Influence of the functional layer thickness on the light output property of tandem organic light emitting diode：a numerical study

ABSTRACTWe investigated the electroluminescence (EL) properties of Eu-doped GaN-based light-emitting diodes (LEDs) grown by organometallic vapor phase epitaxy (OMVPE). The thickness of the active layer was varied to increase the light output power. With increasing the active layer thickness, the light output power monotonically increased. The maximum light output power of 50 μW was obtained for an active layer thickness of 900 nm with an injected current of 20 mA, which is the highest value ever reported. The corresponding external quantum efficiency was 0.12%. The applied voltage for the LED operation also increased with the active layer thickness due to an increase in the resistance of the LED. Therefore, in terms of power efficiency, the optimized active layer thickness was around 600 nm. These results indicate that the optimization of the LED structure would effectively improve the luminescence properties.

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Modeling and Analysis of Organic Light Emitting Diode with Thin Film Anti-Reflective Coatings

Journal of Nanoelectronics and Optoelectronics ◽

10.1166/jno.2020.2751 ◽

2020 ◽

Vol 15 (4) ◽

pp. 425-431

Author(s):

B. M. Chaya ◽

Prasant Kumar Pattnaik ◽

K. Narayan

Keyword(s):

Power Efficiency ◽

Light Emitting Diode ◽

Fdtd Method ◽

Light Output ◽

Single Layer ◽

Light Emitting ◽

Organic Light Emitting Diode ◽

Reflective Coating ◽

Organic Light ◽

Reflective Coatings

The effects of anti-reflective coatings (ARC) on organic light emitting diode (OLED) optical characteristics are reported in this paper. The light output produced from the OLED is not 100%. But the emitted light is trapped due to various Modes. The losses at the glass air substrate interfaces of an OLED are addressed in this work. The Anti-Reflective coatings increase the light output by reducing OLED reflections at the interface between glass and air. The Finite Difference Time Domain (FDTD) method and the Fresnel theory have been used to design the device and study the effects on OLED of the Single Layer Anti-Reflective Coating (SLAR) and Double Layer Anti-Reflective Coating (DLAR). The thicknesses and refractive indices of the layers of the anti-reflective coatings were optimized. We also compared the light out coupling power efficiency of the SLAR coated OLED with that of an OLED with a DLAR coating and also with Conventional OLED. The results show that the enhancement in light output efficiency of the DLAR coated OLED was slightly higher than that of the SLAR coated OLED.

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Internal Field Distribution in Organic Light Emitting Diodes with Double Layer Structure

MRS Proceedings ◽

10.1557/proc-488-121 ◽

1997 ◽

Vol 488 ◽

Cited By ~ 4

Author(s):

C. Hochfilzer ◽

T. Jost ◽

A. Niko ◽

W. Graupner ◽

G. Leising ◽

...

Keyword(s):

Layer Thickness ◽

Field Distribution ◽

Double Layer ◽

Layer Structure ◽

Thick Layer ◽

Internal Field ◽

Internal Electric Field ◽

Light Emitting ◽

Light Emitting Devices ◽

Organic Light

AbstractDouble layer organic light emitting devices (OLED) are constructed by evaporating tris(8 -hydroxy) quinoline aluminum (Alq3) on a spin cast thin film of a methyl substituted ladder type poly -para -phenylene (m -LPPP). A thick layer of Mg:Ag is used as the cathode material. These organic materials are very suitable for application in OLEDs both, as transporting materials as well as active layers. Alq3 predominantly transports electrons while m - LPPP is a conjugated polymer having higher hole mobilities. Due to these transport properties the formation and radiative recombination of the excitons in ITO/m -LPPP/Alq3/Mg:Ag devices occur close to the m -LPPP/Alq3 interface. We compare the device performance of OLEDs with varying Alq3 layer thickness (0, 50, 150, 300, 500Å) and constant m -LPPP layer thickness (900Å). A difference in the device parameters and performance as a function of the Alq3 layer thickness is observed. We analyze these results with respect to the internal electric field distribution of the double layer devices derived from electroabsorption measurements.

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