Efficiency Enhancement of Organic Light Emitting Diodes (OLEDs) by Micro/nano-structuring the Substrate Layer

Akter, Tasmima; Arafat, Arif Istiaq; Ahsan, Md. Shamim

doi:10.1109/icecit54077.2021.9641370

Cited by 1 publication

(6 citation statements)

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“…The light scattering micro/nano-structures were made of Si3N4. Table 1 summarizes the materials used for designing the OLEDs and their properties [24]. During the simulation, we considered a large variety of micro/nano-scale structures including plano-convex & plano-concave micro-lens array (MLA), nano-pillars (flat-top and round-top), and wavy structure on the outer surface of the 2nd SiO2 layer.…”

Section: Methodsmentioning

confidence: 99%

“…During 2D FDTD simulations, we considered a span of 30 µm length (x-axis) and 8.8 µm width (y-axis) on the simulation layout. Perfectly matched layer (PML) condition was set on the simulation boundary to avoid unnecessary reflection of light [24]. We carried out the 2D FDTD simulations for 500 fs at a temperature of 300°K.…”

Section: Methodsmentioning

confidence: 99%

“…OLED Structures and Light Emitting Mechanism OLEDs are primarily classified as: small molecule OLEDs (SMOLEDs), polymer OLEDs (PLEDs), surface-emitting OLEDs, bottomemitting OLEDs, transparent OLEDs, foldable & flexible OLEDs, and active matrix OLEDs (AMOLEDs) [24]. We designed surface emitting white OLEDs the conventional structure of which consists of a substrate layer (can be a combination of several sub-layers), anode, hole transport layer (HTL), electron transport layer (ETL), and cathode.…”

Section: Fundamental Conceptsmentioning

confidence: 99%

“…Quantum Efficiency Two most important parameters of an OLED are the internal quantum efficiency (ηint) and external quantum efficiency (ηext). Internal quantum efficiency (IQE) can be defined as the ratio of the radiative recombination rate (Rr) to the total recombination rate in the OLED [24].…”

Section: Fundamental Conceptsmentioning

confidence: 99%

“…where Rnr is the non-radiative recombination rate. On the contrary, the external quantum efficiency (EQE), i.e., light out-coupling efficiency is defined by the ratio of the transmitted power (Pt) to the power of the light source (Pd) [24].…”

Section: Fundamental Conceptsmentioning

confidence: 99%

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Light Extraction Efficiency Enhancement of White Organic Light-Emitting Diodes (OLEDs) by Micro/Nano-Patterning the Substrate Layer

Ahsan,

Arafat,

Akter

et al. 2024

DDF

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We demonstrate the enhancement of light extraction efficiency of surface-emitting white Organic Light Emitting Diodes (OLEDs) by incorporating micro/nano-metric structures on the outer surface of the 3-layer substrate (SiO2-Si3N4-SiO2). To enhance light extraction efficiency of the OLEDs, various light scattering structures including plano-convex & plano-concave micro-lens array, flat-top & round-top nano-pillars array, and wavy structures were engraved on the outer surface of the substrate layer. For optimization, we varied the thickness of the internal layers of the OLEDs, and height, width, period, and radius of the micro/nano-scale structures. The performance of the micro/nano-structured OLEDs was simulated and analyzed using Lumerical FDTD and GPVDM simulators. We examined the far field light intensity, transmitted power, angular distribution of light, photon escape probability, photon density, internal & external quantum efficiency, and current-voltage curve of the designed OLEDs. We investigated the results in different locations, especially after the substrate layer: Far Field-1 (0 μm), and Far Field-2 (2.5 μm). Compared to conventional OLEDs, the micro/nano-structured OLEDs showed higher external quantum efficiency. The highest external quantum efficiency of 67.304% (Far Field-1) was detected in the round-top nano-pillars array engraved white OLED having structure period of 1.2 μm. We strongly believe that, the proposed micro/nano-structured white OLEDs are suitable for lighting applications.

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Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Section: Fundamental Conceptsmentioning

confidence: 99%

Section: Fundamental Conceptsmentioning

confidence: 99%

Section: Fundamental Conceptsmentioning

confidence: 99%

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