Abstract
Nanoscale systems are forecast to be a means of integrating desirable attributes of molecular and bulk regimes into easily processed materials. Notable examples include plastic light-emitting devices and organic solar cells, the operation of which hinge on the formation of electronic excited states, excitons, in complex nanostructured materials. The spectroscopy of nanoscale materials reveals details of their collective excited states, characterized by atoms or molecules working together to capture and redistribute excitation. What is special about excitons in nanometre-sized materials? Here we present a cross-disciplinary review of the essential characteristics of excitons in nanoscience. Topics covered include confinement effects, localization versus delocalization, exciton binding energy, exchange interactions and exciton fine structure, exciton–vibration coupling and dynamics of excitons. Important examples are presented in a commentary that overviews the present understanding of excitons in quantum dots, conjugated polymers, carbon nanotubes and photosynthetic light-harvesting antenna complexes.
This is a preview of subscription content, access via your institution
Access options
Subscribe to this journal
Receive 12 print issues and online access
$259.00 per year
only $21.58 per issue
Buy this article
- Purchase on Springer Link
- Instant access to full article PDF
Prices may be subject to local taxes which are calculated during checkout
Similar content being viewed by others
References
Friend, R. H. et al. Electroluminescence in conjugated polymers. Nature 397, 121–128 (1999).
Gregg, B. A. Excitonic solar cells. J. Phys. Chem. B 107, 4688–4698 (2003).
Klimov, V. I. et al. Optical gain and stimulated emission in nanocrystal quantum dots. Science 290, 314–317 (2000).
Koch, S. W., Kira, M., Khitrova, G. & Gibbs, H. M. Semiconductor excitons in a new light. Nature Mater. 5, 523–531 (2006).
Elliott, R. J. in Polarons and Excitons (eds Kuper, C. G. & Whitfield, G. D.) 269–293 (Plenum, New York, 1962).
Knox, R. S. in Collective Excitations in Solids (ed. Bartolo, B. D.) 183–245 (Plenum, New York, 1981).
McRae, E. G. & Kasha, M. in Physical Processes in Radiation Biology, 23–42 (Academic, New York, 1964).
Slater, J. C. & Shockley, W. Optical absorption by the alkali halides. Phys. Rev. 50, 705–719 (1936).
Hoffmann, R. How chemistry meets physics in the solid state. Angew. Chem. Int. Edn. Engl. 26, 846–878 (1987).
Cohen, M. L. Nanotubes, nanoscience, and nanotechnology. Mater. Sci. Eng. C. 15, 1–11 (2001).
Cohen, M. L. The theory of real materials. Annu. Rev. Mater. Sci. 30, 1–26 (2000).
Tretiak, S. & Mukamel, S. Density matrix analysis and simulation of electronic excitations in conjugated and aggregated molecules. Chem. Rev. 102, 3171–3212 (2002).
Brédas, J. L., Beljonne, D., Coropceanu, V. & Cornil, J. Charge-transfer and energy-transfer processes in pi-conjugated oligomers and polymers: a molecular picture. Chem. Rev. 104, 4971–5003 (2004).
Sundström, V., Pullerits, T. & van Grondelle, R. Photosynthetic light-harvesting: reconciling dynamics and structure of purple bacterial LH2 reveals function of photosynthetic unit. J. Phys. Chem. B 103, 2327–2346 (1999).
Scholes, G. D. & Fleming, G. R. Energy transfer and photosynthetic light harvesting. Adv. Chem. Phys. 132, 57–130 (2005).
Scholes, G. D. Long-range resonance energy transfer in molecular systems. Annu. Rev. Phys. Chem. 54, 57–87 (2003).
Doust, A. B., Wilk, K. E., Curmi, P. M. G. & Scholes, G. D. The photophysics of cryptophyte light harvesting. J. Photochem. Photobiol. A. Chem. (in the press); doi:10.1016/j.jphotochem.2006.06.006.
Scholes, G. D., Jordanides, X. J. & Fleming, G. R. Adapting the Förster theory of energy transfer for modeling dynamics in aggregated molecular assemblies. J. Phys. Chem. B 105, 1640–1651 (2001).
