Efficient charge carrier injection and balance achieved by low electrochemical doping in solution-processed polymer light-emitting diodes
File(s)
Accepted version
Supporting information
Author(s)
Type
Journal Article
Abstract
Charge carrier injection and transport in polymer light‐emitting diodes (PLEDs) is strongly limited by the energy level offset at organic/(in)organic interfaces and the mismatch in electron and hole mobilities. Herein, these limitations are overcome via electrochemical doping of a light‐emitting polymer. Less than 1 wt% of doping agent is enough to effectively tune charge injection and balance and hence significantly improve PLED performance. For thick single‐layer (1.2 µm) PLEDs, dramatic reductions in current and luminance turn‐on voltages (VJ = 11.6 V from 20.0 V and VL = 12.7 V from 19.8 V with/without doping) accompanied by reduced efficiency roll‐off are observed. For thinner (<100 nm) PLEDs, electrochemical doping removes a thickness dependence on VJ and VL, enabling homogeneous electroluminescence emission in large‐area doped devices. Such efficient charge injection and balance properties achieved in doped PLEDs are attributed to a strong electrochemical interaction between the polymer and the doping agents, which is probed by in situ electric‐field‐dependent Raman spectroscopy combined with further electrical and energetic analysis. This approach to control charge injection and balance in solution‐processed PLEDs by low electrochemical doping provides a simple yet feasible strategy for developing high‐quality and efficient lighting applications that are fully compatible with printing technologies.
Date Issued
2019-10-04
Date Acceptance
2019-07-23
Citation
Advanced Functional Materials, 2019, 29 (40), pp.1-9
ISSN
1616-301X
Publisher
Wiley
Start Page
1
End Page
9
Journal / Book Title
Advanced Functional Materials
Volume
29
Issue
40
Copyright Statement
© 2019 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim. This is the accepted version of the following article: Yan, H., Limbu, S., Wang, X., Nightingale, J., Hamilton, I., Wade, J., Kwon, S., Lee, K., Kim, J.‐S., Efficient Charge Carrier Injection and Balance Achieved by Low Electrochemical Doping in Solution‐Processed Polymer Light‐Emitting Diodes. Adv. Funct. Mater. 2019, 29, 1904092, which has been published in final form at https://doi.org/10.1002/adfm.201904092
Identifier
http://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcApp=PARTNER_APP&SrcAuth=LinksAMR&KeyUT=WOS:000481144700001&DestLinkType=FullRecord&DestApp=ALL_WOS&UsrCustomerID=1ba7043ffcc86c417c072aa74d649202
Subjects
Science & Technology
Physical Sciences
Technology
Chemistry, Multidisciplinary
Chemistry, Physical
Nanoscience & Nanotechnology
Materials Science, Multidisciplinary
Physics, Applied
Physics, Condensed Matter
Chemistry
Science & Technology - Other Topics
Materials Science
Physics
charge injection and balance
electrochemical doping
organic light-emitting diodes
organic semiconductors
solid-state ionic liquids
ENERGY-LEVEL ALIGNMENT
DEGRADATION MECHANISMS
TRANSPORT PROPERTIES
IONIC LIQUIDS
DEVICES
METAL
LAYER
Publication Status
Published
Article Number
ARTN 1904092
Date Publish Online
2019-08-15