Light-emitting Diode Chip Research Articles

Stabilizing perovskite nanocrystals by controlling protective surface ligands density

After nanocrystals synthesis, the purification process with anti-solvents is an essential step to get clean nanocrystals, which could get rid of the by-products of the synthesis. It is generally recognized that this process could bring a positive effect for the afterward optoelectronic applications. Unfortunately, we found that the optical properties and photostability of perovskite CsPbBr3 nanocrystals were unavoidably deteriorated after they were washed with anti-solvents, and this deterioration is strongly related to the decreasing of surface ligands density. Therefore, in this paper, we tried to purposely not wash the CsPbBr3 nanocrystals solution after adding didodecyl dimethylammonium bromide (DDAB), and found the existing of DDAB in solution could result in a dramatically enhanced photostability. Inspired by these results, we proposed a new strategy to stabilize perovskite nanocrystals from the view of packaging process: adding protective ligands into the perovskite nanocrystals resin directly, then encapsulating them on blue light-emitting diodes (LED) chips. Surprisingly, stable LED devices (20 mA, 2.7V) were achieved by this way, which can keep 80% of the initial photoluminescence (PL) intensity for more than 50 h, while the devices with CsPbBr3 nanocrystals without adding protective ligands into resin dropped to 50% of their initial PL intensity within 6 h. This approach offers a new thought to stabilize perovskite nanocrystals as down-conversion phosphor in quantum dots liquid crystal display.

Inorganic antimony halide hybrids with broad yellow emissions

Lead halide perovskites exhibit unexceptionable photoelectric properties. However, these materials are unsatisfactory in terms of stability and toxicity. Herein, we report Rb7Sb3Cl16 as a new kind of lead free perovskite variants. This material can be easily obtained through hydrothermal reactions. The composition is determined through structure refinement, elemental analysis and X-ray photoelectron spectra. Rb7Sb3Cl16 exhibits a broad yellow emission at 560 nm, with a Stokes shift of 175 nm and a photoluminescence quantum yield (PLQY) around 26%. Rb7Sb3Cl16 also shows good thermal and water stability due to its inorganic composition. White light-emitting diodes (LEDs) are constructed by combining Rb7Sb3Cl16 as yellow phosphors, our previously reported Cs2SnCl6:2.75%Bi as blue phosphors, and commercial UV LED chips as the excitation source, producing a white light with the Commission Internationale de’Eclairage (CIE) color coordinates at (0.39, 0.38).

Thermally stable lead-free phosphor in glass enhancement performance of light emitting diodes application.

A co-sintering method for preparing PIG is proposed, a Ce3+ doped yttrium aluminum garnet (YAG:Ce) phosphor in glass (PIG) slice is fabricated through co-sintering polycrystalline Ce:YAG phosphor, and a new, to the best of our knowledge, homemade matrix glass SiO2-K2O-BaO-B2O3 glass powder is detected to confirm crystal phase by X-ray powder diffractions (XRD) and micromorphology by scanning electron microscope (SEM). The YAG:Ce phosphor particles dispersed in the matrix are vividly observed and their distributions are relatively uniform. The PIG packaged light-emitting diode (LED) sample shows a relatively lower correlated color temperature (CCT) than the conventional phosphor-dispensing LED sample. White light can be achieved in the PIG slice under 465nm LED excitation by controlling the phosphor concentration or thickness. The highest luminous efficacy of the PIG slice packaged white LED is 94.67lm/W at 100mA. Controllable geometrical and optical properties of the YAG:Ce PIG can generate evident improvements in the manufacturing of identical CCTs for high-power white LEDs. The combination of PIG with a blue LED chip of a specific wavelength, if measured before final assembly, enables targeted production of specific CCT white LEDs. PIG technology allows the realization of high stability and thermal conductivity for the phosphor layer. This simple method provides many possibilities for LED packaging, including thin film flip chip and remote phosphor technology.

