AI Chat Paper
Discover the SciOpen Platform and Achieve Your Research Goals with Ease.
The energy and charge transfer dynamics of directly coupled Au–CdSe hybrid nanocrystals have been studied using time-resolved photoluminescence (PL) techniques. The PL of such nanohybrids was found to be quenched dramatically compared to that of both CdSe quantum dots and mixtures of CdSe quantum dots with Au nanoparticles. Fluorescence decay curves of the Au–CdSe nanohybrids show three distinct decay channels with the fastest one associated with the transfer of electrons from the CdSe portion to the Au portion. The holes on the CdSe portion created by such charge transfer were then quickly taken away by the solution, while the electrons on the Au portion slowly leaked into the solution as well, thus serving as a reductant for redox reactions. Using a model reaction based on the reduction of methylene blue by the leaking electrons, our photocatalytic experiments indicate that the electrons can be temporarily retained in the Au portion (most likely at the Au–capping agent interface) for a dramatically long timescale, up to 100 min. Finally, by merging all of the observations in the time-resolved PL measurements, we were able to figure out a relatively complete picture of charge transfer and retention in the Au–CdSe nanohybrids. This picture is expected to guide researchers in designing modern photocatalysts and solar cells constructed from nanoscale metal–semiconductor hybrids.
Atwater, H. A.; Polman, A. Plasmonics for improved photovoltaic devices. Nat. Mater. 2010, 9, 205–213.
Costi, R.; Saunders, A. E.; Banin, U. Colloidal hybrid nanostructures: A new type of functional materials. Angew. Chem. Int. Ed. 2010, 49, 4878–4897.
Cozzoli, P. D.; Pellegrino, T.; Manna, L. Synthesis, properties and perspectives of hybrid nanocrystal structures. Chem. Soc. Rev. 2006, 35, 1195–1208.
Achermann, M. Exciton–plasmon interactions in metal–semiconductor nanostructures. J. Phys. Chem. Lett. 2010, 1, 2837–2843.
Gueroui, Z.; Libchaber, A. Single-molecule measurements of gold-quenched quantum dots. Phys. Rev. Lett. 2004, 93, 166108.
Shimizu, K. T.; Woo, W. K.; Fisher, B. R.; Eisler, H. J.; Bawendi, M. G. Surface-enhanced emission from single semiconductor nanocrystals. Phys. Rev. Lett. 2002, 89, 117401.
Biteen, J. S.; Pacifici, D.; Lewis, N. S.; Atwater, H. A. Enhanced radiative emission rate and quantum efficiency in coupled silicon nanocrystal–nanostructured gold emitters. Nano Lett. 2005, 5, 1768–1773.
Govorov, A. O.; Lee, J.; Kotov, N. A. Theory of plasmon-enhanced Förster energy transfer in optically excited semiconductor and metal nanoparticles. Phys. Rev. B 2007, 76, 125308.
Anger, P.; Bharadwaj, P.; Novotny, L. Enhancement and quenching of single-molecule fluorescence. Phys. Rev. Lett., 2006, 96, 113002.
Kühn, S.; Mori, G.; Agio, M.; Sandoghdar, V. Modification of single molecule fluorescence close to a nanostructure: Radiation pattern, spontaneous emission and quenching. Mol. Phys. 2008, 106, 893–908.
Dong, Z. C.; Zhang, X. L.; Gao, H. Y.; Luo, Y.; Zhang, C.; Chen, L.G.; Zhang, R.; Tao, X.; Zhang, Y.; Yang, J. L.; Hou, J. G. Generation of molecular hot electroluminescence by resonant nanocavity plasmons. Nat. Photonics 2010, 4, 50–54.
Mokari, T.; Rothenberg, E.; Popov, I.; Costi, R.; Banin, U. Selective growth of metal tips onto semiconductor quantum rods and tetrapods. Science 2004, 304, 1787–1790.
Gu, H. W.; Yang, Z. M.; Gao, J. H.; Chang, C. K.; Xu, B. Heterodimers of nanoparticles: Formation at a liquid–liquid interface and particle-specific surface modification by functional molecules. J. Am. Chem. Soc. 2005, 127, 34–35.
Yu, H.; Chen, M.; Rice, P. M.; Wang, S. X.; White, R. L.; Sun, S. H. Dumbbell-like bifunctional Au–Fe3O4 nanoparticles. Nano Lett. 2005, 5, 379–382.
Gu, H. W.; Zheng, R. K.; Zhang, X. X.; Xu, B. Facile one-pot synthesis of bifunctional heterodimers of nanoparticles: A conjugate of quantum dot and magnetic nanoparticles. J. Am. Chem. Soc. 2004, 126, 5664–5665.
Mokari, T.; Sztrum, G. C.; Salant, A.; Rabani, E.; Banin, U. Formation of asymmetric one-sided metal-tipped semiconductor nanocrystal dots and rods. Nat. Mater. 2005, 4, 855–863.
