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Enhanced luminescence and nonlinear optical properties of nanocomposites of ZnO–Cu

Published online by Cambridge University Press:  31 January 2011

Litty Irimpan ,
V.P.N. Nampoori  and
P. Radhakrishnan
Litty Irimpan*
Affiliation:
International School of Photonics, Cochin University of Science and Technology, Cochin, Kerala 682022, India
V.P.N. Nampoori
Affiliation:
International School of Photonics, Cochin University of Science and Technology, Cochin, Kerala 682022, India
P. Radhakrishnan
Affiliation:
International School of Photonics, Cochin University of Science and Technology, Cochin, Kerala 682022, India
*
a)Address all correspondence to this author. e-mail: [email protected]
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Abstract

In this article, we present the spectral and nonlinear optical properties of ZnO–Cu nanocomposites prepared by colloidal chemical synthesis. The emission consisted of two peaks. The 385-nm ultraviolet (UV) peak is attributed to ZnO and the 550-nm visible peak is attributed to Cu nanocolloids. Obvious enhancement of UV and visible emission of the samples is observed and the strongest UV emission of a typical ZnO–Cu nanocomposite is over three times stronger than that of pure ZnO. Cu acts as a sensitizer and the enhancement of UV emission are caused by excitons formed at the interface between Cu and ZnO. As the volume fraction of Cu increases beyond a particular value, the intensity of the UV peak decreases while the intensity of the visible peak increases, and the strongest visible emission of a typical ZnO–Cu nanocomposite is over ten times stronger than that of pure Cu. The emission mechanism is discussed. Nonlinear optical response of these samples is studied using nanosecond laser pulses from a tunable laser in the wavelength range of 450–650 nm, which includes the surface plasmon absorption (SPA) band. The nonlinear response is wavelength dependent and switching from reverse saturable absorption (RSA) to saturable absorption (SA) has been observed for Cu nanocolloids as the excitation wavelength changes from the low absorption window region to higher absorption regime near the SPA band. However, ZnO colloids and ZnO–Cu nanocomposites exhibit induced absorption at this wavelength. Such a changeover in the sign of the nonlinearity of ZnO–Cu nanocomposites, with respect to Cu nanocolloids, is related to the interplay of plasmon band bleach and optical limiting mechanisms. The SA again changes back to RSA when we move over to the infrared region. The ZnO–Cu nanocomposites show self-defocusing nonlinearity and good nonlinear absorption behavior. The nonlinear refractive index and the nonlinear absorption increases with increasing Cu volume fraction at 532 nm. The observed nonlinear absorption is explained through two-photon absorption followed by weak free-carrier absorption and interband absorption mechanisms. This study is important in identifying the spectral range and composition over which the nonlinear material acts as a RSA-based optical limiter. ZnO–Cu is a potential nanocomposite material for the light emission and for the development of nonlinear optical devices with a relatively small limiting threshold.

Keywords

CuLuminescenceNanoscale
Type
Articles
Information
Journal of Materials Research , Volume 23 , Issue 11 , November 2008 , pp. 2836 - 2845
Copyright
Copyright © Materials Research Society 2008

