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Xiaogang Peng. Nano Research (2022) The currently ubiquitous light-emitting diodes (LEDs) have revolutionized the lighting industry. Contrary to common belief, however, LEDs are much more than
The prepared symmetric supercapacitor (SSC) device is successfully tested to switch on four red-light-emitting diodes for >24 seconds, a digital watch and an electronic calculator glow up to 51 s and 30 s, respectively, after 15 s of charging through a DC power supply.
LEDs are one of the most common types of diodes due to their usefulness and efficiency. LEDs produce a narrow band of visible or infrared light, and are extremely efficient at converting electrical energy into light or infrared radiation. Like other kinds of diodes, LEDs will only allow current to pass when they are forward-biased. This means
A compact capacitor discharge and strobe light beacon system is disclosed which is designed to be used in a conventional incandescent aircraft warning light fixture. The system comprises: a step-up transformer; a pulse shaping network for rectifying the output of the transformer to pulsating DC, capacitor means connected to the output of the pulse
Based on the energy consumption profiles and requirements of the typical elements found at homes and offices, three distinctive groups are established: light-emitting diode (LED) lighting
Generally, the energy storage capacitor used for fast discharge applications is classified as slow, medium, and fast which regulates the discharging rate
A voltage-programming-based pixel circuit with three thin-film transistors (TFTs) and one capacitor (3T1C) is proposed and simulated for active-matrix organic light-emitting diode (AMOLED) displays. Unlike the previously published voltage-programming pixel circuits, which only compensate for threshold voltage ( V T ) unevenness, this circuit
The factors that cause LED chip failure mainly include: electrostatic discharge, current and temperature. Electrostatic discharge (ESD) can release instantaneous ultra-high voltage, causing great harm to LED chips. LED chip failure caused by ESD is divided into two modes: soft failure and hard failure.
The lifetime of light-emitting diode (LED) drivers is mainly affected by electrolytic capacitors. Therefore, it is necessary to eliminate electrolytic capacitors from LED drivers. The energy storage capacitor which absorbs excess energy when the input power is high and releases stored energy in the hour of input power, is also
Abstract: While LEDs enjoy relatively long lifetime up to 10 years, the lifetime of traditional LED drivers using electrolytic capacitor as storage element is
In this paper, a new method is proposed to eliminate electrolytic capacitors in a two-stage ac-dc light-emitting diode (LED) driver. DC-biased sinusoidal or square-wave LED driving-current can help to reduce the power imbalance between ac input and dc output. In doing so, film capacitors can be adopted to improve LED driver''s
It has recently been shown how the injection barriers at the electrode interfaces and the built-in voltage (Vbi) of organic light emitting diodes can be obtaine It has recently been shown how the injection barriers at the electrode interfaces and the built-in voltage (V bi) of organic light emitting diodes can be obtained from measurements of
Achievement of blue phosphorescent organic light-emitting diode with high efficiency, low driving voltage, and long lifetime by exciplex-triplet energy transfer technology. SID Symp Dig Tech Pap
The LCA in this article compared two technologies used in road lighting: HPS and LED luminaires. The luminaires are illustrated in Fig. 1 with measurements. The assessment was conducted according to the international standards (ISO 14040, 2006, ISO 14044, 2006).The goal was to study the environmental performance of the road lighting
While LEDs enjoy relatively long lifetime up to 10 years, the lifetime of traditional LED drivers using electrolytic capacitor as storage element is limited to typically less than 5 years. In this paper, an ac/dc LED driver without electrolytic capacitor is studied. Compared with other methods to eliminate electrolytic capacitor, the proposed driver
In the night mode of operation, the high voltage transformer T-2 is pulsed for a shorter period of time sufficient to provide enough energy to one bank of capacitors, C-21 in series with C-22, to discharge them through xenon lamps 30 and provide about 2,000 candela of light. In the night mode, capacitor energy storage bank C-23 is switched out
