The Built-In Potential in Blue Polyfluorene-Based Light-Emitting Diodes


  • We thank the EPSRC and the European Commission (THREADMILL – MRTN-CT-2006-036040) for financial support.


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Energy level alignment in polyfluorene-based polymer light-emitting diodes (PLEDs) is studied with electroabsorption spectroscopy and cyclic voltammetry (CV). Using an active layer containing a blend of three polyfluorenes, it is found that the built-in potential values are determined by the interplay of the contacts' work function and the lowest and highest lying energy levels of the blend components.