- Email: [email protected]
Luminescence properties of Tb3+-doped PbO–Bi2O3–GeO2 glasses
March 2002
Materials Letters 53 Ž2002. 25–29 www.elsevier.comrlocatermatlet
Luminescence properties of Tb 3q-doped PbO–Bi 2 O 3 –GeO 2 glasses N. Sooraj Hussain, Y. Prabhakara Reddy, S. Buddhudu) Department of Physics, Sri Venkateswara UniÕersity, Tirupati 517 502, India Received 9 March 2001; accepted 10 May 2001
Abstract This paper reports the luminescence properties of Ž13 y x .PbO–25Bi 2 O 3 –62GeO 2 glasses doped with Tb 3q ions Ž x s 0.2, 0.5, 1.0, 1.5 and 2.0 mol%. that have been investigated upon excitation at lex s 248, 261, 352, 370 and 380 nm, respectively. At excitation wavelength of 370 nm, 1 mol% Tb 3q glass has shown an intense green emission and the photoluminescence spectral features have been analyzed. q 2002 Elsevier Science B.V. All rights reserved. Keywords: Terbium-doped lead–bismuth–germanate glasses
1. Introduction In the past decade, a great deal of research work has been carried out to identify new optical glasses having potential applications in glass laser technology w1,2x. These systems are very attractive because of the fact that those materials could be prepared in different shapes and sizes, which accept rare-earth ions without inducing any crystallization and such glasses display good optical transparency. In order to optimize the dopant rare-earth content and to confirm suitable excitation wavelength, photoluminescence spectra of these lead–bismuth–germanate glasses are considered important. Among the differ-
) Corresponding author. Tel.: q91-8574-28611; fax: q918574-27499. E-mail address: [email protected] ŽS. Buddhudu..
ent glasses studied earlier, it was reported that germanate glasses w3–5x have lesser influence on the vibrational frequencies compared to that of silicate, phosphate and borate glasses w6,7x. Lead germanate glasses are of particular interest since these can be readily made into fiber form for their use in optoelectronics w8x. Further germania-based glasses containing Pb and Bi oxides are more suitable for waveguide applications. Miller et al. w9x have observed that the glasses in the GeO 2 –PbO–Bi 2 O 3 compositions have significant Raman scattering cross-sections compared with the silica-based composition. A recent work by Wachtler et al. w10x reports optical characterization of Nd 3q ions binary lead–germanate glass, and Balda et al. w11x studied the optical properties of Nd 3q ions in six different compositions of glasses based on GeO 2 , PbO and Bi 2 O 3 by using steady state and time-resolved laser spectroscopy. In our laboratory, we have recently studied the luminescence properties of Eu3q-doped
00167-577Xr02r$ - see front matter q 2002 Elsevier Science B.V. All rights reserved. PII: S 0 1 6 7 - 5 7 7 X Ž 0 1 . 0 0 4 4 7 - 5
26
N. Sooraj Hussain et al.r Materials Letters 53 (2002) 25–29
GeO 2 –PbO–Bi 2 O 3 glasses w12x in five different europium concentrations. In the present work, we report the spectral analysis of Tb 3q-doped PbO– Bi 2 O 3 –GeO 2 glasses.
2. Experimental studies Lead–bismuth–germanate glasses in the following five chemical compositions of Ž13 y x .PbO– 25Bi 2 O 3 –62GeO 2 doped with terbium in different concentrations Ž x s 0.2, 0.5, 1.0, 1.5 and 2.0 mol% of Tb 3q . were prepared as was reported in our earlier paper w12x. The appropriate quantities of high purity Ž99.99%. chemicals of PbO, GeO 2 , Bi 2 O 3 and Tb 2 O 3 were melted in platinum crucible placed in a vertical tubular furnace at a temperature between 1100 and 1200 8C for about 1 h. Then, each of these melts was poured onto a steel plate and pressed with another steel plate in obtaining circular glass windows of 2–3 cm in diameter with a uniform thickness of 0.3 cm. These glasses were annealed at 450 8C for the removal of the stress present in the glass matrices. The glass density Ž d s 5.937 grcm3 . and refractive index Ž n d s 1.863. were obtained by employing the conventional procedures. The excitation and emission spectra of terbium glasses were recorded on a Spex Fluorolog-3 spectrofluorometer with a Xe lamp Ž450 W. and silicon photodiode Ž928. reference detector for steady state photoluminescence spectral measurements. A Xe flash lamp
Fig. 1. UV excitation spectrum of Tb 3q-doped Ž1 mol%. 12PbO– 25Bi 2 O 3 –62GeO 2 glass.
