Abstract
Currently, intensive research efforts focus on the fabrication of meso-structures of assembled colloidal quantum dots (QDs) with original optical and electronic properties. Such collective features originate from the QDs coupling, depending on the number of connected units and their distance. However, the development of general methodologies to assemble colloidal QD with precise stoichiometry and particle-particle spacing remains a key challenge. Here, we demonstrate that dimers of CdSe QDs, stable in solution, can be obtained by engineering QD surface chemistry, reducing the surface steric hindrance and favoring the link between two QDs. The connection is made by using alkyl dithiols as bifunctional linkers and different chain lengths are used to tune the interparticle distance from few nm down to 0.5 nm. The spectroscopic investigation highlights that coupling phenomena between the QDs in dimers are strongly dependent on the interparticle distance and QD size, ultimately affecting the exciton dissociation efficiency.

References
Suárez Alvarez, I. Active photonic devices based on colloidal semiconductor nanocrystals and organometallic halide perovskites. Eur. Phys. J. Appl. Phys.2016, 75, 30001.
Kovalenko, M. V.; Manna, L.; Cabot, A.; Hens, Z.; Talapin, D. V.; Kagan, C. R.; Klimov, V. I.; Rogach, A. L.; Reiss, P.; Milliron, D. J. et al. Prospects of nanoscience with nanocrystals. ACS Nano2015, 9, 1012–1057.
Litvin, A. P.; Martynenko, I. V.; Purcell-Milton, F.; Baranov, A. V.; Fedorov, A. V.; Gun’ko, Y. K. Colloidal quantum dots for optoelectronics. J Mater. Chem. A2017, 5, 13252–13275.
Kim, T. H.; Cho, K. S.; Lee, E. K.; Lee, S. J.; Chae, J.; Kim, J. W.; Kim, D. H.; Kwon, J. Y.; Amaratunga, G.; Lee, S. Y. et al. Full-colour quantum dot displays fabricated by transfer printing. Nat. Photonics2011, 5, 176–182.
Shirasaki, Y.; Supran, G. J.; Bawendi, M. G.; Bulović, V. Emergence of colloidal quantum-dot light-emitting technologies. Nat. Photonics2013, 7, 13–23.
Zhao, T. S.; Goodwin, E. D.; Guo, J. C.; Wang, H.; Diroll, B. T.; Murray, C. B.; Kagan, C. R. Advanced architecture for colloidal PbS quantum dot solar cells exploiting a CdSe quantum dot buffer layer. ACS Nano2016, 10, 9267–9273.
Carey, G. H.; Abdelhady, A. L.; Ning, Z. J.; Thon, S. M.; Bakr, O. M.; Sargent, E. H. Colloidal quantum dot solar cells. Chem. Rev.2015, 115, 12732–12763.
Morales-Narváez, E.; Golmohammadi, H.; Naghdi, T.; Yousefi, H.; Kostiv, U.; Horák, D.; Pourreza, N.; Merkoçi, A. Nanopaper as an optical sensing platform. ACS Nano2015, 9, 7296–7305.
Wang, G.; Leng, Y. K.; Dou, H. J.; Wang, L.; Li, W. W.; Wang, X. B.; Sun, K.; Shen, L. S.; Yuan, X. L.; Li, J. Y.et al. Highly efficient preparation of multiscaled quantum dot barcodes for multiplexed hepatitis B detection. ACS Nano2013, 7, 471–481.
Lee, J. S.; Kovalenko, M. V.; Huang, J.; Chung, D. S.; Talapin, D. V. Band-like transport, high electron mobility and high photoconductivity in all-inorganic nanocrystal arrays. Nat. Nanotechnol.2011, 6, 348–352.
Semonin, O. E.; Luther, J. M.; Beard, M. C. Quantum dots for next-generation photovoltaics. Mater. Today2012, 15, 508–515.
Balazs, D. M.; Rizkia, N.; Fang, H. H.; Dirin, D. N.; Momand, J.; Kooi, B. J.; Kovalenko, M. V.; Loi, M. A. Colloidal quantum dot inks for single-step-fabricated field-effect transistors: The importance of postdeposition ligand removal. ACS Appl. Mater. Interfaces2018, 10, 5626–5632.
Zhang, H. T.; Hu, B.; Sun, L. F.; Hovden, R.; Wise, F. W.; Muller, D. A.; Robinson, R. D. Surfactant ligand removal and rational fabrication of inorganically connected quantum dots. Nano Lett.2011, 11, 5356–5361.
