An Improved Blue Polymer Light-Emitting Diode by Using Sodium Hydroxide/Ca/Al Cathode
MA Liang1,2, XIE Zhi-Yuan1, LIU Jun1, YANG Jun-Wei1, CHENG Yan-Xiang1, WANG Li-Xiang1, WANG Fo-Song1
1State Key Laboratory of Polymer Physics and Chemistry, Changchun Institute of Applied Chemistry,
Changchun 130022
2Graduate School of the Chinese Academy of Sciences, Chinese Academy of Sciences, Changchun 130022
An Improved Blue Polymer Light-Emitting Diode by Using Sodium Hydroxide/Ca/Al Cathode
MA Liang1,2;XIE Zhi-Yuan1;LIU Jun1;YANG Jun-Wei1;CHENG Yan-Xiang1;WANG Li-Xiang1;WANG Fo-Song1
1State Key Laboratory of Polymer Physics and Chemistry, Changchun Institute of Applied Chemistry,
Changchun 130022
2Graduate School of the Chinese Academy of Sciences, Chinese Academy of Sciences, Changchun 130022
Abstract： The performance of blue polymer light-emitting diodes (PLEDs) based on poly(9,9-dioctylfluorene) (PFO) is improved by introducing a thin layer of sodium hydroxide (NaOH) between the calcium cathode and the PFO emissive layer. By replacing the commonly used Ca/Al cathode by a NaOH (2.5nm)/Ca (10nm)/Al cathode, the driving voltage is reduced from 8.3V to 5.4V and the light-emitting efficiency is enhanced from 0.46cd/A to 0.72cd/A for achieving a luminance of 500cdm2, respectively. Moreover, the device with NaOH/Ca/Al cathode shows a pure blue emission of (0.17, 0.12) at high brightnesses. These improvements are attributed to introduction of a thin layer of NaOH that can lower the interfacial barrier and facilitate electron injection.
MA Liang;XIE Zhi-Yuan;LIU Jun;YANG Jun-Wei;CHENG Yan-Xiang;WANG Li-Xiang;WANG Fo-Song. An Improved Blue Polymer Light-Emitting Diode by Using Sodium Hydroxide/Ca/Al Cathode[J]. 中国物理快报, 2005, 22(12): 3196-3188.
MA Liang, XIE Zhi-Yuan, LIU Jun, YANG Jun-Wei, CHENG Yan-Xiang, WANG Li-Xiang, WANG Fo-Song. An Improved Blue Polymer Light-Emitting Diode by Using Sodium Hydroxide/Ca/Al Cathode. Chin. Phys. Lett., 2005, 22(12): 3196-3188.
2005, Vol. 22 