Fig. 2. Visible excitation spectrum of Tb 3q-doped Ž1 mol%. 12PbO–25Bi 2 O 3 –62GeO 2 glass.
was used to measure the lifetimes of the emission transitions of the terbium glasses. Double exponential fitting analysis was carried out in evaluating the lifetimes of the emission transitions by employing an original program.
3. Results and discussion The UV and near visible excitation spectra of Tb 3q-doped Ž1 mol%. Ž13 y x .PbO–25Bi 2 O 3 – 62GeO 2 glass are shown in Figs. 1 and 2. From these, the following five excitation transitions have
Fig. 3. Emission spectra of Ž x mol%. Tb 3q-doped Ž13y x .PbO– 25Bi 2 O 3 –62GeO 2 glasses with lex s 370 nm ŽXe source. with different concentrations.
N. Sooraj Hussain et al.r Materials Letters 53 (2002) 25–29
27
Table 2 Emission level effective bandwidth, D l p Žnm. and stimulated emission cross-section, spE Ž=10y2 1 cm2 . for the recorded green emission 5 D4 ™7 F5 at 542 nm of Tb 3q-doped 12PbO–25Bi 2 O 3 – 62GeO 2 glasses at different terbium concentrations with lex s 370 nm Chemical composition Žmol%.
Fig. 4. Excitation wavelength dependence on the green emission Ž5 D4 ™7 F5 at 542 nm. of Tb 3q-doped 12PbO–25Bi 2 O 3 –62GeO 2 glass at different excitation wavelengths.
been identified: 7 F6 ™5 K 8 Ž248 nm.; 5 F2 Ž261 nm.; D 2 Ž352 nm.; 5 L 10 Ž370 nm.; and 5 D 3 Ž380 nm.. Among these, 7 F6 ™5 L 10 Ž lex s 370 nm. excitation is more intense, hence, photoluminescence spectra were recorded with this excitation wavelength. Fig. 3 shows the luminescence spectra of the Tb 3q-doped Ž13 y x .PbO–25Bi 2 O 3 –62GeO 2 Žwhere x s 0.2, 0.5, 1.0, 1.5 and 2.0 mol% of Tb 3q . glasses upon excitation with lex s 370 nm, revealing the following four emission transitions: 5 D4 ™7 F6 Ž484 nm.; 7 F5 Ž542 nm.; 7 F4 Ž583 nm.; and 7 F3 Ž619 nm.. Among these, the green emission transition 5 D4 ™7 F5 at 542 nm is brighter. The emission intensities are observed to be increasing gradually from 0.2 to 1.0 mol% and above this concentration, the emission intensities are decreasing due to concentration quenching. Hence, 1.0 mol% of Tb 3q becomes an
12.8PbO–25Bi 2 O 3 – 62GeO 2 –0.2Tb 2 O 3 12.5PbO–25Bi 2 O 3 – 62GeO 2 –0.5Tb 2 O 3 12PbO–25Bi 2 O 3 – 62GeO 2 –1.0Tb 2 O 3 11.5PbO–25Bi 2 O 3 – 62GeO 2 –1.5Tb 2 O 3 11PbO–25Bi 2 O 3 – 62GeO 2 –2.0Tb 2 O 3
Green emission transition 5 D4 ™7 F5 Ž542 nm. D lp
spE
8.0
1.84
8.4
1.75
8.8
1.67
8.4
1.75
8.0
1.84
5
optimum concentration. Fig. 4 shows the excitation wavelength dependence on the green emission transition. Tables 1 and 2 summarize the results of the effective bandwidth Ž D l p . and stimulated emission cross-section Ž spE . of the green emission 5 D4 ™7 F5 at 542 nm of Tb 3q-doped lead–bismuth–germanate glasses at different excitation wavelengths and concentrations. The procedures used in evaluating these
Table 1 Effective bandwidth, D l p Žnm. and stimulated emission cross-section, spE Ž=10y2 1 cm2 . of the brighter green emission transition 5 D4 ™7 F5 at 542 nm of Tb 3q-doped Ž1 mol%. 12PbO–25Bi 2 O 3 – 62GeO 2 glass at different excitation wavelengths Emission parameter
Dl p spE
Excitation wavelengths UV region Visible region 248 nm
261 nm
352 nm
370 nm
380 nm
7 2.56
6 2.94
8 1.92
8 1.83
8 1.84
Fig. 5. Decay curves of the green emission Ž5 D4 ™7 F5 at 542 nm. of Tb 3q-doped 12PbO–25Bi 2 O 3 –62GeO 2 glass at different excitation wavelengths.
