三波長型(three bands)白光LED是藉紫外光發光二極體(UV LED)激發三種螢光材料而成。螢光材料最近的研究動向著重於R、G、B三原色螢光粉體之開發。本論文旨在研究可受UV激發之SrAl2O4：Eu2+螢光粉體光致發光(Photoluminescence)材料，檢討其主體晶格陽離子之取代效應，對螢光粉體之效率及光性質之影響。本實驗之螢光材料主要是掺雜銪(Eu)之鹼土鋁酸鹽螢光粉體CaxSr1-xAl2O4：Eu2+ 1mol%及BaxSr1-xAl2O4：Eu2+ 1mol%。上述螢光粉體是以固態法固溶法合成，稱之為s系列；以不同比例之CaAl2O4：Eu2+、BaAl2O4：Eu2+與SrAl2O4：Eu2+螢光粉體藉粉末混合法製備者稱之為m系列。螢光粉體之色度是藉由反射式及穿透式二種方式來進行量測，其他光學性質包括相對量子效率 (Qr)、發射波峰 (λp)及色度，是以PL光譜儀測量及解析；晶體結構是藉X光繞射儀檢測。
Ca1-xEuxAl2O4、Sr1-xEuxAl2O4及Ba1-xEuxAl2O4 三種螢光粉體之吸收光譜是源自於Eu2+離子4f7 → 4f65d1(t2g)電子遷移所造成的吸收，分別為320-420nm、320-460nm及320-450nm，光譜均呈現寬廣之波形。發射波峰則是分別位於440、520及500 nm。合成的CaxSr1-xAl2O4:Eu2+螢光粉體在Ca2+取代量達20mol%時，其結構由單斜晶(monoclinic)轉變為六方晶相(hexagonal)。此螢光粉體之PL波峰(λp)範圍是介於440 nm ~ 530 nm，在x=0~0.3時，Ca2+的增加使得波峰從520 nm位移至530 nm。當Ca2+取代量達70 mol%以上時，波峰位置並無明顯位移，λp約位於440 nm附近。BaxSr1-xAl2O4 :Eu2+螢光粉體在Ba2+取代量達50 mol%時，其結構由單斜晶轉變為六方晶相，PL波峰隨著x值的遞增(x = 0 ~ 1)從520 nm位移至500 nm。PL波峰位移是藉晶體場效應(crystal field effect)來解釋。主體晶格中鹼土陽離子的取代會形成不同的庫侖吸引力，這改變了晶體場的強度並進而產生色度變化。合成的Ca0.5Sr0.5Al2O4：Eu2+1 mol%螢光粉體其發射光譜呈現寬化之特性，因而具有白色發光之現象。此現象是以非均質寬化(inhomogeneous broadening)及再吸收效應(reabsorption)加以解釋。非均質寬化效應形成的原因是主體晶格中Ca2+/Sr2+離子的組成分佈 (compositional distribution)所致，此效應是藉由EPR光譜圖的分析得知。以383nm之晶片進行封裝後，Ca0.5Sr0.5Al2O4：Eu2+螢光粉體LED的發射峰強度會隨順向驅動電流量的增加而增強，放光會更趨向標準白光。順向電流為50 mA時，此LED之CRI值可達91。

Three bands white-LED are mostly pumped by UV-LED recently. The research of fluorescence materials are focused on multiple (R, G, B) phosphors. Therefore, SrAl2O4：Eu2+ photoluminescence material was investigated in this thesis. According to the cations substitution in host lattice, the efficiency and luminescent properties were affected. Solid solution systems (s series) of Eu2+ doped (1 mol %) alkaline earth aluminate phosphors including CaxSr1-xAl2O4 and BaxSr1-xAl2O4 were synthesized. Powder mixing systems (m series) were prepared by ratios of CaAl2O4:Eu2+, SrAl2O4:Eu2+, BaAl2O4:Eu2+ phosphors. The crystal structure, relative quantum efficiency (Qr), peak wavelength (λp) and chromaticity were investigated by XRD patterns and photoluminescence (PL) respectively.