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References

REFERENCES

1Kayanuma, Y.: Quantum-size effects of interacting electrons and holes in semiconductor microcrystals with spherical shape. Phys. Rev. B: Condens. Matter 38, 9797 1988CrossRefGoogle ScholarPubMed
2Irimpan, L., Krishnan, B., Nampoori, V.P.N., Radhakrishnan, P.: Luminescence tuning and enhanced nonlinear optical properties of nanocomposites of ZnO–TiO2. J. Colloids Interface Sci. 324, 99 2008CrossRefGoogle ScholarPubMed
3Kreibig, U., Vollmer, M.: Optical Properties of Metal Clusters Springer Berlin 1995CrossRefGoogle Scholar
4Kraeutler, B., Bard, A.J.: Heterogeneous photocatalytic preparation of supported catalysts. Photodeposition of platinum on TiO2 powder and other substrates. J. Am. Chem. Soc. 100, 4317 1978CrossRefGoogle Scholar
5Sekino, T., Nakajima, T., Ueda, S., Niihara, K.: Reduction and sintering of a nickel-dispersed-alumina composite and its properties. J. Am. Ceram. Soc. 80(5), 1139 1997CrossRefGoogle Scholar
6Sun, Y., Riggs, J.E., Henbest, K.B., Martin, R.B.: Nanomaterials as optical limiters. J. Nonlinear Opt. Phys. Mater. 9, 481 2000CrossRefGoogle Scholar
7Uchida, K., Kaneko, S., Omi, S., Hata, C., Tanji, H., Asahara, Y., Ikushima, A.J., Tokizaki, T., Nakamura, A.: Optical nonlinearities of a high concentration of small metal particles dispersed in glass, copper and silver particles. J. Opt. Soc. Am. 11(7), 1236 1994CrossRefGoogle Scholar
8Irimpan, L., Deepthy, A., Krishnan, B., Nampoori, V.P.N., Radhakrishnan, P.: Size dependent fluorescence spectroscopy of nanocolloids of ZnO. J. Appl. Phys. 102, 063524 2007CrossRefGoogle Scholar
9Bagnall, D.M., Chen, Y.F., Zhu, Z., Yao, T., Koyama, S., Shen, M.Y., Goto, T.: Optically pumped lasing of ZnO at room temperature. Appl. Phys. Lett. 70, 2230 1997CrossRefGoogle Scholar
10Özgür, Ü., Alivov, Ya.I., Liu, C., Teke, A., Reshchikov, M.A., Doğan, S., Avrutin, V., Cho, S-J., Morkoç, H.: A comprehensive review of ZnO materials and devices. J. Appl. Phys. 98, 041301 2005CrossRefGoogle Scholar
11Tsukazaki, A., Ohtomo, A., Onuma, T., Ohtani, M., Makino, T., Sumiya, M., Ohtani, K., Chichibu, S.F., Fuke, S., Segawa, Y., Ohno, H., Koinuma, H., Kawasaki, M.: Repeated temperature modulation epitaxy for p-type doping and light-emitting diode based on ZnO. Nat. Mater. 4, 42 2005CrossRefGoogle Scholar
12Irimpan, L., Deepthy, A., Krishnan, B., Nampoori, V.P.N., Radhakrishnan, P.: Nonlinear optical characteristics of self assembled films of ZnO. Appl. Phys. B 90, 547 2008CrossRefGoogle Scholar
13Khosravi, A.A., Kundu, M., Jatwa, L., Deshpande, S.K., Bhagwat, U.A., Sastry, M., Kulkarni, S.K.: Green luminescence from copper doped zinc sulphide quantum particles. Appl. Phys. Lett. 67, 18 1995CrossRefGoogle Scholar
14Bahae, M.S., Said, A.A., van Stryland, E.W.: High-sensitivity, single-beam n 2 measurements. Opt. Lett. 14, 955 1989CrossRefGoogle Scholar
15Irimpan, L., Krishnan, B., Deepthy, A., Nampoori, V.P.N., Radhakrishnan, P.: Size dependent enhancement of nonlinear optical properties in nano colloids of ZnO. J. Appl. Phys. 103, 033105 2008CrossRefGoogle Scholar
16Moreno, D.L., Rosa-Cruz, E.D., Cuevas, F.J., Regalado, L.E., Salas, P., Rodriguez, R., Castano, V.M.: Refractive index measurement of pure and Er3+-doped ZrO2–SiO2 sol-gel film by using the Brewster angle technique. Opt. Mater. 19, 275 2002CrossRefGoogle Scholar
17Irimpan, L., Nampoori, V.P.N., Radhakrishnan, P.: Spectral and nonlinear optical characteristics of nanocomposites of ZnO–Ag. Chem. Phys. Lett. 455, 265 2008CrossRefGoogle Scholar
18Linnert, T., Mulvaney, P., Henglein, A.: Surface chemistry of colloidal silver: Surface plasmon damping by chemisorbed iodide, hydrosulfide (SH−), and phenylthiolate. J. Phys. Chem. 97, 679 1993CrossRefGoogle Scholar
19Stroyuk, A.L., Shvalagin, V.V., Kuchmii, S.Ya.: Photochemical synthesis, spectral-optical and electrophysical properties of composite nanoparticles of ZnO/Ag. Theor. Exp. Chem. 40(2), 98 2004CrossRefGoogle Scholar
20Duan, L., Lin, B., Zhang, W., Zhong, S., Fua, Z.: Enhancement of ultraviolet emissions from ZnO films by Ag doping. Appl. Phys. Lett. 88, 232110 2006CrossRefGoogle Scholar
