Newsletter - fh-muenster · 2020. 3. 23. · accelerated deep ultraviolet adoption by OEM manufacturers in additional high growth segments such as point of consumption drinking water

NewsletterNewsletterTailored Optical MaterialsTailored Optical Materials

Natalie PasbergNatalie Pasberg

Research &

Development

Latest

Publications

Recent Ap-

plied Patents

Thomas JüstelThomas Jüstel

April 2020April 2020Volume 14 Issue 04Volume 14 Issue 04

Signify horticultural business continu-Signify horticultural business continu-es to sprout, with six new farms coming es to sprout, with six new farms coming

Conception: Prof. Dr. rer. nat.Thomas Jüstel

Edited by: Natalie Pasberg

Contact: [email protected]

Volume 14 Issue 04 April 2020

Research & Development .................................................................................................................. 3

Superbug-Inactivating Emitters From Bolb Inc. Poised to Lower Healthcare Costs and Enhance Food Safety....................................................................................................................................... 3

Packaged LED news: Osram Opto, Plessey, Everlight, and Seoul .................................................. 5

Researchers Develop Bacteria-killing Coating Activated by Light ................................................. 7

Light-Emitting Textiles for Smart Clothing ..................................................................................... 8

Comfortable smart clothing .............................................................................................................. 8

Conductive pantyhose ...................................................................................................................... 8

Futuristic fabrics ............................................................................................................................... 9

Study: Photonic Tech Aids Sustainability ...................................................................................... 10

Korean Researchers Develop New Blue Light Emitting Material to Replace GaN ...................... 12

Signify horticultural business continues to sprout, with six new farms coming ............................ 13

Latest Publications ........................................................................................................................... 15

Ca8Mg7Si9N22:Ce3+-A Yellow-Emitting Nitride Phosphor for White Light Emitting Diodes ...... 15

Novel efficient deep-red-emitting Ca2LuTaO6:Mn4+ double-perovskite phosphors for plant growth LEDs ............................................................................................................................................... 15

Solid state synthesis and luminescent properties of bright blue-emitting Ba2P2O7:Eu2+ phosphor16

Novel Mn4+ doped red phosphors composed of MgAl2O4 and CaAl12O19 phases for light-emitting diodes.............................................................................................................................................. 16

Tunable thermal quenching properties of Na3Sc2(PO4)3:Eu2+ phosphors tailored by phase transformation details ..................................................................................................................... 16

Recent Applied Patents .................................................................................................................... 18

Led lighting module and a display having the led lighting module ............................................... 18

Method of manufacturing light emitting device comprising phosphors and fillers having specified particle sizes ................................................................................................................................... 18

Liquid crystal display using nanostructured phosphor film for improved color gamut ................. 19

LED filaments with colored off state masking using thermochromic material overcoat ............... 19

Light emitting device with high near-field contrast ratio ............................................................... 20


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Research & Development

Superbug-Inactivating Emitters From Bolb Inc. Poised to Lower Healthcare

Costs and Enhance Food Safety LIVERMORE, Calif.--(BUSINESS WIRE)--Germicidal LED (G-LED) supplier Bolb Inc., based in Livermore, California, the globally recognized performance leader in deep ultra-violet technology, today announces further advancements of its high performance, versatile, and cost-saving deep ultraviolet emitter arrays to combat the rise of antibiotic-resistant pathogens. With new products offering configurable features for generating from 2W to over 10W of targeted optical power in a convenient fixture, a new class of novel chemical-free pathogen reduction platforms has arrived.

In a recent test by a third-party laboratory, Bolb’s Blazar G-LED fixture has demonstrated 5log10 kill of methicillin-

resistant staphylococcus aureus (MRSA), a dangerous pathogen that is resistant to penicillin and amoxicillin among other common antibiotics. Such a high kill rate was achieved with its deep-ultraviolet G-LED array in under 1 minute from a distance of 1 meter to the targeted surface, covering approximately 1 square meter in area. Using compact solid-state G-LED technology, this is unmatched performance against a particularly egregious pathogen. Multiple arrays can be assembled and positioned to cover larger areas for quick disinfection.

