Abstract
Uniform thickness and colloidal-stable CdS quantum disks have been reproducibly prepared using cadmium acetate, elemental sulfur, fatty acids and octadecene as the starting materials without any size/shape sorting. The thickness could be varied between 1.2 and 2.2 nm, i.e., 4.5, 5.5, 6.5 and 7.5 monolayers of CdS along the thickness direction. These single crystalline disks with lateral dimensions between 20 and 100 nm adopted the zinc blende crystal structure with 〈100〉 (possibly mixed with 〈111〉) as the thickness direction. The basal planes and side facets were terminated with cadmium carboxylates, which dictated the thicknesses to be half a monolayer more than an integer number. Formation of CdS quantum disks probably occurs through a “nucleation-growth” mechanism, instead of aggregation of pre-formed magic clusters. Completion of a full monolayer along the lateral direction was found to be rather fast if two-dimensional nucleation was initiated on existing disks, which helped formation of atomically flat and thickness-controlled disks. As disk thickness decreased, the crystal lattice was found to dilate gradually, which has not been observed with CdS quantum dots. Compared with CdS quantum dots and rods, the disks displayed weakened quantum confinement and their photoluminescence lifetime (tens of picoseconds) was about two orders of magnitude shorter.
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Murray, C. B.; Kagan, C. R.; Bawendi, M. G. Synthesis and characterization of monodisperse nanocrystals and close-packed nanocrystal assemblies. Annu. Rev. Mater. Sci. 2000, 30, 545–610.
Peng, X. G. An essay on synthetic chemistry of colloidal nanocrystals. Nano Res. 2009, 2, 425–447.
Murray, C. B.; Norris, D. J.; Bawendi, M. G. Synthesis and characterization of nearly monodisperse CdE (E = S, Se, Te) semiconductor nanocrystallites. J. Am. Chem. Soc. 1993, 115, 8706–8715.
Peng, Z. A.; Peng, X. G. Formation of high-quality CdTe, CdSe, and CdS nanocrystals using CdO as precursor. J. Am. Chem. Soc. 2001, 123, 183–184.
Peng, X. G.; Manna, L.; Yang, W. D.; Wickham, J.; Scher, E.; Kadavanich, A.; Alivisatos, A. P. Shape control of CdSe nanocrystals. Nature 2000, 404, 59–61.
Peng, Z. A.; Peng, X. G. Nearly monodisperse and shape-controlled CdSe nanocrystals via alternative routes: Nucleation and growth. J. Am. Chem. Soc. 2002, 124, 3343–3353.
Tang, Z. Y.; Zhang, Z. L.; Wang, Y.; Glotzer, S. C.; Kotov, N. A. Self-assembly of CdTe nanocrystals into free-floating sheets. Science 2006, 314, 274–278.
Schliehe, C.; Juarez, B. H.; Pelletier, M.; Jander, S.; Greshnykh, D.; Nagel, M.; Meyer, A.; Foerster, S.; Kornowski, A.; Klinke, C., et al. Ultrathin PbS sheets by two-dimensional oriented attachment. Science 2010, 329, 550–553.
Ithurria, S.; Dubertret, B. Quasi 2D colloidal CdSe platelets with thicknesses controlled at the atomic level. J. Am. Chem. Soc. 2008, 130, 16504–16505.
Ithurria, S.; Bousquet, G.; Dubertret, B. Continuous transition from 3D to 1D confinement observed during the formation of CdSe nanoplatelets. J. Am. Chem. Soc. 2011, 133, 3070–3077.
Joo, J.; Son, J. S.; Kwon, S. G.; Yu, J. H.; Hyeon, T. Low-temperature solution-phase synthesis of quantum well structured CdSe nanoribbons. J. Am. Chem. Soc. 2006, 128, 5632–5633.
Son, J. S.; Wen, X. D.; Joo, J.; Chae, J.; Baek, S. I.; Park, K.; Kim, J. H.; An, K.; Yu, J. H.; Kwon, S. G., et al. Large-scale soft colloidal template synthesis of 1.4 nm thick CdSe nanosheets. Angew. Chem. Int. Edit. 2009, 48, 6861–6864.
Liu, Y. H.; Wayman, V. L.; Gibbons, P. C.; Loomis, R. A.; Buhro, W. E. Origin of high photoluminescence efficiencies in CdSe quantum belts. Nano Lett. 2010, 10, 352–357.
Liu, Y. H.; Wang, F.; Wang, Y.; Gibbons, P. C.; Buhro, W. E. Lamellar assembly of cadmium selenide nanoclusters into quantum belts. J. Am. Chem. Soc. 2011, 133, 17005–17013.
Li, Z.; Peng, X. Size/shape-controlled synthesis of colloidal CdSe quantum disks: Ligand and temperature effects. J. Am. Chem. Soc. 2011, 133, 6578–6586.
