Study of thermal degradation of organic light emitting device structures by X-ray scattering

Degradation Mechanisms and Reactions in Organic Light-Emitting Devices

“…239−241 A very important contribution to this topic has been given by Lee et al, who used a multilayer stack, where the interdiffusion of the different layers was monitored by X-ray reflection at different elevated temperatures. 242 This topic of temperature-dependent morphological changes will be further discussed in section 4.6.1. It is noteworthy that the main results on interdiffusion and crystallization of materials at elevated temperature are mainly based on experiments with single or multiple organic layers without capping electrodes.…”

“…The findings of Lee et al lead to the question of how the "bad" stability of a material can be improved. 242 One possibility stated above is to use the material in a stacked design, which seems to stabilize the material itself. A second approach is to mix the material with other (suitable) materials.…”

Interfaces in organic devices studied with resonant soft x-ray reflectivity

“…XR has been used extensively to investigate polymer thin films and their interfaces, including some organic devices. 21,22 Most of the time, however, the electron density contrast for polymers in conventional XR is rather small. 23,24 Neutron reflectivity has superior sensitivity to carbonaceous soft-condensed matter if one of the components is deuterated.…”

Long-lifetime thin-film encapsulated organic light-emitting diodes

“…NPB, AlQ, and CuPc have a glass transition temperature ͑T g ͒ of 100, 175, and 240°C, respectively. 15,16 From the point of view of thermal property, CuPc is more stable than AlQ and NPB against heat. This means the CuPc solid film is more stable than the AlQ and NPB films and serves as a more robust protective interlayer against the attack of the reactive multilayer sputtering and CVD process at elevated temperature.…”