28
N. Sooraj Hussain et al.r Materials Letters 53 (2002) 25–29
parameters are similar to those used earlier by Reisfeld et al. w13x and others w14–16x. Table 1 presents the green emission transition cross-section values Ž spE . dependence on the dopant Tb 3q content change with a minimum emission cross-section value for 1.0 mol% Tb 3q-doped glass. For any further increase in the dopant content, the cross-section values are increasing correspondingly. Therefore, it is suggested that 1.0 mol% Tb 3q content is an optimum dopant content for brighter green luminescence from the lead–bismuth–germanate glasses studied. Table 2 presents the results in two ways. Firstly, under an UV excitation wavelength of 248 nm Ž7 F6 ™5 K 8 . as shown in Fig. 1, the green emission transition 5 D4 ™7 F5 Ž542 nm. reveals an emission cross-section of 2.56 = 10y2 1 cm2 . Secondly, such a similar trend is observed in the near visible wavelength region as shown in Fig. 2 at 370 nm Ž7 F6 ™5 L 10 . with an emission cross-section of 1.83 = 10y2 1 cm2 . Hence, it is suggested that the green emission cross-section Ž spE . value is significantly lower at lex s 370 nm compared with lex s 248 nm Ž7 F6 ™5 K 8 .. Fig. 5 reveals the decay curves of the green emission 5 D4 ™7 F5 at 542 nm of Tb 3q-doped lead– bismuth–germanate glasses with different excitation wavelengths, while Fig. 6 presents the decay curves of the emission transitions of 5 D4 ™7 F6,5,4,3 , and the fluorescence decay time data are given in Table 3. From Table 3, it is observed that the green colour emission Ž542 nm. shows a long lifetime of 3.55 ms
Table 3 Lifetimes, tm Žms. of the emission transitions 5 D4 ™7 F6,5,4,3 of Tb 3q-doped Ž1 mol%. 12PbO–25Bi 2 O 3 –62GeO 2 glass at different excitations wavelengths Emission transition
Emission wavelength Žnm.
Excitation wavelength Žnm.
Lifetime, tm Žms.
5
D4 ™7 F6 D4 ™7 F5
484 542
D4 ™7 F4 D4 ™7 F3
583 618
370 370 380 352 261 248 370 370
3.24 3.55 3.53 3.39 2.95 2.91 3.16 3.09
5
5 5
at lex s 370 nm among the different excitation wavelengths used.
4. Conclusion We have prepared five terbium-doped lead–bismuth–germanate glasses doped in evaluating its emission performance as a function of concentration change and also on the excitation wavelength change. Due to concentration quenching, the emission intensities decrease gradually beyond 1.0 mol% Tb 3q. Hence, it has been suggested as an ideal content for brighter green emission performance for these optical glasses, and lex s 370 nm as an ideal pump wavelength to observe prominent green emission.
