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Exceptionally efficient organic light emitting devices using high refractive index substrates
Saso Mladenovski1, Kristiaan Neyts, Domagoj Pavicic
1Electronics and Information Systems Department, Ghent University, Gent, Belgium. Saso.Mladenovski@elis.ugent.be
Optics Express
|April 29, 2009
Summary
Researchers developed a green Organic Light Emitting Device (OLED) with record external quantum efficiency (42%) and luminous efficacy (183 lm/W). This breakthrough utilizes a high index substrate and a thick, electrically doped electron transport layer for enhanced light outcoupling.
Area of Science:
- Materials Science
- Optoelectronics
- Solid State Physics
Background:
- Organic light-emitting devices (OLEDs) are utilized in displays but face challenges in lighting applications due to low outcoupling efficiency.
- The high refractive index of organic layers in conventional planar bottom-emitting OLEDs limits light extraction.
Purpose of the Study:
- To enhance the optical outcoupling efficiency of bottom-emitting OLEDs for improved lighting applications.
- To demonstrate a green bottom-emitting OLED with record-breaking efficiency and luminous efficacy.
Main Methods:
- Fabrication of a green bottom-emitting OLED utilizing a high index substrate.
- Incorporation of a thick electron transport layer (ETL) with electrical doping.
- Optical simulations to model and validate efficient light outcoupling.
Main Results:
- Achieved a record external quantum efficiency of 42% for a green bottom-emitting OLED.
- Attained a record luminous efficacy of 183 lm/W.
- Demonstrated effective light outcoupling through the combination of substrate, ETL, and doping.
Conclusions:
- The developed OLED architecture significantly overcomes the limitations of conventional designs.
- The high efficiency and efficacy pave the way for advanced OLED lighting applications.
- Electrical doping in a thick ETL is a viable strategy for boosting OLED performance.
