Article
Chemistry, Multidisciplinary
Sabina Hillebrandt, Chang-Ki Moon, Adriaan J. Taal, Henry Overhauser, Kenneth L. Shepard, Malte C. Gather
Summary: This research demonstrates the direct deposition of ultrabright micro-OLEDs on needle-shaped CMOS chips, enabling high-resolution and fully-filled self-emissive microdisplays. By optimizing the contact conditions and implementing silver interlayers, orange- and blue-emitting OLED stacks can be directly vacuum-deposited on the chips, forming micrometer-sized pixels. Each needle contains electronics that allow individual pixel switching. The OLED pixels achieve an average optical power density of 0.25 mW mm(-2), equivalent to >40,000 cd m(-2), surpassing the requirements for daylight AR applications and optogenetic single-unit activation in the brain.
ADVANCED MATERIALS
(2023)
Article
Chemistry, Multidisciplinary
Geun-Su Choi, Shin-Woo Kang, Eun-Jeong Bae, Eun-Bi Jang, Dong-Hyun Baek, Byeong-Kwon Ju, Young-Wook Park
Summary: The study focuses on fabricating a random nanostructure external light extraction composite layer with high-refractive-index nanoparticles, achieving improved external quantum efficiency in OLEDs. By using a low-temperature mask-free process to control the optical properties, the RNSs can reduce waveguide mode and total reflection.
Article
Chemistry, Multidisciplinary
Geun-Su Choi, Eun-Jeong Bae, Byeong-Kwon Ju, Young-Wook Park
Summary: This study investigates the application of scattering structures on the metal layer in a DMD configuration through plasma treatment to enhance the light extraction efficiency of OLEDs. Different plasma conditions were explored to create scattering structures, and the fabricated devices were characterized for their electrical and optical properties. The results demonstrate that the introduction of scattering structures through plasma treatment effectively improves the light extraction efficiency of OLEDs, specifically using O-2 plasma treatment on the metal layer.
Article
Chemistry, Multidisciplinary
Kunsik An, Chaewon Kim, Sunkuk Kim, Taesoo Lee, Dongyeol Shin, Jaemin Lim, Donghyo Hahm, Wan Ki Bae, Jun Young Kim, Jeonghun Kwak, Jaehoon Kim, Kyung-Tae Kang
Summary: This paper presents a novel light extraction structure called RaDiNa, which enhances the light extraction capability of top-emitting quantum dot light-emitting diodes (TE-QLEDs). By detaching a polydimethylsiloxane (PDMS) film from a ZnO nanorod (ZnO NR) layer and laying it on top of the TE-QLED, the RaDiNa-attached TE-QLED achieves significantly improved external quantum efficiency (EQE) compared to the reference device. This study provides essential information for the commercialization of TE-QLEDs.
Article
Chemistry, Physical
Wenwen Wu, Yue Liu, Xinping Zhang
Summary: Researchers have developed a large-area array of nanoscale organic light-emitting diodes (OLEDs) that produce amplified emission with a selected spectrum in a narrow band. These OLEDs share a common active layer that acts as a waveguide and gain channel for light-emitting signals. The periodic structure of the array allows for diffraction and confinement of the electroluminescence signal, resulting in strong spectral selectivity and amplification.
JOURNAL OF PHYSICAL CHEMISTRY LETTERS
(2023)
Article
Optics
Zhi-Yu Chen, Ru-Jian Zhang, Yu-Ping Wang, Da Yin, Yue-Feng Liu, Yan-Gang Bi, Jing Feng
Summary: In this study, a simple method is proposed to introduce spontaneously formed disordered wrinkles into organic light-emitting devices (OLEDs) in order to enhance light extraction and achieve stretchability. The wrinkled OLEDs show significant improvements in luminance and current efficiency compared to planar devices, and exhibit angle-stable electroluminescent spectra at wide viewing angles due to broadband light scattering induced by the disordered wrinkles.
Article
Optics
Linyu Cao, Kody Klimes, Yunlong Ji, Tyler Fleetham, Jian Li
Summary: The newly developed tetradentate Pd(ii) complex Pd3O8-P with near unity photoluminescent quantum yield has potential applications in high-brightness, long-lifetime OLED devices. Its features include high quantum efficiency, reduced efficiency roll-off, and an estimated operational half-lifetime of several million hours.
