Size-Dependent Non-FRET Photoluminescence Quenching in Nanocomposites Based on Semiconductor Quantum Dots CdSe/ZnS and Functionalized Porphyrin Ligands
We review recent experimental work to utilize the size dependence of the luminescence quenching of colloidal semiconductor quantum dots induced by functionalized porphyrin molecules attached to the surface to describe a photoluminescence (PL) quenching process which is different from usual models of charge transfer (CT) or Foerster resonant energy transfer (FRET). Steady-state and picosecond time-resolved measurements were carried out for nanocomposites based on colloidal CdSe/ZnS and CdSe quantum dots (QDs) of various sizes and surfacely attached tetra-mesopyridyl-substituted porphyrin molecules (“Quantum Dot-Porphyrin” nanocomposites), in toluene at 295？K. It was found that the major part of the observed strong quenching of QD PL in “QD-Porphyrin” nanocomposites can neither be assigned to FRET nor to photoinduced charge transfer between the QD and the chromophore. This PL quenching depends on QD size and shell and is stronger for smaller quantum dots: QD PL quenching rate constants scale inversely with the QD diameter. Based on the comparison of experimental data and quantum mechanical calculations, it has been concluded that QD PL quenching in “QD-Porphyrin” nanocomposites can be understood in terms of a tunneling of the electron (of the excited electron-hole pair) followed by a (self-) localization of the electron or formation of trap states. The major contribution to PL quenching is found to be proportional to the calculated quantum-confined exciton wave function at the QD surface. Our findings highlight that single functionalized molecules can be considered as one of the probes for the complex interface physics and dynamics of colloidal semiconductor QD. 1. Introduction Semiconductor quantum dots (QD), also known as “nanocrystals,” are structures with electronic and optical properties that can be engineered through the size of the structure, not just the composition. During the past decade, colloidal QDs from II–VI semiconductor materials such as CdSe have gained considerable interest due to their physical properties originating from quantum confinement [1–4]. Quantum confinement of charge carriers leads to a wide range of intriguing physical and chemical phenomena and is a new degree of freedom in material design. For instance, advances in the synthesis of semiconductor QDs with controllable size, shape, and optical properties as well as the hybridization of QDs with functional organic ligands make them promising materials for a diverse range of applications including photovoltaics and light emitting devices [3, 5–7], quantum computing [8],
References
[1]
A. P. Alivisatos, “Semiconductor clusters, nanocrystals, and quantum dots,” Science, vol. 271, no. 5251, pp. 933–937, 1996.
[2]
V. Klimov, Nanocrystall Quantum Dots, CRS Press LLC, Washington, DC, USA, 2010.
[3]
A. L. Rogach, Ed., Semiconductor Nanocrystal Quantum Dots (Synthesis, Assembly, Spectroscopy and Applications), Springer, Wien, Austria, 2008.
[4]
S. V. Gaponenko, Optical Properties of Semiconductor Nanocrystals, Cambridge University Press, Cambridge, UK, 2005.
[5]
I. Gur, N. A. Fromer, C. P. Chen, A. G. Kanaras, and A. P. Alivisatos, “Hybrid solar cells with prescribed nanoscale morphologies based on hyperbranched semiconductor nanocrystals,” Nano Letters, vol. 7, no. 2, pp. 409–414, 2007.
[6]
R. Kniprath, J. P. Rabe, J. T. McLeskey, D. Wang, and S. Kirstein, “Hybrid photovoltaic cells with II-VI quantum dot sensitizers fabricated by layer-by-layer deposition of water-soluble components,” Thin Solid Films, vol. 518, no. 1, pp. 295–298, 2009.
[7]
L. Liu, J. Hensel, R. C. Fitzmorris, Y. Li, and J. Z. Zhang, “Preparation and photoelectrochemical properties of CdSe/TiO2 hybrid mesoporous structures,” Journal of Physical Chemistry Letters, vol. 1, no. 1, pp. 155–160, 2010.
[8]
J. R. Petta, A. C. Johnson, J. M. Taylor et al., “Applied physics: coherent manipulation of coupled electron spins in semiconductor quantum dots,” Science, vol. 309, no. 5744, pp. 2180–2184, 2005.
[9]
M. De, P. S. Ghosh, and V. M. Rotello, “Applications of nanoparticles in biology,” Advanced Materials, vol. 20, no. 22, pp. 4225–4241, 2008.
