Article
Optics
Longheng Qi, Peian Li, Xu Zhang, Ka Ming Wong, Kei May Lau
Summary: A prototype of full-color micro-LED micro-display with a pixel density of 391 ppi is demonstrated using InGaN/AlGaInP heterogeneous integration. This display shows the feasibility and prospects of high brightness, good color performance, and high-resolution micro-LED micro-displays in future metaverse applications.
LIGHT-SCIENCE & APPLICATIONS
(2023)
Article
Chemistry, Physical
Do-Yeong Shin, Taehwan Kim, Ozgun Akyuz, Hilmi Volkan Demir, In-Hwan Lee
Summary: This study presents an improved efficiency design for white LEDs by integrating blue nanorod LEDs with green and red-emitting perovskite nanocrystal films. The design utilizes the localized surface plasmon effect of Ag@SiO2 nanoparticles to enhance the photoluminescence intensity of blue LEDs, while the high-power blue LED backlight improves the perovskite photoluminescence intensity. The resulting white LED with Ag@SiO2 nanoparticle-embedded nanorods demonstrates a 62% increase in photoluminescence intensity compared to planar white LEDs.
JOURNAL OF ALLOYS AND COMPOUNDS
(2022)
Article
Optics
Panpan Li, Hongjian Li, Yifan Yao, Kai Shek Qwah, Mike Iza, James S. Speck, Shuji Nakamura, Steven P. Denbaars
Summary: In this work, we demonstrate the vertical integration of nitride-based blue/green micro-light-emitting diode (mu LED) stacks with independent junction control using a hybrid tunnel junction (TJ). The hybrid TJ was grown by metal-organic chemical vapor deposition (p + GaN) and molecular-beam epitaxy (n + GaN). Different junction diodes were able to generate uniform blue, green, and blue/green emissions. The peak external quantum efficiency (EQE) of the TJ blue mu LEDs and green mu LEDs with indium tin oxide contact were 30% and 12%, respectively. Carrier transportation between different junction diodes was discussed. This work suggests a promising approach for vertical mu LED integration to enhance the output power of single LED chips and monolithic mu LEDs with different emission colors and independent junction control.
Article
Multidisciplinary Sciences
Mihyang Sheen, Yunhyuk Ko, Dong-uk Kim, Jongil Kim, Jin-ho Byun, YongSeok Choi, Jonghoon Ha, Ki Young Yeon, Dohyung Kim, Jungwoon Jung, Jinyoung Choi, Ran Kim, Jewon Yoo, Inpyo Kim, Chanwoo Joo, Nami Hong, Joohee Lee, Sang Ho Jeon, Sang Ho Oh, Jaekwang Lee, Nari Ahn, Changhee Lee
Summary: In this study, a blue nanorod LED with high external quantum efficiency (EQE) was demonstrated by reducing the size-dependent efficiency reduction through passivation. This work paves the way for manufacturing self-emissive nanorod LED displays for next-generation display technologies.
Article
Materials Science, Multidisciplinary
Yong-Ho Ra, Cheul-Ro Lee
Summary: A new approach to reduce the size of photonic device chips is reported, utilizing a monolithic light reflector-nanowire LED system. Vertical cavity nanowire structure for surface-lighting emission is developed using selective area epitaxy, with the light reflection provided by Al metal reflector deposited by MBE technique. The approach shows significantly improved light efficiency at specific spectral wavelength, promising a new route for next-generation photonic and electronic devices.
ADVANCED MATERIALS TECHNOLOGIES
(2021)
Review
Materials Science, Multidisciplinary
Wai Yuen Fu, Hoi Wai Choi
Summary: With the increasing interest in full-color microLED display technologies, researchers have been looking for cost-effective solutions to achieve multicolor emission from a single wafer. Monolithic integration of different color emitters onto a single chip or wafer offers higher yield, scalability, robustness, efficiency, and manufacturability compared to traditional heterogeneous integration approaches. This review provides an overview of the main monolithic integration approaches for polychromatic emitters and highlights the potential applications in phosphor-free white light sources, chip-scale color microLED displays, and GaN-based optoelectronic systems and platforms.
PHYSICA STATUS SOLIDI-RAPID RESEARCH LETTERS
(2022)
Article
Chemistry, Physical
Kyung Rock Son, Vignesh Murugadoss, Kyeong Heon Kim, Tae Geun Kim
Summary: This study investigates the effect of different passivation materials on the chemical bonds at the sidewall/passivation layer interface of μ-LEDs. The results show that the right passivation material can suppress non-radiative defects and enhance the light output power and current density of μ-LEDs.
APPLIED SURFACE SCIENCE
(2022)
Article
Optics
Zhe Zhuang, Daisuke Iida, Martin Velazquez-Rizo, Kazuhiro Ohkawa
Summary: The study introduced a method for fabricating ultra-small InGaN μLEDs, successfully realizing different shapes of green μLEDs. It was found that as the size of the μLED decreases, the series resistance and turn-on voltage increase, while the light output power density and external quantum efficiency also improve.
