Review
Chemistry, Physical
Zinan Chen, Haotao Li, Cuixia Yuan, Peili Gao, Qiang Su, Shuming Chen
Summary: Colloidal quantum-dot-based light-emitting diodes (LEDs) with narrow emission linewidth show great potential for high-precision color displays. However, the industrialization of QLED displays still faces challenges including unclear device mechanisms, low blue performance, and immature color patterning processes. This paper provides a comprehensive review of recent advancements in QLED displays and focuses on device mechanisms, blue QLEDs, and color patterning. Opportunities, challenges, solutions, and future research directions are also summarized.
Article
Chemistry, Physical
Lianna Chen, Zhiyuan Qin, Shuming Chen
Summary: In this study, a new method has been developed to achieve high-resolution pixelated emission by controlling the thickness of transparent electrodes, resulting in a color-converting cavity that can selectively convert unpatterned quantum-dot white emission into saturated red, green, and blue emission. This method enables ultrahigh density red, green, and blue emission with a resolution of approximately 1700 pixels per inch, as well as achieving a color gamut of 111% NTSC.
Article
Engineering, Electrical & Electronic
Guanding Mei, Weigao Wang, Dan Wu, Philip Anthony Surman, Kai Wang, Wallace C. H. Choy, Xiaochuan Yang, Wenwei Xu, Xiao Wei Sun
Summary: This study explores the use of microcavities to fabricate full-color quantum dot light-emitting diodes (QLEDs) with a single QD layer. It demonstrates that by enhancing the microcavity and selecting the appropriate spacer thickness, the emitting color of the QLEDs can be tuned. The experimental results align well with the theoretical design and show high color purity and an expanded color gamut.
IEEE PHOTONICS JOURNAL
(2022)
Review
Chemistry, Multidisciplinary
Jaehoon Kim, Jeongkyun Roh, Myoungjin Park, Changhee Lee
Summary: Colloidal quantum dots (QDs) have great potential in display technologies due to their unique optical properties. Significant improvements have been achieved in quantum dot light-emitting diodes (QLEDs) in the past decade, primarily through the development of high-quality QDs and optimized device architectures. This review provides insights into the current status and development direction of QLEDs, guiding the way towards their commercialization.
ADVANCED MATERIALS
(2023)
Article
Chemistry, Multidisciplinary
Jaeyoul Kim, Donghyo Hahm, Wan Ki Bae, Hyunho Lee, Jeonghun Kwak
Summary: This study analyzes the transient electroluminescence signals of dichromatic QLEDs and provides insights into the operation mechanisms such as charge injection, exciton recombination, and electron mobility. Additionally, it quantitatively measures the effects of Förster resonant energy transfer and exciton quenching in QLED operation.
Review
Chemistry, Physical
Taesoo Lee, Minhyung Lee, Hansol Seo, Minjun Kim, Beomsoo Chun, Jeonghun Kwak
Summary: This review summarizes previous studies on top-emitting device structures and discusses ways to improve the performance of top-emitting quantum dot-based light-emitting diodes (TQLEDs). The relevant theories for the optoelectrical properties of TQLEDs are introduced, and advancements in device optimization are presented. Multilateral strategies for TQLEDs to be widely applied in advanced industries are also discussed. This review aims to provide valuable insights for realizing commercial TQLEDs applicable to a broad range of applications.
Article
Nanoscience & Nanotechnology
Yunfeng Fang, Penglong Bai, Jiayi Li, Binbin Xiao, Yiqing Wang, Yanping Wang
Summary: In this study, high-efficiency red QLEDs were obtained by employing specific mixtures of polymers as hole-transport layers. The QLED exhibited excellent luminance performance and long lifetime, with the improvements attributed to more balanced charge transport and efficient hole-electron recombination in the emissive layer.
