RESPONSE TIME MEASURING SYSTEM FOR ORGANIC ELECTROLUMINESCENT DEVICES

In order to analyze the optoelectrical characteristics of organic electroluminescent (OEL) devices, a response time measuring system was established. This system contains a brightness detector with a fast response photoamplifer tube (PMT), a power supply, and a PC computer with an ultra-fast data collection card. The fast response data collection card installed in the PC computer controls the entire course of measurements. The power supply applies a constant voltage to the brightness detector and a pulse voltage to the OEL device to enable it to emit light. The brightness detector receives the light emitted from the OEL device. Both the brightness and driving voltage signals are transferred directly to the computer. Then the voltage-time and brightness-time curves are simultaneously recorded and, finally, the device response time is easily obtained from these curves. The lowest response time of this system that can be measured is 50 ns. With this system, the response times of the OEL devices driven by different voltages have been measured.