OSA's Digital Library

Optical Materials Express

Optical Materials Express

  • Editor: David J. Hagan
  • Vol. 3, Iss. 11 — Nov. 1, 2013
  • pp: 1810–1819
« Show journal navigation

Full-color emission generation from single phased phosphor Sr10[(PO4)5.5(BO4)0.5](BO2): Ce3+, Mn2+, Tb3+ for white light emitting diodes

Ge Zhu, Zhipeng Ci, Qian Wang, Yurong Shi, and Yuhua Wang  »View Author Affiliations


Optical Materials Express, Vol. 3, Issue 11, pp. 1810-1819 (2013)
http://dx.doi.org/10.1364/OME.3.001810


View Full Text Article

Acrobat PDF (1730 KB)





Browse Journals / Lookup Meetings

Browse by Journal and Year


   


Lookup Conference Papers

Close Browse Journals / Lookup Meetings

Article Tools

Share
Citations

Abstract

A single-phase full-color emitting Sr10[(PO4)5.5(BO4)0.5](BO2): Ce3+, Mn2+, Tb3+ phosphor was synthesized by solid-state reaction for the first time. The characteristic luminescence property of Ce3+ is investigated by Gauss fitting. Energy transfer from Ce3+ to Mn2+ and Ce3+ to Tb3+ in Sr10[(PO4)5.5(BO4)0.5](BO2) is detailedly studied by luminescence spectra, energy-transfer efficiency and lifetimes. Through effective energy transfer, the wavelength-tunable warm white light can be realized with superior chromaticity coordinates of (0.35, 0.32), high color rendering index (Ra = 89) and low correlated color temperature (CCT = 4373K) by coupling the emission bands centered at 441, 542 and 649 nm attributed to the contribution from Ce3+, Mn2+ and Tb3+, respectively. The results indicate the white Sr10[(PO4)5.5(BO4)0.5](BO2):Ce3+, Mn2+, Tb3+ phosphor can serve as a promising candidate for phosphor-converted white-light UV-LEDs.

© 2013 OSA

1. Introduction

In the last few decades, there has been a phenomenal growth in investigation of the field of luminescence, and significant progress has been made in solid state lighting [1

1. J. M. Phillips, M. E. Coltrin, M. H. Crawford, A. J. Fischer, M. R. Krames, R. Mueller-Mach, G. O. Mueller, Y. Ohno, L. E. S. Rohwer, J. A. Simmons, and J. Y. Tsao, “Research challenges to ultra-efficient inorganic solid-state lighting,” Laser Photonics Rev. 1(4), 307–333 (2007). [CrossRef]

,2

2. J. H. Ryou and R. D. Dupuis, “Focus issue: Optics in LEDs for lghting,” Opt. Express 19(S4Suppl 4), A897–A899 (2011). [CrossRef] [PubMed]

]. The breakthrough in the development of high performance light-emitting diodes (LEDs) via improvement in both internal quantum efficiency [3

3. D. Feezell, J. Speck, S. DenBaars, and S. Nakamura, “Semipolar (2021) InGaN/GaN Light-Emitting Diodes for high-efficiency solid-state lighting,” J. Display Technology 9, 190–198 (2013). [CrossRef]

7

7. G. Liu, J. Zhang, C. Tan, and N. Tansu, “Efficiency-droop suppression by using large-bandgap AlGaInN thin barrier layers in InGaN Quantum-Well Light-Emitting Diodes,” IEEE Photonics J. 5(2), 2201011 (2013). [CrossRef]

] and extraction efficiency [8

8. Y. K. Ee, P. Kumnorkaew, R. A. Arif, H. Tong, H. Zhao, J. F. Gilchrist, and N. Tansu, “Optimization of Light Extraction Efficiency of III-Nitride Light Emitting Diodes with Self-Assembled Colloidal-based Microlenses,” IEEE J. Sel. Top. Quantum Electron. 15(4), 1218–1225 (2009). [CrossRef]

,9

9. J. Jewell, D. Simeonov, S. Huang, Y. Hu, S. Nakamura, J. Speck, and C. Weisbuch, “Double embedded photonic crystals for extraction of guided light in light-emitting diodes,” Appl. Phys. Lett. 100(17), 171105 (2012). [CrossRef]

] has resulted in practical excitation sources applicable for phosphor-converted white LEDs. Currently, phosphor-converted (pc) white light-emitting diodes (LEDs), with characteristics of high efficiency, long lifetime, and energy saving, have attracted more and more attention [10

10. R. J. Xie, N. Hirosaki, M. Mitomo, K. Sakuma, and N. Kiumra, “Wavelength-tunable and thermally stable Li-α-sialon:Eu2+ oxynitride phosphors for white light-emitting diodes,” Appl. Phys. Lett. 89(24), 241103 (2006). [CrossRef]

,11

11. J. S. Kim, P. E. Jeon, J. C. Choi, H. L. Park, S. I. Mho, and G. C. Kim, “Warm-white-light emitting diode utilizing a single-phase full-color Ba3MgSi2O8:Eu2+, Mn2+ phosphor,” Appl. Phys. Lett. 84(15), 2931–2933 (2004). [CrossRef]

]. By virtue of these advantages, white LEDs are currently the mainstream in the market and are being widely used in not only point light sources, but also wide-illumination equipment, back-lighting of liquid-crystal TVs and high-power automotive headlights [12

12. H. Yamamoto, “White LED phosphors: the next step,” Proc. SPIE 7598, 759808, 759808-10 (2010). [CrossRef]

]. In pc-white LEDs, phosphors are the key component to down-convert near-ultraviolet (n-UV)/ blue pump light from InGaN LEDs into visible light. To date, the most dominant pc-white LEDs is combination of a blue LED with a yellow phosphor ((Y,Gd)3(Al,Ga)5O12:Ce3+). Such generated light color is not true because this system lacks of a red emitting component, which restricts their use in more vivid applications [13

13. L. Wang, X. Zhang, Z. D. Hao, Y. S. Luo, X. J. Wang, and J. H. Zhang, “Enriching red emission of Y3Al5O12: Ce3+ by codoping Pr3+ and Cr3+ for improving color rendering of white LEDs,” Opt. Express 18(24), 25177–25182 (2010). [CrossRef] [PubMed]