ACS APPLIED MATERIALS & INTERFACES
(2022)
Article
Engineering, Electrical & Electronic
Feifan Xu, Tao Tao, Dongqi Zhang, Yang Zhang, Yimeng Sang, Junchi Yu, Ting Zhi, Zhe Zhuang, Zili Xie, Rong Zhang, Bin Liu
Summary: We have developed a simple method for producing green and red colors on GaN-based blue micro-light-emitting diodes (mu LEDs) by patterning quantum dots (QDs) using standard photolithography and dry etching. The fabricated QDs exhibited ultra-high resolution and throughput, with a minimum size of 2 μm on a 4-inch wafer. The individual color converted green and red mu LEDs achieved a peak external quantum efficiency (EQE) of 9.6% and 14.7%, respectively. We further demonstrated the monolithic integration of red, green, and blue (RGB) mu LEDs as a single pixel by sequentially patterning red and green QDs. The resulting RGB mu LEDs covered 83.4% of the Rec. 2020 color space in the CIE 1931 diagram. This method enables high-performance red/green mu LEDs with small feature sizes and scalable fabrication of full-color mu LED displays.
IEEE ELECTRON DEVICE LETTERS
(2023)
Article
Chemistry, Multidisciplinary
Taesoo Lee, Byong Jae Kim, Hyunkoo Lee, Donghyo Hahm, Wan Ki Bae, Jaehoon Lim, Jeonghun Kwak
Summary: This study demonstrates bright and stable QLEDs on a Si substrate, achieving high brightness, efficiency, and stability through tailored interface and optimized device structure, pushing the development and application of QLEDs.
ADVANCED MATERIALS
(2022)
Article
Materials Science, Multidisciplinary
Denglin Zhao, Yueting Zheng, Tingtao Meng, Yangbin Zhu, Jipeng Jing, Xiang Chen, Hongjin Gao, Chaomin Mao, Wenchen Zheng, Hailong Hu, Tailiang Guo, Fushan Li
Summary: This study demonstrated the fabrication of a highly ordered QD monolayer with the LB technique, which significantly improved the performance and lifetime of QLEDs. The LB-HL strategy showed promising scalability for large-area QD monolayers.
SCIENCE CHINA-MATERIALS
(2022)
Article
Computer Science, Information Systems
Ching-Ho Tien, Ni-Pin Yeh, Kuan-Lin Lee, Lung-Chien Chen
Summary: In this study, a display consisting of a 64-cell quantum dot light-emitting diodes (QDLEDs) array was presented, with high operating rate and maximum brightness achieved. The surface modification of perovskite nanocrystal composite using aloe-vera gel as the organic precursor enabled high-quality narrow band photoluminescence emission. The use of an Arduino microcontroller unit for dynamic micro-control terminal and motor drive modules for the display driver circuit demonstrates the potential of perovskite devices for next-generation displays.
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
Chemistry, Multidisciplinary
Geun Woo Baek, Seung Gi Seo, Donghyo Hahm, Yeon Jun Kim, Kyunghwan Kim, Taesoo Lee, Jaeyoul Kim, Wan Ki Bae, Sung Hun Jin, Jeonghun Kwak
Summary: In this study, efficient and stable AM-QLEDs for next-generation displays are demonstrated by comparing different configurations of QLEDs and TFTs. A 5x5 AM-QLED display array controlled using SWNT TFTs is successfully demonstrated, contributing to the development of advanced AM-QLED displays.
ADVANCED MATERIALS
(2023)
Article
Chemistry, Physical
Suhyeon Lee, Donghyo Hahm, Suk-Young Yoon, Heesun Yang, Wan Ki Bae, Jeonghun Kwak
Summary: In this study, a novel concept of QD-organic hybrid light-emitting diodes (QLEDs) is presented, which improves the performance of QLEDs and simplifies the manufacturing process, leading to higher resolution and full-color displays.
