Cathode Formed by Thermal Evaporation of Ba:Al Alloy and Estimations of Barrier Height in an Organic LED
DING Lei1**, ZHANG Fang-Hui1,2
1School of Electrical and Information Engineering, Shaanxi University of Science and Technology, Xi'an 710021 2Shaanxi Panel Display Engineering Center, Xi'an 710021
Cathode Formed by Thermal Evaporation of Ba:Al Alloy and Estimations of Barrier Height in an Organic LED
DING Lei1**, ZHANG Fang-Hui1,2
1School of Electrical and Information Engineering, Shaanxi University of Science and Technology, Xi'an 710021 2Shaanxi Panel Display Engineering Center, Xi'an 710021
摘要It is demonstrated that barium and aluminum alloy synthesized by melting in a glass tube under low vacuum is applicable for organic laser emitting diodes (LEDs) as a thin film cathode. The alloy film obtained by the thermal evaporation of pre-synthesized alloy is used in a single-boat organic LED device with the structure: indium tin oxide (ITO)/4,4'-bis[N−(1-naphthyl)-N−phenylamino]biphenyl(NPB)/tris-(8-hydroxyquinoline) aluminum(Alq3)/barium:aluminum alloy. The experimental results show that devices with this alloy film cathode exhibit better current density-voltage-luminance characteristics than those with a conventional pure Al cathode, and more weight of barium in aluminum leads to better performance of the devices. Characteristics of current density versus voltage for the electron-only devices are fitted by the Richardson–Schottky emission model, indicating that the electron injection barrier has a decrease of about 0.3 eV by this alloy cathode.
Abstract：It is demonstrated that barium and aluminum alloy synthesized by melting in a glass tube under low vacuum is applicable for organic laser emitting diodes (LEDs) as a thin film cathode. The alloy film obtained by the thermal evaporation of pre-synthesized alloy is used in a single-boat organic LED device with the structure: indium tin oxide (ITO)/4,4'-bis[N−(1-naphthyl)-N−phenylamino]biphenyl(NPB)/tris-(8-hydroxyquinoline) aluminum(Alq3)/barium:aluminum alloy. The experimental results show that devices with this alloy film cathode exhibit better current density-voltage-luminance characteristics than those with a conventional pure Al cathode, and more weight of barium in aluminum leads to better performance of the devices. Characteristics of current density versus voltage for the electron-only devices are fitted by the Richardson–Schottky emission model, indicating that the electron injection barrier has a decrease of about 0.3 eV by this alloy cathode.
DING Lei**;ZHANG Fang-Hui;
. Cathode Formed by Thermal Evaporation of Ba:Al Alloy and Estimations of Barrier Height in an Organic LED[J]. 中国物理快报, 2011, 28(6): 67801-067801.
DING Lei**, ZHANG Fang-Hui,
. Cathode Formed by Thermal Evaporation of Ba:Al Alloy and Estimations of Barrier Height in an Organic LED. Chin. Phys. Lett., 2011, 28(6): 67801-067801.
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2011, Vol. 28 
