共查询到20条相似文献,搜索用时 46 毫秒
1.
Tatsuya Ryowa Takeshi Ishida Yusuke Sakakibara Keisuke Kitano Masaya Ueda Makoto Izumi Yuko Ogura Masanori Tanaka Soichiro Nikata Mayuko Watanabe Mikihiro Takasaki Tetsuji Itoh Akiharu Miyanaga 《Journal of the Society for Information Display》2020,28(5):401-409
We report outstanding electroluminescence properties of high‐efficiency blue cadmium‐free quantum dot light‐emitting diodes (QD‐LED). External quantum efficiency (EQE) of 14.7% was achieved for QD‐LED emitting at 428 nm. Furthermore, we developed high‐efficiency and narrow wavelength emission zinc selenide (ZnSe) nanocrystals emitting at 445 nm and achieved QD‐LED with an EQE of 10.7%. These new QDs have great potential to be used in next‐generation QD‐LED display with wide color gamut. 相似文献
2.
Efficiency enhancement of InP‐based inverted QD‐LEDs by incorporation of a polyethylenimine modified Al:ZnO layer 下载免费PDF全文
Yohan Kim Christian Ippen Bert Fischer Alexander Lange Armin Wedel 《Journal of the Society for Information Display》2015,23(8):377-383
We report efficiency enhancement of indium phosphide (InP) quantum dot‐based light‐emitting diodes (QD‐LEDs) by using an polyethylenimine (PEI) surface modifier. By adapting a solution processed PEI layer on top of a aluminum doped zinc oxide (Al:ZnO) nanoparticle (NP) film, the leakage current of the inverted device was substantially suppressed. In addition, the electron injection into the conduction band edge (CBE) of InP/ZnSe/ZnS QDs was also facilitated by the low work function (WF) of the Al:ZnO film which was realized by the strong interfacial dipoles of the thin film of PEI. As a result, the charge balance in the inverted devices was controlled by the change of surface roughness, the WF and the thickness of neighboring layers via spin‐coating the PEI dissolved in alcohol mixture on the Al:ZnO layer such that the current efficiency was dramatically increased from 0.07 cd/A to 3.17 cd/A. The performance of our device is not comparable to Cd‐based devices; however, it shows the great potential for using an interfacial dipole layer to develop highly efficient InP‐based inverted QD‐LEDs. 相似文献
3.
Color tuning of indium phosphide quantum dots for cadmium‐free quantum dot light‐emitting devices with high efficiency and color saturation 下载免费PDF全文
Christian Ippen Tonino Greco Yohan Kim Christopher Pries Jiwan Kim Min Suk Oh Chul Jong Han Armin Wedel 《Journal of the Society for Information Display》2015,23(7):285-293
Semiconductor quantum dots (QDs) promise facile color tuning and high color saturation in quantum‐dot light‐emitting devices (QD‐LEDs) by controlling nanoparticle size and size distribution. Here, we demonstrate how this promise can be practically realized for the cadmium‐free InP/ZnSe/ZnS multishell quantum dots. We developed a set of synthesis conditions and core/shell compositions that result in QDs with green, yellow, and red emission color. The QD‐LEDs employing these QDs show efficient electroluminescence (EL) with luminance up to 1800 cd/m2 and efficiency up to 5.1 cd/ A . The color coordinates calculated from the EL spectra clearly demonstrate the outstanding color saturation as an outcome of the narrow particle size distribution. These results prove that the performance gap between cadmium‐free and cadmium‐based QDs in QD‐LEDs is shrinking rapidly. 相似文献
4.
Toward high‐resolution,inkjet‐printed,quantum dot light‐emitting diodes for next‐generation displays 下载免费PDF全文
Jongseok Han Donghyun Ko Myeongjin Park Jeongkyun Roh Heeyoung Jung Yeonkyung Lee Yongwon Kwon Jiho Sohn Wan Ki Bae Byung Doo Chin Changhee Lee 《Journal of the Society for Information Display》2016,24(9):545-551
We have investigated the possibility of fabricating quantum dot light‐emitting diodes (QLEDs) using inkjet printing technology, which is the most attractive method for the full‐color patterning of QLED displays. By controlling the quantum dot (QD) ink formulation and inkjet printing condition, we successfully patterned QLED pixels in the 60‐in ultrahigh definition TV format, which has a resolution of 73 pixels per inch. The inkjet‐printed QLEDs exhibited a maximum luminance of 2500 cd/m2. Although the performance of inkjet‐printed QLEDs is low compared with that of QLEDs fabricated using the spin‐coating process, our results clearly indicate that the inkjet printing technology is suitable for patterning QD emissive layers to realize high‐resolution, full‐color QLED displays. 相似文献
5.