Qu, L. H.; Peng, X. G. Control of photoluminescence properties of CdSe nanocrystals in growth. J. Am. Chem. Soc. 2002, 124, 2049–2055.
Bruchez, M.; Moronne, M.; Gin, P.; Weiss, S.; Alivisatos, A. P. Semiconductor nanocrystals as fluorescent biological labels. Science 1998, 281, 2013–2016.
Chan, W. C. W.; Nie, S. M. Quantum dot bioconjugates for ultrasensitive nonisotopic detection. Science 1998, 281, 2016–2018.
Colvin, V. L.; Schlamp, M. C.; Alivisatos, A. P. Light-emitting-diodes made from cadmium selenide nanocrystals and a semiconducting polymer. Nature 1994, 370, 354–357.
Coe, S.; Woo, W. K.; Bawendi, M.; Bulovic, V. Electro-luminescence from single monolayers of nanocrystals in molecular organic devices. Nature 2002, 420, 800–803.
Ithurria, S.; Tessier, M. D.; Mahler, B.; Lobo, R. P. S. M.; Dubertret, B.; Efros, A. L. Colloidal nanoplatelets with two-dimensional electronic structure. Nat. Mater. 2011, 10, 936–941.
Pradhan, N.; Xu, H. F.; Peng, X. G. Colloidal CdSe quantum wires by oriented attachment. Nano Lett. 2006, 6, 720–724.
Yu, W. W.; Peng, X. G. Formation of high-quality CdS and other II–VI semiconductor nanocrystals in noncoordinating solvents: Tunable reactivity of monomers. Angew. Chem. Int. Edit. 2002, 41, 2368–2371.
Li, Z.; Ji, Y.; Xie, R.; Grisham, S. Y.; Peng, X. Correlation of CdS nanocrystal formation with elemental sulfur activation and its implication in synthetic development. J. Am. Chem. Soc. 2011, 133, 17248–17256.
Ouyang, J.; Zaman, M. B.; Yan, F. J.; Johnston, D.; Li, G.; Wu, X.; Leek, D.; Ratcliffe, C. I.; Ripmeester, J. A.; Yu, K. Multiple families of magic-sized CdSe nanocrystals with strong bandgap photoluminescence via noninjection one-pot syntheses. J. Phys. Chem. C 2008, 112, 13805–13811.
Li, M. J.; Ouyang, J. Y.; Ratcliffe, C. I.; Pietri, L.; Wu, X. H.; Leek, D. M.; Moudrakovski, I.; Lin, Q.; Yang, B.; Yu, K. CdS Magic-sized nanocrystals exhibiting bright band gap photoemission via thermodynamically driven formation. ACS Nano 2009, 3, 3832–3838.
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. 2003, 15, 2854–2860.
Mullin, J. W. Crystallization. Butterworth-Heinemann: Oxford, 2004.
Krishna, M. V. R.; Friesner, R. A. Quantum confinement effects in semiconductor clusters. J. Chem. Phys. 1991, 95, 8309–8322.
Pandey, A.; Guyot-Sionnest, P. Intraband spectroscopy and band offsets of colloidal II–VI core/shell structures. J. Chem. Phys. 2007, 127, 104710.
Efros, A. L.; Rosen, M. Quantum size level structure of narrow-gap semiconductor nanocrystals: Effect of band coupling. Phys. Rev. B 1998, 58, 7120–7135.
Kang, C. -C.; Lai, C. -W.; Peng, H. -C.; Shyue, J. -J.; Chou, P. -T. Surfactant- and temperature-controlled CdS nanowire formation. Small 2007, 3, 1882–1885.
Zhuang, Z. B.; Lu, X. T.; Peng, Q.; Li, Y. D. Direct synthesis of water-soluble ultrathin CdS nanorods and reversible tuning of the solubility by alkalinity. J. Am. Chem. Soc. 2010, 132, 1819–1821.
Dandrea, A.; Delsole, R. D. Excitons in semiconductor confined systems. Solid State Commun. 1990, 74, 1121–1124.
Yoffe, A. D. Low-dimensional systems-quantum-size effects and electronic-properties of semiconductor microcrystallites (zero-dimensional systems) and some quasi-2-dimensional systems. Adv. Phys. 1993, 42, 173–262.
Yu, Z. H.; Li, J. B.; O’Connor, D. B.; Wang, L. W.; Barbara, P. F. Large resonant stokes shift in CdS nanocrystals. J. Phys. Chem. B 2003, 107, 5670–5674.
Yang, B. Q.; Schneeloch, J. E.; Pan, Z. W.; Furis, M.; Achermann, M. Radiative lifetimes and orbital symmetry of electronic energy levels of CdS nanocrystals: Size dependence. Phys. Rev. B 2010, 81, 073401.
