Colloidal Quantum Dots Make LEDs Shine Bright in the Infrared
ICFO researchers report on the development of a colloidal quantum-dot light emitting diode with unprecedented quantum and power conversion efficiencies in the infrared range. The ideal optoelectronic semiconductor material should be a strong light emitter i.e. should emit light very efficiently upon optical excitation as well as be an efficient charge conductor to allow for electrical injection in devices. These two conditions when met can lead to highly efficient light emitting diodes as well as to solar cells with the possibility to approach the Shockley-Queisser limit. Until now the materials that have come close to meeting these conditions have been based on epitaxially-grown costly III-V semiconductors that cannot be monolithically integrated to CMOS electronics.
Read more »
Researchers Push Perovskite LEDs' Efficiency To Rivaling Best OLEDs
Compared to OLEDs, which are widely used in high-end consumer electronics, the perovskite-based LEDs, developed by researchers at the University of Cambridge, can be made at much lower costs, and can be tuned to emit light across the visible and near-infrared spectra with high colour purity. Now, researchers have set a new efficiency record for LEDs based on perovskite semiconductors, rivalling that of the best Organic LEDs (OLEDs).
Read more »
Laser Technology for Lighting Applications: A Review and Analysis of a Promising Technology
LpR 68 Article, page 44: LEDs are currently the dominating light source: efficient and cost effective. But LEDs also have some drawbacks. Another interesting technology developed slowly in the shadow of LEDs and has become an interesting solution for some specific applications: GaN based blue solid state laser devices. Although this technology offers some very interesting advantages, it also has challenges. Nicola Trivellin, Matteo Buffolo, Carlo De Santi, Gaudenzio Meneghesso, Enrico Zanoni and Matteo Meneghini from the University of Padova and its spin-off LightCube have been working toward the development of experimental systems and demonstrators and disclose their findings of the comparison between LED and LD systems.
Read more »
New Algorithm Can More Quickly Predict Phosphor Materials for LEDs
Jakoah Brgoch, assistant professor of chemistry at the University of Houston, and members of his lab published a paper on Oct. 22 in Nature Communications describing how machine learning speeds discovery of new materials. By scanning a huge number of compounds for their key attributes they were looking for a new light conversion material that could be used in white LEDs.
Read more »
Spanish Researchers Develop Sand that Produces White Sun-Like LEDs
The team led by the chemist-technologist Rubén Costa of IMDEA Materials (Madrid) and the chemists Jesús Berenguer of the University of La Rioja and Javier García of the University of Alicante has overcome one of the biggest obstacles in the progress towards new sources of healthier artificial lighting.
Read more »
Dynamic In-Car Lighting Scenarios - Osram's Osire E4633i Prototype with Inova's Serial Control Driver
The more autonomous a car becomes, the more the way in which it is used will change. As developments continue toward autonomous driving, more and more attention is being focused on the passenger cell. Light will become an integral part of the passenger cell, taking on functional and design-specific tasks. Previously static light, which could only be switched on and off, has now been given a dynamic dimension with the prototype of the Osire E4633i – with countless design options for car manufacturer.
Read more »
Electron Beam Patterning for Full-Color HR OLED Displays
OLED microdisplays are increasingly establishing themselves in consumer-ready wearables and data glasses. In order to meet the requirements for higher efficiency, higher contrast, and higher resolutions in these applications, Fraunhofer FEP scientists have developed a new micropatterning approach for OLEDs on silicon substrates. This might eliminate the use of color filters and shadow masks in the future and allow full-color displays to be developed by means of a new process. An increase in efficiency and considerably broader color gamut have already been demonstrated in first experiments.
Read more »
Electrical Over Stress - How to Prevent an LED Failing Earlier than Expected
Article from LpR 66, page 70: While LEDS are, in general, very robust, failures still happen due to electrical over stress. Mauro Ceresa, EMEA Field Application Engineer Manager at Cree, will cover all aspects related to electrical over stress, or when an LED fails due to being subjected to a voltage beyond its specification limits. He will explain why the failure occurs and how to prevent this from happening. The article will explain the fundamental aspects of a good PCB layout design and how this is linked to the longevity of an LED.