References
Fig. 6. Decay curves of the emission transitions 5 D4 ™7 F6,5,4,3 of Tb 3q-doped 12PbO–25Bi 2 O 3 –62GeO 2 glass with lex s 370 nm.
w1x M.J. Weber, J. Non-Cryst. Solids 123 Ž1990. 208. w2x G. Blasse, J. Less-Common. Met. 112 Ž1985. 1. w3x R. Balda, J. Fernandez, A. de Pablos, M. Fdez-Navarro, J. Phys.: Condens. Matter 11 Ž1999. 7411. w4x Z. Pan, S.H. Morgan, A. Loper, V. King, B.H. Long, W.E. Collins, J. Appl. Phys. 77 Ž9. Ž1995. 4688. w5x M. Wachtler, A. Speghini, S. Pigorini, R. Rolli, M. Bettinelli, J. Non-Cryst. Solids 217 Ž1997. 111. w6x H. Verweij, J.H.J.M. Buster, J. Non-Cryst. Solids 34 Ž1999. 81. w7x S.J.L. Ribeiro, J. Dexpert-Ghys, B. Piriou, V.R. Mastelaro, J. Non-Cryst. Solids 159 Ž1993. 213. w8x D. Lezal, J. Pedlikova, J. Harak, J. Non-Cryst. Solids 196 Ž1996. 178.
N. Sooraj Hussain et al.r Materials Letters 53 (2002) 25–29 w9x A.E. Miller, K. Nassau, K.B. Lyons, M.E. Lines, J. NonCryst. Solids 99 Ž1988. 289. w10x M. Wachtler, A. Speghini, K. Gatterer, H.P. Fritzer, D. Ajo, M. Bettinelli, J. Am. Ceram. Soc. 81 Ž1998. 2045. w11x R. Balda, J. Fernandez, M. Sanz, A. de Pablos, J.M. FdezNavarro, J. Mugnier, Phys. Rev. B 61 Ž5. Ž2000. 3384. w12x N. Sooraj Hussain, Y. Prabhakara Reddy, S. Buddhudu, Mater. Res. Bull. 36 Ž10. Ž2001. in press.
29
w13x R. Reisfeld, E. Greenberg, R.N. Brown, M.G. Drexhage, Chem. Phys. Lett. 95 Ž1983. 91. w14x R. Cases, M.A. Chamarro, R. Alcala, V.D. Rodriguez, J. Lumin. 48r49 Ž1991. 509. w15x A. Shankar, A. Dasgupta, B. Basu, A. Paul, J. Mater. Sci. Lett. 4 Ž1983. 697. w16x M.A. Chamarro, R. Cases, R. Alcala, Ann. Phys. ŽParis. 16 Ž1991. 227.
Materials Letters 53 Ž2002. 25–29 www.elsevier.comrlocatermatlet
Luminescence properties of Tb 3q-doped PbO–Bi 2 O 3 –GeO 2 glasses N. Sooraj Hussain, Y. Prabhakara Reddy, S. Buddhudu) Department of Physics, Sri Venkateswara UniÕersity, Tirupati 517 502, India Received 9 March 2001; accepted 10 May 2001
Abstract This paper reports the luminescence properties of Ž13 y x .PbO–25Bi 2 O 3 –62GeO 2 glasses doped with Tb 3q ions Ž x s 0.2, 0.5, 1.0, 1.5 and 2.0 mol%. that have been investigated upon excitation at lex s 248, 261, 352, 370 and 380 nm, respectively. At excitation wavelength of 370 nm, 1 mol% Tb 3q glass has shown an intense green emission and the photoluminescence spectral features have been analyzed. q 2002 Elsevier Science B.V. All rights reserved. Keywords: Terbium-doped lead–bismuth–germanate glasses
1. Introduction In the past decade, a great deal of research work has been carried out to identify new optical glasses having potential applications in glass laser technology w1,2x. These systems are very attractive because of the fact that those materials could be prepared in different shapes and sizes, which accept rare-earth ions without inducing any crystallization and such glasses display good optical transparency. In order to optimize the dopant rare-earth content and to confirm suitable excitation wavelength, photoluminescence spectra of these lead–bismuth–germanate glasses are considered important. Among the differ-
) Corresponding author. Tel.: q91-8574-28611; fax: q918574-27499. E-mail address: [email protected] ŽS. Buddhudu..
