Poly(3-pentylmethoxythiophene)/Alq3 heterostructure light emitting diodes

The electroluminescence efficiency of an organic light emitting diode (OLED) based on poly(3-pentylmethoxythiophene) (P5OMe) is improved by two orders of magnitude by employing the heterostructure architecture realized with a thin layer of tris(8-hydroxy)quinoline aluminium (Alq3), which acts as both electron transport and emitting layer. The emission can be tuned from the red to the green spectral region by varying the applied voltage. An additional emission observed both in photoluminescence and electroluminescence at the polymer/Alq3 interface is tentatively assigned to exciplex emission.