Article
Chemistry, Multidisciplinary
Shiyun Lei, Yuanyuan Xiao, Kanglin Yu, Biao Xiao, Ming Wan, Liyong Zou, Qingliang You, Renqiang Yang
Summary: This study investigates the hole injection mechanism in quantum dot light-emitting diodes (QLEDs) through a combination of experiments and simulations. It reveals that applied bias reduces the barrier height, facilitating hole injection and confining electrons within the quantum dots. The research also demonstrates that thermally assisted tunneling is the predominant pathway for hole injection. This study is significant for understanding the hole injection mechanism in QLEDs.
ADVANCED FUNCTIONAL MATERIALS
(2023)
Article
Nanoscience & Nanotechnology
Pengfei Wang, Huan Yang, Jiye Li, Xiaohui Zhang, Lei Wang, Juncheng Xiao, Bin Zhao, Shengdong Zhang, Lei Lu
Summary: The large-area low-temperature processing capability and versatile characteristics of amorphous oxide semiconductor (AOS) thin-film transistors (TFTs) are highly expected to promote the developments of next-generation displays and electronics. However, the abundance of defects in AOSs limits the performance and integration scale. To overcome this challenge, a bilayer AOS channel with an abrupt metal-oxide heterojunction is proposed to enhance the performance and reliability of AOS TFTs.
ADVANCED ELECTRONIC MATERIALS
(2023)
Article
Nanoscience & Nanotechnology
Xijian Duan, Jingrui Ma, Wenda Zhang, Pai Liu, Haochen Liu, Junjie Hao, Kai Wang, Lars Samuelson, Xiao Wei Sun
Summary: HF processing was used to eliminate the InPOx defect in red InP quantum dots and improve the fluorescence efficiency. The record-breaking red InP quantum dots were synthesized with the assistance of tri(dimethylamino)phosphine [(DMA)3P], achieving a maximum photoluminescence quantum yield of 97.7%. The external quantum efficiency and brightness of the quantum dot light-emitting diode device were also improved accordingly.
ACS APPLIED MATERIALS & INTERFACES
(2023)
Article
Nanoscience & Nanotechnology
Jiye Li, Yuqing Zhang, Jialiang Wang, Huan Yang, Xiaoliang Zhou, Mansun Chan, Xinwei Wang, Lei Lu, Shengdong Zhang
Summary: Researchers successfully eliminated the defective interface in amorphous InGaZnO (a-IGZO) thin-film transistors by preoxidizing a-IGZO with nitrous oxide (N2O) plasma, achieving high performance and stability. This study is of great significance for addressing the interface reaction issue between high-k dielectrics and amorphous oxide semiconductors (AOSs) in next-generation thin-film transistors.
ACS APPLIED MATERIALS & INTERFACES
(2023)
Article
Materials Science, Multidisciplinary
Jing-Jie Shi, Ting Song, Peng-Tang Qi, Xiao-Yun Wang, Zi-Jiang Liu, Xiao-Wei Sun
Summary: The structural stabilities and half-metallic properties of the new quaternary Heusler alloys OsTiVIn and OsZrVIn under high pressure are investigated using first-principles calculations. The study finds the lowest energy structures in a ferromagnetic state for both alloys. Through calculations of formation enthalpy, phonon dispersion, and elastic constants, it is determined that OsTiVIn and OsZrVIn are thermodynamically, dynamically, and mechanically stable. The calculation of band gap, magnetic moment, and spin polarizability near the Fermi level confirms that OsTiVIn maintains its half-metallic property up to 98 GPa, while OsZrVIn exhibits half-metallic property in the pressure range of 0-100 GPa.
JOURNAL OF MAGNETISM AND MAGNETIC MATERIALS
(2023)
Article
Nanoscience & Nanotechnology
Lixuan Chen, Jinyang Zhao, Zhiqing Shi, Miao Zhou, Shengdong Zhang, Xiao Wei Sun, Xin Zhang
Summary: Semiconductor quantum rods (QRs) emit polarized light and have great potential for energy-efficient and color-enhancing modern display devices. We present the stretching of an aligned QR polarized film to improve brightness and optical efficiency in quantum-dot based displays. The study of QR material, stretching ratio, and alignment degree guides the fabrication of highly polarized QR film. A large-area film with an alignment degree of 0.635 achieved more than 1.6-fold enhancement in brightness and transmittance compared to traditional structures, making it a viable option for various energy-saving display devices.