Rothberg, L. J. et al. Photophysics of phenylenevinylene polymers. Synth. Met. 80, 41–58 (1996).
Bässler, H. & Schweitzer, B. Site-selective fluorescence spectroscopy of conjugated polymers and oligomers. Acc. Chem. Res. 32, 173–182 (1999).
Sariciftci, N. S. (ed.) Primary Excitations in Conjugated Polymers: Molecular Exciton versus Semiconductor Band Model (World Scientific, Singapore, 1997).
Barbara, P. F., Gesquiere, A. J., Park, S.-J. & Lee, Y. J. Single-molecule spectroscopy of conjugated polymers. Acc. Chem. Res. 38, 602–610 (2005).
Köhler, A. et al. Charge separation in localized and delocalized electronic states in polymeric semiconductors. Nature 392, 903–906 (1998).
Morteani, A. C. et al. Barrier-free electron–hole capture in polymer blend heterojunction light-emitting diodes. Adv. Mater. 15, 1708–1712 (2003).
Morteani, A. C., Sreearunothai, P., Hertz, L. M., Friend, R. H. & Silva, C. Exciton regeneration at polymeric semiconductor heterojunctions. Phys. Rev. Lett. 92, 247402 (2004).
Knibbe, H., Røllig, K., Schä fer, F. P. & Weller, A. Charge-transfer complex and solvent-shared ion pair in fluorescence quenching. J. Chem. Phys. 47, 1184–1185 (1967).
Terrones, M., Hsu, W. K., Kroto, H. W. & Walton, D. R. M. Nanotubes: a revolution in materials science and electronics. Top. Curr. Chem. 199, 189–234 (1999).
O'Connell, M. J. et al. Bandgap fluorescence from individual single-walled carbon nanotubes. Science 297, 593–596 (2002).
Ando, T. Excitons in carbon nanotubes. J. Phys. Soc. Japan 66, 1066–1073 (1997).
Bachilo, S. M. et al. Structure-assigned optical spectra of single-walled carbon nanotubes. Science 298, 2361–2366 (2002).
Reich, S., Thomsen, C. & Maultzsch, J. Carbon nanotubes: basic concepts and physical properties (Wiley, New York, 2004).
Jones, M. et al. Analysis of photoluminescence from solubilized single-walled carbon nanotubes. Phys. Rev. B 71, 115426 (2005).
Didraga, C. & Knoester, J. Exchange narrowing in circular and cylindrical molecular aggregates: degenerate versus nondegenerate states. Chem. Phys. 275, 307–318 (2002).
Gaponenko, S. V. Optical Properties of Semiconductor Nanocrystals (Cambridge Univ. Press, Cambridge, 1998).
Alivisatos, A. P. Perspectives on the physical chemistry of semiconductor nanocrystals. J. Phys. Chem. 100, 13226–13239 (1996).
Burda, C., Chen, X. B., Narayanan, R. & El-Sayed, M. A. Chemistry and properties of nanocrystals of different shapes. Chem. Rev. 105, 1025–1102 (2005).
Weller, H. Colloidal semiconductor Q-particles: chemistry in the transition region between solid state and molecules. Angew. Chem. Int. Edn Engl. 32, 41–53 (1993).
Klimov, V. I. (ed.) Semiconductor and metal nanocrystals: synthesis and electronic and optical properties (Marcel Dekker, New York, 2004).
Bimberg, D., Grundman, M. & Ledentsov, N. N. Quantum Dot Heterostructures (Wiley, Chichester, 1999).
Yoffe, A. D. Semiconductor quantum dots and related systems: electronic, optical, luminescence and related properties of low dimensional systems. Adv. Phys. 50, 1–208 (2001).
Efros, A. L. & Efros, A. L. Interband absorption of light in a semiconductor sphere. Sov. Phys. Semicond. 16, 772–775 (1982).
Ekimov, A. I. et al. Absorption and intensity-dependent photoluminescence measurement on CdSe quantum dots: assignment of the first electronic transitions. J. Opt. Soc. Am. B 10, 100 (1993).
