Electroluminescent characteristics of scandium and yttrium 8-quinolinolates

Efficient electroluminescence (EL) was obtained in organic light-emitting devices using 8-quinolinolate complexes of scandium (Scq3) and yttrium (Yq3) as emitters. Compared to the device based on the analogous Alq3 complex, no notable difference in the EL performances of the Yq3 device can be found; however, the EL characteristics of device with Scq3 were significantly enhanced. The device with the configuration of indium tin oxide/ N,N′-bis(3-methylphenyl)-N,N′-diphenylbenzidine/Scq3/Yb exhibits a maximum current efficiency of 4.6 cd/A and a maximum power efficiency of 2.6 lm/W at a luminance of 300 cd/m2. The improvement of the performance of this device should be attributed to the higher hole mobility of the Scq3 as compared to Alq3 or a smaller barrier for hole injection into Scq3 compared to Alq3.