We have fabricated and characterized hole-only and double-layer-type devices based on a single-walled carbon nanotube (SWCNT)–polyvinylcarbazole (PVK) composite. Studies of luminescence and device characteristics demonstrate that as the fraction of SWCNTs in the PVK medium increases in the range of 0–1.0 wt.%, the hole mobility and device performance are significantly improved due to the efficient hole injection and transport through highly conductive nanotubes. The dye-doped composite devices reveal a complete energy transfer and higher external quantum efficiencies.