[10]
R. Gill, M. Zayatz, and I. Wilner, “Halbleiterquantenpunkte für die bioanalyse,” Angewandte Chemie, vol. 120, no. 40, pp. 7714–7736, 2008.
[11]
M. F. Frasco, V. Vamvakaki, and N. Chaniotakis, “Porphyrin decorated CdSe quantum dots for direct fluorescent sensing of metal ions,” Journal of Nanoparticle Research, vol. 12, no. 4, pp. 1449–1458, 2010.
[12]
B. Zhang, X. Liang, L. Hao et al., “Quantum dots/particle-based immunofluorescence assay: synthesis, characterization and application,” Journal of Photochemistry and Photobiology B, vol. 94, no. 1, pp. 45–50, 2009.
[13]
M. McDowell, A. E. Wright, and N. I. Hammer, “Semiconductor nanocrystals hybridized with functional ligands: new composite materials with tunable properties,” Materials, vol. 3, no. 1, pp. 614–637, 2010.
[14]
A. C. S. Samia, S. Dayal, and C. Burda, “Quantum dot-based energy transfer: perspectives and potential for applications in photodynamic therapy,” Photochemistry and Photobiology, vol. 82, no. 3, pp. 617–625, 2006.
[15]
J. M. Tsay, M. Trzoss, L. Shi et al., “Singlet oxygen production by peptide-coated quantum dot-photosensitizer conjugates,” Journal of the American Chemical Society, vol. 129, no. 21, pp. 6865–6871, 2007.
[16]
J. Ma, J. Y. Chen, M. Idowu, and T. Nyokong, “Generation of singlet oxygen via the composites of water-soluble thiol-capped CdTe quantum dots-sulfonated aluminum phthalocyanines,” Journal of Physical Chemistry B, vol. 112, no. 15, pp. 4465–4469, 2008.
[17]
P. Juzenas, W. Chen, Y. P. Sun et al., “Quantum dots and nanoparticles for photodynamic and radiation therapies of cancer,” Advanced Drug Delivery Reviews, vol. 60, no. 15, pp. 1600–1614, 2008.
[18]
A. Rakovich, T. Rakovich, V. Kelly et al., “Photosensitizer methylene blue-semiconductor nanocrystals hybrid system for photodynamic therapy,” Journal of Nanoscience and Nanotechnology, vol. 10, no. 4, pp. 2656–2662, 2010.
[19]
M. Anni, L. Manna, R. Cingolani, D. Valerini, A. Cretí, and M. Lomascolo, “F？rster energy transfer from blue-emitting polymers to colloidal CdSe/ZnS core shell quantum dots,” Applied Physics Letters, vol. 85, no. 18, pp. 4169–4171, 2004.
[20]
M. Sykora, M. A. Petruska, J. Alstrum-Acevedo, I. Bezel, T. J. Meyer, and V. I. Klimov, “Photoinduced charge transfer between CdSe nanocrystal quantum dots and Ru-polypyridine complexes,” Journal of the American Chemical Society, vol. 128, no. 31, pp. 9984–9985, 2006.
[21]
I. Potapova, R. Mruk, C. Hübner, R. Zentel, T. Basché, and A. Mews, “CdSe/ZnS nanocrystals with dye-functionalized polymer ligands containing many anchor goups,” Angewandte Chemie, vol. 117, pp. 2490–2493, 2005.
[22]
A. R. Clapp, I. L. Medintz, J. M. Mauro, B. R. Fisher, M. G. Bawendi, and H. Mattoussi, “Fluorescence resonance energy transfer between quantum dot donors and dye-labeled protein acceptors,” Journal of the American Chemical Society, vol. 126, no. 1, pp. 301–310, 2004.
[23]
A. J. Morris-Cohen, M. D. Donakowski, K. E. Knowles, and E. A. Weiss, “The effect of a common purification procedure on the chemical composition of the surfaces of CdSe quantum dots synthesized with trioctylphosphine oxide (TOPO),” Journal of Physical Chemistry C, vol. 114, no. 2, pp. 897–906, 2010.
[24]
K. E. Knowles, D. B. Tice, E. A. McArthur, G. C. Solomon, and E. A. Weiss, “Chemical control of the photoluminescence of CdSe quantum dot-organic complexes with a series of p-substituted aniline ligands,” Journal of the American Chemical Society, vol. 132, no. 3, pp. 1041–1050, 2010.
