利用阱结构作为发光层,阱由8-羟基喹啉铝和4,4′-N,N′-dicarbazole-biphenyl变替蒸发长成,改善了器件的效率,这归因于增加空穴和电子在薄发光层的堆积,形成的激子有效地被限制在薄的发光层中发光.器件的最大电流效率在外加电压8V时达到4.1cd/A,与一般异质结器件相比效率提高了2倍多.这说明在适当阱数时用简单办法可提高器件的效率.
The well structure which was fabricated by alternating deposition of constituent tris-(8-hydroxyquinoline) aluminum (Alq) and 4,4′-N, N′ - dicarbazole-biphenyl (CBP) layers, improved the current efficiency. The enhanced efficiency can be attributed to the strong accumulation of electrons and holes in the thin Alq3 layer, which leads to an increase of the exciton formation and exciton recombination probability. The single well device exhibits the highest current efficiency of 4.1 cd/A,which is more than twice than that of the conventional heterostructure device. It is an effective and simple way to improve the efficiency of EL devices by utilizing well structure as the emitting layer with proper well number.