scholarly journals Advances in Quantum-Dot-Based Displays

Nanomaterials ◽  
2020 ◽  
Vol 10 (7) ◽  
pp. 1327 ◽  
Author(s):  
Yu-Ming Huang ◽  
Konthoujam James Singh ◽  
An-Chen Liu ◽  
Chien-Chung Lin ◽  
Zhong Chen ◽  
...  
Keyword(s):  
High Efficiency ◽  
Low Cost ◽  
Flexible Substrate ◽  
Potential Candidate ◽  
White Leds ◽  
Full Color ◽  
Color Displays ◽  
High Illumination ◽  
Coating Methods ◽  
Good Potential

In terms of their use in displays, quantum dots (QDs) exhibit several advantages, including high illumination efficiency and color rendering, low-cost, and capacity for mass production. Furthermore, they are environmentally friendly. Excellent luminescence and charge transport properties of QDs led to their application in QD-based light-emitting diodes (LEDs), which have attracted considerable attention in display and solid-state lighting applications. In this review, we discuss the applications of QDs which are used on color conversion filter that exhibit high efficiency in white LEDs, full-color micro-LED devices, and liquid-type structure devices, among others. Furthermore, we discuss different QD printing processes and coating methods to achieve the full-color micro-LED. With the rise in popularity of wearable and see-through red, green, and blue (RGB) full-color displays, the flexible substrate is considered as a good potential candidate. The anisotropic conductive film method provides a small controllable linewidth of electrically conductive particles. Finally, we discuss the advanced application for flexible full-color and highly efficient QD micro-LEDs. The general conclusion of this study also involves the demand for a more straightforward QD deposition technique, whose breakthrough is expected.

Efficient pure-red perovskite light-emitting diodes using dual-Lewis-base molecules for interfacial modification

2021 ◽  
Author(s):  
Rui Yang ◽  
Yanqing Li ◽  
Minglei Guo ◽  
Xiao-Yi Cai ◽  
Jianxin Tang
Keyword(s):  
Light Emitting Diodes ◽  
Low Cost ◽  
Lewis Base ◽  
Color Purity ◽  
Light Emitting ◽  
Full Color ◽  
Color Displays ◽  
Interfacial Modification ◽  
High Color Purity

Perovskite light-emitting diodes (PeLEDs) are promising for full-color displays due to high color purity, low-cost and solution processability. However, pure-red PeLEDs still lag behind their green and deep-red counterparts in...

Tuning the Edge-Site Activity of 2H Phase MoSe2 for Hydrogen Evolution Reaction via Sulfur Substitution and Strain Engineering

2020 ◽  
Vol 12 (10) ◽  
pp. 1446-1456
Author(s):  
Ziwei Xu ◽  
Guanghui Zhao ◽  
Mingyuan Wang ◽  
Jingjing Liang ◽  
Shahid Hussain ◽  
...  
Keyword(s):  
Catalytic Activity ◽  
Hydrogen Evolution ◽  
Hydrogen Evolution Reaction ◽  
Density Functional ◽  
High Efficiency ◽  
Low Cost ◽  
Catalytic Efficiency ◽  
Strain Engineering ◽  
Catalyst Design ◽  
Potential Candidate

The 2H phase MoSe2 of high chemical stability and excellent catalytic activity is a promising catalyst for the hydrogen evolution reaction (HER) as a potential candidate, due to its low cost, high efficiency and abundant production. However, the HER catalytic efficiency of MoSe2 largely depends on the activity of reaction sites including the basal plane and the edges, and remains low because only the Mo edge sites are active. Herein, we have calculated the structural stability, catalytic activity, and strain engineering on sulfur substituted MoSe2 catalytic structures (Mo(Se1–xSx)2) by density functional theory. The results demonstrate that most of Mo(Se1–xSx)2 monolayers are thermodynamically stable and the HER activity of the Mo(Se1–xSx)2 monolayers can be effectively tuned by both element substitution and strain engineering with the mechanisms uncovered at the atomic level. This study provides the experiments theoretical references for the novel catalyst design of the hydrogen evolution reaction.