[25]
E. I. Zenkevich, A. M. Shulga, T. Blaudeck, F. Cichos, and C. von Borczyskowski, “Physics, chemistry and applications of nanostructures,” in Reviews and Short Notes to Nanomeeting, V. I. Borisenko, S. V. Gaponenko, and V. S. Gurin, Eds., vol. 367, p. 367, World Scientific, Singapore, 2005.
[26]
E. I. Zenkevich, T. Blaudeck, A. M. Shulga, F. Cichos, and C. von Borczyskowski, “Identification and assignment of porphyrin-CdSe hetero-nanoassemblies,” Journal of Luminescence, vol. 122-123, no. 1-2, pp. 784–788, 2007.
[27]
T. C. Lim, V. J. Bailey, Y. P. Ho, and T. H. Wang, “Intercalating dye as an acceptor in quantum-dot-mediated FRET,” Nanotechnology, vol. 19, no. 7, Article ID 075701, 2008.
[28]
A. De La Escosura-Mu？iz, C. Parolo, and A. Merkoi, “Immunosensing using nanoparticles,” Materials Today, vol. 13, no. 7-8, pp. 24–34, 2010.
[29]
M. Wang, S. J. Moon, M. Xu et al., “Efficient and stable solid-state dye-sensitized solar cells based on a high-molar-extinction-coefficient sensitizer,” Small, vol. 6, no. 2, pp. 319–324, 2010.
[30]
I. L. Medintz, M. H. Stewart, S. A. Trammell et al., “Quantum-dot/dopamine bioconjugates function as redox coupled assemblies for in vitro and intracellular pH sensing,” Nature Materials, vol. 9, no. 8, pp. 676–684, 2010.
[31]
O. Labeau, P. Tamarat, and B. Lounis, “Temperature dependence of the luminescence lifetime of single CdSe/ZnS quantum dots,” Physical Review Letters, vol. 90, no. 25, pp. 2574041–2574044, 2003.
[32]
S. F. Wuister, C. De Mello Donegá, and A. Meijerink, “Influence of thiol capping on the exciton luminescence and decay kinetics of CdTe and CdSe quantum dots,” Journal of Physical Chemistry B, vol. 108, no. 45, pp. 17393–17397, 2004.
[33]
J. Frenzel, J.-O. Joswig, and G. Seifert, “Optical excitations in cadmium sulfide nanoparticles,” Journal of Physical Chemistry C, vol. 111, no. 29, pp. 10761–10770, 2007.
[34]
M. Liras, M. Gonzalez-Bejar, and J. C. Scaiano, “On-off QD switch that memorizes past recovery from quenching by diazonium salts,” Physical Chemistry Chemical Physics, vol. 12, no. 33, pp. 9757–9762, 2010.
[35]
C. A. Leatherdale and M. G. Bawendi, “Observation of solvatochromism in CdSe colloidal quantum dots,” Physical Review B, vol. 63, no. 16, Article ID 165315, pp. 1–6, 2001.
[36]
O. Schmelz, A. Mews, T. Basché, A. Herrmann, and K. Müllen, “Supramolecular complexes from CdSe nanocrystals and organic fluorophors,” Langmuir, vol. 17, no. 9, pp. 2861–2865, 2001.
[37]
A. Boulesbaa, A. Issac, D. Stockwell et al., “Ultrafast charge separation at CdS quantum dot/rhodamine B molecule interface,” Journal of the American Chemical Society, vol. 129, no. 49, pp. 15132–15133, 2007.
[38]
A. Issac, S. Jin, and T. Lian, “Intermittent electron transfer activity from single CdSe/ZnS quantum dots,” Journal of the American Chemical Society, vol. 130, no. 34, pp. 11280–11281, 2008.
[39]
S. Dayal, R. Królicki, Y. Lou et al., “Femtosecond time-resolved energy transfer from CdSe nanoparticles to phthalocyanines,” Applied Physics B, vol. 84, no. 1-2, pp. 309–315, 2006.
[40]
E. I. Zen'kevich, E. I. Sagun, A. A. Yarovoi et al., “Photoinduced relaxation processes in complexes based on semiconductor CdSe nanocrystals and organic molecules,” Optics and Spectroscopy, vol. 103, no. 6, pp. 958–968, 2007.
