Browsing by Author "Wang, De-Yin"

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A Novel Tunable Green- to Yellow-Emitting beta-YFS:Ce(3+) Phosphor for Solid-State Lighting
(2011-08-01)
Wu, Yun-Chen
;
Wang, De-Yin
;
Chen, Teng-Ming
;
Lee, Chi-Shen
;
Chen, Kuo-Ju
A Ce(3+)-activated fluorosulfide phosphor (beta-YFS: Ce(3+)) was synthesized by solid-state reaction in a sealed tube. The crystal structure has been refined from the XRD profiles and there are two different crystallographic rare earth sites, namely, Y(1) and Y(2), where the Ce(3+) ions occupied. The emission band with a maximum at 495 nm of beta-Y(0.99)Ce(0.01) FS phosphor was characterized by the 4f-5d transitions of Ce(3+) ion. With increasing Ce(3+) concentration, the emission variations were observed from 495 to 547 nm. When beta-YFS:Ce(3+) phosphors were utilized to incorporate with n-UV/blue chip, greenish-white light with color rendering index of 65-77 were obtained. The results indicate that the tunable green- to yellow-emitting beta-YFS:Ce(3+) can serve as a potential phosphor for incorporation in fabrication for solid-state lighting. The preparation, spectroscopic characterization, quantum efficiency, thermal-quenching behavior, and related LED device data are also presented.
A Novel Tunable Green- to Yellow-Emitting beta-YFS:Ce3+ Phosphor for Solid-State Lighting
(2011-08-01)
Wu, Yun-Chen
;
Wang, De-Yin
;
Chen, Teng-Ming
;
Lee, Chi-Shen
;
Chen, Kuo-Ju
A Ce3+-activated fluorosulfide phosphor (beta-YFS: Ce3+) was synthesized by solid-state reaction in a sealed tube. The crystal structure has been refined from the XRD profiles and there are two different crystallographic rare earth sites, namely, Y(1) and Y(2), where the Ce3+ ions occupied. The emission band with a maximum at 495 nm of beta-Y0.99Ce0.01 FS phosphor was characterized by the 4f-5d transitions of Ce3+ ion. With increasing Ce3+ concentration, the emission variations were observed from 495 to 547 nm. When beta-YFS:Ce3+ phosphors were utilized to incorporate with n-UV/blue chip, greenish-white light with color rendering index of 65-77 were obtained. The results indicate that the tunable green- to yellow-emitting beta-YFS:Ce3+ can serve as a potential phosphor for incorporation in fabrication for solid-state lighting. The preparation, spectroscopic characterization, quantum efficiency, thermal-quenching behavior, and related LED device data are also presented.
alpha-(Y,Gd)FS:Ce(3+): a novel red-emitting fluorosulfide phosphor for solid-state lighting
(2011-01-01)
Wu, Yun-Chen
;
Chen, Yi-Chin
;
Wang, De-Yin
;
Lee, Chi-Shen
;
Sun, Ching-Cherng
A novel Ce(3+)-doped fluorosulfide phosphor, alpha-(Y,Gd)FS:Ce(3+), was first investigated as a new candidate for application in phosphor-converted light emitting diodes (LEDs) and thin-film electroluminescence (TFEL) devices. The detailed crystal structure was investigated based on X-ray diffraction profiles using Rietveld refinement methods. This phosphor shows good absorption ranging from ultraviolet to visible region and broad saturated red emission, which can be tuned from 660 to 672 nm, and the photoluminescence (PL) intensity was demonstrated to be effectively enhanced by Gd(3+) substitution.
alpha-(Y,Gd)FS:Ce3+: a novel red-emitting fluorosulfide phosphor for solid-state lighting
(2011-01-01)
Wu, Yun-Chen
;
Chen, Yi-Chin
;
Wang, De-Yin
;
Lee, Chi-Shen
;
Sun, Ching-Cherng
A novel Ce3+-doped fluorosulfide phosphor, alpha-(Y,Gd)FS:Ce3+, was first investigated as a new candidate for application in phosphor-converted light emitting diodes (LEDs) and thin-film electroluminescence (TFEL) devices. The detailed crystal structure was investigated based on X-ray diffraction profiles using Rietveld refinement methods. This phosphor shows good absorption ranging from ultraviolet to visible region and broad saturated red emission, which can be tuned from 660 to 672 nm, and the photoluminescence (PL) intensity was demonstrated to be effectively enhanced by Gd3+ substitution.
