ELECTROLUMINESCENCE IN POLY(3-ALKYLTHIENYLENE)S

We report on measurements of electroluminescence (EL) in poly(3-hexylt hienylene), and compare its EL properties with those of poly(3-dodecyl thienylene) using calcium and aluminium as electron-injecting contacts . We find efficiencies significantly higher than those reported elsewh ere, and achieve values of 0.2 % photons per electron in poly(3-dodecy lthienylene). We present detailed EL spectra showing well-resolved pho non structure and highlight the role of defects in the performance of the devices.