Multi-Domain Modelling of LEDs for Supporting Virtual Prototyping of Luminaires

This paper presents our approaches to chip level multi-domain LED (light emitting diode) modelling, targeting luminaire design in the Industry 4.0 era, to support virtual prototyping of LED luminaires through luminaire level multi-domain simulations. The primary goal of such virtual prototypes is to predict the light output characteristics of LED luminaires under different operating conditions. The key component in such digital twins of a luminaire is an appropriate multi-domain model for packaged LED devices that captures the electrical, thermal, and light output characteristics and their mutual dependence simultaneously and consistently. We developed two such models with this goal in mind that are presented in detail in this paper. The first model is a semi analytical, quasi black-box model that can be implemented on the basis of the built-in diode models of spice-like circuit simulators and a few added controlled sources. Our second presented model is derived from the physics of the operation of today’s power LEDs realized with multiple quantum well heterojunction structures. Both models have been implemented in the form of visual basic macros as well as circuit models suitable for usual spice circuit simulators. The primary test bench for the two circuit models was an LTspice simulation environment. Then, to support the design of different demonstrator luminaires of the Delphi4LED project, a spreadsheet application was developed, which ensured seamless integration of the two models with additional models representing the LED chips’ thermal environment in a luminaire. The usability of our proposed models is demonstrated by real design case studies during which simulated light output characteristics (such as hot lumens) were confirmed by luminaire level physical tests.

Windowing Techniques for Reducing PAPR of OFDM in Li-Fi Systems

Abstract In this paper, Li-Fi system based on orthogonal frequency division multiplexing (Li-Fi-OFDM) is presented. In these systems, light-emitting diodes (LEDs) are used to send information data using intensity modulation. LEDs have a limited dynamic range and the voltage-current characteristic shows a nonlinear behavior. Li-Fi-OFDM signal is used to drive these transmitter LEDs. However, LEDs chip overheating and nonlinear distortions occur, due to high peak-to-average power ratio (PAPR) of the OFDM signal. The proposed approach develops a new PAPR reduction method of OFDM in Li-Fi systems based on time-domain windowing techniques. Several windows such as rectangular, Hanning and raised cosine methods have been applied to the OFDM time-domain signal in order to reduce its PAPR while maintain acceptable bit error rate (BER) performance at receiver side. The simulation results of the work have shown the advantages of the offered method; the proposed scheme achieves a significant PAPR reduction compare to the unwindowed signals. Our proposed system also slightly improves the BER performance for all windowing methods employed.

Application of Hexagonal Boron Nitride to a Heat-Transfer Medium of an InGaN/GaN Quantum-Well Green LED.

Group III-nitride light-emitting diodes (LEDs) fabricated on sapphire substrates typically suffer from insufficient heat dissipation, largely due to the low thermal conductivities (TCs) of their epitaxial layers and substrates. In the current work, we significantly improved the heat-dissipation characteristics of an InGaN/GaN quantum-well (QW) green LED by using hexagonal boron nitride (hBN) as a heat-transfer medium. Multiple-layer hBN with an average thickness of 11 nm was attached to the back of an InGaN/GaN-QW LED (hBN-LED). As a reference, an LED without the hBN (Ref-LED) was also prepared. After injecting current, heat-transfer characteristics inside each LED were analyzed by measuring temperature distribution throughout the LED as a function of time. For both LED chips, the maximum temperature was measured on the edge n-type electrode brightly shining fabricated on an n-type GaN cladding layer and the minimum temperature was measured at the relatively dark-contrast top surface between the p-type electrodes. The hBN-LED took 6 s to reach its maximum temperature (136.1 °C), whereas the Ref-LED took considerably longer, specifically 11 s. After being switched off, the hBN-LED took 35 s to cool down to 37.5 °C and the Ref-LED took much longer, specifically 265 s. These results confirmed the considerable contribution of the attached hBN to the transfer and dissipation of heat in the LED. The spatial heat-transfer and distribution characteristics along the vertical direction of each LED were theoretically analyzed by carrying out simulations based on the TCs, thicknesses, and thermal resistances of the materials used in the chips. The results of these simulations agreed well with the experimental results.

Synthesis and luminescence properties of rare-earth free narrow band green emitting Na2ZnSiO4:Mn2+ phosphor for white LEDs