Rabani, E., Hetenyi, B., Berne, B. J. & Brus, L. E. Electronic properties of CdSe nanocrystals in the absence and presence of a dielectric medium. J. Chem. Phys. 110, 5355–5369 (1999).
Yin, Y. & Alivisatos, A. P. Colloidal nanocrystal synthesis and the organic-inorganic interface. Nature 437, 664–670 (2005).
Klevens, H. B. & Platt, J. R. Spectral resemblances of cata-condensed hydrocarbons. J. Chem. Phys. 17, 470–481 (1949).
Hines, M. A. & Scholes, G. D. Colloidal PbS nanocrystals with size-tunable near-infrared emission: observation of post-synthesis self-narrowing of the particle size distribution. Adv. Mater. 15, 1844–1849 (2003).
Micic, O. I. et al. Size-dependent spectroscopy of InP quantum dots. J. Phys. Chem. B 101, 4904 (1997).
Yu, W. W., Qu, L. H., Guo, W. Z. & Peng, X. G. Experimental determination of the extinction coefficient of CdTe, CdSe, and CdS nanocrystals. Chem. Mater. 15, 2854–2860 (2003).
Nesher, G., Kronik, L. & Chelikowsky, J. R. Ab initio absorption spectra of Ge nanocrystals. Phys. Rev. B 71, 35344 (2005).
Pariser, R. & Parr, R. G. A semi-empirical theory of the electronic spectra and electronic structure of complex unsaturated molecules. I. J. Chem. Phys. 21, 466–471 (1953).
Efros, A. L. et al. Band-edge exciton in quantum dots of semiconductors with a degenerate valence band: dark and bright exciton states. Phys. Rev. B 54, 4843–4856 (1996).
Leung, K., Pokrant, S. & Whaley, K. B. Exciton fine structure in CdSe nanoclusters. Phys. Rev. B 57, 12291–12301 (1998).
Hertel, D. et al. Phosphorescence in conjugated poly(para-phenylene)-derivatives. Adv. Mater. 13, 65–70 (2001).
Köhler, A. & Beljonne, D. The singlet–triplet exchange energy in conjugated polymers. Adv. Funct. Mater. 14, 11–18 (2004).
Wasserberg, D., Marsal, P., Meskers, S. C. J., Janssen, R. A. J. & Beljonne, D. Phosphorescence and triplet state energies of oligothiophenes. J. Phys. Chem. B 109, 4410–4415 (2005).
Chi, C. Y., Im, C. & Wegner, G. Lifetime determination of fluorescence and phosphorescence of a series of oligofluorenes. J. Chem. Phys. 124, 24907 (2006).
McGlynn, S. P., Azumi, T. & Kinoshita, M. Molecular Spectroscopy of the Triplet State (Prentice-Hall, Englewood Cliffs, NJ, 1969).
Catalán, J. & de Paz, J. L. G. On the ordering of the first two excited electronic states in all-trans linear polyenes. J. Chem. Phys. 120, 1864–1872 (2004).
Perebeinos, V., Tersoff, J. & Avouris, P. Radiative lifetime of excitons in carbon nanotubes. Nanoletters 5, 2495–2499 (2005).
Fanceschetti, A. & Zunger, A. Direct pseudopotential calculation of exciton coulomb and exchange energies in semiconductor quantum dots. Phys. Rev. Lett. 78, 915–918 (1997).
Fu, H. X. & Zunger, A. InP quantum dots: electronic structure, surface effects, and the redshifted emission. Phys. Rev. B 56, 1496–1508 (1997).
Leung, K. & Whaley, K. B. Electron–hole interactions in silicon nanocrystals. Phys. Rev. B 56, 7455–7468 (1997).
Banin, U., Lee, J. C., Guzelian, A. A., Kadavanich, A. V. & Alivisatos, A. P. Exchange interaction in InAs nanocrystal quantum dots. Superlattices Microstruct. 22, 559–567 (1997).
Lavallard, P. et al. Exchange interaction and acoustical phonon modes in CdTe nanocrystals. Solid State Commun. 127, 439–442 (2003).
