| 초록 |
Control of surface composition of a hole-injecting conducting polymer complexes based on poly(3,4-ethylenedioxy thiophene) (PEDOT) doped with a polystyrene sulfonate (PSS) has been conducted in the spin-cast films. We found that the work function of the polymeric complex films formed via single spin-coating can be greatly increased up to 5.44 eV for the PEDOT/PSS compositions by increasing the surface concentration of the PSS dopant. When we add a perfluorinated ionomer (PFI) into the PEDOT/PSS compositions, PFI become richer instead of PSS. The work function of PEDOT/PSS/PFI has a strong dependence on the PFI/PSS ratio on the surface and increased up to ~5.95 eV. Our results prove that surface composition control of the spin-cast film by molecular engineering is very effective to tune the work function and the device performance. This implies that the enriched surface layer (PSS or PFI) of the spin-cast films plays a key role in making high performance PLEDs. |