Novel rare-earth free green-emitting phosphor Na2ZnSiO4:Mn2+ was prepared by conventional high temperature solid state reaction method in the carbon reducing atmosphere at 900 °C. The crystal structure was confirmed by X-ray diffraction (XRD) and the structure information was refined by the Rietveld method. The luminescence properties of Na2ZnSiO4:Mn2+ phosphors as a function of Mn2+ concentrations were investigated. The excitation band peaking at ∼359, 383, 427, 449, and 467 nm are attributed to ground level 6A1(6S) to excited levels 4E(4D), 4T2(4D), [4A(4G), 4E(4G)], 4T2(4G), and 4T1(4G) transitions of Mn2+ ion, respectively, which indicates that Na2ZnSiO4:Mn2+ phosphor may be excited by (near) ultraviolet and blue region light-emitting diode chip. The narrow emission band peaks at ∼515 nm generated by 4T1(4G)→6A1(6S) transition of the Mn2+ can exhibit strong green emission. The luminescence mechanism was explained by the Tanabe-Sugano diagram. The optimum Mn2+ doping concentration was 0.5 mol%. The critical distance between Mn2+ was calculated to be 33.7 Å. The concentration quenching mechanism can be interpreted by the dipole-dipole interaction of Mn2+ ions. With the Mn2+ doping concentration increasing in the range of 0.2–0.8 mol%, the lifetime of this phosphor decreased from 7.51 to 7.39 ms. These phosphors also possessed good thermal stability at high temperature, and the emission intensity at 125 °C was about 74.9% of that at 25 °C. The present work suggests that Na2ZnSiO4:Mn2+ phosphor is a kind of potential green-emitting phosphor to provide a bright green component in the red/green/blue tri-color system w-LEDs.

Highly Thermally Conducting Polymer-Based Films with Magnetic Field-Assisted Vertically Aligned Hexagonal Boron Nitride for Flexible Electronic Encapsulation.

Here, a facile, low-cost, and high-efficiency method to construct a vertically aligned hexagonal boron nitride nanosheet (hBNN) thermal conduction channel structure is proposed to improve the thermal conductivity. First, exfoliated negatively charged BNNs and positively charged FeCo nanocubes self-assemble to form complex nanomaterials by strong electrostatic interactions. Then, the BNNs can orient with FeCo nanocubes in magnetic field, and the {001} facets of BNNs adsorb on the {100} facets of FeCo nanocubes. The large scale range and high-density FeCo/hBN-aligned structures are observed by scanning electron microscopy, which can act as thermal dissipation channels by conveying more phonons through a preponderant thermally conductive direction. The thermal conductivity of the composite films with 30 wt % FeCo and 50 wt % BN filler is 2.25 W m-1 K-1, 7 times higher than that of the films only containing 50 wt % randomly distributed hBN filler (0.325 W m-1 K-1) and 20 times higher than pure polydimethylsiloxane films (0.114 W m-1 K-1). The thermal management capability of the composite films is evaluated as a thermal conducting substrate of a light-emitting diode chip and the infrared thermal technology. Apart from the surprising thermal conductivity, FeCo-BNNs composite films also exhibit superb flexibility.

High-luminous efficacy green light-emitting diodes with InGaN/GaN quasi-superlattice interlayer and Al-doped indium tin oxide film

High-luminous efficacy green light-emitting diodes (LEDs) with InGaN/GaN quasi-superlattice (QSL) interlayer and Al-doped indium tin oxide (ITO) current spreading film have been demonstrated. The photoluminescence mapping results revealed that the 2-inch green LED wafer with the QSL interlayer had a longer average peak wavelength as compared to that without the QSL interlayer. In addition, the forward voltage was decreased and the light output power was considerably improved for the green LED chips fabricated from the wafer with the QSL interlayer. Then, an Al-doped ITO film was employed in the green LEDs showing a further improvement in external quantum efficiency. It was mainly ascribed to the increased internal quantum efficiency by analyzing the injection efficiency, light extraction efficiency and X-ray photoelectron spectroscopy spectrum. Finally, at an injected current of 20 mA, a high luminous efficacy of 264.7 lm/W and peak wavelength of 537.2 nm was achieved for the green LEDs with a chip-on-board silicone encapsulation. We determine that the high luminous efficacy was attributed to the improved electrical and light output performance of the LEDs due to the use of the InGaN/GaN QSL interlayer, the Al-doped ITO and the chip packaging structure.

