Day 2 | Thursday
On Day 2 of the conference, attendees are not limited to one interest area and are free to attend presentations in either conference track!
Day 2 | Phosphor Track
This session will feature presentations on what is driving innovation in the phosphor industry what challenges lay ahead and what is needed.
LED Phosphors Under High Driving Conditions
Dr. Marie Anne van de Haar | Project Manager of Seaborough Research
The high brightness and small chip size of current LEDs set demanding conditions for on-chip phosphors used to convert the primary radiation into the desired emission color. Apart from high chemical stability and good thermal quenching behavior, the converter materials have to be able to process the high flux densities without losing efficiency. Although this photo-saturation is a well-recognized, and even a pronounced issue in current state of the art LEDs, the underlying mechanisms are still poorly understood. We will discuss the results of a systematic study on photo-thermal saturation behavior of LED phosphors and give an outlook on potentially interesting materials like Eu3+ emitters.
Impact of Ceramic Microstructure on YAG Ceramic Converter Performances
Dr. Philippe Auroy | R&D Director of Baikowski
Using Baikowski nanophosphor powders, prototypes of Ce doped YAG ceramic converters were fabricated using pressing, sintering and hipping. The microstructure of those ceramics parts is controlled both by the powder design and by the ceramic process conditions (for instance, sintering temperature and dwell time). Ce is shown to have a +IV oxidation degree and to be very homogeneously distributed. On the other hand, ceramic grain size, secondary heat treatment and addition of a small amount of a secondary phase have a non trivial effect on the optical performance. Impact of those findings on ultrathin (a few 10µm) ceramic converters, enabled by Baikowski YAG and LuAG powders will also be discussed.
Phosphor Stabilization by CVD Coating
Dr. Dominik Uhlich | CTO | Leuchtstoffwerk Breitungen GmbH (LWB)
Inorganic phosphors are widely used in several applications. These materials have to be stable during processing and in final application e.g. in light sources. The stability has a strong impact on light intensity, color point, live time and other properties. Some phosphors systems cannot be used easily since they are unstable against air, moisture, Hg-vapor or UV-radiation. An option is, to cover the phosphor with a protective layer. LWB developed an industrial CVD method and is able to improve the properties of several kinds of phosphors, e.g. zinc sulfide or barium silicate based phosphors. This presentation will address the challenges and advantages of chemical vapor deposition on some practical examples.
Coffee & Networking Break
This sessiomn will explore the academic research and scientific studies that are fueling continued improvements and advancement of phosphor technology.
2018 Poster Session Winner: Mn4+ Activated Flouride Compounds
Dr. Thomas Jansen | Research Scientist of EMD Performance Materials
Since the commercialization of K2SiF6:Mn4+, Manganese activated phosphors are considered as suitable red emitting luminescent materials for obtaining phosphor converted light emitting diodes (pcLEDs). For high power pcLEDs, a high thermal quenching temperature of the Mn4+ luminescence is a very important performance parameter. The thermal quenching temperature of the Mn4+ luminescence can be close to that of widely applied LED phosphors, e.g. Ce3+ doped garnets or (Ca,Sr)AlSiN3:Eu2+, but it varies in a wide temperature range in dependence of the host composition. A shortcoming of Mn4+ comprising phosphors, mainly in fluoride compounds, are their low photochemical and thermal stability due to the degradation of the host. A way to circumvent this bottleneck is the use of Mn4+ activated oxide hosts. Unfortunately, this red-shifts the photoluminescence towards the 650 to 700 nm range, which is much less suitable for lighting applications due to the low sensitivity of the human eye in this spectral region. Therefore, current research on Mn4+ activated LED phosphors deals with the stabilization of K2SiF6:Mn4+ or K2TiF6:Mn4+ and on the finding of novel Mn4+ activated fluorides with better thermal as well as photochemical stability [1-5].
On Halide Derivatives of Rare-earth Metal Molybdates and Tungstates as Promising Luminescent Materials – F and D in Harmony
Dr. Ingo Hartenbach | University Researcher of University of Stuttgart
Halide derivatives of rare-earth metal oxidomolybdates and -tungstates represent promising materials for luminescence applications, since they offer a plethora of different chemical compositions, resulting in host lattices with hardness variations and diverse coordination numbers of the refractory metal cations as well as various condensation grades of the complex molybdate and tungstate anions, respectively. The latter two adjustment possibilities directly influence the ligand-to-metal charge transfer excitation range of the aforementioned units, and thus their material properties, e.g. towards excitation with a blue LED.