It is a timely development given global public health officials continue to sound a piercing alarm concerning the unabated rise in Anti-Microbial Resistant Pathogens, commonly known as superbugs. According to the United States Centers for Disease Control and Prevention, more than 3 million antibiotic-resistant infections occur in the US each year, and more than 47,800 people die as a result. United Nations projects 10 million annual deaths worldwide due to superbug infection by

2050 if the current trend continues. Urgent actions are needed to counter the lack of effective new antibiotics and the spiraling costs associated with protecting patients and healthcare workers, including effectively dealing with contaminated surfaces and biohazard waste in acute care, surgical and clinical facilities, as well as compounding pharmacies and mobile medicine.

G-LED emitters now enable universal and cost-effective pathogen reduction solutions where footprint, upfront and operational cost, and ease of implementation matter. Bolb asserts that every 10W of implemented optical power can result in saving a typical hospital $1M in annual expenses. Given the market for such solutions can reach over 100M optical watts generated per year by 2025, $10 Billion in global Healthcare Delivery cost savings is achievable. This is significant when considering $30B was spent just in the USA in 2019 on environmental cleaning and waste remediation and removal, and overcoming medical complications and legal liabilities due to patients suffering Healthcare Associated Infections.

GLED technical advancement enables ubiquitous distributed disinfection solutions for a highly contaminated and highly mobile world. The realization of such capabilities has accelerated deep ultraviolet adoption by OEM manufacturers in additional high growth segments such as point of consumption drinking water treatment, enhanced functionality white goods and appliances, and life science analysis. Similar solutions are soon to be implemented in concentrated farm and horticulture operations, where chemical-free preventive disinfection measures are crucial for animal health, plant protection, supply chain sanitation, and consumer food safety,


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greatly contributing to a cleaner, safer, and healthier world.

Source: https://www.businesswire.com/news/home/20191218005697/en/Superbug-Inactivating-Emitters-Bolb-Poised-Healthcare-Costs-Enhance


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Packaged LED news: Osram Opto, Plessey, Everlight, and Seoul Osram Opto has used phosphor-converted red in an LED for automotive rear-facing applications while we have UV-C news and also a development in micro LED technology.

Autor - Maury Wright Mar 11th, 2020

The new Synios P2720 CR Series packaged LEDs from Osram Opto Semiconductors are designed to deliver improved brightness in a compact footprint for automotive rear lamps and fog lamps. (Photo credit: Image courtesy of Osram Opto Semiconductors.)

Osram Opto Semiconductors has announced the Synios P2720 CR series of LEDs for rear-facing automotive applications such as fog lights with a phosphor-conversion approach delivering greater output at high-temperature conditions common in automotive-lighting cavities. Plessey Semiconductors has announced that it added passive-matrix micro LED displays to the Data-Vµ product family. Everlight Electronics has announced new ELUC3535NUB LEDs that radiate in the UV-C (100–280 nm) band and that can be used in disinfection applications. Seoul Semiconductor claims assert that coronavirus drives increased interest in ultraviolet (UV) LEDs.

Automotive lighting

The Osram automotive-centric LED reminds us that there are diverse approaches to color LEDs that can be matched to application requirements. We covered such technologies and applications in a feature article a couple of years ago on color LEDs. In automotive applications, monochromatic color LEDs are used most often, but Osram found a specific reason to use phosphor conversion in the Synios P2720 CR — with the CR standing for converted red.

LEDs in exterior automotive applications are operated at relatively high drive currents which in turn minimizes the number of LEDs required to implement any specific function such as fog lights. Moreover, fog lights operate for extended periods unlike turn or braking indicators. The combination of high currents and extended operating time result is high temperature at the semiconductor junction.

Meanwhile, the compound semiconductor materials used in monochromatic red LEDs exhibit losses in output of up to 50% at operating temperatures in the 60–70°C range. The blue-pump LEDs used in phosphor converted designs do not suffer such severe output losses thus the Osram decision to utilize phosphor-converted red.

The Synios P2720 CR LEDs are integrated in a 2×2.7×0.6-mm package. There are two versions of the LED, one with 49 lm nominal output and the other with 103 lm nominal output. As you can see in the nearby photo, the phosphor coating has an unexpected shape. Seeing that photo led us to suspect that there may have been multiple emitters in the package, especially when Osram stressed the case for multi-functional lights in automotive applications. But there is in fact only one emitter and the additional phosphor covers the portion of the package cavity where wire bonds exit the package.