Preparation of ZrO2/silicone hybrid materials for LED encapsulation via in situ sol‐gel reaction

Organic silicones have been used as encapsulant materials for light‐emitting diodes (LEDs) for many years, while their performances need to be improved in order to satisfy the requirements of high‐power LEDs. A ZrO2/silicone hybrid resin (ZHR) was synthesized for LEDs encapsulation by in situ sol‐gel reactions. The oligosiloxane was synthesized as polymeric matrix by nonaqueous sol‐gel condensation using diphenylsilanediol (DPSD), vinyltrimethoxysilane (VTMS), and 3‐methacryloxy propyl trimethoxysilane (MPTMS) as monomers. Then zirconium propoxide was added into this polymeric matrix to be hydrolyzed to obtain the hybrid resin with a uniform dispersion of ZrO2 nanoparticles. The Si–O–Zr covalent bond was detected and benefited for excellent dispersibility of the ZrO2 nanoparticles and the well compatibility between organic and inorganic phases. The cured ZHR with 5 wt% ZrO2 content showed high light transmittance (greater than 80% in visible light range), high refractive index (=1.56), and high thermal stability (no yellowing at 150°C for 240 hours). The luminous flux of the LED chip with ZHR encapsulant was 10% higher than that of the pure silicone resin, suggesting that ZHR has great application potential in the field of LED packaging.

Ultraviolet to blue blocking and wavelength convertible films using carbon dots for interrupting eye damage caused by general lighting

Our eyes are regularly exposed to ultraviolet (UV) and blue light emitting diode (LED) light-based devices. However, the blue light induces macular degeneration, optic nerve crush, eye strain, and increases reactive oxygen species, which negatively influence eye-related cells (photoreceptor and retinal pigmented epithelial cells). UV light is also harmful to humans. It induces photokeratitis, cataract, and ocular surface squamous neoplasia. Here, we present carbon dot films with different carbon dot contents, prepared by a simple method. The films exhibit strong UV and blue light absorption. The transmittance of carbon dot films is >70% in the visible region (>500 nm). The UV light blocking ratio of commercial blue blocking filter and carbon dot film using UV LED chips is 94.1% and 95.9% (40 wt%), respectively. The blue light blocking ratio of commercial blue blocking filter and carbon dot film using blue LED chips is 10.2% and 82.3% (40 wt%), respectively. These results indicate that the prepared carbon dot films have a UV blocking rate similar to that of commercial blue blocking filters and a much better blue blocking rate than commercial blue blocking filters. Therefore, they can be effectively used as UV and blue blocking films in various applications.

395 nm GaN-based near-ultraviolet light-emitting diodes on Si substrates with a high wall-plug efficiency of 52.0%@350 mA.

The high-performance 395 nm GaN-based near-ultraviolet (UV) light emitting diodes (LEDs) on Si substrates have been obtained by designing an AlN buffer layer to decrease the dislocations density of the GaN layer. By adopting a multi-layer structure with a high- and low-V/III ratio alternation, a high-quality AlN buffer layer has been obtained with a small full-width at half-maximum (FWHM) for AlN(0002) X-ray rocking curve (XRC) of 648 arcsec and a small root-mean-square roughness of 0.11 nm. By applying the optimized AlN buffer layer, the high-quality GaN layer with GaN(0002) and GaN(10-12) XRC FWHM of 260 and 270 arcsec have been obtained, and the high-performance GaN-based near-UV LED wafers and chips have been fabricated accordingly. The as-fabricated near-UV LED chips exhibit a light output power of 550 mW with a forward voltage of 3.02 V at 350 mA, corresponding to a wall-plug efficiency of 52.0%. These chips with outstanding performance are of paramount importance in the application of curing, sterilization, efficient white lighting, etc.

Quantum Dot-Acrylic Acrylate Oligomer Hybrid Films for Stable White Light-Emitting Diodes.

White light-emitting diodes (LEDs) have been achieved using photopolymerization. Red and green CdSe/ZnS core–shell quantum dots (QDs) are dispersed in photopolymerized aliphatic acrylic acrylate resins, cured by using 36 W UV light for 1.5 min producing QD–acrylate nanocomposites, and then a hybrid LED device is achieved using the QD–acrylate nanocomposite with two emission wavelengths excited by using a blue InGaN LED chip. The cured QD–acrylate nanocomposite films are characterized by using ultraviolet–visible, fluorescence, scanning electron microscopy, atomic force microscopy, and thermogravimetric analysis measurements. Photopolymerization is conveniently employed to adjust several parameters of the CIE-1931 coordinate (x, y), color temperature, and color rending index (CRI). Good white balance of the red-green hybrid device achieves a luminance of 7976 lm/m2 at a 30 mA working current. The light emission efficiency, CRI, and color temperature of 14%, 47, and 11 204 K, respectively, are attained at this working current.