ent glasses studied earlier, it was reported that germanate glasses w3–5x have lesser influence on the vibrational frequencies compared to that of silicate, phosphate and borate glasses w6,7x. Lead germanate glasses are of particular interest since these can be readily made into fiber form for their use in optoelectronics w8x. Further germania-based glasses containing Pb and Bi oxides are more suitable for waveguide applications. Miller et al. w9x have observed that the glasses in the GeO 2 –PbO–Bi 2 O 3 compositions have significant Raman scattering cross-sections compared with the silica-based composition. A recent work by Wachtler et al. w10x reports optical characterization of Nd 3q ions binary lead–germanate glass, and Balda et al. w11x studied the optical properties of Nd 3q ions in six different compositions of glasses based on GeO 2 , PbO and Bi 2 O 3 by using steady state and time-resolved laser spectroscopy. In our laboratory, we have recently studied the luminescence properties of Eu3q-doped
00167-577Xr02r$ - see front matter q 2002 Elsevier Science B.V. All rights reserved. PII: S 0 1 6 7 - 5 7 7 X Ž 0 1 . 0 0 4 4 7 - 5
26
N. Sooraj Hussain et al.r Materials Letters 53 (2002) 25–29
GeO 2 –PbO–Bi 2 O 3 glasses w12x in five different europium concentrations. In the present work, we report the spectral analysis of Tb 3q-doped PbO– Bi 2 O 3 –GeO 2 glasses.
2. Experimental studies Lead–bismuth–germanate glasses in the following five chemical compositions of Ž13 y x .PbO– 25Bi 2 O 3 –62GeO 2 doped with terbium in different concentrations Ž x s 0.2, 0.5, 1.0, 1.5 and 2.0 mol% of Tb 3q . were prepared as was reported in our earlier paper w12x. The appropriate quantities of high purity Ž99.99%. chemicals of PbO, GeO 2 , Bi 2 O 3 and Tb 2 O 3 were melted in platinum crucible placed in a vertical tubular furnace at a temperature between 1100 and 1200 8C for about 1 h. Then, each of these melts was poured onto a steel plate and pressed with another steel plate in obtaining circular glass windows of 2–3 cm in diameter with a uniform thickness of 0.3 cm. These glasses were annealed at 450 8C for the removal of the stress present in the glass matrices. The glass density Ž d s 5.937 grcm3 . and refractive index Ž n d s 1.863. were obtained by employing the conventional procedures. The excitation and emission spectra of terbium glasses were recorded on a Spex Fluorolog-3 spectrofluorometer with a Xe lamp Ž450 W. and silicon photodiode Ž928. reference detector for steady state photoluminescence spectral measurements. A Xe flash lamp
Fig. 1. UV excitation spectrum of Tb 3q-doped Ž1 mol%. 12PbO– 25Bi 2 O 3 –62GeO 2 glass.
Fig. 2. Visible excitation spectrum of Tb 3q-doped Ž1 mol%. 12PbO–25Bi 2 O 3 –62GeO 2 glass.
was used to measure the lifetimes of the emission transitions of the terbium glasses. Double exponential fitting analysis was carried out in evaluating the lifetimes of the emission transitions by employing an original program.
3. Results and discussion The UV and near visible excitation spectra of Tb 3q-doped Ž1 mol%. Ž13 y x .PbO–25Bi 2 O 3 – 62GeO 2 glass are shown in Figs. 1 and 2. From these, the following five excitation transitions have
Fig. 3. Emission spectra of Ž x mol%. Tb 3q-doped Ž13y x .PbO– 25Bi 2 O 3 –62GeO 2 glasses with lex s 370 nm ŽXe source. with different concentrations.
N. Sooraj Hussain et al.r Materials Letters 53 (2002) 25–29
27
Table 2 Emission level effective bandwidth, D l p Žnm. and stimulated emission cross-section, spE Ž=10y2 1 cm2 . for the recorded green emission 5 D4 ™7 F5 at 542 nm of Tb 3q-doped 12PbO–25Bi 2 O 3 – 62GeO 2 glasses at different terbium concentrations with lex s 370 nm Chemical composition Žmol%.