Synthesis and Photophysical Properties of Crosslinkable Multi-Branched Ethynyl Fluorene-Labeled Molecules

2012 ◽  
Vol 486 ◽  
pp. 211-213
Author(s):  
Xiao Dan Hu ◽  
Shao Hong Wang ◽  
Zhao Xia Hou
Keyword(s):  
Solid State ◽  
Phase Transfer Catalysis ◽  
Phase Transfer ◽  
Uv Light ◽  
Low Cost ◽  
Photophysical Properties ◽  
Solid State Lighting ◽  
Full Color ◽  
Color Displays

The simple way to synthesize crosslinkable multi-branched ethynyl fluorene-labeled molecules has been reported in this work. A three-armed molecule, OxDBFP is prepared by cyclotrimerization and phase transfer catalysis methods. 3-(6-Bromo-2-oxahexyl)-3-methyloxetane tethered to 9-position of fluorene is crosslinked when exposed to UV light. This kind of compounds can be proper candidates for full-color displays or solid-state lighting by low-cost solution prosessing.

Intrinsic and interfacial kinetics of perovskite solar cells under photo and bias-induced degradation and recovery

2017 ◽  
Vol 5 (31) ◽  
pp. 7799-7805 ◽  
Author(s):  
Pankaj Yadav ◽  
Daniel Prochowicz ◽  
Essa A. Alharbi ◽  
Shaik M. Zakeeruddin ◽  
Michael Grätzel
Keyword(s):  
Solar Cells ◽  
High Efficiency ◽  
Low Cost ◽  
Perovskite Solar Cells ◽  
Potential Candidate ◽  
Interfacial Kinetics ◽  
Photovoltaic Technology ◽  
Kinetics Of

Perovskite solar cells (PSCs) have emerged as a potential candidate for high efficiency low-cost photovoltaic technology.

Light Emitting Polymermaterials: the Working Base for Flexible Full Color Displays

2003 ◽  
Vol 769 ◽  
Author(s):  
Heinrich Becker ◽  
Esther Breuning ◽  
Arne Büsing ◽  
Aurelie Falcou ◽  
Susanne Heun ◽  
...  
Keyword(s):  
High Efficiency ◽  
Blue Emission ◽  
Current Status ◽  
Light Emitting ◽  
Material Development ◽  
Full Color ◽  
Color Displays ◽  
Operational Lifetime ◽  
Jet Printing ◽  
Efficient Manufacturing

AbstractIn the last few years, industrial research into materials fulfilling the needs of the maturing OLED display industry has intensified considerably. A first generation of polymers (phenyl- PPVs) is now being commercially exploited in first monochrome polymer LED display applications. Based on these materials, non-planar displays have already been demonstrated. However, those proof of concept devices have been monochrome. Especially the RGB materials need considerable improvement to be suitable for flexible full color displays.We will therefore report on the progress in the development of polymers for red, green, and blue emission. Our main focus here is on improving the properties of various polymers derived from the spiro-bifluorene core.Depending on the color, the main issues vary strongly: For BLUE polymers, efficiency, color coordinates, and processibility are already at a commercial level while operational lifetime still needs strong improvement. RED materials are in an almost contrary situation: here, the operational lifetime is excellent, whereas the efficiency and the driving current are requiring further improvement. For GREEN, achieving saturated emission, whilst maintaining the other properties (high efficiency, long operational lifetime), is still challenging. We will demonstrate the current status of material development within Covion.In addition, we achieved advances in full-color patterning, especially techniques based on Ink-Jet printing. This technology potentially allows the efficient manufacturing of high resolution RGB devices on a variety of substrates, including flexible layers.

Reel-to- Reel Cassette Cluster Tool System for Thin Film Transistor and Four Terminal Solar Cell Fabrication

2004 ◽  
Vol 814 ◽  
Author(s):  
Arun Madan
Keyword(s):  
Thin Film ◽  
Solar Cells ◽  
High Efficiency ◽  
Low Cost ◽  
Flexible Substrate ◽  
Plastic Substrate ◽  
Silicon Thin Film ◽  
Device Structure ◽  
Nano Crystalline ◽  
Cluster Tool

AbstractWe present a new type of system architecture to fabricate thin film silicon devices on flexible substrates, which uses the inherent advantages of a cluster tool normally used in the production of amorphous silicon thin film transistors, solar cells, etc. In this, the flexible substrate material is contained within a cassette which includes a reel to reel operation. As in the current cluster tools used for planar substrates, the cassette is transported to a process chamber using a robotic arm. When the entire roll in the cassette has been processed, it is transported into other chambers for further processing. We also show that a four terminal device structure (e.g. amorphous Si and stable low band gap nano-crystalline Si cells) potentially can lead to high efficiency (>15%), stable, low cost solar cells on a plastic substrate. Lastly we discuss the use of a pulsed PECVD deposition technique, which allows that the structure of the nano-crystalline Si films can be altered from 111 to 220 in a controllable way at a low temperature of <170C.