Color Converted White Light-Emitting Diodes With 637.6 MHz Modulation Bandwidth

High bandwidth GaN-based white light-emitting diode (LED) was fabricated using GHz bandwidth blue LED chip combined with CdSe/ZnS semiconductor quantum dots (QDs). The maximum optical power of the blue LED chip can reach 7.2 mW. By changing the optical power ratio of the LED chip to the white LED, we have investigated the modulation properties and established a frequency response function of QD-converted white LED. The behaviors of the measured and simulated bandwidths using the function are in good agreement with each other. After optimizing the optical power ratio and decreasing the chip carrier lifetime, the 637.6 MHz bandwidth of QD-converted white LED was achieved, which can support 675 Mb/s real-time non-return-to-zero on-off-keying signal at a low bit error rate of 4.35 × 10 <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">-8</sup> without optical filters. Our findings can help to design high bandwidth white LEDs for visible light communication applications in free space.

Novel high color-purity Eu3+-activated Ba3Lu4O9 red-emitting phosphors with high quantum efficiency and good thermal stability for warm white LEDs

In this work, a series of novel Eu3+-activated Ba3Lu4O9 red phosphors were synthesized via a traditional high-temperature solid-state reaction method and their phase purity, crystal structure, morphologies, luminescence properties, thermal stability, and internal quantum efficiency were characterized in detail. All the samples showed intense red emission band with a primary peak centered at around 614 nm when excited by near-ultraviolet light at 396 nm. What's more, the optimal Eu3+ doping concentration in the Ba3Lu4O9 host was 25 mol% with a corresponding internal quantum efficiency up to 82%. The CIE chromaticity coordinates of Ba3Lu4O9:0.25Eu3+ sample were calculated to be (0.6687, 0.3307), which were very close to that of ideal red light. Moreover, the color purity of Ba3Lu4O9:0.25Eu3+ sample was determined to be as high as 98%. Meanwhile, Ba3Lu4O9:Eu3+ phosphors also possessed good thermal stability and the emission intensity at 423 K still remained about 64% of that at initial temperature. Finally, a prototype warm white light-emitting diode (LED) lamp with a high value of color render index (~94) and low correlation color temperature (~ 3051 K) was fabricated by coating blue phosphors (BaMgAl10O17:Eu2+), green phosphors ((Ba,Sr)2SiO4:Eu2+), and red phosphors (Ba3Lu4O9:Eu3+) on a 395 nm near-ultraviolet-emitting LED chip. Consequently, the results indicated that the as-obtained red-emitting Ba3Lu4O9:Eu3+ phosphors were promising red components for warm white LEDs.

Broadband Cr3+ , Sn4+ -Doped Oxide Nanophosphors for Infrared Mini Light-Emitting Diodes.

Light-emitting diodes break barriers of size and performance for displays. With devices becoming smaller, the materials also need to get smaller. Chromium(III)-doped oxide phosphors, which emit near-infrared (NIR) light, have recently been used in small electronic devices. In this work, mesoporous silica nanoparticles were used as nanocarriers. The nanophosphor ZnGa2 O4 :Cr3+ ,Sn4+ formed in the mesopore after sintering. Good dispersity and morphology were performed with average diameters of 71±7 nm. It emitted light at 600-850 nm; the intensity was optimized by tuning the doping ratio of Cr3+ and Sn4+ . Meanwhile, the light conversion efficiency increased from 7.8 % to 37 % and the molar concentration increased from 0.125 m to 0.5 m. The higher radiant flux of 3.3 mW was obtained by operating an input current of 45 mA. However, the NIR nanophosphor showed good performance on mini light-emitting diode chips.

Recyclable Phosphor Films: Three Water-Soluble Binder Systems Enabling the Recovery of Phosphor Powders in White LEDs

A recyclable luminescence down-conversion film as utilised in commercial white light-emitting diodes (LEDs) is introduced to avoid waste of valuable materials such as rare-earth metal-containing phosphors. As proof of principle, the commercial phosphor Y3Al5O12:Ce3+ is embedded in three easy soluble binders instead of the commonly utilised non-recyclable silicone binder. It will be demonstrated that these phosphor films allow for a highly efficient reuse of the phosphor. The investigated binders are, first, soluble sodium silicates (water glass) mixed with water in a ratio of 1:3, second, a 1 wt.%/vol.% solution of hydroxyethyl cellulose (HEC) in a 1:1 mixture of water and ethanol and, third, a 5 wt.%/vol.% solution of polyvinyl alcohol (PVA) in water. The phosphor-containing films show the same quality as comparable state-of-the-art phosphor converter films as demonstrated by preparation of fully functional white surface-mount device (SMD) LEDs based on commercially available blue SMD LED chips. It is demonstrated that the converter films can be recycled by dissolving the films in water at room temperature for HEC and PVA and at 60°C for the sodium silicates. Subsequently, the phosphor is reclaimed by sedimentation. The average recycling rates are 98.7 wt.% for sodium silicates, 95.6 wt.% for HEC and 98.0 wt.% for PVA. The phosphor does not suffer any losses of quality or functionality during this process as shown by fluorescence spectroscopy.