Micro LEDs


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Moving to emerging micro LEDs, Plessey continues to push its monolithic approach to building displays with such technology. Using wafer-level technology enables the monolithic manufacturing scheme but for now essentially limits displays to monochromatic operation. The new passive-matrix displays feature 48×36-pixel resolution targeted at augmented reality (AR) and what Plessey calls mixed-reality applications.

The displays are manufactured using Plessey’s gallium-nitride-on-silicon (GaN-on-Si) technology and the company said it has technology that will enable color displays. “Micro LED displays are now the go-to technology for next-generation developments requiring power-efficient and ultrabright displays,” said Leon Baruah, Plessey’s senior micro LED product sales manager. “With the introduction of our Data-Vµ passive-matrix displays, applications where dynamic content needs to be displayed in a small form factor that is outdoor readable without compromising on battery life has become reality.”

Everlight offers new UV-C LEDs in three different

intensity options to cover a variety of applications, from sterilization and disinfection to medical applications. (Photo credit: Image courtesy of Everlight Electronics.)

UV LEDs and disinfection

Moving to ultraviolet (UV) LED technology, Everlight’s new 280-nm devices can kill pathogens and is packaged in inorganic quartz glass, enabling mounting in contact with water or other liquids. The company announced versions of the LED in 2-, 10-, and 30-mW packages. Everlight says the products can be used for water purification and sterilization of surfaces. We have covered such applications several times previously, including the ability for UV-C to sterilize running water.

Everlight did not mention the outbreak of the coronavirus in its press release. Presumably, UV-C energy would kill such a pathogen. Seoul Semiconductor has asserted that it has seen an uptick in customer inquiries relative to the company’s violeds products that it attributes to the spread of the coronavirus

Source: https://www.ledsmagazine.com/leds-ssl-design/article/14169536/packaged-led-news-osram-opto-plessey-everlight-and-seoul


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Researchers Develop Bacteria-killing Coating Activated by Light

A research team at University College London published its development of an antimicrobial coating which kills bacteria when exposed to light. The creation can be used to coat phones screen, keyboards, and the inside of catheters and breathing tubes for prevent the spread of diseases in hospitals and healthcare institutes. The research, published today in Nature Communications, is the first to show a light activated antimicrobial coating successfully killing bacteria in low intensity, ambient light (300 Lux), such as that found in wards and waiting rooms to stop healthcare-associated infections (HCAIs). Previously, similar coatings needed intense light (3,000 Lux), like that found in operating theatres, to activate their killing properties.

(Image: UCL)

The new bactericidal coating is made of tiny clusters of chemically modified gold embedded in a polymer with crystal violet, a dye with antibacterial and antifungal properties. First author, Dr. Gi Byoung Hwang (UCL Chemistry), said, "Dyes such as crystal violet are promising candidates for killing bacteria and keeping surfaces sterile as they are widely used to disinfect wounds. When exposed to bright light, they create reactive oxygen species, which in turn kill bacteria by damaging their protective membranes and

DNA. This is amplified when they are paired with metals such as silver, gold and zinc oxide." "Other coatings have effectively killed bacteria but only after exposure to UV light, which is dangerous to humans, or very intense light sources, which aren't very practical. We are surprised to see just how effective our coating is in killing both S. aureus and E. coli in ambient light, making it promising for use in a variety of healthcare environments," added Professor Ivan Parkin (UCL Chemistry), senior author and Dean of UCL Mathematical & Physical Sciences. The team of chemists, chemical engineers and microbiologists created the bactericidal coating using a scalable method and tested how well it killed S. aureus and E. coli against control coatings and under different lighting conditions. The bacteria-killing coating was discovered unexpectedly by the team when producing hydrogen peroxide, a relatively mild reagent used in contact lens cleaner solutions. It works by chemically attacking the cell membrane, and therefore takes longer to work on bacteria with more layers of protection. The research was funded by the Engineering and Physical Sciences Research Council, through the Advanced Flow Technology for Healthcare Materials Manufacturing (MAFuMa) project.