Tingjing Ji Shuang Jin Heng Zhang Shuming Chen Xiao Wei Sun 《Journal of the Society for Information Display》2018,26(3):121-127
Quantum dot light‐emitting diodes are promising candidates for next generation displays. For display application, a pixel consists of red (R), green (G), and blue (B) side‐by‐side sub‐pixels, which thereby requires a high resolution patterning of the light‐emission layers. In this work, the quantum dot (QD) light‐emitting layers are fine patterned by using the photolithography and the lift‐off techniques. To facilitate the lift‐off process, reverse photoresist AZ5214E is used because of its special inverted trapezoidal structure after developing. To prevent the QDs being washed off during the lift‐off process, the ZnMgO layer is treated by the hydrophobic material hexamethyldisilazane. With hexamethyldisilazane treatment, the adhesion between the QDs and the ZnMgO is effectively improved. As a result, side‐by‐side R/G/B QD with pixel size of 30 μm × 120 μm is successfully achieved. After patterning, the R, G, and B‐quantum dot light‐emitting diodes exhibit a maximum current efficiency of 11.6 cd/A, 29.7 cd/A, and 1.5 cd/A, respectively. This work confirms the feasibility of patterning QDs by using the photolithography and the lift‐off techniques. 相似文献
6.
Yohei Nakanishi Tomohiro Takeshita Yang Qu Hiroki Imabayashi Shota Okamoto Hisayuki Utsumi Masayuki Kanehiro Enrico Angioni Edward A. Boardman Iain Hamilton Andrea Zampetti Valerie Berryman‐Bousquet Tim M. Smeeton Takeshi Ishida 《Journal of the Society for Information Display》2020,28(6):499-508
We have developed full colour top emitting quantum dot light‐emitting diode (QD‐LED) display driven by a 176‐ppi active matrix of metal oxide thin‐film transistors. Red, green and blue (RGB) QD‐LED subpixel emission layers are patterned by our original UV photolithography process and materials. We also demonstrate the potential to achieve high resolution such as 528 ppi using this process. 相似文献
7.
Chaoqun Yang Jiuhui Zhu Chang‐Chih Huang Guanghui Liu Zhifu Li 《Journal of the Society for Information Display》2020,28(7):623-628
In this paper, we got wide color gamut of quantum dot (QD) films by optimizing the spectra width and optical density (OD) of quantum dots. The specific methods to achieve the following: QD R: one layer of color filter R film was coated below the QD R layer. QD G: one layer of yellow‐green film was coated below the QD G film. By a structure optimal design, we got wide color gamut up to 99.2% BT2020 (equal to 132.86% NTSC) in Cd‐based QD and 93.6% BT2020 (equal to 125.35% NTSC) in Cd‐free QD. Furthermore, the gamut of QD display will continue to be improved by continuous refining the structure of QD display. 相似文献
8.
Shikai Yan Qing Li Xu Zhang Sheng Tang Wei Lei Jing Chen 《Journal of the Society for Information Display》2020,28(1):9-15
In this work, the vertical structure photodetector based on CsPbBr3 quantum dots (QDs) with a structure of indium tin oxide (ITO)/zinc oxide (ZnO)/CsPbBr3 QDs/Au is reported. In this device, CsPbBr3 QDs film works as the light‐harvesting layer, and ZnO QDs film acts as the electron transport channel, which can extract the electron efficiently and improve the quality of CsPbBr3 QDs film. As a result, the on/off ratio, detectivity and rise time (decay time) of CsPbBr3/ZnO hybrid photodetector are measured to be 2.4 × 106, 2.25 × 1011, and 62 milliseconds (82 ms) under 0‐V bias. This work inspires the development of vertical structure photodetectors based on the all‐inorganic perovskite QDs. 相似文献
9.
