Enhanced Hole Injection Characteristics of a Top Emission Organic Light-Emitting Diode with Pure Aluminum Anode

Park, Chan Young; Choi, Byoungdeog

doi:10.3390/nano11112869

Cited by 7 publications

(4 citation statements)

References 23 publications

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“…We investigated the characteristics of white OLED devices with a reflective Al anode and fabricated a high-efficiency, top emitting white OLED device with an Al anode by improving the hole-injection characteristics [5].…”

Section: Discussionmentioning

confidence: 99%

P‐124: Efficiency Enhanced Top Emitting OLED‐on‐Silicon Microdisplay with Aluminum Anode

Park,

Hyun,

Choi

2023

Symp Digest of Tech Papers

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A top emitting organic light emitting diode‐on‐silicon (OLEDoS) panel with aluminum (Al) anode for high‐resolution microdisplays was proposed and fabricated. The low work function of the Al anode increases the energy barrier of the interface between the anode and hole injection layer (HIL), and has poor hole‐injection properties, which causes the low efficiency of the device. To enhance the hole‐injection characteristics of the Al anode, we applied optimized HIL and hole transportation layer (HTL) materials. The proposed single stack structure white OLED display panel with Al anode was fabricated on CMOS backplane and the white OLED device improved efficiency by up to 20 cd/A at 1000 nit, which is 90% of the level of conventional OLEDs with indium tin oxide (ITO) anode.

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Section: Discussionmentioning

confidence: 99%

P‐124: Efficiency Enhanced Top Emitting OLED‐on‐Silicon Microdisplay with Aluminum Anode

Park,

Hyun,

Choi

2023

Symp Digest of Tech Papers

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“…To achieve the optimized carrier injection, the work function of the anode needs to match well with the (HOMO) energy level of HIL. Due to the HOMO energy level of most commonly used organic materials is greater than 5.0 eV [32], the work function of anode needs to be high enough. Therefore, the work functions of Al (150 nm)/ITO (10 nm) and Ag (120 nm)/ITO (5 nm) were analyzed by UPS.…”

Section: Physical and Electrical Properties Of Metal/ito Anodesmentioning

confidence: 99%

High-efficiency top-emitting organic light-emitting diodes based on metal/ITO composite electrodes

Zhao,

Pi,

et al. 2024

Phys. Scr.

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High-performance top-emitting organic light-emitting diodes (TEOLEDs) integrating the metal/ITO composite anodes were developed. The results revealed that covering the surface of Al anode with ITO layer could effectively improve the charge injection efficiency and balance the hole-electron charge. The effect of the thickness of ITO on the performance of TEOLEDs with Al/ITO anodes was further studied. The TEOLEDs with Al/ITO (5 nm) anode showed optimized performance, with the current efficiency (CE) and external quantum efficiency (EQE) enhanced by 40.0% and 34.5% compared to that of the OELD with pure Al anode, and increased by 93.1% and 33.5% compared to that of bottom-emitting OLEDs. In addition, the full width at half maximum (FWHM) was narrowed to 36 nm due to the micro-cavity effect of the top-emitting structure and the turn-on voltage decreased to as low as 2.3 V owing to the efficient charge injection and well-matched energy level. In addition, TEOLEDs using Ag/ITO as anode exhibited a slow roll-off of CE and EQE and a narrower FWHM of 30 nm, greatly improving the color purity. The strategy is simple and can significantly improve the efficiency of the TEOLEDs, which promotes the applications of OLEDs in the fields of ultra-high-definition displays and micro-displays.

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“…[1][2][3][4][5] Benefiting from the high aperture ratio, the inverted top-emitting OLEDs (TEOLEDs) have been widely adopted to achieve high-efficiency active-matrix display. [6][7][8][9][10] The full width at half…”

Section: Introductionmentioning

confidence: 99%

“…[ 1–5 ] Benefiting from the high aperture ratio, the inverted top‐emitting OLEDs (TEOLEDs) have been widely adopted to achieve high‐efficiency active‐matrix display. [ 6–10 ] The full width at half maximum (FWHM) and current efficiency (CE) of the TEOLEDs are significantly optimized owing to the micro‐cavity effect of the top‐emitting structure, promoting the applications in ultra‐high‐definition displays and micro‐displays. [ 11,12 ] However, one major challenge of the TEOLEDs is the severe waveguide and plasmonic losses, which hinders the light output‐coupling and results in the low external quantum efficiency (EQE).…”

