Polymer light-emitting electrochemical cells: frozen-junction operation of an “ionic liquid” device
2005 (English)In: Applied Physics Letters, ISSN 0003-6951, E-ISSN 1077-3118, Vol. 87, no 4, 043506Article in journal (Refereed) Published
We report frozen-junction operation of a polymer light-emitting electrochemical cell containing a mixture of poly[2-methoxy-5-(2(')-ethyl-hexyloxy)-1,4-phenylenevinylene] (MEH-PPV) and the ionic liquid tetra-n-butylammonium trifluoromethanesulfonate (TBA-TF) as the active material. We find fast turn-on time, unipolar light emission, and significant operational lifetime up to T=200 K for planar Au/(TBA-TF+MEH-PPV)/Au surface cells, which had been charged (i.e., electrochemically p- and n-type doped in situ) at T=393 K and V=4 V and then cooled to 80 K at V=4 V. We employed differential scanning calorimetry to demonstrate that (TBA-TF+MEH-PPV) exhibits two melting transitions of TBA-TF crystalline phases located at T(m,1)approximate to 280 K and T(m,2)approximate to 380 K, respectively. The lower T-m,T-1 sets the upper limit for frozen-junction operation (with zero-ionic conductivity), while the larger T-m,T-2 correlates to the lower limit for the charging regime (with high ionic conductivity).
Place, publisher, year, edition, pages
Melville: American Institute of Physics (AIP), 2005. Vol. 87, no 4, 043506
I-N junction, morphology, stability, efficient, kinetics, salt
IdentifiersURN: urn:nbn:se:umu:diva-12199DOI: 10.1063/1.1999009ISI: 000230725900068OAI: oai:DiVA.org:umu-12199DiVA: diva2:151870