Enhanced hole injection and improved performance in organic light-emitting devices by utilizing a novel composite hole injection layer

✍ Scribed by Hua-Ping Lin; Dong-Bin Yu; Xiao-Wen Zhang; Jun Li; Liang Zhang; Xue-Yin Jiang; Zhi-Lin Zhang

• Publisher: Elsevier Science
• Year: 2010
• Tongue: English
• Weight: 573 KB
• Volume: 150
• Category: Article
• ISSN: 0038-1098
• DOI: 10.1016/j.ssc.2010.06.046

✦ Synopsis

Organic light-emitting devices (OLEDs) with MoO x , Ag 2 O and a composite layer consisting of Ag 2 O//MoO x as hole injection layers (HIL) have been investigated. We have observed that the insertion of such a composite layer leads to a striking improvement in the electrical properties with lower driving voltage, higher power and current efficiencies. At a current density of 20 mA/cm 2 , the driving voltage of the device using an Ag 2 O//MoO x composite HIL (Cell-AM) is 5.9 V, which is 2.2 V, 3.8 V and 4.5 V lower than that of the devices using MoOx (Cell-M), Ag 2 O (Cell-A) as HIL and the device (Cell-I) without HIL, respectively. Its power efficiency is 2.56 Lm/W, which is 1.8, 2.4 and 3.6 times higher than that of Cell-M, Cell-A, and Cell-I, respectively. The current efficiency is 4.88 cd/A, which is 33.7%, 58.4% and 110.3% higher than Cell-M, Cell-A, and Cell-I, respectively. These improvements are attributed to its high hole injection ability. The result is verified by using the J-V curves of 'only' devices and further explained with the help of the Fowler-Nordheim (F-N) tunneling theory.