Gogolin, O., Mshvelidze, G., Tsitishvili, E., Djanelidze, R. & Klingshirn, C. Exchange interaction in argentum iodide nanocrystals. J. Lumin. 102, 414–416 (2003).
Wang, F., Dukovic, G., Brus, L. E. & Heinz, T. F. Time-resolved fluorescence of carbon nanotubes and its implication for radiative lifetimes. Phys. Rev. Lett. 92, 177401 (2004).
Huxter, V. M., Kovalevskij, V. & Scholes, G. D. Dynamics within the exciton fine structure of colloidal CdSe quantum dots. J. Phys. Chem. B 109, 20060–20063 (2005).
Yaron, D., Moore, E. E., Shuai, Z. & Brédas, J. L. Comparison of density matrix renormalization group calculations with electron–hole models of exciton binding in conjugated polymers. J. Chem. Phys. 108, 7451–7458 (1998).
Halls, J. J. M. et al. Efficient photodiodes from interpenetrating polymer networks. Nature 376, 498–500 (1995).
Sariciftci, N. S., Smilowitz, L., Heeger, A. J. & Wudl, F. Photoinduced electron transfer from a conducting polymer to buckminsterfullerene. Science 258, 1474–1476 (1992).
Huynh, W. U., Dittmer, J. J. & Alivisatos, A. P. Hybrid nanorod–polymer solar cells. Science 295, 2425–2427 (2002).
Spataru, C. D., Ismail-Beigi, S., Benedict, L. X. & Louie, S. G. Excitonic effects and optical spectra of single-walled carbon nanotubes. Phys. Rev. Lett. 92, 77402 (2004).
Chang, E., Bussi, G., Ruini, A. & Molinari, E. Excitons in carbon nanotubes: an ab initio symmetry-based approach. Phys. Rev. Lett. 92, 196401 (2004).
Zhao, H. & Mazumdar, S. Electron–electron interaction effects on the optical excitations of semiconducting single-walled carbon nanotubes. Phys. Rev. Lett. 93, 157402 (2004).
Wang, F., Dukovic, G., Brus, L. E. & Heinz, T. F. The optical resonances in carbon nanotubes arise from excitons. Science 308, 838–841 (2005).
Ma, Y.-Z., Valkunas, L., Bachilo, S. M. & Fleming, G. R. Exciton binding energy in semiconducting single-walled carbon nanotubes. J. Phys. Chem. B 109, 15671–15674 (2005).
Heijs, D. J., Malyshev, V. A. & Knoester, J. Decoherence of excitons in multichromophoric systems: thermal line broadening and destruction of superradiant emission. Phys. Rev. Lett. 95, 177402 (2005).
Brédas, J.-L., Cornil, J., Beljonne, D., dos Santos, D. A. & Shuai, Z. Excited-state electronic structure of conjugated oligomers and polymers: a quantum-chemical approach to optical phenomena. Acc. Chem. Res. 32, 267–276 (1999).
Moses, D., Wang, J., Heeger, A. J., Kirova, N. & Brazovski, S. Singlet exciton binding energy in poly(phenylene vinylene). Proc. Natl Acad. Sci. 98, 13496–13500 (2001).
Silva, C. et al. Exciton and polaron dynamics in a step-ladder polymeric semiconductor: the influence of interchain order. J. Phys.: Condens. Matter 14, 9803–9824 (2002).
Arkhipov, V. I. & Bässler, H. Exciton dissociation and charge photogeneration in pristine and doped conjugated polymers. Phys. Status Solidi A 201, 1152–1187 (2004).
Brédas, J. L., Cornil, J. & Heeger, A. J. The exciton binding energy in luminescent conjugated polymers. Adv. Mater. 8, 447–452 (1996).
Lax, M. The Franck–Condon principle and its application to crystals. J. Chem. Phys. 20, 1752–1760 (1952).
Sumi, H. Exciton–lattice interaction and the line shape of exciton absorption in molecular crystals. J. Chem. Phys. 67, 2943–2954 (1977).
Scholes, G. D., Harcourt, R. D. & Ghiggino, K. P. Rate expressions for excitation transfer. III. An ab initio study of electronic factors in excitation transfer and exciton resonance interactions. J. Chem. Phys. 102, 9574–9581 (1995).
