In situ photoluminescence spectroscopy study of dynamic doping in sandwich-type light-emitting electrochemical cells

摘要

Photoluminescence (PL) spectroscopy has been performed in-situ on iridium(III) ionic transition metal complex (iTMC)-based sandwich-type light-emitting electrochemical cells (LECs) during device operation and after switch-off. It isdemonstrated that driving the device leads to a considerable decrease of the PL intensity of the active layer. Twodifferent time regimes for this decrease have been identified. The first one is characterized by a complete recovery of thePL after the device is turned off corroborating the existence of dynamically formed doped regions also in iTMC-basedLECs. In the second regime the PL does not completely recover which is attributed to a permanent degradation of theactive layer that is the main source for the low lifetime of the devices.Additionally, it is demonstrated how to externally stabilize the dynamic configuration leading to a half lifetime in excessof 1000 hours at simultaneous high brightness of more than 1000 cd/msup2/sup and fast turn-on of less than one second.© (2012) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.