Source: https://www.ledinside.com/news/2020/3/ucl_bacteria_killing_coating


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Light-Emitting Textiles for Smart Clothing Meeri Kim

The changeable patterned e-textile worn on pantyhose over a mannequin leg. [Image: The Carmichael Lab]

Light-emitting textiles have the potential to expand the capabilities of clothing in the realms of fashion, advertising, sports and worker safety. Current approaches mostly include sewing electronic components, optical fibers and light-emitting diodes (LEDs) directly into fabric. However, clothing made in this way suffers from rigidity and bulkiness, making it relatively uncomfortable to wear.

A team of researchers from the University of Windsor, Canada, reports a new technique for the fabrication of light-emitting textiles that deposits metal directly on the individual fibers of an ultrasheer fabric (Matter, doi: 10.1016/j.matt.2020.01.017 ). The method produces a wearable, conductive and highly stretchable electronic textile.

Comfortable smart clothing

Wearable electronics like smart watches and activity trackers have already broken into the mainstream, and many experts believe that smart clothing represents the next step. Smart clothing may have sensors to detect biometric data, batteries or solar cells as power sources, and LEDs to display patterns or data output.

More often than not, today’s smart clothing is made by simply stitching electronic components into the fabric. But having stiff optical fibers running through a sweater or an inflexible electrode in the sleeve of a workout shirt is less than ideal. Clothing should be comfortable, durable and washable—attributes that conflict with the vast majority of electronic parts.

“Instead of trying to apply conventional thin-film device-fabrication methods to fabrics, we wanted to see if we could use the intrinsic structure of the fabric as an integral part of the design,” said Tricia Carmichael, senior author and professor of surface and materials chemistry at the University of Windsor.

Conductive pantyhose

Light-emitting textiles displaying a smiley face emoji, a rectangular spiral and the number 8. [Image: The Carmichael Lab]

Carmichael and her colleagues started with an ultrasheer knitted fabric made of 87% nylon and 13% spandex—pantyhose. They used electroless nickel-immersion gold metallization, a solution-based technique commonly used in printed circuit board fabrication, to deposit a gold metal film on the surface of the fibers. Scanning electron microscopy confirmed that both the nylon and


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spandex fibers had an approximately 100-nm thick uniform gold coating. The pantyhose material retained its softness, stretchiness and transparency.

“We found that the technique was a good way to integrate metal into fabrics, and that it could coat even tiny fibers with metal,” said Carmichael. “The resulting textile still feels like fabric, just shinier, and the conductivity is very good.”

The gold-coated ultrasheer fabric exhibited an average sheet resistance of 3.6 ohms per square, which is slightly higher than the sheet resistance of a flat gold film of similar thickness. The conductivity of the textile remained remarkably stable throughout durability testing, which included 200% strain in both directions and a thousand repeated stretching episodes of 50% strain. The fabric also successfully withstood 10 simulated laundry cycles, complete with laundry detergent, agitation and a drying cycle.

Futuristic fabrics

Lastly, the researchers used a low-cost stencil-printing method to fabricate patterned e-textile electrodes in the shape of a smiley face and a dynamic display of the numbers 0 to 9. A cold-wax medium was applied to the pantyhose before metallization to act as a stencil and dissolved afterwards to create the different patterns.

“We see this technique being used for any application where self-illumination provides an advantage. Anybody working at night where visibility is important, like first responders, or even people walking around at night,” said Carmichael. “My strength is not coming up with fashion ideas, but when this type of fabric is available, it tends to capture people’s imagination.”

Source: https://www.osa-opn.org/home/newsroom/2020/march/light-emitting_textiles_for_smart_clothing/


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Study: Photonic Tech Aids Sustainability

Stewart Wills

[Image: Getty Images]

A recently released report from several German trade and research organizations argues that photonic technologies can represent “a driver of global sustainability,” and that the application of these technologies can prevent some 2.92 billion tons of annual CO2 emissions by 2030. Those avoided emissions, according to the study, would “correspond to at least 11% of the agreed target” of carbon reductions needed to cap the total industrial-age increase in global mean temperatures at 1.5 °C, a key goal set by the Paris climate accord of 2015.

Eight technologies in the spotlight

The report, “Light as the Key to Global Environment Sustainability,” was developed by Messe München, an organizer of international trade fairs (including the behemoth Laser World of Photonics), and the German optics and photonics trade organization Spectaris e.V., in cooperation with Fraunhofer ILT, Fraunhofer Light & Surfaces, the France-based photonics consulting firm Tematys, and the Photonics21 public-private partnership.