Article
Nanoscience & Nanotechnology
Songman Ju, Chaomin Mao, Jinping Zheng, Kaiyu Yang, Lihua Lin, Tailiang Guo, Hailong Hu, Fushan Li
Summary: This work proposes a new strategy to enhance the electroluminescent performance of perovskite quantum dots (PQDs) by creating a PQD film. By manipulating the ion distribution and trap density in the PQD film through varying pre-bias voltage and time, the device's capacitance value and luminous efficiency can be modified. The external quantum efficiency of the device increased from 2.81% to 7.95% through this strategy. This research provides a new approach for achieving perovskite quantum dot light-emitting devices with high luminous efficiency.
ACS APPLIED NANO MATERIALS
(2023)
Article
Physics, Applied
Tian-Run Zhang, Ya-Nan Wang, Yue-Feng Liu, Jing Feng
Summary: A transparent ultrathin Ag nanomesh electrode was fabricated using nanosphere lithography and a dielectric wetting layer. The nanomesh electrode exhibited higher figure of merit and improved optical and electrical performance compared to traditional ultrathin film Ag electrodes.
APPLIED PHYSICS LETTERS
(2022)
Article
Engineering, Electrical & Electronic
Kun Wang, Ye Liu, Rong Chen, Chaoxing Wu, Xiongtu Zhou, Yongai Zhang, Zhiqiang Liu, Tailiang Guo
Summary: The study demonstrates that LEDs operating in the Noncarrier Injection mode can split a single light pulse into multiple pulses with small widths using combined signals. Theoretical equations and experimental evidence are provided to explain and validate this light-pulse splitting phenomenon, offering insights into the working mechanisms of NCI mode and its potential applications in advanced light-pulse technology.
IEEE ELECTRON DEVICE LETTERS
(2021)
Article
Optics
Bo -Yen Lin, Ya-Xun Lin, Shao-Ju Lin, Yi-Yen Lin, Su-Hua Chen, Mao-Kuo Wei
Summary: The use of self-assembly microlens array films (MAFs) made of silica microspheres and acrylic resin significantly improves the light extraction efficiency (LEE) and angular-spectrum stability of organic light emitting diodes (OLEDs). The MAFs, fabricated through a simple and cost-effective spin-coating process, have a high fill factor of 71.42% and exhibit high transmittance (86.2-90.6%) and high haze (78.9-82.4%) in the UV-Vis regime. The incorporation of MAFs enhances the external quantum efficiency (EQE) of OLEDs by 66% compared to reference OLEDs, while maintaining a small angular shift of CIE-indices and a wide viewing angle range.
JOURNAL OF LUMINESCENCE
(2023)
Article
Chemistry, Multidisciplinary
Xiangyu Fu, Yash Mehta, Yi-An Chen, Lei Lei, Liping Zhu, Nilesh Barange, Qi Dong, Shichen Yin, Juliana Mendes, Siliang He, Renuka Gogusetti, Chih-Hao Chang, Franky So
Summary: The study demonstrates highly directional and polarized light emission from LEDs by selectively diffracting the TE waveguide mode, showing potential for more efficient photonic applications.
ADVANCED MATERIALS
(2021)
Article
Materials Science, Multidisciplinary
Ian Sachs, Marc Fuhrmann, Inge Verboven, Indranil Basak, Wim Deferme, Hildegard Moebius
Summary: Research on enhancing the out-coupling efficiency of organic light-emitting diodes (OLEDs) is ongoing, with the use of macrolenses to prevent total internal reflection at the glass-air interface. The design of the lenses considers the dimensions of the OLED and the contact angle, and a process based on inkjet etching and printing allows for the printing of lenses with defined radius and contact angle, resulting in improved luminance measurements.
ADVANCED ENGINEERING MATERIALS
(2021)
Article
Materials Science, Multidisciplinary
Zhanxu Chen, Jialing Zhang, Runhong Ding, Feng Wu, An Wang, Guanghui Liu, Wei Wan
Summary: The study investigates the patterning of p-GaN and/or indium-tin-oxide (ITO) surfaces to improve light extraction efficiency for GaN-based LEDs. The results show that nanopillar-patterned p-GaN, ITO, and dual nanopillar-patterned p-GaN and ITO layers significantly enhance light output. The study also explores the mechanism of light extraction enhancement using 3D finite-difference time-domain method, and finds that LEDs with dual nanopillar-patterned p-GaN and ITO layers offer the best light extraction efficiency.
