We observed EL properties based on poly(3,6-N-2-ethylhexyl carbazolyl cyanoterephthalidene) (PECCP) and PECCP/Alq3 emitting material devices with doped PPy conducting layer (>5 S/cm) on top of rough ITO (surface resistance: less than 7 Ω/□). The ITO/PECCP/Alq3/Al device shows relatively high luminance efficiency, (0.17 lm/W), because of the PECCP layer. The PPy conducting layer is working on improving I-V characteristics of PECCP/Alq3 small molecule EML and PECCP EML system on ITO which has a rough surface of more than 1000 angstroms peak to peak level. In the PECCP EML device, when PPy is layered on top of ITO, the turn-on voltage is lowered from 15 to 9 V.
Park, J. W., Lee, J. H., Lee, J. Y., Kho, S. I., & Kim, T. W. (2000). Characteristics of organic electroluminescent devices using polypyrrole conducting layer and undoped conjugated polymer layer. Thin Solid Films, 363(1), 259–262. https://doi.org/10.1016/S0040-6090(99)01071-8