The study’s stated aim, according to one of the several introductions to the piece, is to examine “the profitable use of photonics for the sustainable treatment of resources from all angles.” To do so, it breaks out eight photonic technology examples—photovoltaics (PVs), energy-efficient lighting, optical communication in data centers, fiber optic networks, energy-efficient displays, optical early forest-fire detection, laser-supported metal recycling, and optical communication in 5G networks—and attempts to quantify the avoided CO2 (or CO2 equivalent) contributed by each.

The report’s calculations conclude that as of 2019, these eight photonic-technology segments are already allowing the avoidance of 1.13 billion tons of atmospheric CO2 equivalent that more polluting alternatives would otherwise churn out. And its growth calculations suggest that the total annual avoided CO2 equivalent from these technologies could reach 2.92 billion tons by the end of the current decade.

Big solar impact

Not surprisingly, the lion’s share of the contribution comes from increased deployment of PVs for energy, which accounts for 0.57 billion tons, or around half, of the estimated 1.13 billion tons of avoided CO2 attributable to photonics in 2019. That number is based on estimated global energy production from PVs of 711 terawatt-hours (TWh), or 3.1% of total global energy production.

The report’s authors envision that proportion growing to 10.5% of global production, or 3,268 TWh, by 2030. In that scenario, the avoided CO2 contribution attributable to PV alone would be 2.13 billion tons—a whopping 73% of the total CO2 avoidance for the year attributed to the eight photonic technologies.


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Of the other technologies, energy-efficient lighting carried the second-biggest potential impact, at around half a billion tons of CO2 equivalent avoided in the year 2030. For the other six technologies, the gains were far more fractional (and, arguably, at least a bit more speculative) in nature. In those six, avoided annual CO2 equivalent by 2030 ranged from 81 million tons from better early detection of forest fires via optical technology, to only 1.1 million tons of CO2-equivalent avoidance via “innovative photonic network components” in data centers.

Emphasis on Germany

Also unsurprisingly, perhaps, given the organizations authoring and underwriting it, the report devoted more than half of its pages to a section on “German high-tech solutions for environmental sustainability.” The section recounted a range of German projects in which lasers and other optical technologies play a role in metals recycling, climate research, lightweight-automobile construction, industrial production, sustainable agriculture and a host of other areas.

In a press release accompanying the report, Reinhart Poprawe, a former director of the Fraunhofer Institute for Laser Technology ILT, speaking from a German perspective, suggested that the report underscores that “photonics makes it possible to constructively combine economy and environmental protection.”

“This is achieved,” said Poprawe, “by both increasing the efficiency of manufacturing processes and producing optimized components for Germany’s transition to renewable energy, particularly through precision work using ultra-short-pulse lasers or by using additive manufacturing processes. Components optimized according to economic and environmental criteria can be found in solar, battery and wind power technologies, for example.”

Source: https://www.osa-opn.org/home/industry/2020/march/study_photonic_tech_aids_sustainability/


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Korean Researchers Develop New Blue Light Emitting Material to Replace GaN

Researchers of the Korea Institute of Science and Technology (KIST) develop a new material for blue light emitting LEDs which can replace gallium nitride (GaN). According to the report of BusinessKorea, the new technology breakthrough might enable Korea to reduce the dependence of Japan on LED materials. Published on Scientific Report on March 04, 2020, the study titled “Intrinsically p-type cuprous iodide semiconductor for hybrid light emitting diodes,” demonstrate the single crystal epitaxy of cuprous iodide (CuI) film grown on Si and sapphire substrate by molecular beam epitaxy.

(Image: KIST)

The researchers managed to grow CuI semiconductors on large size Si substrate (300mm) with few defects. They also found that the blue light emitting by CuI semiconductors is 10 times brighter than GaN-based LED. In addition, higher photoelectric efficiency and longer stability was also featured. The finding of the new semiconductor material for LED is significant for businesses in Korea. As the research team claimed that CuI can replace GaN in producing blue LED, businesses in Korea would be able to lessen their dependence on Japan’s exclusive GaN.

Source: https://www.ledinside.com/news/2020/3/kist_new_led_material


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Signify horticultural business continues to sprout, with six new farms coming Deal with Italy’s Planet Farms will start with a new facility north of Milan this year, followed by Switzerland and the UK.