Fig. 4. Excitation wavelength dependence on the green emission Ž5 D4 ™7 F5 at 542 nm. of Tb 3q-doped 12PbO–25Bi 2 O 3 –62GeO 2 glass at different excitation wavelengths.
been identified: 7 F6 ™5 K 8 Ž248 nm.; 5 F2 Ž261 nm.; D 2 Ž352 nm.; 5 L 10 Ž370 nm.; and 5 D 3 Ž380 nm.. Among these, 7 F6 ™5 L 10 Ž lex s 370 nm. excitation is more intense, hence, photoluminescence spectra were recorded with this excitation wavelength. Fig. 3 shows the luminescence spectra of the Tb 3q-doped Ž13 y x .PbO–25Bi 2 O 3 –62GeO 2 Žwhere x s 0.2, 0.5, 1.0, 1.5 and 2.0 mol% of Tb 3q . glasses upon excitation with lex s 370 nm, revealing the following four emission transitions: 5 D4 ™7 F6 Ž484 nm.; 7 F5 Ž542 nm.; 7 F4 Ž583 nm.; and 7 F3 Ž619 nm.. Among these, the green emission transition 5 D4 ™7 F5 at 542 nm is brighter. The emission intensities are observed to be increasing gradually from 0.2 to 1.0 mol% and above this concentration, the emission intensities are decreasing due to concentration quenching. Hence, 1.0 mol% of Tb 3q becomes an
12.8PbO–25Bi 2 O 3 – 62GeO 2 –0.2Tb 2 O 3 12.5PbO–25Bi 2 O 3 – 62GeO 2 –0.5Tb 2 O 3 12PbO–25Bi 2 O 3 – 62GeO 2 –1.0Tb 2 O 3 11.5PbO–25Bi 2 O 3 – 62GeO 2 –1.5Tb 2 O 3 11PbO–25Bi 2 O 3 – 62GeO 2 –2.0Tb 2 O 3
Green emission transition 5 D4 ™7 F5 Ž542 nm. D lp
spE
8.0
1.84
8.4
1.75
8.8
1.67
8.4
1.75
8.0
1.84
5
optimum concentration. Fig. 4 shows the excitation wavelength dependence on the green emission transition. Tables 1 and 2 summarize the results of the effective bandwidth Ž D l p . and stimulated emission cross-section Ž spE . of the green emission 5 D4 ™7 F5 at 542 nm of Tb 3q-doped lead–bismuth–germanate glasses at different excitation wavelengths and concentrations. The procedures used in evaluating these
Table 1 Effective bandwidth, D l p Žnm. and stimulated emission cross-section, spE Ž=10y2 1 cm2 . of the brighter green emission transition 5 D4 ™7 F5 at 542 nm of Tb 3q-doped Ž1 mol%. 12PbO–25Bi 2 O 3 – 62GeO 2 glass at different excitation wavelengths Emission parameter
Dl p spE
Excitation wavelengths UV region Visible region 248 nm
261 nm
352 nm
370 nm
380 nm
7 2.56
6 2.94
8 1.92
8 1.83
8 1.84
Fig. 5. Decay curves of the green emission Ž5 D4 ™7 F5 at 542 nm. of Tb 3q-doped 12PbO–25Bi 2 O 3 –62GeO 2 glass at different excitation wavelengths.
28
N. Sooraj Hussain et al.r Materials Letters 53 (2002) 25–29
parameters are similar to those used earlier by Reisfeld et al. w13x and others w14–16x. Table 1 presents the green emission transition cross-section values Ž spE . dependence on the dopant Tb 3q content change with a minimum emission cross-section value for 1.0 mol% Tb 3q-doped glass. For any further increase in the dopant content, the cross-section values are increasing correspondingly. Therefore, it is suggested that 1.0 mol% Tb 3q content is an optimum dopant content for brighter green luminescence from the lead–bismuth–germanate glasses studied. Table 2 presents the results in two ways. Firstly, under an UV excitation wavelength of 248 nm Ž7 F6 ™5 K 8 . as shown in Fig. 1, the green emission transition 5 D4 ™7 F5 Ž542 nm. reveals an emission cross-section of 2.56 = 10y2 1 cm2 . Secondly, such a similar trend is observed in the near visible wavelength region as shown in Fig. 2 at 370 nm Ž7 F6 ™5 L 10 . with an emission cross-section of 1.83 = 10y2 1 cm2 . Hence, it is suggested that the green emission cross-section Ž spE . value is significantly lower at lex s 370 nm compared with lex s 248 nm Ž7 F6 ™5 K 8 .. Fig. 5 reveals the decay curves of the green emission 5 D4 ™7 F5 at 542 nm of Tb 3q-doped lead– bismuth–germanate glasses with different excitation wavelengths, while Fig. 6 presents the decay curves of the emission transitions of 5 D4 ™7 F6,5,4,3 , and the fluorescence decay time data are given in Table 3. From Table 3, it is observed that the green colour emission Ž542 nm. shows a long lifetime of 3.55 ms
Table 3 Lifetimes, tm Žms. of the emission transitions 5 D4 ™7 F6,5,4,3 of Tb 3q-doped Ž1 mol%. 12PbO–25Bi 2 O 3 –62GeO 2 glass at different excitations wavelengths Emission transition
Emission wavelength Žnm.
