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05:51
Fabrication of White Light-emitting Electrochemical Cells with Stable Emission from Exciplexes
Published on: November 15, 2016
The efficiency of light-emitting electrochemical cells
Peter Pachler1, Franz P Wenzl, Ullrich Scherf
1Institut fuer Festkoerperphysik, TU-Graz, Austria.
The Journal of Physical Chemistry. B
|July 21, 2006
Summary
Light-emitting electrochemical cells (LECs) using mLPPP and a solid-state electrolyte show efficiency loss at high current densities. This is due to luminance quenching effects from pin-junction formation, not just device degradation.
Area of Science:
- Materials Science
- Organic Electronics
- Electrochemistry
Background:
- Methyl-substituted ladder-type poly(p-phenylene) (mLPPP) is used in organic electronics.
- Light-emitting electrochemical cells (LECs) offer potential advantages over organic light-emitting diodes (oLEDs).
- Understanding efficiency limitations in LECs is crucial for device optimization.
Purpose of the Study:
- To investigate the efficiency behavior of mLPPP-based LECs.
- To identify the causes of efficiency loss at high current densities.
- To elucidate the intrinsic operating mechanism of these LECs.
Main Methods:
- Fabrication of LECs using mLPPP blended with a crown ether-based solid-state electrolyte.
- Analysis of device efficiency under varying current densities.
- Scan rate dependent studies to probe operational dynamics.
- Investigation of luminance quenching effects.
Main Results:
- LECs fabricated with mLPPP exhibit efficiency loss at elevated current densities, unlike oLEDs.
- Scan rate studies indicate that device decomposition is not the sole cause of efficiency drop.
- Intrinsic operating modes reveal luminance quenching effects.
- Pin-junction formation leads to a decreasing intrinsic region width, causing quenching.
Conclusions:
- The efficiency drop in mLPPP-based LECs is attributed to luminance quenching effects.
- These quenching effects are linked to the formation of a pin-junction and the associated reduction in the intrinsic region.
- The findings provide insight into the operational mechanisms and limitations of LECs.
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