Balanced ambipolar charge carrier mobility in mixed layers for application in hybrid white organic light-emitting diodes
Journal
Applied Physics Letters
Journal Volume
93
Journal Issue
7
Pages
073304
Date Issued
2008-01
Author(s)
Abstract
We investigate the electron and hole mobility in mixed layers of N, N′ -di(naphthalen-1-yl)- N, N′ -diphenyl-benzidine and bis(2-methyl-8-quinolinato)-4-phenylphenolate aluminum with different mix ratios, using both space-charge limited currents of single-carrier devices with electrically doped charge transport layers and time-of-flight measurements. Both experimental methods yield consistent results. The 1:1 blend shows balanced ambipolar charge carrier transport, which is advantageous for the application as exciton blocking interlayer in hybrid white organic light-emitting diodes: The electroluminescence spectrum is rather stable against changes in interlayer thickness and driving current. Moreover, the external quantum efficiency is enhanced by a factor of 2.5 as compared to a device without interlayer. © 2008 American Institute of Physics.
Other Subjects
Alumina; Charge carriers; Civil aviation; Hole mobility; Light; Light emission; Light emitting diodes; Light metals; Organic light emitting diodes (OLED); Ambipolar; Charge transport layers; Charge-carrier mobilities; Charge-carrier transport; Driving currents; Electroluminescence spectrum; Experimental methods; External quantum efficiency; Interlayer thickness; Mixed layering; Single carriers; Space-charge limited currents; Time-of-flight measurements; White organic light-emitting diodes; Carrier mobility
Type
journal article