Autor - Mark Halper

Mar 5th, 2020

It’s Luca, lights, and lettuce as Planet Farms co-founder Luca Travaglini shows off a tray of baby leaf lettuce, next to racks of red mustard and arugula under Signify LEDs. (Photo credit: Image courtesy of Signify.)

Signify is expanding its footprint in horticultural lighting, announcing that it will install tunable LED hardware and software at six European vertical farms operated by Italian grower Planet Farms, which is a research partner to the Dutch lighting giant.

Milan-based Planet Farms plans to open a 9000m2 indoor vertical farm (roughly the size of 45 tennis courts) later this year north of Milan in Cavenego, Italy, where Signify is providing its GreenPower LED modules and GrowWise control software.

The combination allows Planet Farms to tune brightness and frequencies to different levels that are optimal for different crops.

“Thanks to the collaboration we’re able to grow high-quality crops all year round and that’s why we’re now expanding our collaboration,” said Luca Travaglini, co-founder and co-CEO of Planet Farms. “The GrowWise Control System helps us easily

adjust light recipes and continuously enhance the taste of our crops, which is crucial for us.”

The commercial deployment follows two years of joint research by Signify and Planet Farms, which has been sampling Signify technology on a number of plants including basil and other herbs as well as lettuces and on leafy vegetables such as wasabi arugula, an ultra-peppery version of arugula (also known as rocket). Planet Farms opened a research lab in 2019. It works with a third company, Travaglini FarmTech — founded by Luca Travaglini’s father Arnaldo in 1950 — as well as with Signify.

“This next step in our collaboration shows that we can really help vertical farmers around the globe to improve the quality, yield, and taste of their produce,” said Udo van Slooten, Business Leader Horticulture lighting at Signify. “The plans to build another five farms across Europe shows that vertical farming is rapidly growing and evolving. It’s a thrilling time to be involved in vertical farming, and we’re excited to help shape its future.”

Signify declined to reveal the cost of the lighting at Cavenego.

Following Cavenego, Planet Farms plans to deploy Signify horticultural lighting technology at five farms it intends to build in Europe, including in Switzerland and the UK. It did not release a timescale.

Being in northern Italy, the Cavenego farm is in a region that has been hit by the coronavirus.

“We and our local partners are taking all necessary precautions, construction is still on schedule, Planet Farms and everybody involved is continuously monitoring the situation as the health and wellbeing of their employees and contracted parties is top priority,” a Signify spokesperson told LEDs

Magazine.


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The Planet Farms expansion marks the latest step forward for Signify in the important horticultural market, where customers have included Japanese 7-Eleven provider Prime Delica, French cucumber growers Jardins Réunis and Cheminant, tomato farms including France’s Le Jardin de Rabelais and Russia’s Agro-Inwest, rose growers in Holland, and others.

The horticultural market is driving many investments either directly or indirectly in lighting. Earlier this week, investors Ospraie Ag Science invested $15 million in Freight Farms, which runs LED-lit vertical farms called Greenery in shipping containers.

Cannabis is shaping up as one of the livelier horticultural lighting segments.

Source:

https://www.ledsmagazine.com/horticultural-lighting/article/14169212/signify-horticultural-business-continues-to-sprout-with-six-new-farms-coming


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Latest Publications

Ca8Mg7Si9N22:Ce3+-A Yellow-Emitting Nitride Phosphor for White Light

Emitting Diodes

Nitridomagnesosilicates phosphors are promising candidates for white light emitting diodes. Here, we report a yellow nitride phosphor Ca8Mg7Si9N22:Ce3+, which exhibits a broad band emission in spectral range of 475-675 nm under the excitation of 445 nm. The photoluminescence intensity of Ca8-xMg7Si9N22:xCe3+ (0.01 ≤ x ≤ 0.11) reaches max. when x = 0.05. CIE coordinates and color purity of Ca7.95Mg7Si9N22:0.05Ce3+ are (0.449, 0.531) and 84.0%, resp. Ca7.95Mg7Si9N22:0.05Ce3+ phosphor exhibits a good color drifting resistance with a max. chromaticity shift of 0.0085 at 475 K. By combining the as-synthesized yellow nitride phosphor Ca7.95Mg7Si9N22:0.05Ce3+ and red nitride phosphor SrLiAl3N4:Eu2+ with a com. blue InGaN chip, an all-nitride white light

emitting diode device is fabricated, and a warm white light is generated with chromatic coordinates (0.471, 0.364) and color temp. 2194 K.

