Salmon DNA improves OLED performance

Incorporating salmon DNA into the structure of a conventional OLED makes it ten times more efficient and thirty times brighter, say researchers in the US.

Salmon DNA could hold the key to more efficient and brighter OLEDs, according to researchers in the US. By incorporating a thin layer of DNA into the OLED structure, the team says its "BioLEDs" are as much as ten times more efficient and thirty times brighter than their conventional counterparts.

The team's idea involves using the DNA as an electron-blocking layer. This improves the probability of electrons and holes recombining and emitting photons, which in turn enhances the device's luminance. "It turns out that DNA has nearly ideal energy levels that allow hole transport to proceed unimpeded while it prevents electrons being transported too quickly," says Andrew Steckl from the University of Cincinnati.

The team tested a green- and blue-emitting BioLED against conventional OLEDs and found that the DNA electron blocking layer improved the luminance in both cases. For a current density of 200 mA/cm2, the green BioLED achieved 15000 cd/m2, whereas the baseline device reached just 4500 cd/m2. On the other hand, the blue BioLED had a luminance of 1500 cd/m2 at 200 mA/cm2, while the corresponding baseline device reached around 800 cd/m2.

Conventional OLEDs are renowned for having lifetime issues but Steckl and colleagues believe the DNA could also play a role here. "Our preliminary results show that the lifetime of the BioLEDs are significantly longer than that of equivalent OLEDs without the DNA layer," said Steckl. "We are working on understanding the difference in degradation mechanisms."

Shak Gohir