,14

14. W. R. Liu, C. C. Lin, Y. C. Chiu, Y. T. Yeh, S. M. Jang, and R. S. Liu, “ZnB2O4:Bi3+,Eu3+:a highly efficient, red-emitting phosphor,” Opt. Express 18(3), 2946–2951 (2010). [CrossRef] [PubMed]

]. In order to obtain a warm white light, the new technologies are based on the combination of a near-ultraviolet/ultraviolet (n-UV/UV) LED chip with three phosphors emitting red, green, and blue (RGB) colors [15

15. Y. Zhang, L. Wu, M. Ji, B. Wang, Y. Kong, and J. Xu, “Structure and photoluminescence properties of KSr4(BO3)3:Eu3+ red-emitting phosphor,” Opt. Mater. Express 2(1), 92–102 (2012). [CrossRef]

,16

16. H. C. Kuo, C. W. Hung, H. C. Chen, K. J. Chen, C. H. Wang, C. W. Sher, C. C. Yeh, C. C. Lin, C. H. Chen, and Y. J. Cheng, “Patterned structure of remote phosphor for phosphor-converted white LEDs,” Opt. Express 19(S4Suppl 4), A930–A936 (2011). [CrossRef] [PubMed]

]. However, different phosphors experience different light output degradation rates, leading to unstable white light, and poor luminous efficiency attributed to reabsorption has commonly been encountered [17

17. C. Huang, T. Chan, W. Liu, D. Wang, Y. Chiu, Y. Yeh, and T. Chen, “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,” J. Mater. Chem. 22(38), 20210–20216 (2012).

]. Therefore, this type white LEDs still face large challenges. For these reasons, people are making more efforts in developing a full-color emitting phosphor based on a single host to avoid the intrinsic color balance, device complication, and high-cost problems. One of the strategies for generating white light from single-phased phosphors is by codoping sensitizer and activator into the same host, such as Eu2+ to Mn2+ ion [18

18. C. Chang and T. Chen, “White light generation under violet-blue excitation from tunable green-to-red emitting Ca2MgSi2O7: Eu, Mn through energy transfer,” Appl. Phys. Lett. 90(16), 161901 (2007). [CrossRef]

], Ce3+ to Tb3+ ion [19

19. S. S. Sanayea and B. S. Dhabekar, “Energy transfer process in CaSO4: Tb, Ce phosphor,” J. Lumin. 105(1), 1–8 (2003). [CrossRef]

], or Ce3+ to Mn2+ ion [20

20. C. Chang and T. Chen, “Sr3B2O6: Ce3+, Eu2+: A potential single-phased white-emitting borate phosphor for ultraviolet light-emitting diodes,” Appl. Phys. Lett. 91(8), 081902–081904 (2007). [CrossRef]

].

2. Experimental

2.1 Materials and synthesis

All the powder samples were synthesized by traditional solid-state reaction method. The starting materials were SrCO3 (A.R. 99.9%), (NH4)2HPO4 (A.R. 99.9%), H3BO3 (A.R. 99.9%), MnCO3 (A.R. 99.9%), CeO2 (A.R. 99.99%) and Tb4O7 (A.R. 99.99%). The stoichiometric raw materials were ground thoroughly in an agate mortar and then heated to 773 K in air for 3h. Subsequently the preheated mixture was ground again and fired to 1423 K for 8 h in an alumina crucible under N2-H2 (8%) atmosphere in horizontal tube furnaces. Finally the as-synthesized samples were slowly cooled to room temperature inside the tube furnace under H2-N2 flow.

2.2 Measurements and characterization

The crystal structure of the synthesized samples was identified by using a Rigaku D/Max-2400 X-ray diffractometer (XRD) with Nifiltered Cu Kα radiation. The diffuse-reflectance spectra (DRS) were obtained by a UV-visible spectrophotometer (PE Lambda 950) using BaSO4 as a reference. The photoluminescence (PL) and PL excitation (PLE) spectra of the samples were measured by using an FLS-920T fluorescence spectrophotometer equipped with a 450W Xe light source and double excitation monochromators. The PL decay curves were measured by an FLS-920T fluorescence spectrophotometer with nF900 nanosecond Flashlamp as the light source. The quantum efficiency (QE) was measured by a Fluorlog-3 spectrofluorometer equipped with 450W xenon lamp (Horiba Jobin Yvon). Thermal quenching was tested using a heating apparatus (TAP-02) in combination with PL equipment. All of the measurements were performed at room temperature.

3. Results and discussion

3.1 Phase identification of as-prepared phosphors

Figures 1(a)
Fig. 1 (a) The experimental, calculated, and difference results of the XRD refinement of SPB host; (b) The representative XRD patterns of SPB: 0.03Ce3+, SPB: 0.03Ce3+, 0.05Mn2+ and SPB: 0.03Ce3+, 0.05Mn2+, 0.03Tb3+ samples. The calculated data of SPB is shown as reference..
and 1(b) display the results of Rietveld refinement of the XRD data profiles of SPB host by GSAS program [23

23. A. C. Larson and R. B. Von Dreele, “General Structure Analysis System (GSAS) ,” Los Alamos Nat. Lab., Report, LAUR 86–748, 2000.

] (Rwp = 7.24, χ2 = 2.946) and the representative XRD patterns of SPB: 0.03Ce3+, SPB: 0.03Ce3+, 0.05Mn2+ and SPB: 0.03Ce3+, 0.05Mn2+, 0.03Tb3+ samples. No detectable impurity phase is observed in the obtained samples even at high doping concentration. The XRD profiles are well fitted with the calculated data according to Chen’s report [24

24. S. Chen, S. Hoffmann, W. Carrillo-Cabrera, L. G. Akselrud, Y. Prots, U. Schwarz, J. T. Zhao, and R. Kniep, “Sr10[(PO4)5.5(BO4)0.5](BO2): Growth and crystal structure of a strontium phosphate orthoborate metaborate closely related to the apatite-type crystal structure,” J. Solid State Chem. 183(3), 658–661 (2010). [CrossRef]

], indicating that the obtained samples are single phase and the rare earth ions have been successfully incorporated in the SPB host lattices without changing the crystal structure.