High-efficiency and thermally stable far-red emission of Mn4+ in double cubic perovskite Sr9Y2W4O24 for plant cultivation

A new Mn4+ activated Sr9Y2W4O24 far-red phosphor was synthesized by high temperature solid state reaction. The samples were characterized by X-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM), photoluminescence spectra, temperature-dependent emission spectra (298–548 K) and electroluminescence spectra. Finally, a 365 nm ultraviolet (UV) light-emitting diode (LED) chip combined with Sr9Y2W4O24:0.005 Mn4+ far-red phosphor was used to fabricate the LED device. It is found that Sr9Y2W4O24:Mn4+ phosphor has a strong broad excitation band in the range of 300–550 nm. There is a wide emission band centered at 680 nm between 650 nm and 800 nm. The optimum doping concentration of Mn4+ is about 0.5 mol%. Importantly, Sr9Y2W4O24:0.005 Mn4+ has an IQE of up to 49.8%. The thermal activation energy Ea = 0.448 eV. In short, the emission spectra of Sr9Y2W4O24:0.005 Mn4+ phosphors are well matched with the absorption bands of PFR in plants excited by near ultraviolet light, so Sr9Y2W4O24:Mn4+ phosphors have potential applications in indoor plant cultivation.

Highly efficient and thermally stable CaYMgSbO6:Mn4+ double perovskite red phosphor for indoor plant growth

A novel Mn4+ activated CaYMgSbO6 (CYMS) far-red phosphor was synthesized by high temperature solid state reaction. The sample was characterized by X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), luminescence spectra, ultraviolet–visible spectra, emission-temperature relationship and internal quantum efficiency (IQE). It is found that CYMS:Mn4+ phosphor has a strong broad excitation band in the range of 200–550 nm. The sample can be excited by ultraviolet and blue light. There is a wide emission band centered at 688 nm between 600 and 760 nm. The optimum doping concentration of Mn4+ is approximately 0.2 mol%. In addition, all the Commission Internationale de L’Eclairage (CIE) chromaticity coordinates of CYMS:0.002Mn4+ located in the far-red region. The concentration quenching mechanism is the dipole-quadrupole interaction of Mn4+ activator. The sample has excellent thermal stability (I423K/I298K = 53.2%). Importantly, the CYMS:0.002 Mn4+ phosphor has an IQE up to 51.5%. Finally, a 365 nm ultraviolet light emitting diode chip combined with CYMS:0.002 Mn4+ phosphor was used to fabricate the LED device. All the results indicated that CYMS:Mn4+ phosphors have potential applications in indoor plant cultivation.

Synthesis and Photoluminescence Properties of Double Perovskite Phosphor Ba6Y2W3O18: Mg2+, Mn4+ for Plant Cultivation

A novel far-red emission phosphor Ba6Y2W3O18: Mg2+, Mn4+ is firstly synthesized through high temperature solid reaction and its luminescence properties are investigated. The results show that Mn4+ doped Ba6Y2W3O18 phosphors have intense absorption in both ultraviolet and blue region, and can exhibit efficient far-red emission centered at 692 nm, which has large overlapping with the characteristic absorption bands of photosensitive pigments PFR. The optimum Mn4+ doping content, internal quantum efficiency, the content and temperature dependent luminescence behavior are discussed. The effects of “Mn-Mn” bond and crystal field strength on the luminescent property of Mn4+ are discussed in detail. Moreover, it is impressive that the co-doping of Mg2+ can significantly improve the emission intensity of Mn4+ and the related mechanisms are studied systematically. Finally, a red light emitting diode is fabricated based on Ba6Y2W3O18: Mn4+, Mg2+ phosphor and a 365 nm light emitting diode chip. The results indicate Ba6Y2W3O18: Mn4+, Mg2+ phosphor can be used as a potential spectral converter for plant growing.