Influence of MBE Growth Conditions on Dislocation Densities of GaAs/Ge Epilayers Grown on Silicon Substrates

1985 ◽  
Vol 43 ◽  
pp. 364-365
Author(s):  
K.M. Hones ◽  
P. Sheldon ◽  
B.G. Yacobi ◽  
A. Mason
Keyword(s):  
High Efficiency ◽  
Lattice Mismatch ◽  
Low Cost ◽  
Growth Conditions ◽  
Nonradiative Recombination ◽  
Device Structure ◽  
Si Substrates ◽  
Transmission Electron ◽  
Dislocation Densities ◽  
Dislocation Type

There is increasing interest in growing epitaxial GaAs on Si substrates. Such a device structure would allow low-cost substrates to be used for high-efficiency cascade- junction solar cells. However, high-defect densities may result from the large lattice mismatch (∼4%) between the GaAs epilayer and the silicon substrate. These defects can act as nonradiative recombination centers that can degrade the optical and electrical properties of the epitaxially grown GaAs. For this reason, it is important to optimize epilayer growth conditions in order to minimize resulting dislocation densities. The purpose of this paper is to provide an indication of the quality of the epitaxially grown GaAs layers by using transmission electron microscopy (TEM) to examine dislocation type and density as a function of various growth conditions. In this study an intermediate Ge layer was used to avoid nucleation difficulties observed for GaAs growth directly on Si substrates. GaAs/Ge epilayers were grown by molecular beam epitaxy (MBE) on Si substrates in a manner similar to that described previously.

Improvement of Ti/RuO2–IrO2 Anode Lifetime and Electrocatalytical Properties by Using an Eco-Friendly Thermal Decomposition Method Using Polyvinyl Alcohol as Solvent

2019 ◽  
Author(s):  
Charlys Bezerra ◽  
Géssica Santos ◽  
Marilia Pupo ◽  
Maria Gomes ◽  
Ronaldo Silva ◽  
...  
Keyword(s):  
Thermal Decomposition ◽  
Polyvinyl Alcohol ◽  
High Efficiency ◽  
Electrochemical Impedance ◽  
Pechini Method ◽  
Low Cost ◽  
Charge Transfer Resistance ◽  
Transfer Resistance ◽  
Calcination Temperatures ◽  
Service Lifetime

<p>Electrochemical oxidation processes are promising solutions for wastewater treatment due to their high efficiency, easy control and versatility. Mixed metal oxides (MMO) anodes are particularly attractive due to their low cost and specific catalytic properties. Here, we propose an innovative thermal decomposition methodology using <a>polyvinyl alcohol (PVA)</a> as a solvent to prepare Ti/RuO<sub>2</sub>–IrO<sub>2</sub> anodes. Comparative anodes were prepared by conventional method employing a polymeric precursor solvent (Pechini method). The calcination temperatures studied were 300, 400 and 500 °C. The physical characterisation of all materials was performed by X-ray diffraction and scanning electron microscopy coupled with energy dispersive spectroscopy, while electrochemical characterisation was done by cyclic voltammetry, accelerated service lifetime and electrochemical impedance spectroscopy. Both RuO<sub>2</sub> and IrO<sub>2</sub> have rutile-type structures for all anodes. Rougher and more compact surfaces are formed for the anodes prepared using PVA. Amongst temperatures studied, 300 °C using PVA as solvent is the most suitable one to produce anodes with expressive increase in voltammetric charge (250%) and accelerated service lifetime (4.3 times longer) besides reducing charge-transfer resistance (8 times lower). Moreover, the electrocatalytic activity of the anodes synthesised with PVA toward the Reactive Blue 21 dye removal in chloride medium (100 % in 30 min) is higher than that prepared by Pechini method (60 min). Additionally, the removal total organic carbon point out improved mineralisation potential of PVA anodes. Finally, this study reports a novel methodology using PVA as solvent to synthesise Ti/RuO<sub>2</sub>–IrO<sub>2</sub> anodes with improved properties that can be further extended to synthesise other MMO compositions.</p>

