DNA derived from salmon can improve the performance of quantum-dot devices.

It was at a seminar in May 2007 that Liming Dai, a professor of materials engineering at the University of Dayton, decided it would be a good idea to put salmon DNA into his quantum-dot light-emitting diodes (LEDs). James Grote of the Air Force Research Laboratory was describing the use of a complex made of DNA and cetyltrimetylammonium (DNA-CTMA) in LEDs based on small organic molecules, and both researchers recognized that this unique material could help solve a problem that was hindering the development of quantum-dot LEDs.

Dai's group had previously worked on polymer-based LEDs, and was attracted by the narrow, tunable emission of quantum dots. However, an energy barrier between the materials transporting charge to the quantum dots and the dots themselves was reducing the efficiency of the LEDs. The introduction of DNA-CTMA reduced the size of the barrier, and also reduced the amount of charge that was leaking from the dots without generating light. Combined with an annealing step to remove ligands from the dots, the collaboration — which also included Ocean Nanotech, who supplied the quantum dots — was able to demonstrate improved colour purity, brightness and efficiency (ACS Nano doi: 10.1021/nn8009079; 2009).

Each partner in the collaboration had different goals, according to Dai: university researchers were looking for a “detailed understanding of the underlying physical mechanism”; the Air Force was focused on accomplishing specific mission goals; and Ocean Nanotech concentrated on production. Nevertheless, says Dai, the collaboration allowed all three parties “to rapidly achieve results that cannot be easily worked out by a single group”. However, Dai stresses that it is important that the overall objective of the project is not lost amid these different goals. To this end, he recommends the use of project websites that “allow all researchers in the team easy access to the latest progress status of all research components”.