Excitation wavelength Žnm.
Lifetime, tm Žms.
5
D4 ™7 F6 D4 ™7 F5
484 542
D4 ™7 F4 D4 ™7 F3
583 618
370 370 380 352 261 248 370 370
3.24 3.55 3.53 3.39 2.95 2.91 3.16 3.09
5
5 5
at lex s 370 nm among the different excitation wavelengths used.
4. Conclusion We have prepared five terbium-doped lead–bismuth–germanate glasses doped in evaluating its emission performance as a function of concentration change and also on the excitation wavelength change. Due to concentration quenching, the emission intensities decrease gradually beyond 1.0 mol% Tb 3q. Hence, it has been suggested as an ideal content for brighter green emission performance for these optical glasses, and lex s 370 nm as an ideal pump wavelength to observe prominent green emission.
References
Fig. 6. Decay curves of the emission transitions 5 D4 ™7 F6,5,4,3 of Tb 3q-doped 12PbO–25Bi 2 O 3 –62GeO 2 glass with lex s 370 nm.
w1x M.J. Weber, J. Non-Cryst. Solids 123 Ž1990. 208. w2x G. Blasse, J. Less-Common. Met. 112 Ž1985. 1. w3x R. Balda, J. Fernandez, A. de Pablos, M. Fdez-Navarro, J. Phys.: Condens. Matter 11 Ž1999. 7411. w4x Z. Pan, S.H. Morgan, A. Loper, V. King, B.H. Long, W.E. Collins, J. Appl. Phys. 77 Ž9. Ž1995. 4688. w5x M. Wachtler, A. Speghini, S. Pigorini, R. Rolli, M. Bettinelli, J. Non-Cryst. Solids 217 Ž1997. 111. w6x H. Verweij, J.H.J.M. Buster, J. Non-Cryst. Solids 34 Ž1999. 81. w7x S.J.L. Ribeiro, J. Dexpert-Ghys, B. Piriou, V.R. Mastelaro, J. Non-Cryst. Solids 159 Ž1993. 213. w8x D. Lezal, J. Pedlikova, J. Harak, J. Non-Cryst. Solids 196 Ž1996. 178.
N. Sooraj Hussain et al.r Materials Letters 53 (2002) 25–29 w9x A.E. Miller, K. Nassau, K.B. Lyons, M.E. Lines, J. NonCryst. Solids 99 Ž1988. 289. w10x M. Wachtler, A. Speghini, K. Gatterer, H.P. Fritzer, D. Ajo, M. Bettinelli, J. Am. Ceram. Soc. 81 Ž1998. 2045. w11x R. Balda, J. Fernandez, M. Sanz, A. de Pablos, J.M. FdezNavarro, J. Mugnier, Phys. Rev. B 61 Ž5. Ž2000. 3384. w12x N. Sooraj Hussain, Y. Prabhakara Reddy, S. Buddhudu, Mater. Res. Bull. 36 Ž10. Ž2001. in press.
29
w13x R. Reisfeld, E. Greenberg, R.N. Brown, M.G. Drexhage, Chem. Phys. Lett. 95 Ž1983. 91. w14x R. Cases, M.A. Chamarro, R. Alcala, V.D. Rodriguez, J. Lumin. 48r49 Ž1991. 509. w15x A. Shankar, A. Dasgupta, B. Basu, A. Paul, J. Mater. Sci. Lett. 4 Ž1983. 697. w16x M.A. Chamarro, R. Cases, R. Alcala, Ann. Phys. ŽParis. 16 Ž1991. 227.