Emergence and control of photonic band structure in stacked OLED microcavities

AbstractWe demonstrate an electrically-driven metal-dielectric photonic crystal emitter by fabricating a series of organic light emitting diode microcavities in a vertical stack. The states of the individual microcavities are shown to split into bands of hybridized photonic energy states through interaction with adjacent cavities. The propagating photonic modes within the crystal depend sensitively on the unit cell geometry and the optical properties of the component materials. By systematically varying the metallic layer thicknesses, we show control over the density of states and band center. The emergence of a tunable photonic band gap due to an asymmetry-introduced Peierls distortion is demonstrated and correlated to the unit cell configuration. This work develops a class of one dimensional, planar, photonic crystal emitter architectures enabling either narrow linewidth, multi-mode, or broadband emission with a high degree of tunability.

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Study on Microlens Photonic Crystal Fabricated on Organic Light-Emitting Diode Substrate

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.395-396.125 ◽

2013 ◽

Vol 395-396 ◽

pp. 125-130

Author(s):

Yang Li ◽

Wei Xu

Keyword(s):

Photonic Crystal ◽

Band Gap ◽

Nanoimprint Lithography ◽

Photonic Band Gap ◽

Light Emitting Diode ◽

Gap Effect ◽

Organic Layer ◽

Organic Light Emitting Diode ◽

Micro Structures ◽

Photonic Band

Transferable microlens-structures were fabricated on the substrate of OLED by using nanoimprint lithography. As a result, the waveguide effect on each organic layer was reduced, which can facilitate the optical coupling of the substrate and is expected to increase luminous efficiency, and finally, the device with high brightness can be fabricated. Firstly, ultraviolet exposure and wet etching technology were combined to fabricate high-precision nanoimprint template with quartz glass; secondly, the cleaning and anti-adhesion treatment were used and finally transferable microlens-structures were fabricated on the substrate of OLED by using hot nanoimprint lithography. The result shows that the lens micro-structures are characterized by good flatness, high nanoimprinting precision. The parameters of micro-structures such as period, diameter and length were optimized using Finite-difference time-domain (FDTD) and finally, the optical crystal micro-structure with the photonic band gap effect was fabricated. The light outcoupling efficiency can be increased effectively due to the photonic band gap effect produced by photonic crystal structures on the substrate of OLED. The measuring result showed that both the emission spectrum and the light intensity were increased.

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Reduction of operating voltage in organic light-emitting diode by corrugated photonic crystal structure

Applied Physics Letters ◽

10.1063/1.1836867 ◽

2004 ◽

Vol 85 (23) ◽

pp. 5769-5771 ◽

Cited By ~ 59

Author(s):

Masayuki Fujita ◽

Tetsuya Ueno ◽

Kuniaki Ishihara ◽

Takashi Asano ◽

Susumu Noda ◽

...

Keyword(s):

Crystal Structure ◽

Photonic Crystal ◽

Light Emitting Diode ◽

Photonic Crystal Structure ◽

Operating Voltage ◽

Light Emitting ◽

Organic Light Emitting Diode ◽

Organic Light

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Far-field radiation of photonic crystal organic light-emitting diode

Optics Express ◽

10.1364/opex.13.005864 ◽

2005 ◽

Vol 13 (15) ◽

pp. 5864 ◽

Cited By ~ 36

Author(s):

Yong-Jae Lee ◽

Se-Heon Kim ◽

Guk-Hyun Kim ◽

Yong-Hee Lee ◽

Sang-Hwan Cho ◽

...

Keyword(s):

Photonic Crystal ◽

Light Emitting Diode ◽

Far Field ◽

Light Emitting ◽

Organic Light Emitting Diode ◽

Organic Light ◽

Field Radiation

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Metasurface-driven OLED displays beyond 10,000 pixels per inch

Science ◽

10.1126/science.abc8530 ◽

2020 ◽

Vol 370 (6515) ◽

pp. 459-463 ◽

Cited By ~ 3

Author(s):

Won-Jae Joo ◽

Jisoo Kyoung ◽

Majid Esfandyarpour ◽

Sung-Hoon Lee ◽

Hyun Koo ◽

...

Keyword(s):

Nanoimprint Lithography ◽

Light Emitting Diode ◽

Light Emitters ◽

Light Emitting ◽

Organic Light Emitting Diode ◽

Luminescence Efficiency ◽

Light Waves ◽

Integrated Devices ◽

Emission Modulation ◽

And Control

Optical metasurfaces are starting to find their way into integrated devices, where they can enhance and control the emission, modulation, dynamic shaping, and detection of light waves. In this study, we show that the architecture of organic light-emitting diode (OLED) displays can be completely reenvisioned through the introduction of nanopatterned metasurface mirrors. In the resulting meta-OLED displays, different metasurface patterns define red, green, and blue pixels and ensure optimized extraction of these colors from organic, white light emitters. This new architecture facilitates the creation of devices at the ultrahigh pixel densities (>10,000 pixels per inch) required in emerging display applications (for instance, augmented reality) that use scalable nanoimprint lithography. The fabricated pixels also offer twice the luminescence efficiency and superior color purity relative to standard color-filtered white OLEDs.