3.2 Photoluminescence properties of SPB: Ce3+ and SPB: Mn2+

Figure 2
Fig. 2 PLE and PL spectra of SPB: Ce3+ (a) and SPB: Mn2+ (b); The inset shows the relationship of the PL intensity of Ce3+ with Ce3+ doping concentration (in Fig. a) and the overlap between the PL of Ce3+ and the PLE of Mn2+ (in Fig. b)
shows the PL and PLE spectra for SPB: Ce3+ (a) and SPB: 0.01Mn2+ (b). The PLE spectrum of SPB: Ce3+ at 354 nm excitation extends from 240 to 420 nm with two distinct bands peaking at 297 and 354 nm attributed to the 4f–5d transition of Ce3+ ions, which indicates that the phosphors can be effectively excited by UV light. The emission spectra show asymmetric broadband characteristic of Ce3+ ions, but the FWHM value amounts to 5030 cm−1, which is not comparable to that typically observed for Ce3+ activated phosphors containing a single type of luminescent center (~4000cm−1) [25

25. G. Blasse and A. Bril, “Investigation of Some Ce-Activated Phosphors,” J. Chem. Phys. 47(12), 5139–5145 (1967). [CrossRef]

]. Considering that there are two different cationic sites in SPB (as illustrated in Fig. 2(a)), then we take Gaussian fitting algorithm and find that the curve can be well fitted into four emission bands, which centered at 419 and 454 nm, with an energy difference of 1840 cm−1 and the other two bands peaked at 509 and 562 nm with an energy difference of 1850 cm−1, respectively, which is close to the theoretical energy difference value of Ce3+ (~2000 cm−1) [26

26. L. G. Van Uitert, “An empirical relation fitting the position in energy of the lower d-band edge for Eu2+ or Ce3+ in various compounds,” J. Lumin. 29, 1–9 (1984).

]. So the four peaks can be justifiably assigned to the 5d-4f (2F5/2, 2F7/2) emissions of Ce3+ ions occupying two Sr sites (Sr1/2, Sr3). Due to a slight difference between crystal fields of Sr1 and Sr2 sites, the bands are not resolved distinctly. Generally, the bond length (R) of Sr-O affects the crystal field strength (Dq) significantly, i.e., Dq is proportional to 1/R5 [27

27. P. D. Rack and P. H. Holloway, “The structure, device physics, and material properties of thin film electroluminescent displays,” Mater. Sci. Eng. Rep. 21(4), 171–219 (1998). [CrossRef]

]. So the bands peaking at 419 and 454 nm are assigned to Ce3+ ions occupying Sr1/2 sites due to weak crystal field (average distance Sr1/2–O≈2.749 Å) and the bands peaking at 509 and 562 nm are attributed to Ce3+ ions occupying Sr3 sites due to strong crystal field (Sr3–O≈2.635 Å). Meanwhile, the PL intensity is found to increase gradually with increasing Ce3+ ions concentration until it reaches concentration quenching when x = 0.03. In Fig. 2(b), the red emission band of 649 nm is attributed to the 4T16A1 transition of 3d5 level of Mn2+ ions and the corresponding PLE spectrum shows typical d-d transitions of Mn2+ ions. Based on the observed significant overlap between the PLE spectrum of Mn2+ and the PL spectrum of Ce3+ ions (inset in Fig. 2(b)), the effective resonance-type energy transfer is expected to take place from Ce3+ to Mn2+ ions. It can be seen that the Ce3+ or Mn2+ ions singly doped SPB emits blue or red light, so it is possible to obtain color-tunable white light emission by adjusting the concentration of Ce3+ and Mn2+ ions in SPB based on the energy transfer.

3.3 Photoluminescence properties of SPB: Ce3+, Mn2+ and luminescence dynamics

In SPB: 0.03Ce3+, xMn2+(0.005≤x≤0.05) (Fig. 3(a)
Fig. 3 (a) PL spectra of SPB:0.03Ce3+, xMn2+; (b) Relative intensity of the blue and red emission bands; (c) Decay curves of Ce3+ for SPB:0.03Ce3+, xMn2+ monitored at 421 nm; (d) The correlation between ηT/τ and x under 354 nm excitation.
), the PL spectra upon Ce3+ excitation at 354nm not only exhibit the Ce3+ blue emission at 441 nm but also the Mn2+ red emission at 649 nm. Meanwhile, as an increase of Mn2+ at fixed Ce3+ concentration, the intensity of the blue band decreases gradually while the red component increases (see Fig. 3(b)). These results further support the occurrence of energy transfer from Ce3+ to Mn2+. To further understand the process of energy transfer, the PL decay curves of Ce3+ in SPB: 0.03Ce3+, xMn2+ excited at 354 nm are measured and depicted in Fig. 3(c). The corresponding luminescent decay times can be fitted by a second-order exponential mode and the average decay time τ can be determined by the formula [28

28. N. Ruelle, M. P. Thi, and C. Fouassier, “Cathodoluminescent properties and energy transfer in red calcium sulfide phosphors CaS: Eu, Mn,” Jpn. J. Appl. Phys. 31(Part 1, No. 9A), 2786–2790 (1992). [CrossRef]

]
τ=A1τ12+A2τ22A1τ1+A2τ2
(1)
where A1 and A2 are constant, τ1 and τ2 are the two exponential component of the decay time. The calculated decay times are listed in Fig. 3(c). According to Dexter’s formulation [29

29. D. J. Dexter, “A Theory of Sensitized Luminescence in Solids,” J. Chem. Phys. 21(5), 836–850 (1953). [CrossRef]

], the energy transfer rate is given by
P(R)QARbτDfD(E)FA(E)ECdE
(2)
where τD is the decay time of the donor emission, QA is the total absorption cross section of the acceptor ion, R is the distance between the donor and the acceptor, and b and c are parameters dependent on the type of energy transfer. The probability functions fD(E) and FA(E) represent the observed shapes of the donor emission band and the acceptor absorption band, respectively. Thus, according to Eq. (2), it becomes clear that the energy transfer rate P is in inverse proportion to the decay time τD. It can be seen that the decay lifetime of the Ce3+ decreases monotonically with an add up of the Mn2+ doping concentration, which also supports the energy transfer from the Ce3+ to Mn2+. Moreover, the energy transfer efficiency ηCe→Mn can be expressed by [30