Akira Miyamoto Hiromi Kikuchi Hiroaki Onuma Hideyuki Tsuboi Michihisa Koyama Nozomu Hatakeyama Akira Endou Hiromitsu Takaba Momoji Kubo Carlos A. Del Carpio 《Journal of the Society for Information Display》2007,15(5):307-313
Abstract— The tight‐binding quantum chemical molecular dynamics code, Colors, has been successfully applied to the electronic‐structure calculations of the MgO‐protecting‐layer model in plasma‐display panels (PDPs). The code succeeded in reproducing the band‐gap energy of the MgO crystal structure. The energy gap between the bottom of the conduction band (CB) and the top of valence band (VB) was 7.45 eV, which is in quantitative agreement with the experimental and previous theoretical results. The electronic structure of the undoped MgO model and Si‐doped MgO model was also calculated. The impurity level was 2.15 eV lower than that for the bottom of the CB. This result was in qualitative agreement with recent cathodoluminescence measurements. In addition, we have already succeeded in developing a novel electrical conductivity simulator using the spatial distribution of the probability density of wave functions obtained from the tight‐binding quantum chemical molecular dynamics code, Colors. The electrical conductivity of the MgO‐protecting‐layer model was estimated with and without an oxygen defect and a significant change in the electrical conductivity of the MgO‐protecting‐layer materials was observed with the introduction of oxygen defects. 相似文献
10.
The influence of the hole transport layers on the performance of blue and color tunable quantum dot light‐emitting diodes 下载免费PDF全文
Xiaoyu Huang Sikai Su Qiang Su Heng Zhang Feng Wen Shuming Chen 《Journal of the Society for Information Display》2018,26(8):470-476
The performance of the blue quantum dot light‐emitting diodes (QLEDs) is largely affected by the hole transport layers (HTLs). As a consequence of the deep valance band level of blue quantum dots (QDs), hole injection is relatively difficult in blue QLEDs. To favor the hole injection, HTLs with high hole mobility and deep‐lying highest occupied molecular orbital level are desired. In this work, various HTLs and their influence on the performance of blue QLEDs are demonstrated. Devices with poly(N‐vinylcarbazole) (PVK) HTL exhibit the highest external quantum efficiency while devices with poly[9,9‐dioctylfluorene‐co‐N‐(4‐(3‐methylpropyl))‐diphenylamine] (TFB) exhibit the lowest driving voltage. By combining the advantages of PVK and TFB, the blue QLEDs with TFB/PVK bilayered HTL simultaneously exhibit a low driving voltage of 2.6 V and a high external quantum efficiency of 5.9%. Moreover, the exciplex emission at the interface of HTL/QDs is also observed, and the emission intensity can be tuned by modulating the hole injection. By utilizing PVK doped with 25% poly(3‐hexylthiophene) (P3HT) as HTL, exciplex emission is significantly enhanced at low driving voltage while QD emission is dominant at high driving voltage. By combining the exciplex emission and the QD emission, the emission color can be effectively tuned from red to blue as the driving voltage changing from 2 to 10 V. 相似文献
11.
Tetsuya Masuda Yuki Nakano Yoshiaki Takahashi Hirokatsu Ito Keiji Okinaka Emiko Kambe Yuichiro Kawamura Hitoshi Kuma 《Journal of the Society for Information Display》2018,26(3):146-152
We developed new fluorescent blue dopants (BDs) for achieving high‐efficient blue organic light‐emitting diode. A new BD showed both high photoluminescent quantum yield >0.9 and highly horizontal orientation (S′ > 0.9) in doped film with keeping a chemical stability by introducing suitable substituents. We developed hole transporting materials and optimized the combination of hole transporting layers to decrease a carrier accumulation at the interface between electron blocking layer and emission layer. We found that the external quantum efficiency dependency from low to high current density was turned flat by promoting hole injection into emission layer. The top‐emission organic light‐emitting diode using the new BD and the optimized device architecture exhibited high efficiency of L/J/CIEy around 200 at CIEy = 0.043. 相似文献
12.
Hyo‐Min Kim Misun Ryu James H.J. Cha Hyun Soo Kim Tak Jeong Jin Jang 《Journal of the Society for Information Display》2019,27(6):347-353
A fine patternable quantum dots (QDs) color conversion layer (CCL) for high resolution and full color active matrix (AM) micro‐LED (μ‐LED) display is demonstrated. QDs CCL could be patterned until 10 μm using photolithography process. It is found that multicoatings with red and green QDs (R‐ and G‐QDs) CCLs on LED array can provide full color AM display. 相似文献
13.