Anomalous luminescence from Yb2+-doped Ca2PO4Cl
(2014-04-01)
Wang, De-Yin
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Chiu, Yi-Chen
;
Huang, Chien-Hao
;
Wu, Yun-Chen
;
Chen, Teng-Ming
The photoluminescence of Ca2PO4Cl:Yb2+ has been investigated and compared with that of Ca2PO4Cl: Eu2+, and the application of Ca2PO4Cl:Yb2+ for white LED has been evaluated. The excitation spectra of Ca2PO4Cl:Yb2+ are dominated by an intense excitation band at 395 nm. Under near DV excitation at 395 nm, Ca2PO4Cl:Yb2+ shows a broad asymmetric emission with maximum at 490 nm. This emissions result from two different Yb2+ centers is evidenced by the low temperature (T=100 K) emission spectrum. Yb2+ luminescence differs significantly from that of Eu2+, most notably in the structure of emission spectra, and is characterized by a much broader emission band and lower quenching temperature. Such anomalous luminescence from Yb2+ is ascribed to the de-excitation process of the Yb2+-trapped exciton state. Ca2PO4Cl:Yb2+ has external quantum efficiency of 24% and exhibits 40% of luminescence quenching at 100 degrees C in the air and, therefore, these results reveal its limited potential in the fabrication of white-light LEDs. (C) 2013 Elsevier B.V. All rights reserved.
BaZrSi(3)O(9):Eu(2+): a cyan-emitting phosphor with high quantum efficiency for white light-emitting diodes
(2011-01-01)
Wang, De-Yin
;
Huang, Chien-Hao
;
Wu, Yun-Chen
;
Chen, Teng-Ming
;
應用化學系
In this paper, a cyan-emitting phosphor BaZrSi(3)O(9):Eu(2+) was synthesized and evaluated as a candidate for white light emitting diodes (WLEDs). This phosphor shows strong and broad absorption in 380-420 nm region, and the emission intensity of the optimized BaZrSi(3)O(9):Eu(2+) was found to be 90% and 198% of that of the commercial BaMgAl(10)O(17):Eu(2+) (BAM:Eu(2+)) under excitation at 405 nm and 420 nm, respectively. Upon excitation at 405 nm, the quantum efficiency of the optimized BaZrSi(3)O(9):Eu(2+) is 83% of that of BAM:Eu(2+). The performance of this phosphor was further tested to fabricate white LED lamps. By coating BaZrSi(3)O(9):Eu(2+) with a green-emitting (Ba,Sr)(2)SiO(4):Eu(2+) and a red-emitting CaAlSiN(3):Eu(2+) on a near-ultraviolet (405 nm) LED chip, driven by a 350 mA forward bias current, intense warm white light with a color rendering index of 90 has been produced.
BaZrSi3O9:Eu2+: a cyan-emitting phosphor with high quantum efficiency for white light-emitting diodes
(2011-01-01)
Wang, De-Yin
;
Huang, Chien-Hao
;
Wu, Yun-Chen
;
Chen, Teng-Ming
;
應用化學系
In this paper, a cyan-emitting phosphor BaZrSi3O9:Eu2+ was synthesized and evaluated as a candidate for white light emitting diodes (WLEDs). This phosphor shows strong and broad absorption in 380-420 nm region, and the emission intensity of the optimized BaZrSi3O9:Eu2+ was found to be 90% and 198% of that of the commercial BaMgAl10O17:Eu2+ (BAM:Eu2+) under excitation at 405 nm and 420 nm, respectively. Upon excitation at 405 nm, the quantum efficiency of the optimized BaZrSi3O9:Eu2+ is 83% of that of BAM:Eu2+. The performance of this phosphor was further tested to fabricate white LED lamps. By coating BaZrSi3O9:Eu2+ with a green-emitting (Ba,Sr)(2)SiO4:Eu2+ and a red-emitting CaAlSiN3:Eu2+ on a near-ultraviolet (405 nm) LED chip, driven by a 350 mA forward bias current, intense warm white light with a color rendering index of 90 has been produced.
