Dedoping-induced interfacial instability of poly(ethylene imine)s-treated PEDOT:PSS as a low-work-function electrode

Transparent organic electrodes printed from high-conductivity PEDOT:PSS have become essential for upscaling all-carbon based, low-cost optoelectronic devices. In the printing process, low-work-function PEDOT:PSS electrodes (cathode) are achieved by coating an ultra-thin, non-conjugated polyelectroly...

Full description

Saved in:
Bibliographic Details
Published in:Journal of materials chemistry. C, Materials for optical and electronic devices Materials for optical and electronic devices, 2020, Vol.8 (1), p.328-336
Main Authors: Cai, Wanzhu, Österberg, Thomas, Jafari, Mohammad J, Musumeci, Chiara, Wang, Chuanfei, Zuo, Guangzheng, Yin, Xiaolong, Luo, Xuhao, Johansson, Jim, Kemerink, Martijn, Ouyang, Liangqi, Ederth, Thomas, Inganäs, Olle
Format: Article
Language:English
Subjects:
Chemical bonds
Chemical reactions
Coated electrodes
Interface reactions
Interface stability
Morphology
Optoelectronic devices
Organic chemistry
Polyelectrolytes
Polyethyleneimine
Printing
Work functions
Citations: Items that this one cites
Items that cite this one
Online Access:Get full text
Tags: Add Tag
No Tags, Be the first to tag this record!
Description
Summary:Transparent organic electrodes printed from high-conductivity PEDOT:PSS have become essential for upscaling all-carbon based, low-cost optoelectronic devices. In the printing process, low-work-function PEDOT:PSS electrodes (cathode) are achieved by coating an ultra-thin, non-conjugated polyelectrolyte that is rich in amine groups, such as poly(ethylene imine) (PEI) or its ethoxylated derivative (PEIE), onto PEDOT:PSS surfaces. Here, we mapped the physical and chemical processes that occur at the interface between thin PEIx (indicating either PEI or PEIE) and PEDOT:PSS during printing. We identify that there is a dedoping effect of PEDOT induced by the PEIx. Using infrared spectroscopy, we found that the amine-rich PEIx can form chemical bonds with the dopant, PSS. At lower PSS concentration, PEIx also shows an electron-transfer effect to the charged PEDOT chain. These interface reactions lock the surface morphology of PEDOT:PSS, preventing the redistribution of PSS, and reduce the work function. Subsequent exposure to oxygen during the device fabrication process, on the other hand, can result in redoping of the low-work-function PEDOT:PSS interface, causing problems for printing reproducible devices under ambient conditions. Low-work-function PEDOT:PSS electrodes, suitable for organic photovoltaic modules, were achieved by coating PEIx onto the electrode surface. We mapped the physical and chemical processes that occurred at the interface between PEIx and PEDOT:PSS during printing.
ISSN:2050-7526
2050-7534
2050-7534
DOI:10.1039/c9tc05018c