30. P. I. Paulose, G. Jose, V. Thomas, N. V. Unnikrishnan, and M. K. R. Warrier, “Sensitized fluorescence of Ce3+/Mn2+ system in phosphate glass,” J. Phys. Chem. Solids 64(5), 841–846 (2003). [CrossRef]

]
ηT=1τSτS0
(3)
Where τS is the lifetime of the Ce3+ in the absence of the Mn2+ and τS0 is the lifetime of the Ce3+ in the presence of the Mn2+. The decay lifetime values are used for calculation, and the results are presented in Fig. 3(d). It can be seen that the energy transfer efficiency ηT is found to increase gradually with the increase of Mn2+ content. The critical distance Rc for energy transfer from the Ce3+ to Mn2+ is calculated using the concentration quenching method. The critical distance was estimated according to the equation [25

25. G. Blasse and A. Bril, “Investigation of Some Ce-Activated Phosphors,” J. Chem. Phys. 47(12), 5139–5145 (1967). [CrossRef]

]
RCeMn=2[3V4πxcN]1/3
(4)
where V is the volume of the unit cell, xc is the critical concentration, and N is the number of available sites for the dopant in the unit cell. In our case, N is 10, and V is estimated to be 607.29 Å3. The critical concentration (xc), at which the luminescence intensity of Ce3+ is one-half of that in the sample in the absence of Mn2+, is 0.09. Therefore, the critical distance (Rc) was calculated to be 10.88 Å. This value is longer than 4 Å, indicating the energy transfer is not via exchange interaction mechanism but electric multipolar interaction [31

31. N. Guo, Y. J. Huang, H. P. You, M. Yang, Y. H. Song, K. Liu, and Y. H. Zheng, “Ca9Lu(PO4)7:Eu2+,Mn2+: a potential single-phased white-light-emitting phosphor suitable for white-light-emitting diodes,” Inorg. Chem. 49(23), 10907–10913 (2010). [CrossRef] [PubMed]

, 32

32. C. H. Huang, T. W. Kuo, and T. M. Chen, “Novel red-emitting phosphor Ca9Y(PO4)7:Ce3+,Mn2+ with energy transfer for fluorescent lamp application,” ACS Appl. Mater. Interfaces 2(5), 1395–1399 (2010). [CrossRef] [PubMed]

].

3.4 Photoluminescence properties of SPB: Ce3+, Mn2+, Tb3+

To enhance the low color rendering property due to a green-region deficiency as seen in Fig. 3(a) and obtain warm white emission, we also prepared SPB: Tb3+ and SPB: 0.03Ce3+, 0.05Mn2+, yTb3+ (0.005≤y≤0.03). Figure 4(a)
Fig. 4 (a) PLE spectrum of SPB: Tb3+ and PL spectrum of SPB: Ce3+; (b) DRS of SPB host, SPB:Ce3+, Mn2+ and SPB:Ce3+, Mn2+, Tb3+; (c) PL spectra of SPB:0.03Ce3+,0.05Mn2+, yTb3+; (d) Representation of the CIE chromaticity coordinates for SPB:0.03Ce3+, xMn2+ (point nos. 1-5), SPB:0.03Ce3+, 0.05Mn2+, yTb3+ (point nos. 6-9)
shows the PL spectrum of SPB: Ce3+ and the PLE spectrum of Tb3+. It can be seen that there nearly no spectral overlap between them, which indicates that there may not exist energy transfer between Ce3+ to Tb3+. The DRS of the SPB, SPB: 0.03Ce3+, 0.05Mn2+ and SPB: 0.03Ce3+, 0.05Mn2+, 0.01Tb3+ samples are shown in Fig. 4(b). It is clear that the spectrum of the SPB host exhibits a high reflection in the visible range. For SPB: Ce3+, Mn2+ sample, it displays strong absorption bands between 250 and 450 nm attributed to the 4f→5d electronic transitions of the Ce3+ and d-d transitions absorption of Mn2+. For Ce3+, Mn2+ and Tb3+ co-doped sample SPB, it also shows a strong absorption band in the wavelength range of 250-450 nm except for the enhanced absorption intensity by f-f transition absorption of Tb3+, indicating that the trebly doped phosphor may be suitable for UV LED excitation. The PL spectra of SPB: 0.03Ce3+, 0.05Mn2+, yTb3+ (0.005≤y≤0.03) are illustrated in Fig. 4(c) and the inset indicates the intensity change of different emission bands. Upon 354 nm excitation, the PL spectrum is found to consist of three major emission bands in the entire visible spectral region, one is the blue emission arose from the 5d-4f transitions of Ce3+, another is the green emission due to the 5D4 -7FJ (J = 3,4,5,6) transitions and the third part is a broad red-emitting band caused by Mn2+ d-level spin-forbidden transitions. Along with increasing Tb3+ concentration, the PL intensity of Tb3+ emission is found to increase, and that of Ce3+ emission is observed to decrease. This is because there is competition between absorption of Tb3+ and Ce3+. Both Ce3+ and Tb3+ have the same chance to absorb the photons. The intensity depends on the number of emission center. Therefore, the emission intensity of Tb3+ will increase and that of Ce3 + will decrease with the increase in the number of Tb3+. The emission intensity of Mn2+ will have the same tendency as that of Ce3+. As a result, the emission intensity of Mn2+ also decrease accordingly with Tb3+ concentration increasing, which is in good agreement with experimental result as shown in Fig. 4(c).