Contradiction Analysis and Solution in the R&D of High-Power Solar LED Street Lamp Controller

2019 ◽  
Vol 12 (1) ◽  
pp. 12-19
Author(s):  
Zhengwang Xu ◽  
Wei Mei ◽  
Jiaqi Yu ◽  
Jiarui Zhang ◽  
Yuchun Yi ◽  
...  
Keyword(s):  
Power Supply ◽  
High Efficiency ◽  
Low Cost ◽  
Solar Panel ◽  
Battery Voltage ◽  
Supply Circuit ◽  
Led Light ◽  
Power Supply Circuit ◽  
Side Mode ◽  
Dual Power

As being restricted by factors such as cost, efficiency and size, the development of high-power solar LED street light controller is faced with plenty of difficulties. In case that a structure of two independent DC/DC is applied as the main circuit, it has to face problems such as large size and high cost; in case of applying the bidirectional BUCK/BOOST circuit, it requires change-over switches to control the solar panel and LED light. As being restricted by withstanding voltage, on-resistance and cost, a PMOS device cannot be used as the change-over switch of solar panel and LED light. However, when being used as a change-over switch, an NMOS device must apply the low-side mode under which the negative ends of the mentioned three parts are cut off. In the condition of applying the low-side mode, a differential circuit must be used to detect the voltage of the solar panel. Furthermore, in order to make sure batteries can still be regularly charged after wearing out in daylight, the controller must be supplied with power through a dual power supply circuit that can obtain power from both the solar panel and the battery. The demander has a requirement on extremely low standby power consumption of the product, and thus it is necessary to minimize the circuit that is live while working in standby mode. Methods: The bidirectional BUCK/BOOST circuit structure is applied to the main circuit to realize a higher change-over efficiency while giving considerations to both cost and size. The NMOS device, model IRFB4410ZPBF, with a price of about three yuan, is used as the switching device, and the low-side mode is applied, that is the switches inserted in between negative end of the solar panel or LED light and that of the DC/DC circuit. The low-cost rail-to-rail operational amplifier LM358 is used to form a differential amplification circuit for detecting the voltage of the solar panel. A XL1509-12E1 chip that only costs 0.88 yuan/pc is selected as the main change-over chip for the power supply, which has realized the highly-efficient and low-cost change-over of the power supply. A dual power supply circuit and a step-down protective circuit are designed for the XL1509-12E1 change-over chip. By comparing solar panel voltage with battery voltage, the solar panel booting circuit is realized. Only when solar panel voltage is higher than battery voltage, does the system program start to power it up for running, so that the outage of most of the circuits of the system under standby mode does not consume energy. Furthermore, the solar panel voltage detecting circuit, the solar panel booting circuit and several return difference functions are corrected during system debugging. Results: The circuit board of the entire controller features small size, low cost and high efficiency. It measures about 100*62*18mm in size, costs about 60 yuan, and the charge/discharge change-over efficiency reaches up to over 95%. The controller has many functions: it is capable of operating within a large scope, in which, solar panel voltage is subject to 15~50V, LED light voltage is subject to 15~60V, battery voltage is subject to 10~35V and battery-end charge/discharge current is 10A; it is capable of adapting to monocrystalline silicon/multicrystalline silicon/thin-film and many other kinds of solar panels, as well as lithium/lead-acid and many other kinds of batteries; it is capable of detecting the conversion of day and night, automatically controlling charging and discharging and automatically making adaptive adjustment according to seasonal variations; the current to be consumed during standby will be maintained below 3mA, and thus the power consumption is extremely low. Conclusion: By selecting the bidirectional BUCK/BOOST circuit structure, applying low-side mode for switching of solar panel and LED light, using a differential circuit to detect solar panel voltage, using a low-cost DC/DC chip to realize power supply change-over, designing a dual power supply circuit, introducing solar panel booting circuit and other hardware design, as well as MPPT algorithm, state recognition and control, return difference control and other software design, a solar LED street light control product featuring small size, low cost, high efficiency and multiple functions is successfully developed.

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