Charge transfer luminescence of hafnates under synchrotron vacuum ultraviolet excitation
(2014)
Wang, De-Yin
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Huang, Chien-Hao
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Cheng, Bing-Ming
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Chen, Teng-Ming
;
Wang, Yu-Hua
Under synchrotron vacuum ultraviolet excitation, three different hafnates (BaHf(PO4)(2), BaHf(BO3)(2) and BaHfSi3O9) show self-activated luminescence with peaks ranging from 275-335 nm, which is attributed to the charge-transfer luminescence from the hafnate (HfO68-) group. Upon doping Eu2+ into BaHfSi3O9, host sensitization of Eu2+ emission via hafnate intrinsic emission is demonstrated.
Charge Transfer Luminescence of Several Zirconium-Containing Compounds Using Synchrotron Radiation
(2011)
Wang, De-Yin
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Chen, Teng-Ming
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Cheng, Bing-Ming
;
應用化學系
;
Department of Applied Chemistry
Photoluminescence properties of pristine and Eu(2+)-doped zirconates, viz. BaZr(PO(4))(2), BaZr(4)(PO(4))(6), Ba(2)Zr(2)Si(3)O(12), and Ca(3)ZrSi(2)O(9), excited by vacuum ultraviolet (VUV) light using synchrotron radiation were studied. The undoped zirconates show self-activated emission in the 300-340 nm region under VUV excitation, which is ascribed to the Zr(4+)-O(2-) charge transfer luminescence. Upon doping Eu(2+) into these compounds, no Eu(2+) emission was observed in the rest of compounds, except for a weak Eu(2+) emission observed in Ba(2)Zr(2)Si(3)O(12):Eu(2+). The quenching of Eu(2+) luminescence is rationalized as the presence of Zr(4+)-Eu(2+) metal-metal charge transfer. (C) 2011 The Electrochemical Society. [DOI: 10.1149/1.3605475] All rights reserved.
Charge-Transfer Luminescence and Energy Transfer in Eu(2+)-Doped Barium Zirconosilicates
(2011-01-01)
Wang, De-Yin
;
Wang, Ling-Li
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Lee, Te-Ju
;
Chen, Teng-Ming
;
Cheng, Bing-Ming
Although zirconates are known to show ultraviolet luminescence under X-ray excitation, few have studied the vacuum ultraviolet (VUV) excited luminescence of zirconate compounds. We have investigated the VUV-excited luminescence of zirconate in BaZrSi(3)O(9) and Ba(2)Zr(2)Si(3)O(12) using synchrotron radiation, and examined the possibility of sensitizing Eu(2+) by hosts that contain zirconate. Upon VUV excitation, BaZrSi(3)O(9) and Ba(2)Zr(2)Si(3)O(12) show self-activated emission peaking at 285 nm and 334 nm, which are assigned to Zr(4+)-O(2-) charge transfer (CT) luminescence. The evidence for the occurrence of Zr(4+)-O(2-) charge transfer in BaZrSi(3)O(9) and Ba(2)Zr(2)Si(3)O(12) was further supported by density of state (DOS) calculation. Energy transfer from host excitation (similar to 172 nm) to Eu(2+) was observed in BaZrSi(3)O(9):Eu(2+) and Ba(2)Zr(2)Si(3)O(12):Eu(2+), showing that host sensitization of Eu(2+) occurs in these materials. Despite that the host emission overlaps with the Eu(2+) 4f-5d absorption band significantly, host -to-Eu(2+) energy transfer in Ba(2)Zr(2)Si(3)O(12):Eu(2+) was found to be less efficient than that in BaZrSi(3)O(9):Eu(2+) and Eu(2+) luminescence was found to be inferior in Ba(2)Zr(2)Si(3)O(12):Eu(2+). These observations are ascribed to a smaller Zr-O-Ba(Eu) angles and a lower Eu(2+)-Zr(4+) metal-to-metal charge transfer energy in Ba(2)Zr(2)Si(3)O(12):Eu(2+). (C) 2011 The Electrochemical Society. [DOI: 10.1149/2.008112jes] All rights reserved.
