Electroluminescence from a polyester containing oligothiophenes in the main chain, enhanced by a diimide electron transport agent

Photoluminescence spectra in solution and thin films were measured for a polyester with isolated dimethoxyquaterthiophene units in the main chain. Light-emitting diodes were fabricated using indium—tin oxide (ITO)/polyester/AI sandwiches. N,N-dilauryl naphthalene tetracarboxylic acid diimide, added as an electron transport agent, gave improved performance. The emitted light was orange and had λmax 595 nm. Devices constructed with a 240 nm thick polymer film had an emission threshold of about 15 V and 4 mA cm−2.