Near-infrared polymer light-emitting diodes based on an inverted device structure

Near-infrared polymer light-emitting diodes (NIR-PLEDs) possess great potential in applications ranging from night-vision devices to optical communications. Here, we obtained NIR emission from normal red fluorescent polymers using an inverted device structure with the aid of micro-cavity effects. By tuning the thickness of the emissive layer, the inverted NIR-PLED based on PPF-FSO15-DHTBT10 and MEH-PPV elicited NIR emission with the main peaks located at 700 nm and 706 nm, and maximum external quantum efficiency (EQE(max)) of 0.54% and 1.03%, respectively. An increase in emissive-layer thickness caused relative variation of the recombination area, which led to wide control of electroluminescence (EL) spectra in the inverted device. These results revealed that tuning the EL spectrum using an inverted device structure could be a promising method to realize NIR emission.