Boens, N.; Qin, W.; Basaric, N.; Hofkens, J.; Ameloot, M.; Pouget, J.; Lefevre, J. -P.; Valeur, B.; Gratton, E.; vandeVen, M., et al. Fluorescence lifetime standards for time and frequency domain fluorescence spectroscopy. Anal. Chem. 2007, 79, 2137–2149.
van Driel, A. F.; Allan, G.; Delerue, C.; Lodahl, P.; Vos, W. L.; Vanmaekelbergh, D. Frequency-dependent spontaneous emission rate from CdSe and CdTe nanocrystals: Influence of dark states. Phys. Rev. Lett. 2005, 95, 236804.
Donega, C. D. M.; Bode, M.; Meijerink, A. Size- and temperature-dependence of exciton lifetimes in CdSe quantum dots. Phys. Rev. B 2006, 74, 085320.
Henry, C. H.; Nassau, K. Lifetimes of bound excitons in CdS. Phys. Rev. B 1970, 1, 1628–1634.
Nirmal, M.; Norris, D. J.; Kuno, M.; Bawendi, M. G.; Efros, A. L.; Rosen, M. Observation of the dark exciton in CdSe quantum dots. Phys. Rev. Lett. 1995, 75, 3728–3731.
Efros, A. L.; Rosen, M.; Kuno, M.; Nirmal, M.; Norris, D. J.; Bawendi, M. Band-edge exciton in quantum dots of semiconductors with a degenerate valence band: Dark and bright exciton states. Phys. Rev. B 1996, 54, 4843–4856.
Norris, D. J.; Efros, A. L.; Rosen, M.; Bawendi, M. G. Size dependence of exciton fine structure in CdSe quantum dots. Phys. Rev. B 1996, 53, 16347–16354.
Fomenko, V.; Nesbitt, D. J. Solution control of radiative and nonradiative lifetimes: A novel contribution to quantum dot blinking suppression. Nano Lett. 2008, 8, 287–293.
Hannah, D. C.; Dunn, N. J.; Ithurria, S.; Talapin, D. V.; Chen, L. X.; Pelton, M.; Schatz, G. C.; Schaller, R. D. Observation of size-dependent thermalization in CdSe nano-crystals using time-resolved photoluminescence spectroscopy. Phys. Rev. Lett. 2011, 107, 177403.
Deveaud, B.; Clerot, F.; Roy, N.; Satzke, K.; Sermage, B.; Katzer, D. S. Enhanced radiative recombination of free-excitons in GaAs quantum-wells. Phys. Rev. Lett. 1991, 67, 2355–2358.
Deveaud, B.; Clerot, F.; Roy, N.; Sermage, B.; Katzer, D. S. Enhanced radiative recombination of free-excitons in GaAs quantum-wells. Surf. Sci. 1992, 263, 491–495.
Deveaud, B.; Clerot, F.; Sermage, B.; Dumas, C.; Katzer, D. S. In Optical Phenomena in Semiconductor Structures of Reduced Dimensions, Nato Advanced Research Workshop on Frontiers of Optical Phenomena in Semicondutor Structures of Reduced Dimensions, Dordrecht; Boston, 1993; Lockwood, D. J.; Pinczuk, A.; North Atlantic Treaty Organization. Scientific Affairs, D. Eds. Kluwer Academic: Dordrecht; Boston, 1993; pp. 129–144.
Dahan, M.; Laurence, T.; Pinaud, F.; Chemla, D. S.; Alivisatos, A. P.; Sauer, M.; Weiss, S. Time-gated biological imaging by use of colloidal quantum dots. Opt. Lett. 2001, 26, 825–827.
Berezin, M. Y.; Achilefu, S. Fluorescence lifetime measurements and biological imaging. Chem. Rev. 2010, 110, 2641–2684.
Alivisatos, P. The use of nanocrystals in biological detection. Nat. Biotechnol. 2004, 22, 47–52.
Smit, K. J.; Ghiggino, K. P. Flash-photolysis studies of a sulfonated bis-styryl biphenyl fluorescent dye. Dyes Pigments 1990, 13, 45–53.
Fletcher, A. N.; Bliss, D. E.; Kauffman, J. M. Lasing and fluorescent characteristics of 9 new, flashlamp-pumpable, coumarin dyes in ethanol and ethanol-water. Opt. Commun. 1983, 47, 57–61.
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Li, Z., Qin, H., Guzun, D. et al. Uniform thickness and colloidal-stable CdS quantum disks with tunable thickness: Synthesis and properties. Nano Res. 5, 337–351 (2012). https://doi.org/10.1007/s12274-012-0214-5
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DOI: https://doi.org/10.1007/s12274-012-0214-5