Hydrofluoroethers as heat-transfer fluids for OLEDs: Operational range, stability, and efficiency improvement

In this work we introduce a simple yet very efficient method of heat dissipation by immersing OLED device into hydrofluoroether (HFE) fluids. It is shown that due to highly fluorous nature of this class of fluids, HFE do not damage organic semiconductors which are comprised in the OLED stack and therefore can be used as encapsulation media. HFE also have high thermal conductivity, low viscosity and can efficiently dissipate the heat by means of natural convection with laminar flow. By employing HFE we were able to significantly improve the OLED operating dynamic range. Lifetimes of OLEDs operating in HFE at high currents can be improved by about a factor of 8. Furthermore, HFE fluid significantly improves the light outcoupling by a factor of 70% due to higher than air refractive index (n = 1.3).

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► Effective OLED cooling with hydrofluoroether fluids is demonstrated.
► OLED operating range is increased by 16%.
► Eight times improvement of lifetimes of cooled OLEDs operating at high currents.