Fluoride Ceramic Phosphors for LED Lighting
Dr. Nerine Cherepy | Research Scientist of Lawrence Livermore National Laboratory
New phosphor ceramics that convert blue Light Emitting Diode (LED) light into a tunable white light spectrum can be produced by consolidating multiple phosphors into a fully dense translucent ceramic. Use of a fluoride matrix facilitates formulation of multi-phosphor ceramics for white light emission offering both high CRI and efficacy at various correlated color temperatures. Phosphor ceramics offer improved environmental stability and thermal conductivity for use with high blue light pump flux, since heat generated may be efficiently conducted away, minimizing thermal quenching at high power. In addition, the translucency of the ceramic provides for a longer excitation pathlength in the phosphor, allowing doping level to be reduced, mitigating concentration quenching and improving thermal stability of luminescence, known to be exacerbated at high dopant concentrations. Our team of scientists at LLNL, GE and Ames Laboratory is developing new LED lighting structures based on this new class of phosphor ceramics.
Energy Storage Phosphors: From Glowing Roads to Pressure Memory
Philippe Smet | Assistant Professor of Ghent University Belgium
In general, phosphor development is driven by efficiency, often requiring a low number of defects. Defects can however also be very beneficial, as in the case of persistent or glow-in-the-dark phosphors, e.g. for safety signage, bio imaging and electricity-free illumination. To assess the viability of those applications, we present a method to determine the trapping capacity of persistent phosphors, along with the identification of a loss mechanism, having a close connection to LED phosphors. A second application is based on mechanoluminescent (or pressure sensitive) phosphors. By properly exploiting trap distributions, a memory effect can be added, strongly expanding the application area.
Both Conference Tracks Will Eat Lunch Together
This session will explore innovations being made in Phosphors i.e., novel applications, emergent technology, etc…
Discovering Novel Phosphors Using the Single Particle Diagnosis Approach
Hiroaki Toyoshima | Phosphor Scientist of Denka
Phosphor is a key material to control the efficiency and colour purity of white LED. It is however, difficult to tune drastically the emission properties of phosphors. Thus, exploring novel phosphors, is very important to respond to new development demands for white LED. We found novel phosphors using a single particle diagnostic approach, developed initially by NIMS. This methodology allows us to measure the single particle photo luminescence, excitation spectra, crystal structure and composition. This led to the effective discovery of novel phosphors. In this presentation, we will introduce three novel phosphors and the mass production line-up of Denka’s phosphors.
Spectrum Design of the Red/Deep-red Phosphor
Dr. Shiho Takashina | Engineer, Technical Group LED Materials Department of Mitsubishi Chemical Corporation
In late years, the need for development in blue-light-excited phosphors has been diversifying: it can be not only the improvement in internal quantum efficiency but also the various spectrum design to meet the specific white spectrum targets. To meet these various demands in the phosphor market, we have sought a way to control spectrum shape without losing efficiency. Based on our latest achievements, I am going to argue the recent progress in the nitride red phosphor development, especially the expansion in the control range of both peak wavelength and full width at half maximum (FWHM).
Emerging Applications for Cyan Phosphors
Dr. Wouter Soer | R&D Director of Lumileds
The white pc-LED market is served mostly by royal-blue pumped LEDs with a mixture of green and red phosphors and to a lesser extent by violet pumped LEDs with a mixture of blue, green and red phosphors. Both these LED types can achieve very high color fidelity with CRI Ra>95 over a wide range of CCTs, meeting the requirements of most traditional lighting applications. However, new applications are emerging that can benefit from specific enhancement of a narrow wavelength band centered around 490 nm. Examples of such applications are human-centric lighting that aims to deliver maximum melanopic illuminance, and professional lighting with tailored saturation of object colors. Existing blue and green phosphors partly cover the spectral range of interest, but significant opportunities remain to optimize specifically for cyan content. In this presentation we will discuss several relevant applications, as well as directions for cyan phosphor development to address their requirements.