The main physicochemical properties of as-synthesized SPB serial phosphors are summarized in Fig. 4(d) and Table 1

Table 1. The main physicochemical properties of the synthesized SPB serial phosphors.

table-icon
View This Table
. The correlated color temperature (CCT) was calculated by using McCamy’s approximate formula [33

33. C. S. McCamy, “Correlated color temperature as an explicit function of chromaticity coordinates,” Color Res. Appl. 17(2), 142–144 (1992). [CrossRef]

] and Quantum efficiencies are measured by the integrated sphere method and can be calculated according to the equation
Φ=Ec(1A)EbLaA
(5)
where Ec is the integrated luminescence of the powder caused by direct excitation, Eb is the integrated luminescence of the powder caused by indirect illumination from the sphere and the term La is the integrated excitation profile from an empty integrated sphere (without the sample). A is the powder absorbance, which can be obtained by the following formula
A=L(λ)0Li(λ)L0
(6)
where L0(λ) is the integrated excitation profile when the sample is diffusely illuminated by the integrated sphere’s surface; Li(λ) is the integrated excitation profile when the sample is directly excited by the incident beam. By using Eqs. (5) and (6), the quantum efficiencies of representative phosphors as well as the commercial phosphors YAG are calculated and shown in Table 1. We can see that the emission color of SPB: 0.03Ce3+, xMn2+, yTb3+ phosphors can be tuned from blue to green or red based on the energy transfer from Ce3+ to Mn2+ and Ce3+ to Tb3+, which demonstrates controllable emitting colors as a function of Mn2+ and Tb3+ contents. Hence, the genial warm white light can be realized with excellent CIE (0.35, 0.32), low CCT (4373K) and high CRI (Ra = 89) by appropriately tuning the ratio of the Mn2+ to Tb3+ under the radiation of UV light, which is better than that (CIE≈(0.291, 0.300), CCT≈8500K) of a LED based on YAG: Ce3+ with blue InGaN chip [34

34. C. C. Chiang, M. S. Tsai, and M. H. Hona, “Synthesis and photoluminescent properties of Ce3+ doped terbium aluminum garnet phosphors,” J. Alloy. Comp. 431(1-2), 298–302 (2007). [CrossRef]

] and suitable for the application of warm white light LED. Depending on all above studies and experiments, it can be concluded that the full-color-emitting and color-tunable phosphor Sr10[(PO4)5.5(BO4)0.5](BO2): Ce3+, Mn2+, Tb3+ can serve as a great potential and flexible phosphor for using in warm white-light LED devices.

3.5 Thermal quenching properties of SPB: 0.03Ce3+, 0.05Mn2+, 0.02Tb3+

The thermal quenching property is one of the important technological parameters for phosphors used in solid-state lighting for it has considerable influence on the light output and color rendering index. The temperature dependent emission spectra for SPB: 0.03Ce3+, 0.05Mn2+, 0.02Tb3+ under excitation at 352 nm were measured and illustrated in Fig. 5
Fig. 5 The temperature-dependent emission intensity of the optimized SPB: 0.03Ce3+, 0.05Mn2+, 0.02Tb3+ sample.
. The inset displays a comparison of the thermal luminescence quenching of our phosphor with that of the commercial yellow phosphor YAG: Ce3+ (Mitsubishi Chemical Corporation, Japan). As can be seen in Fig. 5, the thermal stability of SPB: 0.03Ce3+, 0.05Mn2+, 0.02Tb3+ is inferior to that of YAG:Ce3+ when the temperature is above 50 °C, though the intensity of both of them dropped to about 63% of its initial value at a temperature of 200 °C. The observation can be rationalized by the fact that increasing temperature has increased the population of higher vibration levels, the density of phonons and the probability of non-radiative transfer (energy migration to defects). For the application in high power LEDs, thermal quenching property has to be enhanced.

4. Conclusion

In conclusion, a series of single-phase novel emission tunable Sr10[(PO4)5.5(BO4)0.5](BO2): Ce3+, Mn2+, Tb3+ phosphors have been synthesized and the luminescence properties as well as energy transfer from Ce3+ to Mn2+ and Ce3+ to Tb3+ are investigated for the first time. The energy transfer efficiency and critical distance Rc are also calculated. The emission color of SPB: 0.03Ce3+, xMn2+, yTb3+ phosphors can be tuned from blue to green or red based on the effective energy transfer. More importantly, the wavelength-tunable warm white light can be realized with a superior CIE (0.35, 0.32), high CRI (Ra = 89) and low CCT (CCT = 4373K). Our results indicate that the full-color-emitting and color-tunable phosphor Sr10[(PO4)5.5(BO4)0.5](BO2): Ce3+, Mn2+, Tb3+ can be a promising candidate for single-composition phosphor converted white-emitting LEDs.

Acknowledgments

This work is supported by National Science Foundation for Distinguished Young Scholars (No. 50925206) and Specialized Research Fund for the Doctoral Program of Higher Education (No. 20120211130003).

References and links

1.

J. M. Phillips, M. E. Coltrin, M. H. Crawford, A. J. Fischer, M. R. Krames, R. Mueller-Mach, G. O. Mueller, Y. Ohno, L. E. S. Rohwer, J. A. Simmons, and J. Y. Tsao, “Research challenges to ultra-efficient inorganic solid-state lighting,” Laser Photonics Rev. 1(4), 307–333 (2007). [CrossRef]

2.

J. H. Ryou and R. D. Dupuis, “Focus issue: Optics in LEDs for lghting,” Opt. Express 19(S4Suppl 4), A897–A899 (2011). [CrossRef] [PubMed]

3.

D. Feezell, J. Speck, S. DenBaars, and S. Nakamura, “Semipolar (2021) InGaN/GaN Light-Emitting Diodes for high-efficiency solid-state lighting,” J. Display Technology 9, 190–198 (2013). [CrossRef]

4.

R. Arif, Y. Ee, and N. Tansu, “Polarization engineering via staggered InGaN quantum wells for radiative efficiency enhancement of Light Emitting Diodes,” Appl. Phys. Lett. 91(9), 091110–091112 (2007). [CrossRef]

5.

H. Zhao, G. Liu, J. Zhang, R. Arif, and N. Tansu, “Analysis of internal quantum efficiency and current injection efficiency in III-nitride Light-Emitting Diodes,” J. Display Technology 9(4), 212–225 (2013). [CrossRef]

6.

S. Choi, M. Ji, J. Kim, H. Kim, M. Satter, P. Yoder, J. Ryou, R. Dupuis, A. Fischer, and F. Ponce, “Efficiency droop due to electron spill-over and limited hole injection in III-nitride visible light-emitting diodes employing lattice-matched InAlN electron blocking layers,” Appl. Phys. Lett. 101(16), 161110 (2012). [CrossRef]

7.

G. Liu, J. Zhang, C. Tan, and N. Tansu, “Efficiency-droop suppression by using large-bandgap AlGaInN thin barrier layers in InGaN Quantum-Well Light-Emitting Diodes,” IEEE Photonics J. 5(2), 2201011 (2013). [CrossRef]

8.

