Researchers have demonstrated the ability to modulate the electronic properties of a conjugated molecule via interaction with Lewis acids that bind a basic site in the molecule.
Organic materials with narrow bandgaps that absorb into the near infrared (NIR) region of the solar spectrum are increasingly attractive as they have potential to be incorporated into NIR photodetectors, NIR photovoltaic and electrochromic devices. The most common method to extend absorption into the NIR region involves increasing the electron acceptor or donor character of D-A type materials to lower the LUMO energy or raise the HOMO energy. While using this strategy has worked to produce many NIR absorbing materials, the synthesis has often been multi-step and costly. Therefore, new methods to alter the bandgap of organic materials would be advantageous.
Researchers at the University of California, Santa Barbara have demonstrated the ability to modulate the electronic properties of a conjugated molecule via interactions with Lewis acids that bind a basic site in the molecule. Through the selective binding of a Lewis acid, for example, and an accessible nitrogen atom on the acceptor unit, electron density can be removed from the system resulting in a narrowing of the optical band gap. This approach makes it possible to access a range of chromophores starting with a single and well-defined small molecule compound. Control of the optical band-gap can be achieved by varying the strength of the Lewis acid.
|United States Of America||Issued Patent||8,343,382||01/01/2013||2009-701|