Charge-Transfer Luminescence and Energy Transfer in Eu2+-Doped Barium Zirconosilicates
(2011-01-01)
Wang, De-Yin
;
Wang, Ling-Li
;
Lee, Te-Ju
;
Chen, Teng-Ming
;
Cheng, Bing-Ming
Although zirconates are known to show ultraviolet luminescence under X-ray excitation, few have studied the vacuum ultraviolet (VUV) excited luminescence of zirconate compounds. We have investigated the VUV-excited luminescence of zirconate in BaZrSi3O9 and Ba2Zr2Si3O12 using synchrotron radiation, and examined the possibility of sensitizing Eu2+ by hosts that contain zirconate. Upon VUV excitation, BaZrSi3O9 and Ba2Zr2Si3O12 show self-activated emission peaking at 285 nm and 334 nm, which are assigned to Zr4+-O2- charge transfer (CT) luminescence. The evidence for the occurrence of Zr4+-O2- charge transfer in BaZrSi3O9 and Ba2Zr2Si3O12 was further supported by density of state (DOS) calculation. Energy transfer from host excitation (similar to 172 nm) to Eu2+ was observed in BaZrSi3O9:Eu2+ and Ba2Zr2Si3O12:Eu2+, showing that host sensitization of Eu2+ occurs in these materials. Despite that the host emission overlaps with the Eu2+ 4f-5d absorption band significantly, host -to-Eu2+ energy transfer in Ba2Zr2Si3O12:Eu2+ was found to be less efficient than that in BaZrSi3O9:Eu2+ and Eu2+ luminescence was found to be inferior in Ba2Zr2Si3O12:Eu2+. These observations are ascribed to a smaller Zr-O-Ba(Eu) angles and a lower Eu2+-Zr4+ metal-to-metal charge transfer energy in Ba2Zr2Si3O12:Eu2+. (C) 2011 The Electrochemical Society. [DOI: 10.1149/2.008112jes] All rights reserved.
Controlled synthesis and luminescent properties of monodispersed PEI-modified YVO4:Bi3+,Eu3+ nanocrystals by a facile hydrothermal process
(2012)
Chen, Yi-Chin
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Wu, Yun-Chen
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Wang, De-Yin
;
Chen, Teng-Ming
;
應用化學系
A series of water-soluble YVO4:Bi3+, Eu3+ nanocrystals, with surfaces functionalized by a branch polyethylenimine (BPEI) polymer, have been synthesized via a one-pot hydrothermal method. It was found that the particle size and crystal morphology could be efficiently controlled by different reaction temperatures, pH values and molecular weights of the BPEI polymer. The surface modification of the nanocrystals was characterized using Fourier transform infrared spectroscopy (FT-IR). The highly crystalline YVO4:Bi3+, Eu3+ nanoparticles, with an average diameter of 20 nm, can be dispersed in water due to the presence of amino ligands. When conjugated with biomolecules, the YVO4:Bi3+, Eu3+ nanocrystals retain their strong red emission, peaking at 619 nm under near-ultraviolet (n-UV) excitation. The results indicate that YVO4:Bi3+, Eu3+ nanocrystals can serve as a promising candidate for biological imaging, and immunoassay applications.
Crystal structure of blue-white-yellow color-tunable Ca4Si2O7F2:Eu2+,Mn2+ phosphor and investigation of color tunability through energy transfer for single-phase white-light near-ultraviolet LEDs
(2012)
Huang, Chien-Hao
;
Chan, Ting-Shan
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Liu, Wei-Ren
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Wang, De-Yin
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Chiu, Yi-Chen
The crystal structure of Ca4Si2O7F2:Eu2+,Mn2+ was refined and determined from X-ray diffraction (XRD) profiles obtained using a synchrotron light source by the Rietveld refinement method. It was found to crystallize into a monoclinic structure with the P2(1)/c(14) space group. On examining the Mn2+-concentration-dependent photoluminescence properties, we found that the emission colors could be tuned from blue (0.152, 0.112) to white-light (0.351, 0.332) and eventually to yellow (0.430, 0.423) through energy transfer by changing the Eu2+/Mn2+ ratio. Moreover, energy transfer from a sensitizer Eu2+ to an activator Mn2+ occurs via a resonance-type dipole-quadrupole interaction mechanism, and the critical distances of the energy transfer were calculated to be 11.66 angstrom and 12.61 angstrom using concentration quenching and spectral overlap methods, respectively. Combining a 400 nm near-ultraviolet (NUV) chip and a single-phase white-emitting (Ca0.96Eu0.01Mn0.03)(4)Si2O7F2 phosphor produced a white-light NUV LED with CIE chromaticity coordinates of (0.347, 0.338) and a warm color temperature of 4880 K.