Y. K. Ee, P. Kumnorkaew, R. A. Arif, H. Tong, H. Zhao, J. F. Gilchrist, and N. Tansu, “Optimization of Light Extraction Efficiency of III-Nitride Light Emitting Diodes with Self-Assembled Colloidal-based Microlenses,” IEEE J. Sel. Top. Quantum Electron. 15(4), 1218–1225 (2009). [CrossRef]

9.

J. Jewell, D. Simeonov, S. Huang, Y. Hu, S. Nakamura, J. Speck, and C. Weisbuch, “Double embedded photonic crystals for extraction of guided light in light-emitting diodes,” Appl. Phys. Lett. 100(17), 171105 (2012). [CrossRef]

10.

R. J. Xie, N. Hirosaki, M. Mitomo, K. Sakuma, and N. Kiumra, “Wavelength-tunable and thermally stable Li-α-sialon:Eu2+ oxynitride phosphors for white light-emitting diodes,” Appl. Phys. Lett. 89(24), 241103 (2006). [CrossRef]

11.

J. S. Kim, P. E. Jeon, J. C. Choi, H. L. Park, S. I. Mho, and G. C. Kim, “Warm-white-light emitting diode utilizing a single-phase full-color Ba3MgSi2O8:Eu2+, Mn2+ phosphor,” Appl. Phys. Lett. 84(15), 2931–2933 (2004). [CrossRef]

12.

H. Yamamoto, “White LED phosphors: the next step,” Proc. SPIE 7598, 759808, 759808-10 (2010). [CrossRef]

13.

L. Wang, X. Zhang, Z. D. Hao, Y. S. Luo, X. J. Wang, and J. H. Zhang, “Enriching red emission of Y3Al5O12: Ce3+ by codoping Pr3+ and Cr3+ for improving color rendering of white LEDs,” Opt. Express 18(24), 25177–25182 (2010). [CrossRef] [PubMed]

14.

W. R. Liu, C. C. Lin, Y. C. Chiu, Y. T. Yeh, S. M. Jang, and R. S. Liu, “ZnB2O4:Bi3+,Eu3+:a highly efficient, red-emitting phosphor,” Opt. Express 18(3), 2946–2951 (2010). [CrossRef] [PubMed]

15.

Y. Zhang, L. Wu, M. Ji, B. Wang, Y. Kong, and J. Xu, “Structure and photoluminescence properties of KSr4(BO3)3:Eu3+ red-emitting phosphor,” Opt. Mater. Express 2(1), 92–102 (2012). [CrossRef]

16.

H. C. Kuo, C. W. Hung, H. C. Chen, K. J. Chen, C. H. Wang, C. W. Sher, C. C. Yeh, C. C. Lin, C. H. Chen, and Y. J. Cheng, “Patterned structure of remote phosphor for phosphor-converted white LEDs,” Opt. Express 19(S4Suppl 4), A930–A936 (2011). [CrossRef] [PubMed]

17.

C. Huang, T. Chan, W. Liu, D. Wang, Y. Chiu, Y. Yeh, and T. Chen, “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,” J. Mater. Chem. 22(38), 20210–20216 (2012).

18.

C. Chang and T. Chen, “White light generation under violet-blue excitation from tunable green-to-red emitting Ca2MgSi2O7: Eu, Mn through energy transfer,” Appl. Phys. Lett. 90(16), 161901 (2007). [CrossRef]

19.

S. S. Sanayea and B. S. Dhabekar, “Energy transfer process in CaSO4: Tb, Ce phosphor,” J. Lumin. 105(1), 1–8 (2003). [CrossRef]

20.

C. Chang and T. Chen, “Sr3B2O6: Ce3+, Eu2+: A potential single-phased white-emitting borate phosphor for ultraviolet light-emitting diodes,” Appl. Phys. Lett. 91(8), 081902–081904 (2007). [CrossRef]

21.

Y. Huang, X. Wang, H. S. Lee, E. Cho, K. Jang, and Y. Tao, “Synthesis, vacuum ultraviolet and ultraviolet spectroscopy of Ce3+ ion doped olgite Na(Sr, Ba)PO4,” J. Phys. D Appl. Phys. 40(24), 7821–7825 (2007). [CrossRef]

22.

K. Shinde, S. J. Dhoble, H. C. Swart, and K. Park, “Phosphate Phosphors for Solid-State Lighting,” Springer Ser. Mater. Sci. 174, 1–265 (2012). [CrossRef]

23.

A. C. Larson and R. B. Von Dreele, “General Structure Analysis System (GSAS) ,” Los Alamos Nat. Lab., Report, LAUR 86–748, 2000.

24.

S. Chen, S. Hoffmann, W. Carrillo-Cabrera, L. G. Akselrud, Y. Prots, U. Schwarz, J. T. Zhao, and R. Kniep, “Sr10[(PO4)5.5(BO4)0.5](BO2): Growth and crystal structure of a strontium phosphate orthoborate metaborate closely related to the apatite-type crystal structure,” J. Solid State Chem. 183(3), 658–661 (2010). [CrossRef]

25.

G. Blasse and A. Bril, “Investigation of Some Ce-Activated Phosphors,” J. Chem. Phys. 47(12), 5139–5145 (1967). [CrossRef]

26.

L. G. Van Uitert, “An empirical relation fitting the position in energy of the lower d-band edge for Eu2+ or Ce3+ in various compounds,” J. Lumin. 29, 1–9 (1984).

27.

P. D. Rack and P. H. Holloway, “The structure, device physics, and material properties of thin film electroluminescent displays,” Mater. Sci. Eng. Rep. 21(4), 171–219 (1998). [CrossRef]

28.

N. Ruelle, M. P. Thi, and C. Fouassier, “Cathodoluminescent properties and energy transfer in red calcium sulfide phosphors CaS: Eu, Mn,” Jpn. J. Appl. Phys. 31(Part 1, No. 9A), 2786–2790 (1992). [CrossRef]

29.

D. J. Dexter, “A Theory of Sensitized Luminescence in Solids,” J. Chem. Phys. 21(5), 836–850 (1953). [CrossRef]

30.

