17 April 1998 Concentration effects on charge transport in dye-doped polymer light-emitting diodes
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Light emitting diodes made of a single spin-coated layer of poly(9-vinylcarbazole) doped with coumarin-515 dye have been studied. The influence of dye concentration on emission and electrical characteristics is evidenced. Two different regimes are identified. At low concentrations, apparent hole injection barrier raises, holes are trapped and mobility decreases. External quantum efficiency increases with concentration. At concentrations larger than 10%wt, coumarin aggregates, photoluminescence yield drops and electroluminescence yield increases up to 0.1%-photons per electron. We show that using coumarin dye in a single-layer diode improves electron-hole injection and recombination balance more than using an additional hole-blocking layer.
© (1998) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
Jean-Michel Nunzi, Jean-Michel Nunzi, E. Gautier-Thianche, E. Gautier-Thianche, Andre Lorin, Andre Lorin, Christine Denis, Christine Denis, Paul Raimond, Paul Raimond, Carole Sentein, Carole Sentein, } "Concentration effects on charge transport in dye-doped polymer light-emitting diodes", Proc. SPIE 3281, Polymer Photonic Devices, (17 April 1998); doi: 10.1117/12.305434; https://doi.org/10.1117/12.305434

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