Section: Introductionmentioning

confidence: 99%

Enhancing the Light Output‐Coupling of Inverted Top‐Emitting Organic Light‐Emitting Diodes by Using the Localized Surface Plasmon Resonance of Ag Nanoparticles

Zhao

Niu

Shi

et al. 2022

Adv Materials Inter

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maximum (FWHM) and current efficiency (CE) of the TEOLEDs are significantly optimized owing to the micro-cavity effect of the top-emitting structure, promoting the applications in ultra-high-definition displays and micro-displays. [11,12] However, one major challenge of the TEOLEDs is the severe waveguide and plasmonic losses, which hinders the light outputcoupling and results in the low external quantum efficiency (EQE). [13,14] Introducing the localized surface plasmon resonance (LSPR) in the device is an effective way to increase the EQE of the OLEDs. [15,16] The LSPR is generated by overlapping the local electromagnetic field of excitons in the emitting layer and the surface plasmons of the noble metal in form of the nanowire and nanoparticles (NPs). [17][18][19][20][21] When the absorption peak of the metal NPs matches the emission wavelength of the device, the local electromagnetic fields around the NPs at a specific wavelength are enhanced. [22,23] More importantly, the LSPR is greatly influenced by the size of the noble metal NPs. [24,25] By precisely adjusting the size and the spacing of the NPs, the resonance wavelength of the NPs can be tuned to well match the wavelength of the electroluminescence (EL) spectra of OLEDs. [26,27] However, there are few reports on the effect of the LSPR on the inverted TEOLEDs.In this study, we have introduced a light output-coupling layer (LOCL) composed of AgNPs and MoO x on the top capping layer (CPL) of the inverted TEOLED device. The AgNPs in the LOCL could significantly improve the light output-coupling of the TEOLED owing to the LSPR, and the MoO x in the LOCL could effectively protect the water-and oxygen-sensitive electron injection material. In addition, the FWHM is narrowed to 50 nm due to the micro-cavity effect of the top-emitting structure and the turn-on voltage (V on , calculated at the lowest brightness of ≈1 cd m −2 ) is decreased to 2.6 V with Ag 2 O doped 4,7-diphenyl-1,10-phenanthroline (Bphen) as electron injection layer (EIL). Through systematical analysis and the finite difference time domain simulation (FDTD), we found that when the thickness of the AgNPs was 0.5 nm and the thickness of MoO x was 20 nm, the light output-coupling of the device reached the best. The CE and the EQE were increased 1.53 and 1.3 times to 28.3 cd A −1 and 13.11%, and the luminance achieves 34 247 cd m −2 .In this study, a light out-coupling layer (LOCL) composed of Ag nanoparticles (NPs) and MoO x is introduced on top of the inverted top-emitting organic light-emitting diode (OLED). The full width at half maximum (FWHM) is narrowed to 50 nm due to the micro-cavity effect of the top-emitting structure and the turn-on voltage is as low as 2.6 V. The AgNPs in the LOCL significantly improves the light output-coupling of the OLED owing to the localized surface plasmon resonance, and the MoO x in the LOCL effectively protects the water-and oxygen-sensitive electron injection material. As a result, the performance of the OLED with the LOCL is significantly enhanced. The maximum...

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Enhanced Hole Injection Characteristics of a Top Emission Organic Light-Emitting Diode with Pure Aluminum Anode

Cited by 7 publications

References 23 publications

P‐124: Efficiency Enhanced Top Emitting OLED‐on‐Silicon Microdisplay with Aluminum Anode

P‐124: Efficiency Enhanced Top Emitting OLED‐on‐Silicon Microdisplay with Aluminum Anode

High-efficiency top-emitting organic light-emitting diodes based on metal/ITO composite electrodes

Enhancing the Light Output‐Coupling of Inverted Top‐Emitting Organic Light‐Emitting Diodes by Using the Localized Surface Plasmon Resonance of Ag Nanoparticles

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