21Irimpan, L., Krishnan, B., Nampoori, V.P.N., Radhakrishnan, P.: Linear and nonlinear optical characteristics of ZnO–SiO2 nanocomposites. Appl. Opt., 47, 4345 2008CrossRefGoogle ScholarPubMed
22Irimpan, L., Ambika, D., Kumar, V., Nampoori, V.P.N., Radhakrishnan, P.: Effect of annealing on the spectral and nonlinear optical characteristics of thin films of nano ZnO. J. Appl. Phys. 104, 033118 2008CrossRefGoogle Scholar
23Suzuki, A., Shionoya, S.: Mechanism of the green-copper luminescence in ZnS crystals. I. Direct evidence for the pair emission mechanism. J. Phys. Soc. Jpn. 31, 1455 1971CrossRefGoogle Scholar
24Peka, P., Schulz, H.J.: Empirical one-electron model of optical transitions in Cu-doped ZnS and CdS. Physica B (Amsterdam) 193, 57 1994CrossRefGoogle Scholar
25Khosravi, A.A., Kundu, M., Jatwa, L., Deshpande, S.K., Bhagwat, U.A., Sastry, M., Kulkarni, S.K.: Green luminescence from copper-doped zinc sulphide quantum particles. Appl. Phys. Lett. 67, 18 1995CrossRefGoogle Scholar
26Reisfeld, R., Eyal, M., Brusilovsky, D.: Luminescence enhancement of rhodamine 6G in sol-gel films containing silver aggregates. Chem. Phys. Lett. 153, 210 1988CrossRefGoogle Scholar
27Karthikeyan, B., Anija, M., Philip, R.: In situ synthesis and nonlinear optical properties of Au:Ag nanocomposite polymer films. Appl. Phys. Lett. 88, 053104 2006CrossRefGoogle Scholar
28Zhang, X.J., Ji, W., Tang, S.H.: Determination of optical nonlinearities and carrier lifetime in ZnO. J. Opt. Soc. Am. B 14, 1951 1997CrossRefGoogle Scholar
29Kamat, P.V., Flumiani, M., Hartland, G.V.: Picosecond dynamics of silver nanoclusters. Photoejection of electrons and fragmentation. J. Phys. Chem. B 102(7), 3123 1998CrossRefGoogle Scholar
30Philip, R., Kumar, G. Ravindra, Sandhyarani, N., Pradeep, T.: Picosecond optical nolinearity in monolayer-protected gold, silver, and gold-silver alloy nanoclusters. Phys. Rev. B: Condens. Matter 62(19), 13160 2000CrossRefGoogle Scholar
31Qu, S., Song, Y., Liu, H., Wang, Y., Gao, Y., Liu, S., Zhang, X., Li, Y., Zhu, D.: A theoretical and experimental study on optical limiting in platinum nanoparticles. Opt. Commun. 20, 3283 2002Google Scholar
32Karthikeyan, B., Thomas, J., Philip, R.: Optical nonlinearity in glass-embedded silver nanoclusters under ultrafast laser excitation. Chem. Phys. Lett. 414, 346 2005CrossRefGoogle Scholar
33Irimpan, L., Nampoori, V.P.N., Radhakrishnan, P.: Spectral and nonlinear optical characteristics of nanocomposites of ZnO–CdS. J. Appl. Phys. 103,, 094914 2008CrossRefGoogle Scholar
34Ahmadi, T.S., Logunov, S.L., El Sayed, M.A.: Picosecond dynamics of colloidal gold nano particles. J. Phys. Chem. 100, 8053 1996CrossRefGoogle Scholar
35Hamanaka, Y., Nakamura, A., Omi, S., Del Fatti, N., Vallee, F., Flytzanis, C.: Ultrafast response of nonlinear refractive index of silver nanocrystals embedded in glass. Appl. Phys. Lett. 75(12), 1712 1999CrossRefGoogle Scholar
36Gang, W., Yu, Z., Yiping, C., Muyun, D., Mi, L.: Study on the non-linear refraction of silver nanoparticles with aggregation effect. Opt. Commun. 249, 311 2005Google Scholar
37Kiran, P. Prem, De, G., Narayana Rao, D.: Nonlinear optical properties of copper and silver nanoclusters in SiO2 sol-gel films. IEEE Proc. Circuits Devices Syst., 150 (6), 559 2003CrossRefGoogle Scholar
38Yang, G., Guan, D., Wang, W., Wu, W., Chen, Z.: The inherent optical nonlinearities of thin silver films. Opt. Mater. 25(4), 439 2004CrossRefGoogle Scholar
39Han, M.Y., Huang, W., Chew, C.H., Gan, L.M., Zhang, X.J., Ji, W.: Large nonlinear absorption in coated Ag2S/CdS nanoparticles by inverse microemulsion. J. Phys. Chem. B 102, 1884 1998CrossRefGoogle Scholar
40Irimpan, L., Deepthy, A., Krishnan, B., Kukreja, L.M., Nampoori, V.P.N., Radhakrishnan, P.: Effect of self assembly on the nonlinear optical characteristics of ZnO thin films. Opt. Commun. 281, 2938 2008CrossRefGoogle Scholar
41Quereshi, F.M., Martin, S.J., Long, X., Bradley, D.D.C., Heneri, F.Z., Balu, W.J., Smith, E.C., Wang, C.H., Kar, A.K., Anderson, H.L.: Optical limiting properties of a zinc porphyrin polymer and its dimer and monomer model compounds. Chem. Phys. 231, 87 1998CrossRefGoogle Scholar
42Jia, E.P.W., Guo, D.F., Suna, W.: Optical limiting of semiconductor nanoparticles for nanosecond laser pulses. Appl. Phys. Lett. 85(26), 6326 2004CrossRefGoogle Scholar