Page 589 - Book Hosokawa Nanoparticle Technology Handbook

33 DEVELOPMENT OF BRIGHT PHOSPHORS USING GLASSES APPLICATIONS
semiconductor nanoparticles and partially devices and markers using blue and ultraviolet
hydrolyzed TEOS (solution (1)) and a cyclohexane light-emitting diodes (LEDs) as excitation light
solution containing a nonionic surfactant Igepal sources that have recently come into wide use.
CO-520 (polyoxyethylene(5) nonylphenyl ether)
(solution (2)) are prepared. Mixing of solution (1)
with solution (2) results in the formation of inverse References
micelles involving small droplets of solution [1] M. Ando, C.L. Li and N. Murase: Monthly Display,
(1) because cyclohexane is a hydrophobic organic
solvent. Afterwards, hydrolysis of TEOS proceeds 10(8), 67–73 (2004).
and completes in inverse micelles in a relatively [2] N. Murase, K. Hirao: J. Soc. Powder Technol., Jpn.,
short time (several hours), leading to the formation 42(11), 790–798 (2005).
of highly photoluminescent small glass beads [18]. [3] M. Bruchez Jr., M. Moronne, P. Gin, S. Weiss and
The shortened reaction time results in the incorpo- A.P. Alivisatos: Science, 281, 2013–2016 (1998).
ration of nanoparticles in the small glass beads at [4] B.O. Dabbousi, J. Rodriguez-Viejo, F.V. Mikulec, J.R.
high concentration without deterioration. The PL Heine, H. Mattoussi, R. Ober, K.F. Jensen and M.G.
efficiencies of the green- and red-emitting small Bawendi: J. Phys. Chem. B, 101, 9463–9475 (1997).
glass beads incorporating CdTe nanoparticles [5] A.L. Rogach, L. Katsikas, A. Kornowski, D.Su,
reached 27% and 65%, respectively. These values A. Eychmüller and H. Weller: Ber. Bunsen-Ges. Phys.
were the same as those of the initial aqueous solu-
tions of the nanoparticles. Chem., 100, 1772–1778 (1996).
[6] C.L. Li, N. Murase: Langmuir, 20, 1–4 (2004).
(3) Preparation of glass film phosphors [7] C.L. Li, Murase: Chem. Lett., 34, 92–93 (2005).
Glass film phosphors incorporating highly [8] N. Murase, M.Y. Gao, N. Gaponik, T. Yazawa and
concentrated semiconductor nanoparticles can be pre- J. Feldmann: Int. J. Mod. Phys. B, 15, 3881–3884
pared by a layer-by-layer (LbL) self-assembly (2001).
method. In this method alkoxysilanes such as APS [9] N. Murase, M.Y. Gao: Mater. Lett., 58, 3898–3902
and 3-mercaptopropyltrimethoxysilane (MPS) are (2004).
used to link the layers of nanoparticles. A glass [10] K. Nishikawa, C.L. Li, H. Enomoto and N. Murase:
substrate coated with APS or MPS is dipped in an Annual Meeting of the Ceramic Society of Japan,
aqueous solution of nanoparticles and then in a
toluene solution of APS or MPS. By repeating these - 2005 (Okayama), Proceedings, p. 98 (2E02) (2005).
dip-coating processes, glass film phosphors having [11] C.L. Li, K. Nishikawa, M. Ando, H. Enomoto and
alternating layered structure of nanoparticles layers N. Murase: Colloid Surf. A, 294, 33–39 (2007).
and glass layers are obtained [21]. The glass film [12] M.Y. Gao, S. Kirstein, H. Möhwald, A.L. Rogach,
phosphors prepared were found to incorporate semi- A. Kornowski, A. Eychmüller and H. Weller: J. Phys.
conductor nanoparticles at very high concentrations Chem. B, 102, 8360–8363 (1998).
around 0.01 mol/l. It was possible to prepare glass [13] M. Ando, C.L. Li and N. Murase: Mater. Res. Soc.
film phosphors incorporating red- and green-emitting Symp. Proc., 789, 123–128 (2004).
CdTe nanoparticles and blue-emitting ZnSe nanopar- [14] S.T. Selvan, C. Bullen, M. Ashokkumar and
ticles. The PL efficiency of the red-emitting glass P. Mulvaney: Adv. Mater., 13, 985–988 (2001).
film phosphor was estimated to be ca. 24%.
[15] C.L. Li, M. Ando and N. Murase: Phys. Status Solidi C,
The authors have successfully synthesized group 0, 1250–1253 (2003).
II–VI semiconductor nanoparticles showing PL of [16] C.L. Li, M. Ando and N. Murase: J. Non-Cryst.
three primary colors (RGB) with high PL efficien- Solids, 342, 32–38 (2004).
cies by the aqueous solution method. Bright glass [17] S.T. Selvan, C.L. Li, M. Ando and N. Murase: Chem.
phosphors having three different forms (bulk, small Lett., 33, 434–435 (2004).
bead and thin film) incorporating the nanoparticles [18] P. Yang, M. Ando and N. Murase: 18th Fall Meeting of
were prepared by using sol–gel method, inverse the Ceramic Society of Japan (Sakai), Extended
micelle method and LbL self-assembly method. The Abstracts, p. 200 (1G05) (2005).
incorporation of semiconductor nanoparticles into [19] Y. Chan, J.P. Zimmer, M. Stroh, J.S. Steckel, R.K. Jain
glass matrices have improved the long-term stability
of nanoparticles, and retained strong PL that does and M.G. Bawendi: Adv. Mater., 16, 2092–2097 (2004).
not saturate easily when the excitation light inten- [20] D. Gerion, F. Pinaud, S.C. Williams, W.J. Parak,
sity is increased. Research and development of D. Zanchet, S. Weiss and A.P. Alivisatos: J. Phys.
glass phosphors that do not contain toxic Cd have Chem. B, 105, 8861–8871 (2001).
also been explained. These glass phosphors are [21] P. Yang, C.L. Li and N. Murase: Langmuir, 21,
expected to be applied to various luminescent 8913–8917 (2005).

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