Article
Chemistry, Multidisciplinary
Ya-Hui Chang, Yen-Shou Lin, Konthoujam James Singh, Hsiang-Ting Lin, Chiao-Yun Chang, Zheng-Zhe Chen, Yu-Wei Zhang, Shih-Yen Lin, Hao-Chung Kuo, Min-Hsiung Shih
Summary: A multicolor AC-driven light-emitting device was developed by integrating a WSe2 monolayer and AlGaInP-GaInP multiple quantum well (MQW) structures. The CVD-grown WSe2 monolayer was placed on top of an AlGaInP-based LED wafer to create a two-dimensional/three-dimensional heterostructure. These hybrid devices expand the wavelength range of 2-D TMDC-based light emitters and support their implementation in various applications.
Article
Chemistry, Multidisciplinary
Geun-Su Choi, Shin-Woo Kang, Eun-Jeong Bae, Eun-Bi Jang, Dong-Hyun Baek, Byeong-Kwon Ju, Young-Wook Park
Summary: The study focuses on fabricating a random nanostructure external light extraction composite layer with high-refractive-index nanoparticles, achieving improved external quantum efficiency in OLEDs. By using a low-temperature mask-free process to control the optical properties, the RNSs can reduce waveguide mode and total reflection.
Article
Chemistry, Multidisciplinary
Eun-Jeong Bae, Hyeong-Kyu Maeng, Ji-Soo Shin, Dong-Wook Park, Young-Wook Park, Dong-Hyun Baek
Summary: A micro-sphere PDMS film is proposed to improve the external quantum efficiency (EQE) in OLEDs. The film is fabricated through a specific process and the size and distribution of the micro-spheres play essential roles in improving the performance. Additionally, the film, based on polymeric materials, offers advantages in cost control and large-scale production.
Article
Materials Science, Multidisciplinary
Eun Jeong Bae, Jong Woo Kim, Byeong-Kwon Ju, Dong-Hyun Baek, Young Wook Park
Summary: In this study, a flexible porous film was developed as a light-scattering layer to enhance the external light extraction in OLEDs. The properties of the porous film, including pore penetration depth and surface morphology, were influenced by the viscosity of the PDMS solution. The results showed that although the total transmittance was decreased, the EQE was improved by 30% compared to that of OLEDs without the porous film. This improvement can be attributed to the scattering effect resulting from the difference in refractive indices between the embedded air cavities and porous layer.
ORGANIC ELECTRONICS
(2022)
Article
Materials Science, Multidisciplinary
Jong-Woo Kim, Hyun Kyu Seo, Su Yeon Lee, Minsoo Park, Min Kyu Yang, Byeong-Kwon Ju
Summary: This study investigates the effect of gate insulators on a-IGZO thin-film transistors and finds that the dual-layer Ta2O5/SiO2 gate insulator significantly improves device characteristics, such as reducing leakage current, improving on/off ratios, and decreasing subthreshold swing.
Article
Computer Science, Information Systems
Jong-Woo Kim, Seong-Geon Park, Min Kyu Yang, Byeong-Kwon Ju
Summary: Oxide semiconductors have advantages in flexible electronic devices, and low-temperature microwave annealing can enhance transistor characteristics and reduce production time.
Article
Chemistry, Multidisciplinary
Jun-Young Park, Soo-Jong Park, Byeong-Kwon Ju
Summary: In this study, we investigated the degradation features of electrically aged blue TADF OLEDs by analyzing the capacitance-voltage characteristics. The highest stability was observed at the TCTA/EML interface, and the 0 nm-thick ExBL device showed the most stability.
APPLIED SCIENCES-BASEL
(2022)
Article
Chemistry, Physical
Jaehyun Han, Darya Burak, Valeriia Poliukhova, Albert S. S. Lee, Hoseong Jang, Seungsang Hwang, Kyung-Youl Baek, Joonsoo Han, Byeong-Kwon Ju, So-Hye Cho
Summary: Ladder-type polysilsesquioxanes (LPSQs) containing phenyl as a high refractive index unit and cyclic epoxy as a curable unit were combined with luminescent lanthanide metals to fabricate transparent films for color conversion in displays. The films showed high luminescence and transmittance properties due to the chelating properties of LPSQs with lanthanide ions and the light sensitizing effect of phenyl side chains. Addition of nanoparticles to LPSQs improved epoxy conversion rate and wear resistance. The LPSQs-lanthanide hybrid material is an effective color conversion layer for displays.
