Thermal detection of trapped charge carriers in organic transport materials

Degradation Mechanisms and Reactions in Organic Light-Emitting Devices

“…140,141 Thermally stimulated current spectroscopy provides additional information about trap levels of mobile charges in OLEDs. 142 Although these techniques are unquestionably powerful tools to study the inner workings of OLED devices, they have not been significantly used in OLED degradation research so far. Another technique to study trapping and transport in OLEDs is impedance spectroscopy, which provides certain information about charge carrier traps inside the layers and injection behavior at different interfaces.…”

“…This approach, which was referred to as “electric field profiling”, essentially provides information about electric fields as well as mobile or fixed charge densities in operating devices. Alternatively, the electric fields in specific layers can be determined by Stark effect spectroscopy, and the mobile charge densities by charge modulation spectroscopy. , Thermally stimulated current spectroscopy provides additional information about trap levels of mobile charges in OLEDs . Although these techniques are unquestionably powerful tools to study the inner workings of OLED devices, they have not been significantly used in OLED degradation research so far.…”