DOI: 10.1021/acsaelm.0c00004

Novel efficient deep-red-emitting Ca2LuTaO6:Mn4+ double-perovskite phosphors

for plant growth LEDs

Deep-red-emitting phosphors are important for fabricating light-emitting diodes (LEDs) toward applications in plant growth lighting. Herein, we reported on novel efficient deep-red-emitting Mn4+-activated Ca2LuTaO6 (CLT) double-perovskite phosphors. A series of CLT:xMn4+ (x = 0.1, 0.2, 0.4, 0.6, 0.8, and 1.0 mol%) samples were prepd. by the conventional high-temp. solid-state reaction technique, and they were characterized by using X-ray diffraction (XRD), field-emission scanning electron microscope (FE-SEM), elemental mapping, photoluminescence excitation and emission, decay curves, CIE chromaticity coordinates, internal quantum efficiency (IQE), and temp.-dependent emission spectra. The CLT host crystd. in a monoclinic structure with space group of P21/n, and it contained an octahedral

site of TaO6 for Mn4+ doping. Impressively, under 351 UV light excitation these CLT:xMn4+ phosphors exhibited bright deep-red emissions around 682 nm with CIE chromaticity coordinates of (0.7272, 0.2728) and full width at half max. (FWHM) of 25 nm. Notably, the optimal CLT:0.2%Mn4+ sample possessed an IQE of 37% and good resistance to thermal quenching (I423 K/I303K = 47%). Considering the emission spectrum of CLT:0.2%Mn4+ deep-red-emitting phosphors matched well with the absorption spectrum of phytochrome PFR, the as-prepd. CLT:0.2%Mn4+ phosphors showed great potential in plant growth LEDs.

DOI: 10.1016/j.jlumin.2020.117177


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Solid state synthesis and luminescent properties of bright blue-emitting

Ba2P2O7:Eu2+ phosphor

Abstr.: Eu2+-activated Ba2P2O7 pyrophosphates were successfully synthesized by the solid-state reaction under reduced atm. and were characterized by X-ray diffraction (XRD) and NMR and IR (IR)/Raman spectroscopy. The luminescence properties of Ba2-xP2O7: xEu2+ (x = 0.01, 0.05) phosphors were investigated in UV and vacuum UV (VUV) regions. Under 131 or 320 nm excitation, the phosphors exhibit a blue emitting band ranging from 350 to 500 nm, which is provided corresponding to the 5d-4f

transition of Eu2+. The as-synthesized phosphors present good thermal luminescence stability on temp. quenching and high color purity with the CIE coordinate (0.172, 0.031) for Ba2P2O7:1%Eu2+ phosphor. These results suggest that the Ba2P2O7:Eu2+ pyrophosphate might be a promising blue-emitting phosphor for near UV (n-UV) light-emitting diodes (LEDs). DOI: 10.1007/s42452-020-2329-8

Novel Mn4+ doped red phosphors composed of MgAl2O4 and CaAl12O19 phases for

light-emitting diodes

Red emitters based on CaAl12O19:Mn4+ have been attracting extensive attention due to their advantages of being rare-earth-free and chem. stable. However, their relatively low luminescence efficiencies will seriously hinder their application in light-emitting diodes (LEDs). In this regard, the promising red phosphors of CaAl12O19:Mn4+ were synthesized with enhanced luminous efficiency by introducing the coexisting phase of MgAl2O4. Importantly, an approx. 5 times enhancement of integrated intensity in the emission spectrum was obsd. for the phosphor with the coexisting phase compared to that with a single phase. Their crystal structures,

morphologies and photoluminescence properties and the mechanism of improved luminescence were systematically investigated. Upon exciting them by using near-UV or blue LEDs, an efficient red emission was achieved with a max. peak at ∼658 nm. In order to evaluate their potential application, a warm white LED and a plant growth LED were fabricated by using the prepd. phosphors in combination with YAG:Ce3+ and InGaN-based blue chips.