Cohen, E.; Komm, P.; Rosenthal-Strauss, N.; Dehnel, J.; Lifshitz, E.; Yochelis, S.; Levine, R. D.; Remacle, F.; Fresch, B.; Marcus, G. et al. Fast energy transfer in CdSe quantum dot layered structures: Controlling coupling with covalent-bond organic linkers. J.Phys. Chem. C2018, 122, 5753–5758.
Talapin, D. V.; Murray, C. B. PbSe nanocrystal solids for n- and p-channel thin film field-effect transistors. Science2005, 310, 86–89.
Zhao, K.; Mason, T. G. Assembly of colloidal particles in solution. Rep. Prog. Phys.2018, 81, 126601.
Romo-Herrera, J. M.; Alvarez-Puebla, R. A.; Liz-Marzán, L. M. Controlled assembly of plasmonic colloidal nanoparticle clusters. Nanoscale2011, 3, 1304–1315.
Yu, L.; Shiraishi, S.; Wang, G. Q.; Akiyama, Y.; Takarada, T.; Maeda, M. Connecting nanoparticles with different colloidal stability by DNA for programmed anisotropic self-assembly. J.Phys. Chem. C2019, 123, 15293–15300.
Wang, X. J.; Li, G. P.; Chen, T.; Yang, M. X.; Zhang, Z.; Wu, T.; Chen, H. Y. Polymer-encapsulated gold-nanoparticle dimers: Facile preparation and catalytical application in guided growth of dimeric ZnO-nanowires. Nano Lett.2008, 8, 2643–2647.
Chen, G.; Wang, Y.; Tan, L. H.; Yang, M. X.; Tan, L. S.; Chen, Y.; Chen, H. Y. High-purity separation of gold nanoparticle dimers and trimers. J. Am. Chem. Soc.2009, 131, 4218–4219.
Zohar, N.; Chuntonov, L.; Haran, G. The simplest plasmonic molecules: Metal nanoparticle dimers and trimers. J. Photochem. Photobiol. C2014, 21, 26–39.
Fernandez, Y. D.; Sun, L. L.; Gschneidtner, T.; Moth-Poulsen, K. Research update: Progress in synthesis of nanoparticle dimers by self-assembly. APL Mater.2014, 2, 010702.
Yamashita, N.; Ma, Z. P.; Park, S.; Kawai, K.; Hirai, Y.; Tsuchiya, T.; Tabata, O. Formation of gold nanoparticle dimers on silicon by sacrificial DNA origami technique. Micro Nano Lett.2017, 12, 854–859.
Thacker, V. V.; Herrmann, L. O.; Sigle, D. O.; Zhang, T.; Liedl, T.; Baumberg, J. J.; Keyser, U. F. DNA origami based assembly of gold nanoparticle dimers for surface-enhanced Raman scattering. Nat. Commun.2014, 5, 3448.
Hanrath, T. Colloidal nanocrystal quantum dot assemblies as artificial solids. J. Vac. Sci.Technol. A2012, 30, 030802.
Peng, X.G.; Wilson, T. E.; Alivisatos, A. P.; Schultz, P. G. Synthesis and isolatin of a homodimer of cadmium selenide nanocrystals. Angew. Chem., Int. Ed.1997, 36, 145–147.
Koole, R.; Liljeroth, P.; de Mello Donegá, C.; Vanmaekelbergh, D.; Meijerink, A. Electronic coupling and exciton energy transfer in CdTe quantum-dot molecules. J. Am. Chem. Soc.2006, 128, 10436–10441.
Xu, X.X.; Stöttinger, S.; Battagliarin, G.; Hinze, G.; Mugnaioli, E.; Li, C.; Müllen, K.; Basché, T. Assembly and separation of semiconductor quantum dot dimers and trimers. J. Am. Chem. Soc.2011, 133, 18062–18065.
Tanford, C. The Hydrophobic Effect: Formation of Micelles and Biological Membranes; 2nd ed. John Wiley & Sons: New York, 1980.
Wu, S. S.; McGuigan, M.; Tiano, A. L.; Wong, S. S.; Glimm, J. G. A first-principles study of CdSe NANOCLUSTERS capped by thiol ligands. arXiv:1308.4671, 2013.
