Measurement of effective mobility of pure PFO and its blends with MEH-PPV using electroluminescent transient (ELT) spectroscopy. Fowler–Nordheim model was used to estimate the potential barrier height at anode interface in blends. Maximum current efficiency (1.92 cd/A) is found at 2.0 wt.% of blend concentration with white light. The reduction in barrier height is the dominant effect in improving the device characteristics.