In-situ characterisation of the oxygen induced changes in a UHV grown organic light-emitting diode

The in-situ electroluminescence and current voltage characteristics of orga nic light emitting diode deposited in UHV has been observed. Ultra High Vac uum (UHV) allows to study the system in a clean environment and to monitor in situ the effect of degradation associated with oxidizing agents when tho se are introduced in the chamber under controlled conditions. Furthermore t he changes in the i-v characteristics upon oxygen exposure are reported pro ving the degradation even at low oxygen partial pressures (<10(-8) mbar) as well as changes in depth and distribution of the trap states. The results also confirm the p-doping effect over the whole investigated field range.