Methodology for thermal and electrical characterization of large area OLEDs

Poppe, A.; Pohl, László; Kollr, E.; Kohari, Z.; Lifka, H.; Tanase, Cristina

doi:10.1109/stherm.2009.4810740

Cited by 14 publications

(12 citation statements)

References 3 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Various approaches have been evaluated and developed. For example, metal shunting grids may be placed on the anode to improve heat distribution [28,35]; an additional metal plate may be attached to the substrate as a heat sink or a thicker cathode may be used [36]; and replacing the conventional cover glass with thin film encapsulation also enhances heat dissipation [37,38]. In general, employing highly efficient PHOLEDs to reduce non-emissive exciton decay and optimizing the layout design to minimize Joule heating are the two key factors that enable low temperature operation of large-area OLED lighting panels, and long lifetime.…”

Section: Resultsmentioning

confidence: 99%

“…This heat is typically generated by Joule heating in the bus lines, electrodes and non-emissive exciton recombination. This can lead to increased temperatures and/or temperature gradients across the OLED panel, which may result in faster and non-uniform aging [28]. Therefore, the ALT method is not accurate in determining the lifetime of large-area OLED panels.…”

Section: Life Test Of Small Oled Pixelsmentioning

confidence: 99%

See 1 more Smart Citation

Thermal behavior and indirect life test of large-area OLED lighting panels

et al. 2014

View full text Add to dashboard Cite

In this work, we studied the thermal behavior and addressed the challenges of life testing of large area OLED devices. In particular, we developed an indirect method to accurately calculate the life time of large-area OLED lighting panels without physically life-testing the panels. Using small area OLEDs with structures identical with the tested panels, we performed the life tests at desired driving current densities at different temperatures and extracted the relationship between junction temperature and the lifetime for the particular device. By measuring the panel junction temperature during operation under the same current density and using the life time measured on small area test devices, we determine the lifetime of the panels based on the thermal dependence. We test this methodology by predicting the life time of white PHOLED panels and then physically testing the panels. The typical result for the lifetime to 80% of the initial luminance (LT80) of the panel at a constant dc current density of 10 mA/cm 2 (3800 cd/m 2 ), was predicted to be 526 hours in good agreement with the actual life-test at 10 mA/cm 2 of 512 hrs. This good agreement, confirmed in different experiments, validates this novel technique as a practical life time predictor of large-area OLED lighting panels in a time saving manner.

show abstract

Section: Resultsmentioning

confidence: 99%

Section: Life Test Of Small Oled Pixelsmentioning

confidence: 99%

Thermal behavior and indirect life test of large-area OLED lighting panels

et al. 2014

View full text Add to dashboard Cite

show abstract

“…For example, Kollar et al [3] measured optical power output per ampere of current through an OLED to decrease by 1.6 mW/A for a 10K rise in temperature. Similarly, luminous flux decreased by 5% -10% for 10K increase in temperature in an OLED driven at constant current [4]. This change was accompanied by perceptible change in color coordinates.…”

Section: Temperature In An Oled Devicementioning

confidence: 86%

“…Thus, joule heating that could raise the temperature of the device, can also cause loss of control on brightness of the OLEDs in a display or lighting panel. Apart from the life-time and effect on brightness, temperature also impacts the color coordinates of the OLEDs [4]. In short, managing temperature of the device is of critical importance for longevity and consistency, when LEDs are based on organic materials.…”

Section: Introductionmentioning

confidence: 99%

Effect of Heat Extraction by Metal Lines and Two Sided Cooling on Temperatures in Organic Light Emitting Diode Based Devices

Nath¹

2011

JECTC

View full text Add to dashboard Cite

Only a 10 K rise in temperature of organic light emitting diode (OLED) can lower its lifetime by more than 50% and cause other performance deterioration. We have performed two dimensional heat transport analysis and calculated temperatures in an OLED panel. The panel temperatures can easily rise in excess of 10 K. Further we have investigated loss of heat through the metal lines for the extent by which they could lower the temperature. However, this method leads to gradients in temperature which could in turn cause inhomogeneities in a display. But, in lighting panels, it will be feasible to cool the devices from both the sides, which is shown to have a significant impact. The thermal transport model presented here for displays is more extensive in its approach and hence likely to provide more accurate results.

show abstract

“…The same authors proposed a methodology for thermal and electrical characterization of large area OLEDs in [89], and finally, a nonlinear electrothermal model, as shown in Figure 8, was presented in [90]. This electrothermal model takes into account the luminosity dependency of current density [I (V,T)] and temperature (T) distribution in the light-emitting layer.…”

Section: Oled Modelingmentioning

confidence: 99%