The wide absorption spectra of Ca1-xEuxAl2O4(320-420nm)、Sr1-xEuxAl2O4 (320-460nm) and Ba1-xEuxAl2O4(320-450nm) phosphors are resulted from the energy band absorption of 4f7 → 4f65d1(t2g) , and the emission peak wavelength are 440、520及500 nm, respectively. For the s series, the synthesized CaxSr1-xAl2O4:Eu2+ powders show that the structure transforms from monoclinic to hexagonal at x = 0.2 and return to monoclinic at x ≧ 0.5, λp varys from 440 to 530 nm. For the BaxSr1-xAl2O4 : Eu2+ system, the structure transforms from monoclinic to hexagonal at x = 0.5, and λp decreases from 520 to 500 nm continuously from x = 0 to x = 1. The shift in λp could be explained by the crystal field effect, which is affected by different coulomb attractive forces due to the various fraction of alkaline earth cation in the host lattice. Base on the experiments, the variations of crystal field due to the substitution of cations in host lattice lead to the shift of chromaticity. Thus, this effect mentioned above was verified by another silicate phosphor system (M2Sr2-xSiO4: Eu2+ (M: Ca, Ba)) in this study.
According to the experiment, the white-light luminescence and broad band emission of Ca0.5Sr0.5Al2O4:Eu2+ (1 mole %) phosphors were explained by the inhomogeneous broadening effect and reabsorption behavior. The EPR spectra indicated that the inhomogeneous broadening effect could be attributed to the substitutional disorder (compositional disordering) of Ca2+/Sr2+ in the host lattice. When the phosphors sealed with the 383nm LED chips, the emission intensity is increased with the forward current and the chromaticity close to the white light for C50s-LED. And the CRI is 91as the current reach to 50mA.

參考文獻
[1] 蘇勉曾, 吳世康, “螢光材料”發光材料, 4 (1996) 2.
[2] 李碩重, “照明設計學”, 全華科技圖書, 台灣 (1993).
[3] 楊素華, “螢光粉在發光上的運用”,科學發展, 358 (2002) 66.
[4] 楊俊英, “電子產業用螢光材料之應用調查”, 工研院, 台灣 (1992).
[5] Lyuji, Ozawa, “Cathodoluminescence”, Kodansha Ltd. Tokyo (1990).
[6] P. Goldberg, “Luminescence of Inorganic Solids”, Academic Press Inc., New York (1966).
[7] 柯以侃, “儀器分析”, 文京圖書, 台北 (1996).
[8] G. Blasse and B. C. Grabmaier, “Luminescence Material”, Springer, Berlin (1994).
[9] H. Yamamoto, “Physical Chemistry”, Oxford University Press, Tokyo (1998).
[10] 蘇勉曾, 吳世康, “螢光材料”, 發光材料, 4 (1996) 3.
[11] 蘇勉曾, 吳世康, “螢光材料”, 發光材料, 4 (1996) 9.
[12] R. C. Ropp , “Luminescence and the solid state”, Amsterdam Elsevier, New Jersey (1991).
[13] R. B king, “Encyclopedia of Inorganic Chemistry”, John Wiley & Sons, New York (1994).
[14] D. L. Perry, S. L. Phillips Eds., “Handbook of Inorganic Compounds”, CRC Press: Boca Raton, FL (1995).
[15] S. Shionoya, S. Shionoya, W.M. Yen (Eds.), “Phosphor Handbook”, CRC Press, New York (1999).
[16] 蘇鏘, “稀土元素”, 清華大學出版社,長沙 (2000).
[17] E. Douglas, D. H. McDaniel and J. J. Alexander, “Concepts and Models of Inorganic Chemistry-3rd”, John Wiley & Sons Inc., New York (1994).
[18] H. Kitai, ”Solid State Luminescence”, Chapman & Hall, New York (1993).
[19] P. W. Atkins, “Physical Chemistry”, Oxford University Press, Tokyo (1998).
