Morphology and photoluminescence properties of electrospun microfibers of poly(9-vinylcarbazole)/tris-(8-hydroxyquinoline)aluminum and poly(9-vinylcarbazole)/4,7-diphenyl-1,10-phenanthroline blends

Green fluorescent electrospun fibers of poly(9-vinylcarbazole) (PVK)/tris-(8-quinolinolato)aluminum (Alq₃) and PVK/4,7-diphenyl-1,10-phenanthroline (Bphen) with widths on the micrometer scale were successfully obtained from solutions in dichloroethane (DCE). The concentration of the electron-transport molecules (Alq₃ or Bphen) was from 0.5 to 60 (wt%). PVK/Alq₃ fibers were thick and rough whereas PVK/Bphen fibers were thin and uniform; additionally, the electrospinnability of the solutions with Bphen was enhanced significantly. Studies of photoluminescence (PL) indicate an efficient energy transfer from PVK to Alq₃ in electrospun PVK/Alq₃ fibers. As for PVK/Bphen fibers, the consistent decrease of the broad PVK emission is mainly attributed to Bphen favoring the formation of fully overlapping, sandwich-like configurations in the PVK. The parallel decrease of the PLE spectra as Bphen increases corroborates the increment in excimer formation.