Time-Resolved Chemical Mapping in Light-Emitting Electrochemical Cells
2017 (English)In: ACS Applied Materials and Interfaces, ISSN 1944-8244, E-ISSN 1944-8252, Vol. 9, no 3, 2747-2757 p.Article in journal (Refereed) Published
An understanding of the doping and ion distributions in light-emitting electrochemical cells (LECs) is required to approach a realistic conduction model which can precisely explain the electrochemical reactions, p-n junction formation, and ion dynamics in the active layer and to provide relevant information about LECs for systematic improvement of function and manufacture. Here, Fourier-transform infrared (FTIR) microscopy is used to monitor anion density profile and polymer structure in situ and for time-resolved mapping of electrochemical doping in an LEC under bias. The results are in very good agreement with the electrochemical doping model with respect to ion redistribution and formation of a dynamic p-n junction in the active layer. We also physically slow ions by decreasing the working temperature and study frozen-junction formation and immobilization of ions in a fixed-junction LEC device by FTIR imaging. The obtained results show irreversibility of the ion redistribution and polymer doping in a fixed-junction device. In addition, we demonstrate that infrared microscopy is a useful tool for in situ characterization of electroactive organic materials.
Place, publisher, year, edition, pages
AMER CHEMICAL SOC , 2017. Vol. 9, no 3, 2747-2757 p.
light-emitting electrochemical cell; FTIR spectroscopic imaging electrochemical doping doping profile; ion distribution; dynamic p-n junction; infrared microspectroscopy; principal component analysis
IdentifiersURN: urn:nbn:se:liu:diva-135398DOI: 10.1021/acsami.6b14162ISI: 000392909500086PubMedID: 28032741OAI: oai:DiVA.org:liu-135398DiVA: diva2:1081514
Funding Agencies|Power Papers project from the Knut and Alice Wallenberg Foundation [2011-0050]; Swedish Government Strategic Research Area in Materials Science on Functional Materials at Linkoping University [SFO-Mat-LiU 2009-00971]2017-03-142017-03-142017-03-14