Wide Gamut Phosphor Films for Mini LED Applications
Dr. Xianglong Yuan | Director of Phosphor Materials of Intematix Corporation
Wide gamut phosphor films for mini LED applications have been developed using Intematix proprietary narrow band green and narrow band red phosphors. The Intematix narrow band green phosphor has a FWHM of 49nm compared to a FWHM of 55nm for β-SiAlON and is tunable across a peak wavelength range of 535nm to 548nm. Unlike KSF phosphors, the Intematix narrow band red phosphor is also tunable across a broad wavelength range from 615nm to 647nm with a FWHM of 50-55nm. Through phosphor and system optimization, a DCI-P3 gamut coverage of 108% is achievable using industry standard color filters while delivering high brightness and efficiency. Unlike quantum dots, employing these materials in phosphor films requires no additional hermetic protection, and the functional area extends to the edge of the film dimensions. Intematix phosphor films are RoHS and REACH compliant.
- Introduction of new narrow band red and narrow band green phosphors developed by Intematix
- Discussion on phosphor films for wide gamut displays
- Demonstration of gamut improvement vs. B-Sialon and KSF vs. different color standards including options to optimize for gamut vs. brightness
- Optimization of NBG and NBR wavelength selection for DCI-P3 and NTSC gamut
Presentation To Be Confirmed
Coffee and Networking Break
Both Tracks Will Come Together Again for the Conclusion of Day 2
Day 2 | Quantum Dots Track
This session will feature presentations on what is driving innovation in the quantum dot industry what challenges lay ahead and what is needed.
Quantum Dot Developments from Samsung
Dr. Youho Won | Samsung Electronics
Just Confirmed! Abstract coming soon!
QD market forecast, outlook on the QDTV
Bob O'Brien | Co-Founder and President of Display Supply Chain Consultants (DSCC)
The big three brands in the global TV industry have recently achieved unprecedented success in their TV business with sales of OLED and QLED premium TVs. This presentation will review the battles between these competing technologies and competing brands, and the outlook for the other competitors in the TV space. We will review market drivers and new technologies such as QD OLED, MicroLED, 8K and others, and will share DSCC's latest forecast of the TV market.
Developments in Phosphines for Quantum Dot Manufacturers
Bill Stibbs, PhD | Senior Business Development Manager, Phosphorus Specialties of Solvay
Solvay has a long history in phosphorus chemistry and a track record of successful innovation. The quantum dot market has emerged and grown rapidly over recent years. The development of a product portfolio serving this evolving market will be presented.
Coffee and Networking Break
Quantum Dot Light Emitting Diodes: Progress and Challenges
Alex Titov | Lab Manager of NanoPhotonica Inc.
Electroluminescent quantum dot light emitting diodes (QLEDs) made using colloidal quantum dots is a promising new-generation display and lighting technologies because they are efficient, emit pure color, and inexpensive. NanoPhotonica continues to demonstrate highly efficient red, green, and blue QLED devices using innovative transport and emitting layer materials. In this talk, I will present the characteristics and performance of our recent EL-QLED devices, as well as our current efforts to further improve QLED performance and life time. Our work on ink-jet printed QLED will be shared as well.
Quantum Dots Digital Printing Solutions, Printing Fluids, Powders and Equipment for Different Industries
Oxana Astapova | Director of Special R&D Projects Development for Emerging Quantum Dots Technologies, IQDEMY Group of IQDEMY SA
Displays and semiconductors: Special Fluids, Print Head Control electronics and printing machine were developed for IJP black 3D hydrophobic wells that were filled with a specially formulated fluid with RGB QDs. Security printing solutions: Quantum dot water based, UV based inks and varnishes have been introduced to the market for using in printing on fibers, paper, polycarbonate, films, holograms.
Anti-Virus QD Patches for Airports, Hospitals, Educational institutions, Military Sector is a new trend in security solutions. Quantum Dot solutions for Green Houses that boost crop yield twice.
This session will explore innovations being made in QDs i.e., novel applications, emergent technology, etc…
Concerns and Progress in the Development Of Quantum Dot Light Emitting Diodes
Dr. Longjia Wu | Materials Development Expert of TCL Corporate Research
Quantum dot light emitting diodes (QLEDs) that electrically excite quantum dots (QDs) are the future of QD displays, owning to the excellent optical properties of QDs, such as narrow emission spectra, size-controlled emission wavelength, high quantum yield and inherent stability. During the past twenty years, the efficiency of QLEDs has dramatically increased from less than 0.1% to more than 20%, but the operation lifetime of these devices was still far below the requirement of display applications. In this report, we will discuss our concerns of QLEDs and show some methods to improve the performance of QLEDs, especially concerning the operation lifetime.
