Simulation for light extraction efficiency of OLEDs with spheroidal microlenses in hexagonal array

Bae, Hyungchul; Kim, Jun Soo; Hong, Chinsoo

doi:10.1016/j.optcom.2018.01.044

Cited by 19 publications

(9 citation statements)

References 73 publications

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“…1,2 However, the internal light loss within OLEDs remains a major challenge that needs to be overcome to enhance the efficiency of external light extraction. [3][4][5][6] External light extraction plays a crucial role in improving the efficiency and brightness of optoelectronic devices such as OLEDs. Micro/nanostructurebased techniques are commonly employed in external light extraction technology.…”

Section: Introductionmentioning

confidence: 99%

A morphological study of random nanostructured external light extraction layers for enhancing optical characteristics of OLEDs

Choi,

Kang,

Bae

et al. 2023

J. Mater. Chem. C

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Section: Introductionmentioning

confidence: 99%

A morphological study of random nanostructured external light extraction layers for enhancing optical characteristics of OLEDs

Choi,

Kang,

Bae

et al. 2023

J. Mater. Chem. C

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“…Recent development in the field of light extraction has produced different highly efficient solutions, both in optimizing OLED internal and external optical losses -see for example the latest reviews on light outcoupling solutions in OLEDs [1,11,12]. In particular, much research has been done to limit substrate losses by attaching microlenses [13][14][15][16], scattering films [17][18][19][20], introducing scattering particles [21], or using microtextures [22][23][24][25]. These solutions provide high improvements at low cost and, generally, do not affect the electrical properties of the sensitive organic layers.…”

Section: Introductionmentioning

confidence: 99%

Opto-Electronics Review

Kovačič

2022

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External light outcoupling structures provide a cost-effective and highly efficient solution for light extraction in organic light-emitting diodes. Among them, different microtextures, mainly optimized for devices with isotopically oriented emission dipoles, have been proposed as an efficient light extraction solution. In the paper, the outcoupling for a preferential orientation of emission dipoles is studied for the case of a red bottom-emitting organic light-emitting diode. Optical simulations are used to analyse the preferential orientation of dipoles in combination with three different textures, namely hexagonal array of sine-textures, three-sided pyramids, and random pyramids. It is shown that while there are minimal differences between the optimized textures, the highest external quantum efficiency of 51% is predicted by using the three-sided pyramid texture. Further improvements, by employing highly oriented dipole sources, are examined. In this case, the results show that the top outcoupling efficiencies can be achieved with the same texture shape and size, regardless of the preferred orientation of the emission dipoles. Using an optimized three-sided pyramid in combination with ideally parallel oriented dipoles, an efficiency of 62% is achievable. A detailed analysis of the optical situation inside the glass substrate, dominating external light outcoupling, is presented. Depicted results and their analysis offer a simplified further research and development of external light extraction for organic light-emitting devices with highly oriented dipole emission sources.

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“…Because more than 80% of light is lost due to the combined effect of total internal re ection (TIR) and waveguiding at boundaries of different refractive index materials [4,5,6]. Several literature methods such as the microporous polymer [7][8][9], the microlens array (MLAs) [10] have been proposed to counter the problem of light extraction e ciency by inserting the array onto the glass substrate. Because they don't induce any alteration either in the architecture of the device or in the functioning, these micropatterns onto the glass substrate only change the path of light propagation, resulting in the reduction of waveguide mode and an enhancement in external mode [10].…”

Section: Introductionmentioning

confidence: 99%

“…Several literature methods such as the microporous polymer [7][8][9], the microlens array (MLAs) [10] have been proposed to counter the problem of light extraction e ciency by inserting the array onto the glass substrate. Because they don't induce any alteration either in the architecture of the device or in the functioning, these micropatterns onto the glass substrate only change the path of light propagation, resulting in the reduction of waveguide mode and an enhancement in external mode [10]. However, in the processing of large-area substrates, MLAs' fabrication is easy and e cient [11].…”

Section: Introductionmentioning

confidence: 99%

Light Extraction Efficiency Analysis of Phosphorescent OLED Device with Microlens Array on the Glass Substrate

Sharma

Das

2021

Preprint

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The Computational simulation is based on the desired packing type of microlens array, either hexagonal or rectangular, onto the planar dual scheme OLED device's light-emitting surface. Both active layers here acted as a phosphorescent emission layer studied to improve device efficiency. The microlens array (MLAs) with hexagonal packing can increase the external quantum efficiency by 35%, which is more than the literature mentioned earlier. It significantly enhances the outcoupling efficiency below the critical angle observation concerning the substrate surface normal. Besides, a broad spectrum is observed with a slight shoulder band around 650 nm in the E.L. (Electroluminance) emission curve. From the CIE x and CIE y index studied, the OLED device connected with either hexagonal or rectangular microlens arrays are more sensitive than the OLED device without microlens arrays to the viewing angle range. The effect of outcoupled efficiency as a function of ETL-TPBi thickness is studied under different polarization modes. Hence, the study suggested that a microlens array with a hexagonal or rectangular packing type on the OLED device's top significantly enhanced light extraction efficiency and provided better device fabrication results.

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Simulation for light extraction efficiency of OLEDs with spheroidal microlenses in hexagonal array

Cited by 19 publications

References 73 publications

A morphological study of random nanostructured external light extraction layers for enhancing optical characteristics of OLEDs

A morphological study of random nanostructured external light extraction layers for enhancing optical characteristics of OLEDs

Opto-Electronics Review

Light Extraction Efficiency Analysis of Phosphorescent OLED Device with Microlens Array on the Glass Substrate

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