Light-emitting diodes of poly[2-methoxy-5-(2'-ethyl-hexyloxy)-1,4-phenylenevinylene] (MEH-PPV) have been fabricated from sodium sulphonated polystyrene (SSPS) ionomer as an electron-injecting and hole-blocking material and polyaniline doped with camphor sulphonic acid (PANI-CSA) as a polymer anode, The presence of PANI in an ITO/PANI/MEH-PPV/A1 device makes little difference to its optical output and quantum efficiency. SSPS shows good electron injection in an ITO/MEH-PPV/SSPS/A1 device, When SSPS ionomer is introduced in an ITO/PANI/MEH-PPV/SSPS/A1 device, a larger enhancement in optical output is obtained and its quantum efficiency is also enhanced because of its balanced charge injection. The electroluminescent device associated with SSPS ionomer and PANI is a well-designed structure to improve stability and efficiency. Copyright (C) 2000 John Wiley & Sons, Ltd.