[20] G. Blasse, “Structure and Bonding”, Springer Verlag, Heidelberg (1991).
[21] 劉如熹、王健源, “白光發光二極體製作技術-21世紀人類的新曙光”, 全華科技圖書, 台北 (2001).
[22] G. Blasse and A. Bril, "Photoluminescence Efficiency of Phosphors with Electronic Transitions in Localized Centers", J. Electrochem. Soc., 115 (1968) 1067.
[23] B. E. Douglas, D. H. McDaniel and J. J. Alexander, “Concepts and Models of Inorganic Chemistry”, John Wiley & Sons, Inc., New York (1994).
[24] P. W. Atkins, “Physical chemistry”, W.H. Freeman & Company, San Francisco (1988).
[25] 吳健康, “數位影像分析”, 儒林圖書公司, 台北 (1992).
[26] 高啟光編著, “照明設計”, 儒林圖書公司, 台北 (1997).
[27] F. J. Avella, "The Cathodoluminescence of Terbium Activated Indium Orthoborate", J. Electrochem. Soc., 113 (1966) 1225.
[28] R. Jagannathan, S.P. Manoharan, R. P. Rao, R. L. Narayanan and N. Rajaram, Bull. Electrochem., 4 (1988) 597.
[29] T. Justel, H. Nikol and C. Ronda, “New developments in the. field of luminescent materials for lighting and displays”, Angew. Chem. Int. Ed. Engl., 37 (1998) 3084.
[30] W. A. Thornoton, “Luminosity and color-rendering capability of white light” J. Opt., Soc. Am., 61 (1971) 1155.
[31] M. Koedam and J. Opstelten, “Measurement and computer-aided optimization of spectral power distributions”, Lighting Res. Technol., 3 (1971) 205.
[32] 許招庸, ”現代照明實務”, 全華科技圖書, 台北 (1998).
[33] S. Shionoya, S. Shionoya, W.M. Yen Eds, “Phosphor Handbook”, CRC Press, Boca Raton, FL (1998).
[34] T. Matsuzawa, Y. Aoki, N. Takeuchi, Y. Murayama, “A New long phosphorescent phosphor with high brightness, SrAl2O4:Eu2+,Dy3+”, Rare Earths, 29 (1996) 79.
[35] G. Blasse, A. Bril, “Fluorescence of Eu2+ Activated Alkaline-Earth Aluminates”, Philips Res. Repts., 23 (1968) 201.
[36] F. C. Palilla, A.K. Levine, M.R. Tomkus. “Fluorescent. Properties of Alkaline Earth Aluminates of the Type MAl2O4. Activated by Divalent Europium”, J. Electrochem. Soc., 115 (1968) 642.
[37] V. Abbruscato, “Optical and Electrical Properties of SrAl2O4:Eu2+”, J. Electrochem., Soc., 118 (1971) 930.
[38] T. Matsuzawa, Y. Aoki, N. Takeuchi, Y. Murayama, “A New long phosphorescent phosphor with high brightness, SrAl2O4:Eu2+,Dy3+”, J. Electrochem. Soc., 143 (1996) 2670.
[39] E. Nakazawa, T. Mochida, ” Traps in SrAl2O4:Eu2+ phosphor with rare-earth ion doping”, J. Lumin., 72-74, (1997) 236.
[40] T. Matsuzawa, Y. Aoki, N. Takeuchi, Y. Murayama, “A New long phosphorescent phosphor with high brightness, SrAl2O4:Eu2+,Dy3+”, in Proceedings of the 188th Meeting of the Electrochem. Soc., Chicago, 160 (1995).
[41] Y. Murayama, Nikkei Science, Scientific American in Japanese 26 (1996) 20.
[42] Dong Wang, Qingrui Yin, Yongxiang Li, Minquan Wang, “Concentration quenching of Eu2+ in SrO•Al2O3:Eu2+ phosphor”, J. Lumin., 97 (2002) 1.