Article
Physics, Applied
Xiangwei Qu, Guohong Xiang, Jingrui Ma, Pai Liu, Aung Ko Ko Kyaw, Kai Wang, Xiao Wei Sun
Summary: In this work, we find that blue quantum dot light-emitting diodes (QLEDs) exhibit electron over-injection compared to hole injection using impedance spectroscopy and capacitance-voltage characteristics analysis. We also observe the spatial distribution of the exciton recombination zone in blue QLEDs using a red quantum dot as a fluorescent sensor. Our findings provide a practical method for identifying excess carrier in blue QLEDs and have implications for other types of QLEDs.
APPLIED PHYSICS LETTERS
(2023)
Article
Engineering, Electrical & Electronic
Junjun An, Congwei Liao, Yuxuan Zhu, Xin Zheng, Chao Dai, Xin Zhang, Shengdong Zhang
Summary: This study presents a gate driver on array (GOA) circuit for low-temperature polysilicon and oxide thin-film transistor hybrid-driven active matrix organic light-emitting diode (AMOLED) displays, capable of both high and low refresh rate operation. The GOA utilizes shift registers to generate multiple types of scanning signals, allowing for parallel output of three signal pulses within a single stage to drive various TFTs in the AMOLED pixels. This approach reduces the layout area by 30%. Additionally, the scan signals for the emission TFT can be programmed by adjusting the number of input pulses, enabling different refresh rates. The fabricated GOAs demonstrate reliable performance even with a reduced pulse width of 2.9 μs.
IEEE TRANSACTIONS ON CIRCUITS AND SYSTEMS II-EXPRESS BRIEFS
(2023)
Article
Chemistry, Physical
Wengao Pan, Yunping Wang, Yanxin Wang, Zhihe Xia, Fion Sze Yan Yeung, Man Wong, Hoi Sing Kwok, Xinwei Wang, Shengdong Zhang, Lei Lu
Summary: In this work, the multiple effects of hydrogen (H) doping on amorphous InGaZnO (IGZO) TFTs were investigated. The H content influenced the electrical performances of the TFTs, acting as a defect suppressor, donor defect, transition state, and finally an acceptor defect. The oxygen vacancy (Vo) in IGZO determined the diffusion channel of the H dopant and its concentration. Additionally, fluorine (F) doping improved the hydrogen resistibility of IGZO.
JOURNAL OF ALLOYS AND COMPOUNDS
(2023)
Article
Physics, Applied
Gang-Gang Xu, Xiao-Wei Sun, Xiao-Dong Wen, Xi-Xuan Liu, Ting Song, Zi-Jiang Liu
Summary: This study uses a pair of triangular prisms to construct hexagonal-lattice phononic crystal plates that mimic the dual-band elastic valley Hall effect. Based on spatial inversion symmetry conditions, the relationship between the resonance frequencies of the resonators and the valley degeneracies, topological nontrivial bandgaps, and energy band inversion characteristics of multiple resonance modes is investigated. Edge passbands with distinct topology phases exist in each of the two nontrivial bandgaps of the ribbon configuration. This work provides a reference for valley edge protection in subwavelength continuous elastic plate media and for the manipulation of elastic waves at multiple frequencies.
JOURNAL OF APPLIED PHYSICS
(2023)
Article
Materials Science, Multidisciplinary
Ning Li, Jun-Hong Tian, Ting Song, Lie-Juan Li, Zi-Jiang Liu, Xiao-Wei Sun
Summary: The effects of In, Sn, and Sb alloying in PbH4 on the superconductivity at high pressure were investigated using first-principles calculations. The alloying structures exhibited thermodynamical, mechanical, and dynamic stability, as indicated by the calculated formation enthalpy, elastic constants, and phonon dispersion. The superconductivity of Pb2MH12 (M = In, Sn, and Sb) was improved by the addition of M. The superconducting transition temperature increased from 62 K for PbH4 to 70, 69, and 66 K for Pb2MH12 (M = In, Sn, and Sb), respectively. Electronic structure and electron-phonon coupling calculations showed an increase in the contribution of H atoms to the density of states at the Fermi energy and enhancement of the strength of electron-phonon coupling. The results suggest that alloying lighter elements with lower electronegativity is an effective method to improve superconducting properties.