P. I. Paulose, G. Jose, V. Thomas, N. V. Unnikrishnan, and M. K. R. Warrier, “Sensitized fluorescence of Ce3+/Mn2+ system in phosphate glass,” J. Phys. Chem. Solids 64(5), 841–846 (2003). [CrossRef]

31.

N. Guo, Y. J. Huang, H. P. You, M. Yang, Y. H. Song, K. Liu, and Y. H. Zheng, “Ca9Lu(PO4)7:Eu2+,Mn2+: a potential single-phased white-light-emitting phosphor suitable for white-light-emitting diodes,” Inorg. Chem. 49(23), 10907–10913 (2010). [CrossRef] [PubMed]

32.

C. H. Huang, T. W. Kuo, and T. M. Chen, “Novel red-emitting phosphor Ca9Y(PO4)7:Ce3+,Mn2+ with energy transfer for fluorescent lamp application,” ACS Appl. Mater. Interfaces 2(5), 1395–1399 (2010). [CrossRef] [PubMed]

33.

C. S. McCamy, “Correlated color temperature as an explicit function of chromaticity coordinates,” Color Res. Appl. 17(2), 142–144 (1992). [CrossRef]

34.

C. C. Chiang, M. S. Tsai, and M. H. Hona, “Synthesis and photoluminescent properties of Ce3+ doped terbium aluminum garnet phosphors,” J. Alloy. Comp. 431(1-2), 298–302 (2007). [CrossRef]

OCIS Codes
(160.2540) Materials : Fluorescent and luminescent materials
(250.5230) Optoelectronics : Photoluminescence

ToC Category:
Fluorescent and Luminescent Materials

History
Original Manuscript: July 30, 2013
Revised Manuscript: August 23, 2013
Manuscript Accepted: August 23, 2013
Published: October 8, 2013

Citation
Ge Zhu, Zhipeng Ci, Qian Wang, Yurong Shi, and Yuhua Wang, "Full-color emission generation from single phased phosphor Sr10[(PO4)5.5(BO4)0.5](BO2): Ce3+, Mn2+, Tb3+ for white light emitting diodes," Opt. Mater. Express 3, 1810-1819 (2013)
http://www.opticsinfobase.org/ome/abstract.cfm?URI=ome-3-11-1810