Host Sensitization of Tb3+ Ions in Tribarium Lanthanide Borates Ba(3)Ln (BO3)(3) (Ln = Lu and Gd)
(2012-03-05)
Wang, De-Yin
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Chen, Teng-Ming
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Cheng, Bing-Ming
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應用化學系
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Department of Applied Chemistry
The vacuum-ultraviolet (VUV) spectroscopic properties of undoped and Tb3+-doped borates Ba(3)Ln(BO3)(3) (Ln = Lu and Gd) with different crystal structures were investigated by using synchrotron radiation. Ba3Lu(BO3)(3) (BLB) crystallizes in a hexagonal structure, whereas Ba3Gd(BO3)(3) (BGB) crystallizes in a trigonal structure. The maximum host absorption for BLB and BGB was found to locate at similar to 179 and similar to 195 nm, respectively. Upon host excitation, BLB exhibits an intrinsic broad UV emission centered at 339 nm, which is attributed to the recombination of self-trapped excitons that may presumably be associated with band-gap excitations or molecular transitions within the BO33- group. In contrast to BLB, no broad emission but line emission ascribed to a Gd3+ P-6(J)-S-8(7/2) 712 transition was observed in the emission spectrum of BGB. Upon doping of Tb3+ ions into the hosts of BLB and BGB, an efficient energy transfer from the host excitations to Tb3+ via host/Gd3+ emission was observed, showing that host sensitization of Tb3+ occurs in these rare-earth borates.
Photoluminescence investigations on a novel green-emitting phosphor Ba3Sc(BO3)(3):Tb3+ using synchrotron vacuum ultraviolet radiation
(2012)
Wang, De-Yin
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Chen, Yi-Chin
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Huang, Chien-Hao
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Cheng, Bing-Ming
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Chen, Teng-Ming
Vacuum ultraviolet (VUV) spectroscopic properties of undoped and Tb3+-doped Ba3Sc(BO3)(3) were investigated by using synchrotron radiation. The Tb3+-doped Ba3Sc(BO3)(3) sample crystallized in a flower-like shape even was synthesized at 1100 degrees C. Upon VUV excitation, Ba3Sc(BO3)(3) exhibited an intrinsic broad UV emission centered at 336 nm, which results from radiative annihilation of self-trapped exciton (STE) that may presumably be associated with band-gap excitations or molecular transitions within the BO33- group. The maximum host absorption for Ba3Sc(BO3)(3) was found at about 180 nm. Upon doping of Tb3+ ions into Ba3Sc(BO3)(3), an efficient energy transfer from the host excitations to Tb3+ via STE emission was observed, showing host sensitization of Tb3+ occurs. The energy transfer from host to Tb3+ via STE emission in Ba3Sc(BO3)(3):Tb3+ was studied as a function of temperature and Tb3+ doping concentration. It has been demonstrated that the energy transfer efficiency was increased with either increasing temperature or Tb3+ doping concentration. In the case of temperature dependent energy transfer, the energy transfer from the STE to Tb3+ is thermally activated, probably due to exciton mobility, while in the case of concentration dependent energy transfer, the energy transfer from the STE to Tb3+ is promoted due to a closer distance between the STE and Tb3+ at high Tb3+ concentration.
Sr8MgGd(PO4)(7):Eu2+: yellow-emitting phosphor for application in near-ultraviolet-emitting diode based white-light LEDs
(2012)
Huang, Chien-Hao
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Wang, De-Yin
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Chiu, Yi-Chen
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Yeh, Yao-Tsung
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Chen, Teng-Ming
The yellow-emitting phosphor Sr8MgGd(PO4)(7):xEu(2+) (SMGP:xEu(2+)) was successfully synthesized by a solid-state reaction and used for the first time to fabricate white light-emitting diodes (LEDs) with excellent color rendering index (CRI). Furthermore, the luminescence properties' reflectance spectra and fabricated LEDs were firstly investigated. The excitation and reflectance spectra of this phosphor show broad band excitation and absorption in the 240-470 nm near ultraviolet (NUV) region, indicating its potential application in NUV diode based white-light LEDs. Upon excitation at 385 nm, the Eu2+ doped SMGP phosphors showed strong yellow emission centered at 512 and 606 nm, which could be ascribed to the 4f(6)5d(1) -> 4f(7) transitions of Eu2+. The optimal doping concentration of Eu2+ in SMGP was determined to be 0.01 mol. Non-radiative transitions between the Eu2+ ions in the SMGP host were demonstrated to be attributable to dipole-dipole interactions. A white-light NUV LED was fabricated using a phosphor blend of SMGP:0.01Eu(2+) and BAM:Eu2+ pumped by a 385 nm NUV chip, driven by a 350 mA current. The color, chromaticity coordinates (x, y), correlated color temperature (CCT) and Commission Internationale de l'Eclairage (CIE) coordinates can be tuned from yellow ((0.442, 0.481), 3456 K, 75.4) through warm white-light ((0.350, 0.348), 4804 K, 95.6) and eventually to white-light ((0.331, 0.321), 5592 K, 94.1) by weight ratio tuning of the SMGP:0.01Eu(2+) and BAM:Eu2+ phosphors, and the luminous efficacy between 9.6 to 7.6 lm W-1. We are currently evaluating the potential applications of SMGP: xEu(2+) as a yellow-emitting near-ultraviolet (NUV) convertible phosphor in fabricating warm white-light LEDs with excellent CRI.