JOURNAL OF MATERIALS SCIENCE
(2023)
Article
Physics, Condensed Matter
Yuri D. Glinka, Tingchao He, Xiao Wei Sun
Summary: Separate relaxation dynamics of long-lived holes in Bi2Se3 film were observed at room temperature using transient absorption spectroscopy. The ultraslow dynamics and long rise time are attributed to the resonance conditions for multiphoton photoemission and the intervalley scattering in the film. The dynamics of massive Dirac fermions predominantly determines the relaxation of photoexcited carriers.
JOURNAL OF PHYSICS-CONDENSED MATTER
(2023)
Article
Engineering, Electrical & Electronic
Juncheng Xiao, Guang Zeng, Ji Li, Shengdong Zhang
Summary: This study simulated and studied the effect of crystallization on the etching properties of ITO film by annealing ITO films prepared by RF magnetron sputtering. It was found that when the annealing temperature was less than 200 degrees C, the ITO films could be easily etched, but when annealed at higher temperatures, the polycrystalline ITO films became difficult to be removed by etchant due to the formation of large amount of Sn4+ on the surface.
JOURNAL OF THE SOCIETY FOR INFORMATION DISPLAY
(2023)
Article
Nanoscience & Nanotechnology
Jiye Li, Yuhang Guan, Jinxiong Li, Yuqing Zhang, Yuhan Zhang, ManSun Chan, Xinwei Wang, Lei Lu, Shengdong Zhang
Summary: To enhance the downscaling potential of top-gate amorphous oxide semiconductor (AOS) thin-film transistors (TFTs), we implemented the ultra-thin gate insulator (GI) using atomic-layer-deposited (ALD) AlOx and HfOx. Both high-k GIs demonstrated good insulation properties even with a physical thickness of 4 nm. However, the HfOx-gated TFT showed higher gate leakage current and poorer subthreshold slope due to the small band offset and defective interface between a-IGZO and HfOx. The imperfect a-IGZO/HfOx interface also caused noticeable positive bias stress instability.
Article
Materials Science, Multidisciplinary
Xin-Wei Wang, Xiao-Wei Sun, Ting Song, Jun -Hong Tian, Zi-Jiang Liu
Summary: A comprehensive investigation of the melting curve and P-T phase diagram of CaO, a candidate mineral in the Earth's lower mantle, is conducted through atomistic simulations using newly developed interatomic potentials. The efficiency and reliability of the new potentials under high temperature and pressure are verified. The study also explores the structure, diffusion, and other physical properties of CaO.
Article
Chemistry, Physical
Yuhang Guan, Yuqing Zhang, Jinxiong Li, Jiye Li, Yuhan Zhang, Zhenhui Wang, Yuancan Ding, Mansun Chan, Xinwei Wang, Lei Lu, Shengdong Zhang
Summary: In recent years, high-k gate dielectrics have received increasing attention in amorphous oxide semiconductor (AOS) thin-film transistors (TFTs) due to the need for stronger gate controllability. This study developed an ultra-thin top-gate insulator of atomic-layer-deposited (ALD) HfOx for amorphous indium-gallium-zinc oxide (a-IGZO) TFTs. However, the reliability of the 4-nm HfOx-gated a-IGZO transistor is poor due to interface defects caused by the interface reaction between HfOx and a-IGZO during the ALD process. To improve stability, the a-IGZO channel is pre-treated with strong oxidizing plasma. However, further reducing HfOx thickness increases gate leakage current.
APPLIED SURFACE SCIENCE
(2023)
