition metal oxides have come into play. These are famous for their use in super-conductors. They have the ability of making a good contact with organic based devices and in this research scientists have found the mechanism behind this excellent contact between metal oxides and organic molecules.
Researchers have reported,
“We conclusively establish the principle of energy alignment between oxides and molecules. We observe a universal energy-alignment trend for a set of transition-metal oxides—representing a broad diversity in electronic properties—with several organic semiconductors. The trend demonstrates that, despite the variance in their electronic properties, oxide energy alignment is governed by one driving force: electron-chemical-potential equilibration. Using a combination of simple thermodynamics, electrostatics and Fermi statistics we derive a mathematical relation that describes the alignment.”
Professor Lu said,
“The energy-level of molecules on materials surfaces is like a massive jigsaw puzzle that has challenged the scientific community for a very long time. There have been a number of suggested theories with many critical links missing. We have been fortunate to successfully build these links to finally solve this decades-old puzzle.”
Greiner, M. T. et. al. (2011). Universal energy-level alignment of molecules on metal oxides. Nature Materials, doi:10.1038/nmat3159