[43] H. Yamamoto, T. Matsuzawa, ”Mechanism of long phosphorescence of SrAl2O4:Eu2+, Dy3+ and CaAl2O4:Eu2+, Nd3+”, J. Lumin., 73 (1997) 287.
[44] Y. Murayama, N. Takeuchi, Y. Aoki, T. Matsuzawa, “Phosphorescent phosphor”, US Patent, 5424006, (1995).
[45] T. Katsumata, T. Nabae, K. Sasajima, S. Kumuro, T.Morikawa, “Effects of Composition on the Long Phosphorescent SrAl2O4:Eu2+,Dy3+ Phosphor Crystals”, J. Electrochem., Soc., 144 (1997) 243.
[46] M. Akiyama, Xu, C.-N., Liu, Y., Nonaka, K., Watanabe, T., ” Influence of Eu, Dy co-doped strontium aluminate composition on mechanoluminescence intensity”, J. Lumin., 97 (2002) 13-18.
[47] M. Kowatari, Koyama, D., Satoh, Y., Iinuma, K., Uchida, S., “The temperature dependence of luminescence from a long lasting phosphor exposed to ionizing radiation” ”Nucl. Instrum. Methods Phys., Res. A 480 (2002) 431.
[48] Xu, C.-N., Watanabe, T., Akiyama, M. Zheng, X.-G., “Direct view of stress distribution in solid by mechanoluminescence”, Appl. Phys. Lett., 74 (1999) 2414.
[49] K. Kato, I. Tsutai, T. Kamimura, Futao Kaneko, “Thermoluminescence properties of SrAl2O4:Eu sputtered films with long phosphorescence”, J. Lumin., 82 (1999) 213.
[50] Y. H. Lin, Z.T. Zhang, Z.L. Tang, J.Y. Zhang, Z.S. Zheng, X, Lu, “The characterization and mechanism of long afterglow in alkaline earth aluminates phosphors co-doped by Eu2O3 and Dy2O3”, Mater. Chem. Phys., 70 (2001) 156.
[51] I.-Ch. Chen, T.M. Chen, “Sol-gel synthesis and the effect of boron addition on the phosphorescent properties of SrAl2O4 : Eu2+,Dy3+ phosphors”, J. Mater., 16 (2001) 644.
[52] D. D. Jia, J. Zhu, B.Q. Wu, S.E. Paje, ” Luminescence and energy transfer in CaAl4O7:Tb3+, Ce3+”, J. Lumin., 93 (2001) 107.
[53] R. Sakai, T. Katsumata, S. Komurv, T. Morikawa, “Effect of composition on the phosphorescence from BaAl2O4: Eu2+, Dy3+ crystals”, J. Lumin., 85 (1999) 149.
[54] K. Kato, I. Tsutai, T. Kamimura, F. Kaneko, K. Shinbo, M. Ohta, T. Kawakami, ”Thermoluminescence properties of SrAl2O4:Eu sputtered films with long phosphorescence”, J. Lumin., 82 (1999) 213.
[55] A. -R. Schulze, Hk. Muller-Buschbaum, “Zur Struktur von. monoklinem SrA120 4.”, Z. anorg. Allg. Chem. 475 (1981) 205.
[56] D. Ravichandran, S.-T. Johnson, S. Erdei, R. Roy and W. B. White, “Crystal chemistry and luminescence of the Eu2+-activated alkaline earth aluminate phosphors”, Displays, 19 (1999) 197.
[57] K. Kaiya, N. Takahashi, T. Nakamura, T. Matsuzawa, G. M. Smith, P. C. Riedi, ”EPR studies of europium(II)-doped strontium aluminate phosphors”, J. Lumin., 87-89 (2000) 1073.
[58] T. Nakamura, C. Matsuzawa, C. Rowlands, V. Beltran-Lopz, G. M. Smith, P. C. Riedi, “EPR investigations on europium(II)-doped aluminates”, J. Chem. Soc., Faraday Trans., 94, (1998)
[59] 王民權, 王東, “名義組成2SrO‧3Al2O3︰Eu2＋高效磷光體基質的相組成和結構研究”, J. the Chinese Ceramic Soc., 27 (1999) 763.