Sort:  Author  |  Year  |  Journal  |  Reset  

References

  1. J. M. Phillips, M. E. Coltrin, M. H. Crawford, A. J. Fischer, M. R. Krames, R. Mueller-Mach, G. O. Mueller, Y. Ohno, L. E. S. Rohwer, J. A. Simmons, and J. Y. Tsao, “Research challenges to ultra-efficient inorganic solid-state lighting,” Laser Photonics Rev.1(4), 307–333 (2007). [CrossRef]
  2. J. H. Ryou and R. D. Dupuis, “Focus issue: Optics in LEDs for lghting,” Opt. Express19(S4Suppl 4), A897–A899 (2011). [CrossRef] [PubMed]
  3. D. Feezell, J. Speck, S. DenBaars, and S. Nakamura, “Semipolar (20−2−1) InGaN/GaN Light-Emitting Diodes for high-efficiency solid-state lighting,” J. Display Technology9, 190–198 (2013). [CrossRef]
  4. R. Arif, Y. Ee, and N. Tansu, “Polarization engineering via staggered InGaN quantum wells for radiative efficiency enhancement of Light Emitting Diodes,” Appl. Phys. Lett.91(9), 091110–091112 (2007). [CrossRef]
  5. H. Zhao, G. Liu, J. Zhang, R. Arif, and N. Tansu, “Analysis of internal quantum efficiency and current injection efficiency in III-nitride Light-Emitting Diodes,” J. Display Technology9(4), 212–225 (2013). [CrossRef]
  6. S. Choi, M. Ji, J. Kim, H. Kim, M. Satter, P. Yoder, J. Ryou, R. Dupuis, A. Fischer, and F. Ponce, “Efficiency droop due to electron spill-over and limited hole injection in III-nitride visible light-emitting diodes employing lattice-matched InAlN electron blocking layers,” Appl. Phys. Lett.101(16), 161110 (2012). [CrossRef]
  7. G. Liu, J. Zhang, C. Tan, and N. Tansu, “Efficiency-droop suppression by using large-bandgap AlGaInN thin barrier layers in InGaN Quantum-Well Light-Emitting Diodes,” IEEE Photonics J.5(2), 2201011 (2013). [CrossRef]
  8. Y. K. Ee, P. Kumnorkaew, R. A. Arif, H. Tong, H. Zhao, J. F. Gilchrist, and N. Tansu, “Optimization of Light Extraction Efficiency of III-Nitride Light Emitting Diodes with Self-Assembled Colloidal-based Microlenses,” IEEE J. Sel. Top. Quantum Electron.15(4), 1218–1225 (2009). [CrossRef]
  9. J. Jewell, D. Simeonov, S. Huang, Y. Hu, S. Nakamura, J. Speck, and C. Weisbuch, “Double embedded photonic crystals for extraction of guided light in light-emitting diodes,” Appl. Phys. Lett.100(17), 171105 (2012). [CrossRef]
  10. R. J. Xie, N. Hirosaki, M. Mitomo, K. Sakuma, and N. Kiumra, “Wavelength-tunable and thermally stable Li-α-sialon:Eu2+ oxynitride phosphors for white light-emitting diodes,” Appl. Phys. Lett.89(24), 241103 (2006). [CrossRef]
  11. J. S. Kim, P. E. Jeon, J. C. Choi, H. L. Park, S. I. Mho, and G. C. Kim, “Warm-white-light emitting diode utilizing a single-phase full-color Ba3MgSi2O8:Eu2+, Mn2+ phosphor,” Appl. Phys. Lett.84(15), 2931–2933 (2004). [CrossRef]
  12. H. Yamamoto, “White LED phosphors: the next step,” Proc. SPIE7598, 759808, 759808-10 (2010). [CrossRef]
  13. L. Wang, X. Zhang, Z. D. Hao, Y. S. Luo, X. J. Wang, and J. H. Zhang, “Enriching red emission of Y3Al5O12: Ce3+ by codoping Pr3+ and Cr3+ for improving color rendering of white LEDs,” Opt. Express18(24), 25177–25182 (2010). [CrossRef] [PubMed]
  14. W. R. Liu, C. C. Lin, Y. C. Chiu, Y. T. Yeh, S. M. Jang, and R. S. Liu, “ZnB2O4:Bi3+,Eu3+:a highly efficient, red-emitting phosphor,” Opt. Express18(3), 2946–2951 (2010). [CrossRef] [PubMed]
  15. Y. Zhang, L. Wu, M. Ji, B. Wang, Y. Kong, and J. Xu, “Structure and photoluminescence properties of KSr4(BO3)3:Eu3+ red-emitting phosphor,” Opt. Mater. Express2(1), 92–102 (2012). [CrossRef]
  16. H. C. Kuo, C. W. Hung, H. C. Chen, K. J. Chen, C. H. Wang, C. W. Sher, C. C. Yeh, C. C. Lin, C. H. Chen, and Y. J. Cheng, “Patterned structure of remote phosphor for phosphor-converted white LEDs,” Opt. Express19(S4Suppl 4), A930–A936 (2011). [CrossRef] [PubMed]
  17. C. Huang, T. Chan, W. Liu, D. Wang, Y. Chiu, Y. Yeh, and T. Chen, “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,” J. Mater. Chem.22(38), 20210–20216 (2012).
  18. C. Chang and T. Chen, “White light generation under violet-blue excitation from tunable green-to-red emitting Ca2MgSi2O7: Eu, Mn through energy transfer,” Appl. Phys. Lett.90(16), 161901 (2007). [CrossRef]
  19. S. S. Sanayea and B. S. Dhabekar, “Energy transfer process in CaSO4: Tb, Ce phosphor,” J. Lumin.105(1), 1–8 (2003). [CrossRef]
  20. C. Chang and T. Chen, “Sr3B2O6: Ce3+, Eu2+: A potential single-phased white-emitting borate phosphor for ultraviolet light-emitting diodes,” Appl. Phys. Lett.91(8), 081902–081904 (2007). [CrossRef]
  21. Y. Huang, X. Wang, H. S. Lee, E. Cho, K. Jang, and Y. Tao, “Synthesis, vacuum ultraviolet and ultraviolet spectroscopy of Ce3+ ion doped olgite Na(Sr, Ba)PO4,” J. Phys. D Appl. Phys.40(24), 7821–7825 (2007). [CrossRef]
  22. K. Shinde, S. J. Dhoble, H. C. Swart, and K. Park, “Phosphate Phosphors for Solid-State Lighting,” Springer Ser. Mater. Sci.174, 1–265 (2012). [CrossRef]
  23. A. C. Larson and R. B. Von Dreele, “General Structure Analysis System (GSAS),” Los Alamos Nat. Lab., Report, LAUR 86–748, 2000.
  24. S. Chen, S. Hoffmann, W. Carrillo-Cabrera, L. G. Akselrud, Y. Prots, U. Schwarz, J. T. Zhao, and R. Kniep, “Sr10[(PO4)5.5(BO4)0.5](BO2): Growth and crystal structure of a strontium phosphate orthoborate metaborate closely related to the apatite-type crystal structure,” J. Solid State Chem.183(3), 658–661 (2010). [CrossRef]
  25. G. Blasse and A. Bril, “Investigation of Some Ce-Activated Phosphors,” J. Chem. Phys.47(12), 5139–5145 (1967). [CrossRef]
  26. L. G. Van Uitert, “An empirical relation fitting the position in energy of the lower d-band edge for Eu2+ or Ce3+ in various compounds,” J. Lumin.29, 1–9 (1984).
  27. P. D. Rack and P. H. Holloway, “The structure, device physics, and material properties of thin film electroluminescent displays,” Mater. Sci. Eng. Rep.21(4), 171–219 (1998). [CrossRef]
  28. N. Ruelle, M. P. Thi, and C. Fouassier, “Cathodoluminescent properties and energy transfer in red calcium sulfide phosphors CaS: Eu, Mn,” Jpn. J. Appl. Phys.31(Part 1, No. 9A), 2786–2790 (1992). [CrossRef]
  29. D. J. Dexter, “A Theory of Sensitized Luminescence in Solids,” J. Chem. Phys.21(5), 836–850 (1953). [CrossRef]
  30. P. I. Paulose, G. Jose, V. Thomas, N. V. Unnikrishnan, and M. K. R. Warrier, “Sensitized fluorescence of Ce3+/Mn2+ system in phosphate glass,” J. Phys. Chem. Solids64(5), 841–846 (2003). [CrossRef]
  31. N. Guo, Y. J. Huang, H. P. You, M. Yang, Y. H. Song, K. Liu, and Y. H. Zheng, “Ca9Lu(PO4)7:Eu2+,Mn2+: a potential single-phased white-light-emitting phosphor suitable for white-light-emitting diodes,” Inorg. Chem.49(23), 10907–10913 (2010). [CrossRef] [PubMed]
  32. C. H. Huang, T. W. Kuo, and T. M. Chen, “Novel red-emitting phosphor Ca9Y(PO4)7:Ce3+,Mn2+ with energy transfer for fluorescent lamp application,” ACS Appl. Mater. Interfaces2(5), 1395–1399 (2010). [CrossRef] [PubMed]
  33. C. S. McCamy, “Correlated color temperature as an explicit function of chromaticity coordinates,” Color Res. Appl.17(2), 142–144 (1992). [CrossRef]
  34. C. C. Chiang, M. S. Tsai, and M. H. Hona, “Synthesis and photoluminescent properties of Ce3+ doped terbium aluminum garnet phosphors,” J. Alloy. Comp.431(1-2), 298–302 (2007). [CrossRef]

Cited By

Alert me when this paper is cited

OSA is able to provide readers links to articles that cite this paper by participating in CrossRef's Cited-By Linking service. CrossRef includes content from more than 3000 publishers and societies. In addition to listing OSA journal articles that cite this paper, citing articles from other participating publishers will also be listed.

Figures

Fig. 1 Fig. 2 Fig. 3
 
Fig. 4 Fig. 5
 

« Previous Article  |  Next Article »

OSA is a member of CrossRef.

CrossCheck Deposited