DOI: 10.1039/d0dt00118j

Tunable thermal quenching properties of Na3Sc2(PO4)3:Eu2+ phosphors tailored

by phase transformation details

Luminescence thermal quenching of phosphors is one of the prominent problems in restricting their application in high-power LED devices. In the current work, tunable luminescence thermal quenching behaviors,

including abnormal neg. thermal quenching and normal thermal quenching, were demonstrated for Na3Sc2(PO4)3:Eu2+ phosphors tailored by phase transformation details. A series of ionic substitution schemes


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were employed to synthesize α-, β- and γ-Na3Sc2(PO4)3:Eu2+ phosphors, which show discrepant phase transformations during heating. The thermal event assocd. with phase transformation is perceived to be responsible for the observations of abnormal neg. thermal quenching performances, in view of the suppression of non-radiative paths by consuming thermal energy during the phenomenon of phase transformation. Our

results provide an insight into the relationship between the thermal quenching behaviors and phase transformation details of the Na3Sc2(PO4)3:Eu2+ phosphor and offer a useful clue to exploit high thermal stability phosphors.

DOI: 10.1039/d0dt00234h


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Recent Applied Patents

Led lighting module and a display having the led lighting module

An LED lighting module and a display having the LED module are disclosed. The LED lighting module includes a plurality of micro LED arrays and a phosphor film. The micro LED arrays are resp. composed of at least one micro LED. The phosphor film is disposed on one side of the micro LED arrays; and the phosphor film has a transparent substrate and is provided with a plurality of light emitting regions. The plurality of light emitting regions are arranged adjacent to each other and into a matrix form, and are set corresponding to the micro LED arrays collimation resp. A part or the whole of the surface of the plurality of light emitting regions is provided with at least one type of phosphor powder.

EP 3618110A1

Method of manufacturing light emitting device comprising phosphors and fillers

having specified particle sizes

Provided is a method of manufg. a light emitting device, comprising: prepg. a base body having a concave portion; disposing a light emitting element at the bottom of the concave portion; disposing a first resin contg. first phosphor particles having an av. particle size of 10μm or more and 30μm or less and a first filler having an av. particle size of 5μm or more and 20μm or less to cover the light emitting element; centrifugally pptg. the first phosphor particles and the first filler toward the base body; temporarily curing the first resin; disposing a second resin contg. second phosphor particles and a second filler having

an av. particle size of 5 nm or more and 100 nm or less on the first resin temporarily cured; centrifugally pptg. the second phosphor particles and the second filler toward the first resin; and curing the first and second resins.

US 20200066933A1


19

Liquid crystal display using nanostructured phosphor film for improved color

gamut

Embodiments of a display device are described. A display device includes a backlight unit having a light source and a liq. crystal display (LCD) module. The light source is configured to emit a primary light having a first peak wavelength. The LCD module includes a first sub-pixel having a phosphor film and a second sub-pixel having a non-phosphor film. The phosphor film is configured to receive a first portion of the primary light and to convert the first portion of the primary light to emit a secondary light having a second peak wavelength that is different from the first peak wavelength. The non-phosphor film is configured to receive a second portion of the primary light and to optically modify the second portion of the primary light to emit an optically modified primary light having a third peak wavelength that is different from the first and second peak

wavelengths. A display device according to the present invention has improved color gamut.

US 20200057338A1

LED filaments with colored off state masking using thermochromic material

overcoat

LED filaments with colored off state masking are described which comprise an underlying layer exhibiting a first appearance at a first temp., and an over-coated layer comprising a thermochromic material that exhibits at the first temp., a preselected appearance other than the first appearance, and at a second temp., a transparent or translucent appearance.

US 20200058835A1


20

Light emitting device with high near-field contrast ratio

A light emitting device includes an LED having a light emitting top surface and sidewalls. A phosphor structure is attached to the light emitting surface of the LED. The phosphor structure has a light emitting top surface facing away from the LED light emitting surface, and sidewalls. A light reflective material is arranged to cover the sidewalls of the LED and the phosphor structure. A light absorptive region is defined

in the light reflective material around a perimeter of the light emitting surface of the phosphor structure. The light absorptive region may be spaced apart from the perimeter of the phosphor structure by a gap. The light absorptive region may be formed by UV laser illumination of the light reflecting material. WO 2020028763A1

Documents

Newsletter - fh-muenster · 2020. 3. 23. · accelerated deep ultraviolet adoption by OEM manufacturers in additional high growth segments such as point of consumption drinking water