Karen Twietmeyer Sridhar Sadasivan 《Journal of the Society for Information Display》2016,24(5):312-322
Quantum dots (QDs) are increasingly the technology of choice for wide color gamut displays. Two popular options to incorporate QDs into displays include on‐edge and on‐surface solutions. The opto‐mechanical design for an on‐edge QD solution including a LED light bar (“on‐edge QD light bar”) is more complex than the design for a standard white phosphor LED light bar. In this paper, we identify and investigate a range of design parameters for an on‐edge QD light bar, and we show that these parameters have significant influence on system efficiency and color uniformity. The effects of varying these parameters are explored through the use of a custom adjustable testbed and optical raytracing methods. Our testbed data demonstrate the inherent trade‐offs between efficiency and color uniformity and provide guidance for the design of high‐performing displays. The optical raytracing data demonstrate a good predictive capability and support the use of optical modeling methods for a detailed exploration of a wider range of design parameters. 相似文献
14.
Kiyohiko Toshikawa Junichi Miyano Atsushi Yokotani Kou Kurosawa Yoshiie Matsumoto 《Journal of the Society for Information Display》2005,13(5):453-457
Abstract— In photo‐CVD (chemical vapor deposition) in which vacuum‐ultraviolet (VUV) excimer lamps (VUV‐CVD) are used, thin films were deposited at room temperature because VUV photons have the energy to decompose material gases. For the use of OMCTS (octamethylcyclotetrasiloxane), an organic siloxane, we can deposit a self‐flatness film for high‐pressure conditions. The reactants generated by VUV photons have excellent migration characteristics for this condition. Also, the VUV‐CVD film demonstrates low stress, comparatively hard hardness, good electrical properties, and good thermal resistance. The VUV‐CVD film is optimum for planarizing film in the over‐coating deposition step in the production of OLEDs, which requires a low‐temperature process. 相似文献
15.
Christian Ippen Wenzhuo Guo Don Zehnder Daekyoung Kim Jesse Manders Diego Barrera Benjamin Newmeyer Dylan Hamilton Chunming Wang Charlie Hotz Ruiqing Ma Jong‐Kwan Bin ByungGeol Kim KyuNam Kim KyungKook Jang Jaehyun Park Taeyang Lee Wy‐Yong Kim JounHo Lee 《Journal of the Society for Information Display》2019,27(6):338-346
In this paper, we report on our progress on developing heavy metal free (or Cd‐free) QD‐LEDs for all three colors. With improvement in synthesis, we have developed high quantum yield heavy metal free quantum dots (more than 95% for red and green and more than 80% for blue), with peak wavelengths suitable for BT.2020. Building upon these high‐performance quantum dots and through novel device structure design and optimization we have demonstrated high efficiency heavy metal free QD‐LEDs with EQE = 16.9%, 13%, 9% for red, green, and blue, respectively. Specifically, we report a systematic study on the impact of shell thickness to the device efficiency performance. 相似文献
16.
Feng Feng Yibo Liu Ke Zhang Yonghong Lin Ka-Wah Chan Hoi-Sing Kwok Zhaojun Liu 《Journal of the Society for Information Display》2022,30(7):556-566
Displays based on inorganic micro-light-emitting diodes (micro-LEDs) are highly anticipated for next-generation technologies. AlGaN-based deep-ultraviolet (deep-UV) micro-LED as the excitation source for quantum dots display with high efficiency was reported in this paper. To achieve optimized electro-optical performance, deep-UV micro-LEDs with different electrodes were fabricated and analyzed in sizes from 200 × 200 to 10 × 10 μm2. At the same forward bias, the devices with Ti/Al-based electrodes achieved 10 times injection current and three times electroluminescence intensity than those with Cr/Al-based electrodes. The blueshift phenomenon of deep-UV light was observed from 292 nm at 2 A/cm2 to 287 nm at 200 A/cm2 with the increasing current density. By the excitation of deep-UV micro-LED, quantum dot film achieved high light conversion efficiency and optimized color rendering, as the converted color emission peak was separate from the pumping source. The high energy of deep-UV photons and the narrow emission bandwidth of QDs resulted in prominent color purity. The forward voltage and electroluminescence intensity uniformity of a 250 × 250 micro-LED array with each pixel size of 30 × 30 μm2 were further discussed. The optical microscope images of green QD film pumped by a deep-UV micro-LED demonstrated its competitive application in the color-converted display. 相似文献
17.
