Polymer Emits Green and Red

Researchers at the University of Amsterdam and at Philips Natuurkundig Laboratorium in Eindhoven, both in the Netherlands, have developed an electroluminescent polymer that emits red or green light, depending on the bias voltage. They reported on the device in the Jan. 2 issue of Nature.

To fabricate the emitter, they doped a polyphenylenevinylene derivative with a dinuclear ruthenium complex that acted as a triplet emitter and as an electron transfer mediator. Applying a forward bias (+4 V) to the structure caused it to emit red light, but a reverse bias (+4 V) induced a green response. They found that replacing the gold and ITO electrodes with two gold electrodes resulted in red emission at a forward and a reverse bias.