[41]
A. R. Clapp, I. L. Medintz, B. R. Fisher, G. P. Anderson, and H. Mattoussi, “Can luminescent quantum dots be efficient energy acceptors with organic dye donors?” Journal of the American Chemical Society, vol. 127, no. 4, pp. 1242–1250, 2005.
[42]
S. Dayal, Y. Lou, A. C. S. Samia, J. C. Berlin, M. E. Kenney, and C. Burda, “Observation of non-f？rster-type energy-transfer behavior in quantum dot-phthalocyanine conjugates,” Journal of the American Chemical Society, vol. 128, no. 43, pp. 13974–13975, 2006.
[43]
E. I. Zenkevich, E. I. Zenkevich, and A. A. Yarovoi, “Physics, chemistry and applications of nanostructures,” in Reviews and Short Notes to Nanomeeting, V. I. Borisenko, S. V. Gaponenko, and V. S. Gurin, Eds., p. 140, World Scientific, London, UK, 2007.
[44]
T. Ren, P. K. Mandal, W. Erker, et al., “A simple and versatile route to stable quantum dot-dye hybrids in nonaqueous and aqueous solutions,” Journal of the American Chemical Society, vol. 130, no. 51, p. 17242, 2008.
[45]
J. E. Halpert, J. R. Tischler, G. Nair et al., “Electrostatic formation of quantum dot/J-aggregate FRET pairs in solution,” Journal of Physical Chemistry C, vol. 113, no. 23, pp. 9986–9992, 2009.
[46]
J. Lee, H. J. Kim, T. Chen et al., “Control of energy transfer to cdte nanowires via conjugated polymer orientation,” Journal of Physical Chemistry C, vol. 113, no. 1, pp. 109–116, 2009.
[47]
D. Kowerko, S. Krause, N. Amecke, M. Abdel-Mottaleb, J. Schuster, and C. Von Borczyskowski, “Identification of different donor-acceptor structures via F？rster Resonance Energy Transfer (FRET) in quantum-dot-perylene bisimide assemblies,” International Journal of Molecular Sciences, vol. 10, no. 12, pp. 5239–5256, 2009.
[48]
D. Kowerko, J. Schuster, N. Amecke et al., “FRET and ligand related NON-FRET processes in single quantum dot-perylene bisimide assemblies,” Physical Chemistry Chemical Physics, vol. 12, no. 16, pp. 4112–4123, 2010.
[49]
C. Burda, T. C. Green, S. Link, and M. A. El-Sayed, “Electron shuttling across the interface of CdSe nanoparticles monitored by femtosecond laser spectroscopy,” Journal of Physical Chemistry B, vol. 103, no. 11, pp. 1783–1788, 1999.
[50]
M. Sykora, M. A. Petruska, J. Alstrum-Acevedo, I. Bezel, T. J. Meyer, and V. I. Klimov, “Photoinduced charge transfer between CdSe nanocrystal quantum dots and Ru-polypyridine complexes,” Journal of the American Chemical Society, vol. 128, no. 31, pp. 9984–9985, 2006.
[51]
S. Rakshit and S. Vasudevan, “Spectrally resolved resonance energy transfer from ZnO:MgO nanocrystals,” Journal of Physical Chemistry C, vol. 113, no. 37, pp. 16424–16431, 2009.
[52]
J. Lee, H. J. Kim, T. Chen et al., “Control of energy transfer to cdte nanowires via conjugated polymer orientation,” Journal of Physical Chemistry C, vol. 113, no. 1, pp. 109–116, 2009.
[53]
M. A. Jhonsi and R. Renganathan, “Investigations on the photoinduced interaction of water soluble thioglycolic acid (TGA) capped CdTe quantum dots with certain porphyrins,” Journal of Colloid and Interface Science, vol. 344, no. 2, pp. 596–602, 2010.
[54]
T. Pons, I. L. Medintz, X. Wang, D. S. English, and H. Mattoussi, “Solution-phase single quantum dot fluorescence resonance energy transfer,” Journal of the American Chemical Society, vol. 128, no. 47, pp. 15324–15331, 2006.
[55]
A. O. Orlova, M. S. Gubanova, V. G. Maslov, et al., “Spektral'no-lyuminestsentnye svoistva kompleksov, obrazovannykh odnoimenno zaryazhennymi cdte kvantovymi tochkami i molekulami tetrasul'foftalotsianina,” Optika I Spectroscopiya, vol. 6, no. 108, pp. 975–982, 2010 (Russian).