Synthesis, crystal structure, and photoluminescence of a novel blue-green emitting phosphor: BaHfSi(3)O(9):Eu(2+)
(2011-01-01)
Wang, De-Yin
;
Wu, Yun-Chen
;
Chen, Teng-Ming
;
應用化學系
;
Department of Applied Chemistry
BaHfSi(3)O(9) with barizite structure was synthesized and its detailed crystal structure was determined from the XRD profiles using Rietveld refinement. Pristine BaHfSi(3)O(9) shows bright blue emission under UV excitation. The blue emission was proved to be related to the charge transfer luminescence from Ti(4+), which presented as an impurity in the starting material HfO(2). The BaHfSi(3)O(9):Eu(2+) phosphor has been evaluated as a color converter for white LEDs. The results show that BaHfSi(3)O(9):Eu(2+) can be efficiently excited by near-ultraviolet (n-UV) of 380-420 nm and yield an intense blue-green emission. Upon excitation at 405 nm, the absorption and quantum efficiency for BaHfSi(3)O(9):Eu(2+) with optimal composition is about 78% and 50%, respectively. In addition, BaHfSi(3)O(9):Eu(2+) demonstrates high thermal stability, as shown by its luminescence intensity at 150 degrees C maintains about similar to 86% of that at room temperature. The performance of this phosphor was further tested to fabricate white LED lamps. By coating BaHfSi(3)O(9):Eu(2+) with a green-emitting (Ba,Sr)(2)SiO(4):Eu(2+) and a red-emitting CaAlSiN(3):Eu(2+) on an n-UV (405 nm) LED chip, driven by a 150 mA forward bias current, intense warm white light with a color rendering index of 91 was produced.
Synthesis, crystal structure, and photoluminescence of a novel blue-green emitting phosphor: BaHfSi3O9:Eu2+
(2011-01-01)
Wang, De-Yin
;
Wu, Yun-Chen
;
Chen, Teng-Ming
;
應用化學系
;
Department of Applied Chemistry
BaHfSi3O9 with barizite structure was synthesized and its detailed crystal structure was determined from the XRD profiles using Rietveld refinement. Pristine BaHfSi3O9 shows bright blue emission under UV excitation. The blue emission was proved to be related to the charge transfer luminescence from Ti4+, which presented as an impurity in the starting material HfO2. The BaHfSi3O9:Eu2+ phosphor has been evaluated as a color converter for white LEDs. The results show that BaHfSi3O9:Eu2+ can be efficiently excited by near-ultraviolet (n-UV) of 380-420 nm and yield an intense blue-green emission. Upon excitation at 405 nm, the absorption and quantum efficiency for BaHfSi3O9:Eu2+ with optimal composition is about 78% and 50%, respectively. In addition, BaHfSi3O9:Eu2+ demonstrates high thermal stability, as shown by its luminescence intensity at 150 degrees C maintains about similar to 86% of that at room temperature. The performance of this phosphor was further tested to fabricate white LED lamps. By coating BaHfSi3O9:Eu2+ with a green-emitting (Ba,Sr)(2)SiO4:Eu2+ and a red-emitting CaAlSiN3:Eu2+ on an n-UV (405 nm) LED chip, driven by a 150 mA forward bias current, intense warm white light with a color rendering index of 91 was produced.