Highly efficient flexible organic light-emitting diodes based on a high-temperature durable mica substrate

Lai, Yi Ning; Chang, Chih-Hao; Wang, Pei Chun; Chu, Ying‐Hao

doi:10.1016/j.orgel.2019.105442

Cited by 15 publications

(15 citation statements)

References 44 publications

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“…The situation of mutual offset intensifies with the degree of heterojunction, leading to lower current densities. This phenomenon was opposite to the charge generation layer (CGL) structure observed in the tandem devices [23][24][25]. The HAT-CN/TAPC heterojunction is recognized as one of the most effective CGL structures.…”

Section: Structures Of the Hilmentioning

confidence: 77%

A Method to Realize Efficient Deep-Red Phosphorescent OLEDs with a Broad Spectral Profile and Low Operating Voltages

Chen

Huang

et al. 2021

Materials

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Organic light-emitting diodes (OLEDs) used as phototherapy light sources require sufficient spectral distribution in the effective wavelength ranges and low operating voltages. Herein, a double emitting layer structure consisting of a red-emitting Ir(piq)2acac and a deep-red Ir(fliq)2acac was designed to generate a broad electroluminescence spectrum. An efficient TCTA:CN-T2T exciplex system was used as the host of the emitting layer, facilitating effective energy transfer from the exciplex host to the red and deep-red phosphors. The materials used in the exciplex host were also used as the carrier transport layers to eliminate the energy barriers and thus increase the current density. The hole injection layer structures were varied to examine the hole injection capabilities and the carrier balance. The resulting optimized phosphorescent OLEDs with a broad spectral profile exhibit a 90% coverage ratio in the target ranges from 630 to 690 nm, together with a high peak efficiency of 19.1% (10.2 cd/A and 13.8 lm/W). The proposed device only needs 5.2 V to achieve a power density of 5 mW/cm2, implying that the device could be driven via two series-connected button cell batteries. These results illustrate the feasibility of our design concepts and demonstrate the realization of a portable and lightweight OLED phototherapy light source.

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Section: Structures Of the Hilmentioning

confidence: 77%

A Method to Realize Efficient Deep-Red Phosphorescent OLEDs with a Broad Spectral Profile and Low Operating Voltages

Chen

Huang

et al. 2021

Materials

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“…Considering the consistency of the electron-transport materials used in the tandem device ( i.e. , device CT), the electron-transporting B3PyMPM co-doped with lithium carbonate (Li 2 CO 3 ) was adopted as an n-type layer, while HAT-CN with its strong oxidizing property was used to further strengthen the electron injection. , Furthermore, the charge generation interface was expected to form between the HAT-CN layer and the adjacent hole-transporting TAPC layer . Consequently, the optimal tandem device was fabricated with the following generalized design: ITO (120 nm)/TAPC (25 nm)/TCTA (5 nm)/ imM- m -Cz doped with 8 wt % Ir(ppy) 3 (20 nm)/B3PyMPM (40 nm)/B3PyMPM doped with 20 wt % Li 2 CO 3 (10 nm)/HAT-CN (10 nm)/TAPC (75 nm)/TCTA (5 nm)/ imM- m -Cz doped with 8 wt % Ir(ppy) 3 (20 nm)/B3PyMPM (50 nm)/LiF (0.8 nm)/Al (150 nm).…”

Section: Resultsmentioning

confidence: 99%

Dicyano-Imidazole-Based Host Materials Possessing a Balanced Bipolar Nature To Realize Efficient OLEDs with Extremely High Luminance

