Effect of type-II quantum well of m-MTDATA/α-NPD on the performance of green organic light-emitting diodes

The type-II multiple quantum well (MQW) structure is prepared and introduced into green organic green light-emitting diodes consisting of 4,4'-bis-[N-(naphthyl)-N-phenyl-amino]biphenyl (@a-NPD) and tris-(8-hydroxyquinolinato)-aluminum (Alq"3). The quantum well (QW) and wall are fabricated by 4,4',4''-tris-(3-methylphenylphenylamino)triphenylamine (m-MTDATA) and @a-NPD, respectively. The device performance of MQW organic light-emitting diodes (OLEDs) has been improved; the luminous efficiency by 25% and power efficiency by 17% compared with the reference device. The performance improvement can be explained by the increased electron-hole balance in the device due to the hole confinement in the QW structure.