Altomare, M.; Fanizza, E.; Corricelli, M.; Comparelli, R.; Striccoli, M.; Curri, M. L. Patterned assembly of luminescent nanocrystals: Role of the molecular chemistry at the interface. J. Nanopart. Res.2014, 16, 2468.
Anderson, N. C.; Hendricks, M. P.; Choi, J. J.; Owen, J. S. Ligand exchange and the stoichiometry of metal chalcogenide nanocrystals: Spectroscopic observation of facile metal-carboxylate displacement and binding. J. Am. Chem. Soc.2013, 135, 18536–18548.
Kumar, A. P.; Huy, B. T.; Kumar, B. P.; Kim, J. H.; Dao, V. D.; Choi, H. S.; Lee, Y. I. Novel dithiols as capping ligands for CdSe quantum dots: Optical properties and solar cell applications. J. Mater. Chem. C 2015, 3, 1957–1964.
Hostetler, M. J.; Templeton, A. C.; Murray, R. W. Dynamics of place-exchange reactions on monolayer-protected gold cluster molecules. Langmuir1999, 15, 3782–3789.
McCarthy, C. L.; Brutchey, R. L. Solution processing of chalcogenide materials using thiol-amine “alkahest” solvent systems. Chem. Commun.2017, 53, 4888–4902.
Mei, B. C.; Oh, E.; Susumu, K.; Farrell, D.; Mountziaris, T. J.; Mattoussi, H. Effects of ligand coordination number and surface curvature on the stability of gold nanoparticles in aqueous solutions. Langmuir2009, 25, 10604–10611.
Talapin, D. V.; Rogach, A. L.; Kornowski, A.; Haase, M.; Weller, H. Highly luminescent monodisperse CdSe and CdSe/ZnS nanocrystals synthesized in a hexadecylamine-trioctylphosphine oxide-trioctylphospine mixture. Nano Lett.2001, 1, 207–211.
Michen, B.; Geers, C.; Vanhecke, D.; Endes, C.; Rothen-Rutishauser, B.; Balog, S.; Petri-Fink, A. Avoiding drying-artifacts in transmission electron microscopy: Characterizing the size and colloidal state of nanoparticles. Sci. Rep.2015, 5, 9793.
Wuister, S. F.; de Mello Donegá, C.; Meijerink, A. Influence of thiol capping on the exciton luminescence and decay kinetics of CdTe and CdSe quantum dots. J.Phys. Chem. B2004, 108, 17393–17397.
Piston, D. W.; Kremers, G. J. Fluorescent protein FRET: The good, the bad and the ugly. Trends Biochem. Sci.2007, 32, 407–414.
Sapsford, K. E.; Berti, L.; Medintz, I. L. Materials for fluorescence resonance energy transfer analysis: beyond traditional donor-acceptor combinations. Angew. Chem., Int. Ed.2006, 45, 4562–4589.
Chou, K. F.; Dennis, A. M. Förster resonance energy transfer between quantum dot donors and quantum dot acceptors. Sensors2015, 15, 13288–13325.
De Luca, A.; Depalo, N.; Fanizza, E.; Striccoli, M.; Curri, M. L.; Infusino, M.; Rashed, A. R.; La Deda, M.; Strangi, G. Plasmon mediated super-absorber flexible nanocomposites for metamaterials. Nanoscale2013, 5, 6097–6105.
Lakowicz, J. R. Principles of Fluorescence Spectroscopy. Springer: New York, 2006; pp 443–475.
Marcus, R. A.; Sutin, N. Electron transfers in chemistry and biology. Biochim.Biophys. Acta1985, 811, 265–322.
Choi, J. J.; Luria, J.; Hyun, B. R.; Bartnik, A. C.; Sun, L. F.; Lim, Y. F.; Marohn, J. A.; Wise, F. W.; Hanrath, T. Photogenerated exciton dissociation in highly coupled lead salt nanocrystal assemblies. Nano Lett.2010, 10, 1805–1811.
Acknowledgements
This work is financially supported by the H2020 FET project COPAC (Contract agreement n.766563).
The MIUR PRIN 2015 n. 2015XBZ5YA is also acknowledged.
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Dibenedetto, C.N., Fanizza, E., Brescia, R. et al. Coupling effects in QD dimers at sub-nanometer interparticle distance. Nano Res. 13, 1071–1080 (2020). https://doi.org/10.1007/s12274-020-2747-3
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DOI: https://doi.org/10.1007/s12274-020-2747-3
Keywords
- quantum dots
- dimers
- surface chemistry
- dithiols
- coupling