[60] S. Ito, S. Banno, K. Suzuki, M. Inagaki, Z. Phys. Chem. Neue Folge., 105, 173, (1977)
[61] C. M. B. Henderson and D. Taylor, “The structural behavior of the nepheline. family: (1) Sr and Ba aluminates (MAl2O4)”, Miner. Mag., 45 (1982) 111.
[62] W.-M. Yen, Jia, L. W. Lu and H. Yuan, “Phosphor with long-persistent green phosphorescence” , US Patent, 6267911, B1.4, (2001).
[63] T. Peng, H. Yang, X. Pu, B. Hu, Z. Jiang and C. Yan, ”Combustion synthesis and photoluminescence of SrAl2O4: Eu, Dy phosphor nanoparticles”, Mater. Lett., 58 (2004) 352.
[64] H. Takasaki, S. Tanabe, T. Hanada, “Long-Lasting Afterglow Char-. acteristics of Eu, Dy Codoped SrO–Al2O3. Phosphor”, J. Ceram. Soc. Japan, 104 (1995) 322.
[65] T. Matsuzawa, Y. Aoki, N. Takeuchi, Y. Murayama, “A New long phosphorescent phosphor with high brightness, SrAl2O4:Eu2+,Dy3+”, J. Electrochem. Soc., 143 (1996) 2670.
[66] T. Takeyama, T. Nakamura, N. Takahashi, M. Ohta, “Electron Paramagnetic Resonance Studies on the Defects Formed in the Dy(III)-Doped SrAl2O4” , Solid State Sci., 6 (2004). 345.
[67] R. J. Pet, M. van den Nieuwenhof, J.P.H.M. Duister, U.S. Patent, 4795588, (1989).
[68] I.-Ch. Chen, T.M. Chen, “Effect of host compositions on the afterglow properties of phosphorescent strontium aluminate phosphors derived from the sol-gel method”, J. Mater. Res., 16 (2001) 1293.
[69] D. Wang, Q. Yin, Y. Li, M. Wang, ”Influence of B2O3 on matrix forming process and luminescent properties of SrO center dot Al2O3 : Eu2+ phosphor”, J. Electrochem. Soc., 149(3) (2002) H65.
[70] T. Katsumata, K. Sasajima, T. Nabae, S. Komuro, T.Morikawa, “Characteristics of strontium aluminate crystals used for long-duration phosphors”, J. Am. Ceram. Soc., 81 (1998) 413.
[71] Nag. T.R.N. Kutty, “Role of B2O3 on the phase stability and long phosphorescence of SrAl2O4:Eu, Dy”, J. Alloys Compd., 354 (2003) 221.
[72] M. L. Ruiz-Gonzalez, J. M. GonZalez-Calbet, M. Vallet-Regi, E. Cordoncillo, P. Escribano, J. B. Carda, M. Marchal, “Planar defects in a precursor for phosphor materials:SrAl2-xBx O4 (x<0.2)”, J. Mater. Chem., 12 (2002) 1128.
[73] J. Niittykoski, T. Aitasalo, J. Holsa, H. Jungner, M. Lastusaari, M. Parkkinen, M. Tukia, “Effect of boron substitution on the preparation and luminescence of Eu2+ doped strontium aluminates”, J. Alloys Compd., 374 (2004) 108.
[74] M. R. Royce, H. Tamaki, Y. Murazaki, U.S. Patent., 5:376 303, (1994).
[75] G. N. Lvanova, V. A. Kasiyan, N.D. Nedeoglo, “Photoluminescence of ZnSe:Ag single crystals”, J. Lumin., 82 (1999) 277.
[76] D. Denzler, M. Olschewski, K. Sattler,”Luminescence studies of localized gap states in colloidal ZnS nanocrystals”, Appl. Phys. Lett., 84(5) (1998 ) 2841.