Shao

Lin

et al. 2020

J. Phys. Chem. C

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Most phosphorescent devices suffer from severe triplet−triplet annihilation (TTA), and the efficiency recording at high luminance is much lower than that at low luminance, making the practicality worse than expected. In this study, a series of donor−acceptor (D−A) molecules consisting of dicyano-imidazole and phenylcarbazole were synthesized and applied to the host materials. For electroluminescence applications, imM-m-Cz-based green-emitting organic light-emitting diodes show a maximum luminance of 1.68 × 10 5 cd m −2 at 11.2 V, which is 20% higher than that of the benchmark host 4,4′-bis(N-carbazolyl)-1,1′-biphenyl at 13.4 V; in addition, the turn-on voltage (V on ) is only 2.3 V. In terms of hole and electron mobility, imM-m-Cz shows one of the most balanced carrier mobilities in the reported literature (electron and hole mobilities of 3.64 × 10 −5 and 4.23 × 10 −5 cm 2 V −1 s −1 , respectively). The balanced carrier mobility can help expand the recombination region and thus reduce the formation of TTA. Furthermore, the high maximum luminance of about 2.80 × 10 5 cd m −2 obtained in an imM-m-Cz-based tandem device demonstrates a sufficiently high current density/luminance, and the peak efficiency achieves an even higher efficiency of 40.6% (1.51 × 10 5 cd A −1 and 98.6 lm W −1 ), which is among the highest reported properties based on imidazole-based host materials. Combining the balanced carrier mobility with the proper device design in this study, the efficiency roll-off under high luminance can be greatly reduced, and the practicality of the resulting phosphorescent device can be significantly improved.

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“…Advances in internet of things (IoT) applications based on semiconductor sensors have opened the door to wearable devices, smart buildings, and optimization of manufacturing processes. − Many applications involving semiconductor devices require robustness under high-temperature conditions as well as long-term resilience and flexibility. Plastics can be used to create flexible substrates with a high degree of transparency, durability, and robustness; however, they are ill-suited to high-temperature environments and preclude the use of annealing to produce high-quality oxide semiconductors. , Therefore, the choice of flexible substrate materials plays an important role. Mica is highly transparent, flexible, impermeable to moisture, and resistant to high temperatures, making it an excellent candidate substrate for a variety of devices.…”

Section: Introductionmentioning

confidence: 99%

“…Mica is highly transparent, flexible, impermeable to moisture, and resistant to high temperatures, making it an excellent candidate substrate for a variety of devices. Note that mica is also relatively lightweight, inexpensive, and easy to process, with excellent electrical resistance and robustness under acidic and alkaline conditions. , The layered structure of mica can be easily separated due to van der Waals forces, which makes it highly flexible and strong and reduces the requirements for mechanical equipment. , …”

Section: Introductionmentioning

confidence: 99%

“…Plastics can be used to create flexible substrates with a high degree of transparency, durability, and robustness; however, they are illsuited to high-temperature environments and preclude the use of annealing to produce high-quality oxide semiconductors. 4,5 Therefore, the choice of flexible substrate materials plays an important role. Mica is highly transparent, flexible, impermeable to moisture, and resistant to high temperatures, making it an excellent candidate substrate for a variety of devices.…”

Section: ■ Introductionmentioning

confidence: 99%

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Perovskite Quantum Dot–ZnO Nanowire Composites for Ultraviolet–Visible Photodetectors

Tang

Sie

Tseng

et al. 2022

ACS Appl. Nano Mater.

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In this study, we developed a photodetector and humidity sensor based on zinc oxide nanowires (ZnO NWs) with CsPbBr3 perovskite quantum dots (PQDs). PQDs are ideally suited to semiconductor sensors due to their excellent optoelectronic properties, including the high carrier mobility, high absorption coefficient, and effective charge transfer at heterojunctions. The ZnO NWs were created via chemical bath deposition, and PQDs were created via a one-step injection method. I–V curves revealed that the current leakage of PQD/ZnO NWs was lower than that of ZnO NWs. PQD/ZnO NWs also generated a larger number of photogenerated carriers, which improved sensor responses, regardless of the illumination wavelength. Under UV illumination, the photocurrent of both structures decreased with an increase in relative humidity; however, under green light illumination, the photocurrent of PQD/ZnO NWs increased with humidity. This study also investigated the optical properties of the two structures as candidate sensor mechanisms.

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Highly efficient flexible organic light-emitting diodes based on a high-temperature durable mica substrate

Cited by 15 publications

References 44 publications

A Method to Realize Efficient Deep-Red Phosphorescent OLEDs with a Broad Spectral Profile and Low Operating Voltages

A Method to Realize Efficient Deep-Red Phosphorescent OLEDs with a Broad Spectral Profile and Low Operating Voltages

Dicyano-Imidazole-Based Host Materials Possessing a Balanced Bipolar Nature To Realize Efficient OLEDs with Extremely High Luminance

Perovskite Quantum Dot–ZnO Nanowire Composites for Ultraviolet–Visible Photodetectors

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