Introducing molecular chirality into perovskite crystal structures has enabled the control of carrier spin states, giving rise to circularly polarized luminescence (CPL) in thin films and circularly polarized electroluminescence (CPEL) in LEDs. Spin-LEDs can be fabricated either through a spin-filtering layer enabled by chiral-induced spin
Commonly available colors of LED are red, green, blue, yellow, amber and white. The light from red, blue and green colors can be easily combined to produce white light with limited brightness. The working voltage of red, green, amber and yellow colors is around 1.8 volts. The actual range of working voltage of a light emitting diode can be
Light-emitting diodes (LEDs) produce light (or infrared radiation) by the recombination of electrons and electron holes in a semiconductor, a process called "electroluminescence".The wavelength of the light produced depends on the energy band gap of the semiconductors used. Since these materials have a high index of refraction,
This paper proposes a LED (light emitting diode) driver based on a three-phase resonant switched capacitor (SC) converter. The LED lamp employs chip-on-board (COB) technology, as it is possible to
There are many applications which use capacitors as energy sources. They are used in audio equipment, uninterruptible power supplies, camera flashes, pulsed loads such as magnetic coils and lasers and so on. Recently, there have been breakthroughs with ultracapacitors, also called double-layer capacitors or supercapacitors, which have
stored energy rationally pow ers the LEDs for light emitting. The self‑driven integrated system has an overall efficiency of 8.1% with the storage efficiency of 74.24%.
Nowadays, the energy storage systems based on lithium-ion batteries, fuel cells (FCs) and super capacitors (SCs) are playing a key role in several applications
The majority of modern luminous bug zappers use >10 W fluorescent lamps (FLs) as light sources. FLs are inexpensive, yet their UV rays are not efficient in terms of attracting mosquitoes. Under the same UV output, light-emitting diodes (LED) can save over 30% more electric power than FLs 9. Moreover, when used outdoors without utility
The schematic structures and energy diagrams of the devices, along with their respective HOMO and LUMO energy levels, are shown in Fig. 1.The active area of the devices was 2.5 mm × 2.5 mm. The depositions were carried out in a high vacuum of 10 −7 Torr, and at the end of the fabrication process, all devices were encapsulated with glass
Analyzing and optimizing carrier behaviors are essential to achieve high electroluminescence performance in perovskite light-emitting diodes (PeLEDs). In this work, a capacitance–voltage (C–V) model for PeLEDs is established to
In this review article, the authors provide a comparative analysis of recent and ongoing advances in synthesis (top-down and bottom-up), properties, and wide applications in different kinds of next-generation light-emitting diodes such as WLEDs, and energy storage devices such as batteries (Li-B, Na-B) and supercapacitors.
A family of bidirectional single-phase AC-DC three-phase-leg sinusoidal pulse-width-modulation (SPWM) converters with an AC storage capacitor for use in a nanogrid
Moreover, their simple preparation and excellent performance provide for a wide range of applications in the fields of optical sensing, energy storage, biomedical imaging, and white light-emitting diodes (WLEDs). A large number of solid-state photoluminescent CDs have recently been developed and used in WLEDs.
Recently, white light-emitting diodes First of all, many existing LED drivers using electrolytic capacitors as the energy storage do not match the LED lamps in the lifetime. It is well known that the lifetime of a high-quality electrolytic capacitor is typically 10 000 h at 105°C, which is much shorter than the lifetime of LEDs in the
Light-emitting-diode (LED) drivers are required to maintain the power quality of both the AC input and DC output side. The regulation prevents adverse impacts
A device charges to 3 V in 10 s while immersed in water and lights up a green light-emitting diode (2.155 V forward voltage) for ~10 min (Supplementary Fig.
A first-stage isolated power-factor-correction (PFC) pre-regulator is proposed, which allows the storage capacitor to be located in the secondary side of the isolation transformer.
Demonstration experiments illustrate potential applications of these biodegradable MSCs as transient sources of power in the operation of light-emitting diodes and as charging capacitors in integrated circuits for wireless power harvesting. KW - biodegradable materials. KW - biodegradable metals. KW - flexible energy storage devices
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