Abstract
AbstractThe radical ion of the familiar hole‐transport material NPB (i.e., NPB⋅+) absorbs strongly in the blue region of the spectrum. Therefore, it can quench blue luminescence by Förster energy transfer. A high concentration of NPB⋅+ at the interface between an NPB hole‐transport layer (HTL) and a blue light‐emitting layer (LEL) severely limits the luminescence efficiency of the emitting blue dopant. The efficiency can be improved dramatically by modifying either (a) the anode contact with a thin layer of CuPc, thereby increasing the field strength in the HTL, or (b) the cathode contact with a thin layer of Bphen, thereby reducing the field strength in the LEL. Both strategies reduce the difference in electric field strength across the interface, reduce the interfacial concentration of NPB⋅+, and suppress the quenching. Experimental evidence is provided by a spectrum of electrochemically generated NPB⋅+, simultaneous photo‐ and electroluminescence measurements on model OLEDs, and electrical characterization of the devices.
Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