Development of Perovskite Quantum Dots for Color Converter Materials In Displays and Sensors
Luftan Sinatra PhD | VP of Product Development of Quantum Solutions LLC
Perovskite quantum dots (PQDs) have attracted significant attention due to their extraordinary optical properties, which make them an ideal material for color converters materials. The main challenge left for PQDs is their stability from water and heat. Herein, we will give an overview on the current technologies in displays and sensors and followed by the development of these technologies in our company. The talk will focus on the development of high luminescence and high thermal stability of PQDs by using ligands engineering and protective shelling methods. The performance of these PQDs will be highlighted, especially for application in LCD display and high responsivity UV photodetector.
Both Conference Tracks Will Eat Lunch Together
Quantum Dots and Circadian Rhythms
Sarah Morgan | CEO of Nano-Lit Technologies
Light has a profound effect on human’s daily function. The more we can emulate sunlight indoors, the better we will sleep. The evidence is mounting that the health benefits of good light are life changing. Quantum Dots are perfectly positioned to accelerate Lighting for Health and Well-being.
This session will explore innovations being made in quantum dot technology i.e., innovative materials, emergent technologies, improved performance capabilities, and more…
An Organic Chemistry Perspective on Improving Quantum Dots
Kapil Deshpande, PhD | Lead Applications Scientist of Croda
Organic ligands are essential components of quantum dots whether it is for controlling the particle growth, stabilizing particle size, or passivating the surface. However, they are often overlooked when it comes to improving the quantum dot performance. Croda brings a wealth of organic chemistry knowledge that perfectly complements the expertise already in the quantum dot industry. We have developed novel ligands that have unique physical properties and bring minimal impurities and enhanced brightness when used in quantum dot synthesis. Benefits in Photoluminescent Quantum Yield (PLQY) will be presented alongside comparative data with other available options.
Fundamental Science of InP
Dmitri Talapin | Professor, Department of Chemistry and James Franck Institute | University of Chicago
All Inorganic Perovoskite Quantum Dots for the Application in Light Emitting Diodes
Professor Ru-Shi Liu | Professor, Department of Chemistry of National Taiwan University
All-inorganic CsPbX3 (X = I, Br, Cl) perovskite quantum dots (PQDs) have been extensively investigated because of their unique optical properties, such as tunable wavelength, narrow band, and high quantum efficiency. These fascinating features of inorganic nanocrystals have been utilized in light emitting diode (LED) devices. For application in lighting and backlight display, the stability of PQDs should be further improved. Degradation of PQDs is mainly caused by temperature, oxygen, moisture, and light. Surface passivation and surface protective shell can improve the stability of LEDs. We further applied wide color-gamut in PQD-based LEDs for Q-LCD and QLED.
Light Absorption with Quantum Dots - How to Get More With Less
Peter Palomaki, Ph.D | Palomaki Consulting, LLC
There is an unmet need in the display industry to enhance the absorption of quantum dot (QD) materials. If such a need can be met, the industry will realize more rapid adoption of QD technology due to decreased costs and increased efficiency which will pave the way for QDs to become the go-to solution for wide color gamut displays of the future. Improvements in blue light absorption of QDs will accelerate the development of next-generation display technologies such as QD color filter replacements and QD color conversion on micro LEDs, both of which require high blue light absorption in a short path length in order to be viable. We have undergone a thorough analysis and modeling of the literature values for blue light absorption (450 nm) for three common QD material types: cadmium-based QDs, indium phosphide based QDs, and perovskite QDs. Modeling the absorption properties as a function of size, composition, and shell thickness helps guide QD design choices to achieve maximum blue light absorption with the least amount of material possible. Our work has resulted in some counter-intuitive findings which will help the QD community in designing better absorbing QD composites for displays as well as other applications that require a high optical density in a short pathlength material.
Both Tracks Will Come Together Again for the Conclusion of Day 2
Following the final networking break, both audiences will come back together for the announcmement of the winner of the 2019 Student Poster Session and closing remarks.
Student Poster Session Winner Announced