Read more »
Liquid-Suspended White QD LEDs Achieve Luminous Efficacy Record
Quantum dot (QD) white LEDs that show a luminous efficacy of 105 lm/W have been developed. The QDs are liquid-based and, according to researchers, could help the LEDs achieve an efficacy double that of LEDs that incorporate quantum dots in solid films. With further development, researchers say the new LEDs could reach an efficacy over 200 lm/W.
Read more »
InteGreat Project Successfully Researched New Approaches to LED Production
In the InteGreat research project, Osram Opto Semiconductors coordinated a consortium comprising seven partners from science and industry. Between December 2014 and February 2018 the project partners investigated time-honored manufacturing approaches and know-how along the entire LED production process with the aim of identifying potential areas for optimization. The new insights allow for LED products to be given additional superior properties that would have been difficult or even impossible to achieve with the technologies previously used to produce LEDs.
Read more »
A Near Infrared Enhanced LED Lighting Approach
With the evolution of LED lighting, one topic has come more and more in the focus of the lighting industry: Human Centric Lighting (HCL). While HCL is not clearly defined, a common understanding is that this is light and lighting that supports health and the well-being of humans. Some new proposals are going beyond the approach of providing just visible light in adequate quality, but also to providing invisible radiation, UV and/or NIR that support health and well-being. Some research and the evolution of humans show clear evidence for positive effects of this kind of illumination. Scott Zimmerman, CEO at Silas, presents a new approach that adds NIR radiation to LED illumination. He explains the background of this idea, how it also improves the quality of visible light and discusses the health benefits.
Read more »
Full-Color InGaN/AlGaN Nanowire Light-Emitting Diodes for SSL and Displays
III-nitride based nanowire light-emitting diodes (LEDs) have received a staggering response as a future candidate for solid-state lighting and full-color displays due to their unique and exceptional features including drastically reduced polarization fields, dislocation densities as well as the associated quantum confined Stark effect (QCSE) on account of their effective strain relaxation. Moab Rajan Philip and his supervisor Dr. Hieu P Nguyen in the Nano-Optoelectronic Materials and Devices Laboratory at the New Jersey Institute of Technology (NJIT) present astonishing ideas to fabricate and control the color emission of III-nitride nanowire LEDs via molecular beam epitaxy (MBE) growth techniques. The advantage of such LEDs and their characteristics is also discussed.
Read more »
KAIST Team Develops Flexible Blue Vertical Micro LEDs
In CES 2018, micro LED TV was spotlighted as a strong candidate for replacing the active-matrix organic light-emitting diode (AMOLED) display. Micro LED is a sub-100 um light source for red, green and blue light, which has advantages of outstanding optical output, ultra-low power consumption, fast response speed, and excellent flexibility. Professor Keon Jae Lee from the Department of Materials Science and Engineering and his team have developed a low cost production technology for thin-film blue flexible vertical micro LEDs (f-VLEDs).
Read more »
Smart Printing: Fraunhofer IAP Develops Power Generating Films and Luminescent Glass
New inks for inkjet printers make it possible to print organic displays or solar cells on film and glass for the use in architecture, the textile industry and many other industries.
Read more »
Scientists Reveal the Fundamental Limitation of In Concentration in InGaN Solid-State Devices
For the first time an international research group has revealed the core mechanism that limits the indium (In) content in indium gallium nitride ((In, Ga)N) thin films - the key material for blue light emitting diodes (LED). Increasing the In content in InGaN quantum wells is the common approach to shift the emission of III-Nitride based LEDs towards the green and, in particular, red part of the optical spectrum, necessary for the modern RGB devices. The new findings answer the long-standing research question: why does this classical approach fail, when we try to obtain efficient InGaN-based green and red LEDs?
Read more »