[56]
A. Issac, C. Von Borczyskowski, and F. Cichos, “Correlation between photoluminescence intermittency of CdSe quantum dots and self-trapped states in dielectric media,” Physical Review B, vol. 71, Article ID 161302, 2005.
[57]
C. Bullen and P. Mulvaney, “The effects of chemisorption on the luminescence of CdSe quantum dots,” Langmuir, vol. 22, no. 7, pp. 3007–3013, 2006.
[58]
B. Von Holt, S. Kudera, A. Weiss et al., “Ligand exchange of CdSe nanocrystals probed by optical spectroscopy in the visible and mid-IR,” Journal of Materials Chemistry, vol. 18, no. 23, pp. 2728–2732, 2008.
[59]
R. Koole, P. Schapotschnikow, C. de Mello Donegá, T. J. H. Vlugt, and A. Meijerink, “Time-dependent photoluminescence spectroscopy as a tool to measure the ligand exchange kinetics on a quantum dot surface,” ACS Nano, vol. 2, no. 8, pp. 1703–1714, 2008.
[60]
X. Ji, D. Copenhaver, C. Sichmeller, and X. Peng, “Ligand bonding and dynamics on colloidal nanocrystals at room temperature: the case of alkylamines on CdSe nanocrystals,” Journal of the American Chemical Society, vol. 130, no. 17, pp. 5726–5735, 2008.
[61]
A. M. Munro and D. S. Ginger, “Photoluminescence quenching of single CdSe nanocrystals by ligand adsorption,” Nano Letters, vol. 8, no. 8, pp. 2585–2590, 2008.
[62]
P. Schapotschnikow, B. Hommersom, and T. J. H. Vlugt, “Adsorption and binding of ligands to cdse nanocrystals,” Journal of Physical Chemistry C, vol. 113, no. 29, pp. 12690–12698, 2009.
[63]
T. Blaudeck, E. I Zenkevich., F. Cichos, and C. von Borczyskowski, “Probing wave functions at semiconductor quantum-dot surfaces by NON-FRET photoluminescence quenching,” Journal of Physical Chemistry C, vol. 112, no. 51, pp. 20251–20257, 2008.
[64]
é. I. Zen'Kevich, T. Blaudeck, M. Heidern？tsch, F. Cichos, and C. Von Borczyskowski, “Effects of electron tunneling and nonresonance quenching of photoluminescence in semiconducting CdSe/ZnS and CdSe nanocrystals by porphyrin molecules in joint complexes,” Theoretical and Experimental Chemistry, vol. 45, no. 1, pp. 23–34, 2009.
[65]
D. M. Willard, L. L. Carillo, J. Jung, and A. Van Orden, “CdSe-ZnS quantum dots as resonance energy transfer donors in a model protein-protein binding assay,” Nano Letters, vol. 1, no. 9, pp. 469–474, 2001.
[66]
D. S. Kilin, K. Tsemekhman, O. V. Prezhdo, E. I. Zenkevich, and C. von Borczyskowski, “Ab initio study of exciton transfer dynamics from a core-shell semiconductor quantum dot to a porphyrin-sensitizer,” Journal of Photochemistry and Photobiology A, vol. 190, no. 2-3, pp. 342–351, 2007.
[67]
J. E. B. Katari, V. L. Colvin, and A. P. Alivisatos, “X-ray photoelectron spectroscopy of CdSe nanocrystals with applications to studies of the nanocrystal surface,” Journal of Physical Chemistry, vol. 98, no. 15, pp. 4109–4117, 1994.
[68]
F. V. Mikulec, M. Kuno, M. Bennati, D. A. Hall, R. G. Griffin, and M. G. Bawendi, “Organometallic synthesis and spectroscopic characterization of manganese-doped CdSe nanocrystals,” Journal of the American Chemical Society, vol. 122, no. 11, pp. 2532–2540, 2000.
[69]
W. W. Yu, L. Qu, W. Guo, and X. Peng, “Experimental determination of the extinction coefficient of CdTe, CdSe, and CdS nanocrystals,” Chemistry of Materials, vol. 15, no. 14, pp. 2854–2860, 2003.
[70]
E. I. Zenkevich, C. Von Borczyskowski, A. M. Shulga, S. Bachilo, U. Rempel, and A. Willert, “Self-assembled nanoscale photomimetic models: structure and related dynamics,” Chemical Physics, vol. 275, no. 1–3, pp. 185–209, 2002.