[77] G. A. Kumar, P.R. Biju, G. Jose, N.V. Unnikrishnan, “Static energy transfer for Mn2+: Pr3+ system in Phosphate glasses”, Mater. Chem. Phys., 60 (1999) 247.
[78] B. C. Joshi, M. C. Joshi, B. D. Joshi, “Energy transfer from Mn2+ to Pr3+ in phosphate glass”, J. Phys. Chem. Solids, 52 (1991) 939.
[79] R. Reisfeld, E. Greenberg, C. Jacoboni, R.D.E, Pape, “Energy transfer between Manganese (II) and Erbium (III) in various fluorides glasses”, J. Solid State Chem., 53 (1984) 236.
[80] M. Morita, D. Rau, H. Fujii, Y. Yoshita, H. Akiyama, “Photoluminescence of CdS:Mn2+ and Eu3+ nanoparticles dispersed in zirconia sol–gel films”, J. Lumin., 87/89 (2000) 478.
[81] K. Sooklal, B.S. Cullum, S.M. Angel, C.J. Murphy, “Photophysical properties of ZnS nanoclusters with spatially localized Mn2+”, J. Phys. Chem., 100 (1996) 4551.
[82] T. Atkinson, D.L. Segal, “Some recent developments in aqueous sol-gel processing”, J. Sol-gel Sci. Technol., 13 (1998) 133.
[83] S. Indris, D. Bork, P. Heitjans, “Nanocrystalline oxide ceramics prepared by high-energy ball milling”, J. Mater. Synth. Process., 8 (3-4) (2000) 245.
[84] G. Chen, D. Niu, X. Liu, “Preparation of SrAl2O4 from an oxide mixture via a high-energy ball milling”, J. Alloys Compd., 399 (2005) 280.
[85] M. R. Krames, M. Ochiai-Holcomb, G. E. Holfter, C. Carter-Coman, E. I. Chen, I. –H. Tan, P. Grillot, N. F. Gardner, H. C. Chui, “High-power truncated-inverted-pyramid (AlxGa1–x)0.5In0.5P/GaP light-emitting diodes exhibiting >50 external quantum efficiency”, Appl. Phy. Lett., 75 (1999) 2365.
[86] S. A. Robbins, R. G. Rupard, B. J. Weddile, T. R. Maull and K. Gallagher Patrick, “Some observations on the use of strontium carbonate as a temperature standard for DTA”, Thermochim Acta, 43 (1995) 269.
[87] Y. C. Chen, Y. H. Chang, “Synthesis and photoluminescent properties of europium-activated M2SnO4 (M=Ca, Sr, Zn) phosphor”, 61, (2005).
[88] J. M. Rivas Mercury, A.H. De Aza, P. Pena, “Hidratactio de los cementos de aluminatos e calico(Parte I)” J. the Europ. Ceram. Soc., 25 (2005) 3269.
[89] R. D. Shannon, C. T. Prewitt, “Effective ionic radii in oxides and fluorides”, Acta Crystallogr., B 25 (1969) 925.
[90] F. P. Glasser, L. S. Dent Glasser, “Crystal chemistry of some AB2O4 compounds”, J. Am. Cream. Soc., 46 (1963) 377.
[91] S. H. Ju, S. G. Kim, J. C. Choi, H. L. Park, S. –I. Mho, T. W. Kim, “Determination of the solid solubility of SrAl2O4 in CaAl2O4 Through crystal field-dependent Eu2+ signature”, Mater. Res. Bull., 14 (1999) 1905.
[92] Bodner and Pardue, “Chemistry an experimental science”, John Wiley & Sons, New York (1989)
[93] G. Chen, D. Niu, X. Liu, “Preparation of SrAl2O4 from an oxide mixture via a high-energy ball milling”, J. Alloys Compd., 399 (2005) 280-283.
[94] H. Lange, U.S. Patent 294699 (1996).