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Organic light-emitting diode with ITO∕organic photonic crystal

Electronics Letters ◽

10.1049/el:20031126 ◽

2003 ◽

Vol 39 (24) ◽

pp. 1750 ◽

Cited By ~ 33

Author(s):

M. Fujita ◽

T. Ueno ◽

T. Asano ◽

S. Noda ◽

H. Ohhata ◽

...

Keyword(s):

Photonic Crystal ◽

Light Emitting Diode ◽

Light Emitting ◽

Organic Light Emitting Diode ◽

Organic Light

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Mechanically strained a-Si:H AMOLED driver circuits

MRS Proceedings ◽

10.1557/proc-814-i6.13 ◽

2004 ◽

Vol 814 ◽

Cited By ~ 3

Author(s):

P. Servati ◽

S. Tao ◽

E. Horne ◽

D. Striakhilev ◽

K. Sakariya ◽

...

Keyword(s):

Light Emitting Diode ◽

Thin Film Transistor ◽

Mechanical Strain ◽

Drain Current ◽

Active Matrix ◽

Light Emitting ◽

Organic Light Emitting Diode ◽

The Individual ◽

External Strain

AbstractThis paper examines the variations in performance of amorphous silicon (a-Si:H) thin-film transistor (TFT) pixel driver circuits for active-matrix organic light-emitting diode (AMOLED) displays, which are subject to compressive or tensile mechanical strain. The external strain is induced by bending of the TFT substrate, and is measured by the observed changes in resistance of in-situ strain gauges. Mechanical strain impacts the performance of the circuit in terms of its drive current, which may be attributed to mobility and Fermi energy shifts in the individual TFTs. The effect of strain-induced shifts in the TFTs as a function of strain orientation (longitudinal or transverse) with respect to direction of current flow is also examined. Our measurements show that the variation in the drain current of a longitudinally oriented TFT can be as much as ∼ 1.5% for strains as high as 10−3. Proper layout and circuit design can suppress the effect of strain-induced shifts, and should be taken into consideration when designing stable TFT driver circuits for mechanically flexible AMOLED displays.

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Introduction of photonic crystal structure into organic light-emitting diode

10.1117/12.579597 ◽

2005 ◽

Author(s):

Masayuki Fujita ◽

Takashi Asano ◽

Susumu Noda ◽

Hiroshi Ohata ◽

Taishi Tsuji ◽

...

Keyword(s):

Crystal Structure ◽

Photonic Crystal ◽

Light Emitting Diode ◽

Photonic Crystal Structure ◽

Light Emitting ◽

Organic Light Emitting Diode ◽

Organic Light

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Complete polarization of electronic spins in OLEDs

Nature Communications ◽

10.1038/s41467-021-22191-3 ◽

2021 ◽

Vol 12 (1) ◽

Author(s):

Tobias Scharff ◽

Wolfram Ratzke ◽

Jonas Zipfel ◽

Philippe Klemm ◽

Sebastian Bange ◽

...

Keyword(s):

Spin Polarization ◽

Light Emitting Diode ◽

Spin Orbit Coupling ◽

Light Emitting ◽

Singlet Exciton ◽

Organic Light Emitting Diode ◽

Electronic Spin ◽

The Individual ◽

Microscopic Distribution ◽

Triplet Excitons

AbstractAt low temperatures and high magnetic fields, electron and hole spins in an organic light-emitting diode become polarized so that recombination preferentially forms molecular triplet excited-state species. For low device currents, magnetoelectroluminescence perfectly follows Boltzmann activation, implying a virtually complete polarization outcome. As the current increases, the magnetoelectroluminescence effect is reduced because spin polarization is suppressed by the reduction in carrier residence time within the device. Under these conditions, an additional field-dependent process affecting the spin-dependent recombination emerges, possibly related to the build-up of triplet excitons and their interaction with free charge carriers. Suppression of the EL alone does not prove electronic spin polarization. We therefore probe changes in the spin statistics of recombination directly in a dual singlet-triplet emitting material, which shows a concomitant rise in phosphorescence intensity as fluorescence is suppressed. Finite spin-orbit coupling in these materials gives rise to a microscopic distribution in effective g-factors of electrons and holes, Δg, i.e., a distribution in Larmor frequencies. This Δg effect in the pair, which mixes singlet and triplet, further suppresses singlet-exciton formation at high fields in addition to thermal spin polarization of the individual carriers.

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