Nanocrystals Enable Near-IR Organic LEDs

By incorporating InAs-based nanocrystals in a semiconducting polymer, a team at Technion-Israel Institute of Technology in Haifa and Hebrew University in Jerusalem has developed an organic LED that produces 1- to 1.3-µm tunable radiation. The team suggests that extending the output to 1.5 µm with the use of other nanocrystals may enable the production of economical emitters for last-mile telecommunications.

To produce the device, which they reported in the Feb. 22 issue of Science, the researchers coated 2.4-nm-diameter crystals of InAs with a 1.5-monolayer shell of ZnSe in a two-step process. They then introduced the nanocrystals into a solution of MEH-PPV or F6BT and spun-cast the mixture onto an ITO and glass substrate. The LED displayed an external efficiency of 0.5 percent but required a turn-on voltage of 15 V.