[95] N. A. Sirazhiddinov, P.A. Arifov, Russ. “Solid-phase reactions during the formation of strontium monoaluminate”, J. Inorg. Chem., 16 (1971) 76.
[96] I. C. Chen, T. M. Chen,” Sol-gel synthesis and the effect of boron addition on the phosphorescent properties of SrAl2O4 : Eu2+,Dy3+ phosphors”, J. Mater. Res., 16 (2001) 644.
[97] D. Jia, Xiao-iunnWang,W. M. Yan,”Electron traps in Tb3+-doped CaAl2O4”Chwmical Physis Letters, 363 (2002) 241.
[98] J. Sugar,N. Spector, “Spectrum and energy levels of doubly ionized europium (Eu2+)”J. Opt. Soc. Am., 64 (1974) 1484.
[99] A. G. Merzhanov, I. P. Brovinskaya, Dok1 . Akad . Nauk ., SSSR ( chem ) 204 (1972) 429 .
[100] C. Fouassier, B. Latourette, J. Portier, and P. Hagenmuller, Mater. Res. Bull., 11(8) (1976) 933.
[101] J. Y. Sun, C. S. Shi, Y. M. Li, Chinese Scien. Bull., 34 (1989) 703.
[102] J. Qiu, K. Miura, N. Sugimoto, K. Hirao, “Preparation and Fluorescence Properties of Fluoroaluminate Glasses Containing Eu2+ Ions”, NoniCryst. Solid, 266 (1997) 213.
[103] B. S. Tsai, Y. H. Chang, Y. C. Chen, “Nanostructured red-emitting MgGa2O4 : Eu3+ phosphors”, J. Mater. Res., 19 (2004) 1504.
[104] K. Murakami, T. Taguchi, M. Yoshino, “Display Technologies III (the International Society for Optical Engineering”, 4079 (2000) 112.
[105] Y. C. You, J. S. Choi, Y. R. Do, T.W. Kim, and H. L. Park, ”Tunable color emission in a Ba1−xSrxY2S4: Eu2+ phosphor”, Solid State Commun., 99 (1996) 961.
[106] G. Blasse, B. D. Bartolo (Ed.), “Luminescence of Inorganic Solids”, New York, (1978)
[107] S. H. Ju, U. S. Oh, J. C. Choi, H. L. Park, S. -I. Mho, T. W. Kim, C. D. Kim, “Tunable color emission and solid solubility limit in Ba1−xCaxAl2O4:Eu0.0012+ phosphors through the mixed states of CaAl2O4 and BaAl2O4”, Mat. Res. Bull., 35 (2000) 1831.
[108] S. H. Ju, S. G. Kim, J. C. Choi, H. L. Park, S. –I. Mho, T. W. Kim, “Determination of the solid solubility of SrAl2o4 in CaAl2o4 through crystal field-dependent Eu2+ signatures”, Mater. Res. Bull., 34 (1999) 1905.
[109] T. Aitosalo, J. Holsa, H. Jungner, J. –C. Krupa, M. Lahtinen, M. Lastusaari, J. Legendziewicz, J. Niittykoski, J. Valkonen, ”Spectroscopic and structural properties of Ca1-xSrxAl2O4 : Eu2+, Re3+ persistent luminescence materials” Radiat. Eff. Deffects Solides, 158 (2003) 309.
[110] S. K. Choi, H. S. Moon, S. I. Mho, T. W. Kim, H. L. Park,” Tunable Color Emission in a Zn1−xCdxGa2O4 Phosphor and Solid Solubility of CdGa2O4 in ZnGa2O4”, Mater. Res. Bull., 33 (1998) 693.
[111] A. K. Prodjosantoso, B. J. Kennedy, “Solubility of SrAl2O4 in CaAl2O4—a high resolution powder diffraction study”, Mat. Res. Bull., 38 (2003) 79.
[112] A. K. Prodjosantoso, B. J. Kennedy, ”Synthesis and Evolution of the Crystalline Phases in Ca1−xSrxAl2O4“, J. of Solid State Chem., 168 (2002) 229.