| abstract |
The invention provides a tool to select reliable organic LED devices, where the risk for failure before the end of its lifetime is low. This tool comprises the steps of:i) subjecting the device to a high electric field over the electroluminescent layer. This leads to a division of the devices into two, clearly separated, populations, namely one population with a low leakage current (current through the electroluminescent layer in reverse voltage operation) and one population with a high leakage current. In this step, the first population is selected in accordance with a current criterion.ii) detecting instabilities in the leakage current, referred to as noise. It has been established that these instabilities arise in particular at reverse driving voltages between 1 and 10 Volts. These instabilities are a measure of the occurrence of early failures during operation. In this step, the devices are selected in accordance with a noise criterion. |