Near-Infrared Organic Light-Emitting Diodes Based on Donor-pi-Acceptor Oligomers

This letter reports efficient near-infrared (NIR) electroluminescence (EL) of organic light-emitting diodes (OLEDs) based on two donor-pi-acceptor oligomers. The energy gap can be tuned by changing the conjugated length, strengths of the acceptor component, and nonplanarity. EL with peak emission wavelengths of 775 and 905 nm were observed from the two NIR oligomers. External quantum efficiencies up to 3.54%, electrical-to-optical power efficiencies up to 15.8 mW/W, and turn-on voltage of 4.5 V were achieved in OLEDs based on these NIR emitters.