Article
Optics
Yun-Han Chang, Yu-Ming Huang, Fang-Jyun Liou, Chi-Wai Chow, Yang Liu, Hao-Chung Kuo, Chien-Hung Yeh, Wahyu Hendra Gunawan, Tun-Yao Hung, Yin-He Jian
Summary: This paper proposes and implements a high-bandwidth white-light visible light communication system using a semipolar blue micro-LED and yellow phosphor film, achieving high data rate and low bit error rate.
Article
Chemistry, Physical
Priyabrata Sadhukhan, Min Seong Kim, Sung-Doo Baek, Jae-Min Myoung
Summary: Halide perovskites have potential for use in next-generation low-cost, high-efficiency, and highly color-pure light-emitting diodes (LED), but they still lag behind other technologies in terms of performance. This study demonstrates the use of an ionic liquid as a potential additive to improve the performance of perovskite LEDs by controlling their morphology and preventing defects and ion migration.
Article
Materials Science, Ceramics
Hanxiao Kong, Guang Jia, Huilin Li, Zhaoxin Meng, Ning Zhang, Cuimiao Zhang
Summary: A variety of Bi3+ and/or Eu3+ doped KBaYSi2O7 phosphors with different colors have been successfully synthesized. The Bi3+ doped phosphors show intense cyan emission or unique narrow deep blue emission, which can be used for WLEDs. By adjusting the doping concentrations of Bi3+ and Eu3+, the luminescence colors of KBaYSi2O7 can be tuned. The as-synthesized phosphors exhibit great potential for application in WLEDs and solid-state lighting.
CERAMICS INTERNATIONAL
(2023)
Article
Materials Science, Multidisciplinary
Pratik D. Baheti, Rupesh A. Talewar, S. V. Moharil
Summary: This study investigates a phosphor converted white LED using a yellow and red emitting material. K2SiF6:Mn4+ is prepared as the red emitting phosphor using a wet chemical technique. A white LED is fabricated using a blue InGaN LED chip coated with Y3Al5O12:Ce3+ and K2SiF6:Mn4+ phosphor. The effects of K2SiF6:Mn4+ as the red emitting material in combination with the blue InGaN LED chip and Y3Al5O12:Ce3+ phosphor are also studied. The resulting white LED shows a CIE value of (x=0.31, y=0.33) and a CRI of 78.1.
Article
Engineering, Electrical & Electronic
Jiahao Yin, Xiaoshuai An, Liang Chen, Jing Li, Jianan Wu, Yumeng Luo, Qing Wang, Hongyu Yu, Kwai Hei Li
Summary: The study focused on monolithic integrated photodetectors (PDs) in InGaN/GaN LEDs for monitoring LED intensity fluctuations. Through simulation and experiments, it was found that placing the PD in the center of the LED resulted in a 58% increase in detected photocurrent with minimal impact on the LED emission profile compared to placing the PD at the edge. Encapsulating the LED-PD device with yellow phosphor enabled white light emission, and the on-chip PD showed similar sensing behaviors to an external Si-based photodiode. The optimal monolithic PD design offered comparable sensing capabilities, compactness, insensitivity to ambient lighting, and minimal influence on the LED emission profile, making it suitable for real-time monitoring of LED intensity in practical and scientific lighting applications.
IEEE TRANSACTIONS ON ELECTRON DEVICES
(2021)
Article
Engineering, Electrical & Electronic
Qiang Su, Heng Zhang, Shuming Chen
Summary: By utilizing transparent QLED elements, individually addressable red/green/blue emissions can be achieved in tandem QLEDs, with the ability to connect QLED elements in series or in parallel to improve external quantum efficiency.
This new implementation strategy for tandem QLEDs shows promising applications in both display and lighting fields, with enhanced EQE.
NPJ FLEXIBLE ELECTRONICS
(2021)
Article
Chemistry, Multidisciplinary
Shuai Yuan, Lin-Song Cui, Linjie Dai, Yun Liu, Qing-Wei Liu, Yu-Qi Sun, Florian Auras, Miguel Anaya, Xiaopeng Zheng, Edoardo Ruggeri, You-Jun Yu, Yang-Kun Qu, Mojtaba Abdi-Jalebi, Osman M. Bakr, Zhao-Kui Wang, Samuel D. Stranks, Neil C. Greenham, Liang-Sheng Liao, Richard H. Friend
Summary: The research demonstrates that using fluorene-based pi-conjugated cationic polymer blended with perovskite semiconductors can achieve efficient blue LEDs with good electroluminescence and spectral stability. The mixed halide perovskite LEDs exhibit CIE coordinates of (0.08, 0.22) and (0.12, 0.13), showcasing great potential for stable blue perovskite LEDs.
ADVANCED MATERIALS
(2021)