Fleming, G. R., Passino, S. A. & Nagasawa, Y. The interaction of solutes with their environments. Phil. Trans. R. Soc. London A 356, 389–404 (1998).
Nakajima, S. The Physics of Elementary Excitations (Springer, New York, 1980).
Franco, I. & Tretiak, S. Electron-vibrational dynamics of photoexcited polyfluorenes. J. Am. Chem. Soc. 126, 12130–12140 (2004).
Jimenez, R., Dikshit, S. N., Bradforth, S. E. & Fleming, G. R. Electronic excitation transfer in the LH2 complex of Rhodobacter sphaeroides. J. Phys. Chem. 100, 6825–6834 (1996).
Alden, R. G. et al. Calculations of spectroscopic properties of the LH2 bacteriochlorophyll-protein antenna complex from Rhodopseudomonas acidophila. J. Phys. Chem. B 101, 4667–4680 (1997).
Jang, S., Dempster, S. E. & Silbey, R. J. Characterization of the static disorder in the B850 band of LH2. J. Phys. Chem. B 105, 6655–6665 (2001).
Van Oijen, A. M., Ketelaars, M., Kö hler, J., Aartsma, T. J. & Schmidt, J. Unraveling the electronic structure of individual photosynthetic pigment-protein complexes. Science 285, 400–402 (1999).
Pullerits, T., Chachisvilis, M. & Sundström, V. Exciton delocalization length in the B850 antenna of Rhodobacter sphaeroides. J. Phys. Chem. 100, 10787–10792 (1996).
Monshouwer, R., Abrahamsson, M., van Mourik, F. & van Grondelle, R. Superradiance and exciton delocalization in bacterial photosynthetic light-harvesting systems. J. Phys. Chem. B 101, 7241–7248 (1997).
Hu, D. et al. Collapse of stiff conjugated polymers with chemical defects into ordered, cylindrical conformations. Nature 405, 1030–1033 (2000).
Schindler, F. et al. Counting chromophores in conjugated polymers. Angew. Chem. Int. Edn Engl. 44, 1520–1525 (2005).
Beljonne, D. et al. Interchain vs. intrachain energy transfer in acceptor-capped conjugated polymers. Proc. Natl Acad. Sci. 99, 10982–10987 (2002).
Chang, R., Hayashi, M., Lin, S. H., Hsu, J.-H. & Fann, W. S. Ultrafast dynamics of excitations in conjugated polymers: a spectroscopic study. J. Chem. Phys. 115, 4339–4348 (2001).
Wang, X., Dykstra, T. E. & Scholes, G. D. Photon-echo studies of collective absorption and dynamic localization of excitation in conjugated polymers and oligomers. Phys. Rev. B 71, 45203 (2005).
Ruseckas, A. et al. Ultrafast depolarization of the fluorescence in a conjugated polymer. Phys. Rev. B 72, 115214 (2005).
Beenken, W. J. D. & Pullerits, T. Spectroscopic units in conjugated polymers: a quantum chemically founded concept? J. Phys. Chem. B 108, 6164–6169 (2004).
Tretiak, S., Saxena, A., Martin, R. L. & Bishop, A. R. Conformational dynamics of photoexcited conjugated molecules. Phys. Rev. Lett. 89, 97402 (2002).
LĂ©cuiller, R. et al. Fluorescence yield and lifetime of isolated polydiacetylene chains: evidence for a one-dimensional exciton band in a conjugated polymer. Phys. Rev. B 66, 125205 (2002).
Takagahara, T. Electron–phonon interactions and excitonic dephasing in semiconductor nanocrystals. Phys. Rev. Lett. 71, 3577–3580 (1993).
Plentz, F., Ribeiro, H. B., Jorio, A., Strano, M. S. & Pimenta, M. A. Direct experimental evidence of exciton–phonon bound states in carbon nanotubes. Phys. Rev. Lett. 95, 247401 (2005).
Telg, H., Maultzsch, J., Reich, S., Hennrich, F. & Thomsen, C. Chirality distribution and transition energies of carbon nanotubes. Phys. Rev. Lett. 93, 177401 (2004).