Article
Nanoscience & Nanotechnology
Seungwon Lee, Jun-Young Park, Jaewon Park, Jian Cheng Bi, Byeongwoo Kang, Young Hyun Hwang, Jiwon Seok, Young Wook Park, Byeong-Kwon Ju
Summary: This study employs exciton diffusion guidance and energy extraction to enhance the optical efficiency and suppress the roll-off characteristics of mixed-host blue TADF OLEDs. The nanopixel array, created by a nanoscale pixel-defining layer (nPDL), separates excitons and polarons, increasing triplet quenching through secure exciton diffusion. Additionally, a corrugated metal cathode structure enables nonradiative energy transfer to surface plasmon polaritons, boosting emission efficiency. The optimized nPDL structure leads to significant improvements in external quantum efficiency, current efficiency, power efficiency, and critical luminance.
ADVANCED ELECTRONIC MATERIALS
(2023)
Article
Chemistry, Multidisciplinary
Eun-Jeong Bae, Yeon-Sik Kim, Geun-Su Choi, Byeong-Kwon Ju, Dong-hyun Baek, Young-Wook Park
Summary: In this study, a flexible polydimethylsiloxane (PDMS) film with a micro-convex structure was used for the outcoupling of organic light-emitting diodes (OLEDs) using the breath figure (BF) method. The micro-convex pattern could be easily controlled by adjusting the concentration of polystyrene and the humidity during the BF process. The optical properties of the OLEDs, including transmission, diffusion, and electroluminescence, were evaluated with and without the micro-convex structure, and it was found that the shape and density of the micro-convex structure influenced the outcoupling efficiency.
Article
Chemistry, Multidisciplinary
Geun-Su Choi, Eun-Jeong Bae, Byeong-Kwon Ju, Young-Wook Park
Summary: This study investigates the application of scattering structures on the metal layer in a DMD configuration through plasma treatment to enhance the light extraction efficiency of OLEDs. Different plasma conditions were explored to create scattering structures, and the fabricated devices were characterized for their electrical and optical properties. The results demonstrate that the introduction of scattering structures through plasma treatment effectively improves the light extraction efficiency of OLEDs, specifically using O-2 plasma treatment on the metal layer.
Article
Dentistry, Oral Surgery & Medicine
Min Keun Kim, Min Ji Ham, Won Rae Kim, Hyung Giun Kim, Kwang Jun Kwon, Seong Gon Kim, Young Wook Park
Summary: This study aimed to evaluate the accuracy of three-dimensional surgical guides and titanium implants in a rabbit model, as well as the surgical outcomes of mandibulectomy and reconstructive surgery. The accuracy of the implants was within the acceptable error range, while the surgical accuracy varied in different measured areas. The angle between the mandibular lower borders showed the most sensitive results, and the distance between the lingual cusps of the first molars represented the most accurate outcomes. The angle between the mandibular lower borders was found to be a good indicator for evaluating reconstructive surgery outcomes.
MAXILLOFACIAL PLASTIC AND RECONSTRUCTIVE SURGERY
(2023)
Article
Nanoscience & Nanotechnology
Cheol Shin, Seungwon Lee, Kwang Wook Choi, Young Hyun Hwang, Young Wook Park, Byeong-Kwon Ju
Summary: In this study, a nanoscale random rubbed structure (nRRS) was evaluated for its application as a scattering layer in OLEDs. The optimized nRRS, fabricated via rubbing, exhibited high transmittance and haze, making it suitable for OLEDs and improving their external quantum efficiency. The optical performance of the nRRS-OLED was predicted through simulation and verified by experimental results.
NANOMATERIALS AND NANOTECHNOLOGY
(2022)
Article
Dentistry, Oral Surgery & Medicine
Yong-Chan Lee, Hong-Bum Sohn, Young-Wook Park, Ji-Hyeon Oh
Summary: This study evaluated the changes in condylar positions after orthognathic surgery using virtual surgical planning via the BOS system. The results showed that the change mainly occurred downward in the y-axis, with slight changes in the x- and z-axes.
MAXILLOFACIAL PLASTIC AND RECONSTRUCTIVE SURGERY
(2022)