Yoshiki Nakajima Mitsuru Nakata Tatsuya Takei Hirohiko Fukagawa Genichi Motomura Hiroshi Tsuji Takahisa Shimizu Yoshihide Fujisaki Taiichiro Kurita Toshihiro Yamamoto 《Journal of the Society for Information Display》2014,22(3):137-143
An 8‐in. flexible active‐matrix organic light‐emitting diode (AMOLED) display driven by oxide thin‐film transistors (TFTs) has been developed. In‐Ga‐Zn‐O (IGZO)‐TFTs used as driving devices were fabricated directly on a plastic film at a low temperature below 200 °C. To form a SiOx layer for use as the gate insulator of the TFTs, direct current pulse sputtering was used for the deposition at a low temperature. The fabricated TFT shows a good transfer characteristic and enough carrier mobility to drive OLED displays with Video Graphic Array pixels. A solution‐processable photo‐sensitive polymer was also used as a passivation layer of the TFTs. Furthermore, a high‐performance phosphorescent OLED was developed as a red‐light‐emitting device. Both lower power consumption and longer lifetime were achieved in the OLED, which used an efficient energy transfer from the host material to the guest material in the emission layer. By assembling these technologies, a flexible AMOLED display was fabricated on the plastic film. We obtained a clear and uniform moving color image on the display. 相似文献
18.
Manoj Nag Adrian Chasin Maarten Rockele Soeren Steudel Kris Myny Ajay Bhoolokam Ashutosh Tripathi Bas van der Putten Abhishek Kumar Jan‐Laurens van der Steen Jan Genoe Flora Li Joris Maas Erik van Veenendaal Gerwin Gelinck Paul Heremans 《Journal of the Society for Information Display》2013,21(3):129-136
In this study, the authors report on high‐quality amorphous indium–gallium–zinc oxide thin‐film transistors (TFTs) based on a single‐source dual‐layer concept processed at temperatures down to 150°C. The dual‐layer concept allows the precise control of local charge carrier densities by varying the O2/Ar gas ratio during sputtering for the bottom and top layers. Therefore, extensive annealing steps after the deposition can be avoided. In addition, the dual‐layer concept is more robust against variation of the oxygen flow in the deposition chamber. The charge carrier density in the TFT channel is namely adjusted by varying the thickness of the two layers whereby the oxygen concentration during deposition is switched only between no oxygen for the bottom layer and very high concentration for the top layer. The dual‐layer TFTs are more stable under bias conditions in comparison with single‐layer TFTs processed at low temperatures. Finally, the applicability of this dual‐layer concept in logic circuitry such as 19‐stage ring oscillators and a TFT backplane on polyethylene naphthalate foil containing a quarter video graphics array active‐matrix organic light‐emitting diode display demonstrator is proven. 相似文献
19.
Mitsunori Suzuki Hirohiko Fukagawa Yoshiki Nakajima Toshimitsu Tsuzuki Tatsuya Takei Toshihiro Yamamoto Shizuo Tokito 《Journal of the Society for Information Display》2009,17(12):1037-1042
Abstract— A flexible phosphorescent color active‐matrix organic light‐emitting‐diode (AMOLED) display on a plastic substrate has been fabricated. Phosphorescent polymer materials are used for the emitting layer, which is patterned using ink‐jet printing. A mixed solvent system with a high‐viscosity solvent is used for ink formulation to obtain jetting reliability. The effects of evaporation and the baking condition on the film profile and OLED performances were investigated. An organic thin‐film‐transistor (OTFT) backplane, fabricated using pentacene, is used to drive the OLEDs. The OTFT exhibited a current on/off ratio of 106 and a mobility of 0.1 cm2/V‐sec. Color moving images were successfully shown on the fabricated display. 相似文献
20.
T. Takehara W. R. Harshbarger C. C. Tsai D. Toet T. Sigmon 《Journal of the Society for Information Display》2001,9(1):57-60
Low‐temperature polycrystalline‐silicon (poly‐Si) thin‐film‐transistor (TFT) processes, based on PECVD amorphous‐silicon (a‐Si:H) precursor films and excimer‐laser crystallization, have been developed for application in the fabrication of active‐matrix liquid‐crystal‐displays (AMLCDs). The optimum process for depositing the precursor films has been identified. The relationship between excimer‐laser crystallization and poly‐Si film morphology has also been studied. Using these techniques, poly‐Si TFTs with a mobility of 275 cm2/V‐sec and on/off ratios of 1 × 107 have been fabricated. 相似文献