Zeng, J.; Huang, J. L.; Liu, C.; Wu. C. H.; Lin, Y.; Wang, X. P.; Zhang, S. Y.; Hou, J. G.; Xia, Y. N. Gold-based hybrid nanocrystals through heterogeneous nucleation and growth. Adv. Mater. 2010, 22, 1936–1940.
Steiner, D.; Mokari, T.; Banin, U.; Millo. O. Electronic structure of metal–semiconductor nanojunctions in gold CdSe nanodumbbells. Phys. Rev. Lett. 2005, 95, 056805.
Costi, R.; Saunders, A. E.; Elmalem, E.; Salant, A.; Banin, U. Visible light-induced charge retention and photocatalysis with hybrid CdSe–Au nanodumbbells. Nano Lett. 2008, 8, 637–641.
Haldar, K. K.; Sen, T.; Patra, A. Metal conjugated semiconductor hybrid nanoparticle-based fluorescence resonance energy transfer. J. Phys. Chem. C 2010, 114, 4869–4874.
Hosoki, K.; Tayagaki, T.; Yamamato, S.; Matsuda, K.; Kanemitsu, Y. Direct and stepwise energy transfer from excitons to plasmons in close-packed metal and semiconductor nanoparticle monolayer films. Phys. Rev. Lett. 2008, 100, 207404.
Muller, B. R.; Majoni, S.; Meissner, D.; Memming, R. Photocatalytic oxidation of ethanol on micrometer- and nanometer-sized semiconductor particles. J. Photochem. Photobiol. A-Chem. 2002, 151, 253–265.
Menagen, G.; Macdonald, J. E.; Shemesh, Y.; Popov, I.; Banin, U. Au growth on semiconductor nanorods: Photoinduced versus thermal growth mechanisms. J. Am. Chem. Soc. 2009, 131, 17406–17411.
Alvarez, M. M.; Khoury, J. T.; Schaaff, T. G.; Shafigullin, M. N.; Vezmar, I.; Whetten, R. L. Optical absorption spectra of nanocrystal gold molecules. J. Phys. Chem. B 1997, 101, 3706–3712.
Saunders, A. E.; Popov, I.; Banin, U. Synthesis of hybrid CdS–Au colloidal nanostructures. J. Phys. Chem. B 2006, 110, 25421–25429.
Zeng, J.; Lu, W.; Wang, X. P.; Wang, B.; Wang, G. Z.; Hou, J. G. Fine tuning photoluminescence properties of CdSe nanoparticles by surface states modulation. J. Colloid Interface Sci. 2006, 298, 685–688.
Klimov, V. I. Optical nonlinearities and ultrafast carrier dynamics in semiconductor nanocrystals. J. Phys. Chem. B 2000, 104, 6112–6123.
Bawendi, M. G.; Carroll, P. J.; Wilson, W. L.; Brus, L. E. Luminescence properties of CdSe quantum crystallites: Resonance between interior and surface localized states. J. Chem. Phys. 1992, 96, 946–954.
Ito, Y.; Matsuda, K.; Kanemitsu, Y. Mechanism of photoluminescence enhancement in single semiconductor nanocrystals on metal surfaces. Phys. Rev. B 2007, 75, 033309.
Hallock, A. J.; Berman, E. S. F.; Zare, R. N. Ultratrace kinetic measurements of the reduction of methylene blue. J. Am. Chem. Soc. 2003, 125, 1158–1159.
Huang, J.; Huang, Z. Q.; Yang, Y.; Zhu, H. M.; Lian, T. Q. Multiple exciton dissociation in CdSe quantum dots by ultrafast electron transfer to adsorbed methylene blue. J. Am. Chem. Soc. 2010, 132, 4858–4864.
Ohgi, T.; Sheng, H. Y.; Dong, Z. C.; Nejoh, H.; Fujita, D. Charging effects in gold nanoclusters grown on octanedithiol layers. Appl. Phys. Lett. 2001, 79, 2453–2455.
Jana, N. R.; Peng, X. G. Single-phase and gram-scale routes toward nearly monodisperse Au and other noble metal nanocrystals. J. Am. Chem. Soc. 2003, 125, 14280–14281.
Bardhan, M.; Mandal, P.; Tzeng, W. B.; Ganguly, T. Investigations on the photoreactions of phenothiazine and phenoxazine in presence of 9-cyanoanthracene by using steady state and time resolved spectroscopic techniques. J. Fluoresc. 2010, 20, 1061–1068.
Zhang, X. L.; Chen, L. G.; Lv, P.; Gao, H. Y.; Wei, S. J.; Dong, Z. C.; Hou, J. G. Fluorescence decay of quasimonolayered porphyrins near a metal surface separated by short-chain alkanethiols. Appl. Phys. Lett. 2008, 92, 223118.