Brixner, T. et al. Two-dimensional spectroscopy of electronic couplings in photosynthesis. Nature 434, 625–628 (2005).
Valkunas, L., Ma, Y.-Z. & Fleming, G. R. Exciton–exciton annihilation in single-walled carbon nanotubes. Phys. Rev. B 73, 115432 (2006).
De Schryver, F. C. et al. Energy dissipation in multichromophoric single dendrimers. Acc. Chem. Res. 38, 514–522 (2005).
Sternlicht, H., Nieman, G. C. & Robinson, G. W. Triplet–triplet annihilation and delayed fluorescence in molecular aggregates. J. Chem. Phys. 38, 1326–1335 (1963).
Klimov, V. I., McBranch, D. W., Leatherdale, C. A. & Bawendi, M. G. Electron and hole relaxation pathways in semiconductor quantum dots. Phys. Rev. B 60, 13740–13749 (1999).
Klimov, V. I., Mikhailovsky, A. A., McBranch, D. W., Leatherdale, C. A. & Bawendi, M. G. Quantization of multiparticle Auger rates in semiconductor quantum dots. Science 287, 1011–1013 (2000).
Guyot-Sionnest, P., Wehrenberg, B. & Yu, D. Intraband relaxation in CdSe nanocrystals and the strong influence of the surface ligands. J. Chem. Phys. 123, 74709 (2005).
Nozik, A. J. Quantum dot solar cells. Physica E 14, 115–120 (2002).
Schaller, R. D. & Klimov, V. I. High efficiency carrier multiplication in PbSe nanocrystals: Implications for solar energy conversion. Phys. Rev. Lett. 92, 186601 (2004).
Ellingson, R. J. et al. Highly efficient multiple exciton generation in colloidal PbSe and PbS quantum dots. Nanoletters 5, 865–871 (2005).
Scholes, G. D., Ghiggino, K. P., Oliver, A. M. & Paddon-Row, M. N. Through-space and through-bond effects on exciton interactions in rigidly linked dinaphthyl molecules. J. Am. Chem. Soc. 115, 4345–4349 (1993).
Curutchet, C. & Mennucci, B. Toward a molecular scale interpretation of excitation energy transfer in solvated bichromophoric systems. J. Am. Chem. Soc. 127, 16733–16744 (2005).
Fritz, K. P. et al. Structural characterization of CdSe nanorods. J. Cryst. Growth 293, 203–208 (2006).
Gierschner, J., Mack, H.-G., Lü er, L. & Oelkrug, D. Fluorescence and absorption spectra of oligophenylenevinylenes: vibronic coupling, band shapes, and solvatochromism. J. Chem. Phys. 116, 8596–8609 (2002).
Acknowledgements
G.D.S. thanks G. J. Wilson for introducing him to excitons. He acknowledges funding from the Natural Sciences and Engineering Research Council of Canada and the A. P. Sloan Foundation. G.R. acknowledges funding through the Photochemistry and Radiation research program of the US Department of Energy, Office of Science, Office of Basic Energy Sciences, Chemical Sciences, Geosciences and Biosciences (DoE contract DE-AC36-99G010337).
Author information
Authors and Affiliations
Corresponding author
Rights and permissions
About this article
Cite this article
Scholes, G., Rumbles, G. Excitons in nanoscale systems. Nature Mater 5, 683–696 (2006). https://doi.org/10.1038/nmat1710
Issue Date:
DOI: https://doi.org/10.1038/nmat1710
This article is cited by
-
Physical insights into non-fullerene organic photovoltaics
Nature Reviews Physics (2024)
-
Non-Faradaic optoelectrodes for safe electrical neuromodulation
Nature Communications (2024)
-
Nonlocal interaction enhanced biexciton emission in large CsPbBr3 nanocrystals
eLight (2023)
-
Multiphoton excited singlet/triplet mixed self-trapped exciton emission
Nature Communications (2023)
-
Energy transfer in N-component nanosystems enhanced by pulse-driven vibronic many-body entanglement
Scientific Reports (2023)