[71]
E. I. Zenkevich, C. Von Borczyskowski, and A. M. Shulga, “Structure and excited state properties of multiporphyrin arrays formed by supramolecular design,” Journal of Porphyrins and Phthalocyanines, vol. 7, no. 11-12, pp. 731–754, 2003.
[72]
E. I. Sagun, E. I. Zenkevich, V. N. Knyukshto, A. M. Shulga, and N. V. Ivashin, “Self-assembling effects and mechanisms of interchromophore interactions in porphyrin pentads,” Optika i Spektroskopiya, vol. 108, no. 4, pp. 553–570, 2010.
[73]
E. I. Sagun, E. I. Zenkevich, V. N. Knyukshto, and A. M. Shulga, Optika i Spectroskpiya, vol. 110, p. 251, 2011.
[74]
E. I. Zen'kevich, A. M. Shul'ga, A. V. Chernook, and G. P. Gurinovich, Journal of Applied Spectroscopy, vol. 45, no. 6, p. 984, 1986.
[75]
R. A. Marcus, “Electron transfer reactions in chemistry. Theory and experiment,” Reviews of Modern Physics, vol. 65, no. 3, pp. 599–610, 1993.
[76]
E. P. Petrov, F. Cichos, and C. Von Borczyskowski, “Intrinsic photophysics of semiconductor nanocrystals in dielectric media: formation of surface states,” Journal of Luminescence, vol. 119-120, pp. 412–417, 2006.
[77]
E. Zenkevich, T. Blaudeck, M. Abdel-Mottaleb, F. Cichos, A. Shulga, and C. Von Borczyskowski, “Photophysical properties of self-aggregated porphyrin: semiconductor nanoassemblies,” International Journal of Photoenergy, vol. 2006, Article ID 90242, 7 pages, 2006.
[78]
R. K. Sen, E. Yeager, and W. E. O'Grady, “Theory of charge transfer at electrochemical interfaces,” Annual Review of Physical Chemistry, vol. 26, p. 287, 1975.
[79]
H. Lüth, Surfaces and Interfaces of Solid Materials, Springer, Berlin, Germany, 3rd edition, 1995.
[80]
F. Cichos, C. von Borczyskowski, and M. Orrit, “Power-law intermittency of single emitters,” Current Opinion in Colloid and Interface Science, vol. 12, no. 6, pp. 272–284, 2007.
[81]
B. O. Dabbousi, J. Rodriguez-Viejo, F. V. Mikulec et al., “(CdSe)ZnS core-shell quantum dots: synthesis and characterization of a size series of highly luminescent nanocrystallites,” Journal of Physical Chemistry B, vol. 101, no. 46, pp. 9463–9475, 1997.
[82]
J. W. Haus, H. S. Zhou, I. Honma, and H. Komiyama, “Quantum confinement in semiconductor heterostructure nanometer-size particles,” Physical Review B, vol. 47, no. 3, pp. 1359–1365, 1993.
T. S. Marshall and T. M. Wilson, “Electronic structure of free-standing (ZnSe)m(ZnS)n (001) strained-layer superlattices,” Physical Review B, vol. 50, no. 20, pp. 15034–15046, 1994.
[85]
S. Nomura and T. Kobayashi, “Nonparabolicity of the conduction band in CdSe and CdSxSe1-x semiconductor microcrystallites,” Solid State Communications, vol. 78, no. 8, pp. 677–680, 1991.
[86]
M. Nirmal, B. O. Dabbousi, M. G. Bawendi et al., “Fluorescence intermittency in single cadmium selenide nanocrystals,” Nature, vol. 383, no. 6603, pp. 802–804, 1996.
[87]
G. Schlegel, J. Bohnenberger, I. Potapova, and A. Mews, “Fluorescence decay time of single semiconductor nanocrystals,” Physical Review Letters, vol. 88, no. 13, Article ID 137401, pp. 1–4, 2002.
[88]
E. Zenkevich, F. Cichos, A. Shulga, E. P. Petrov, T. Blaudeck, and C. Von Borczyskowski, “Nanoassemblies designed from semiconductor quantum dots and molecular arrays,” Journal of Physical Chemistry B, vol. 109, no. 18, pp. 8679–8692, 2005.
