“Giant” Multishell CdSe Nanocrystal Quantum Dots with Suppressed Blinking

@article{citeulike:2568128, abstract = {Abstract: Semiconductor nanocrystal quantum dots (NQDs) comprise an important class of inorganic fluorophores for applications from optoelectronics to biology. Unfortunately, to date, NQD optical properties (e.g., their efficient and particle-size-tunable photoluminescence) have been susceptible to instabilities at the bulk and single-particle levels. Specifically, ensemble quantum yields (QYs) in emission are dependent upon NQD surface chemistry and chemical environment, while at the single-particle level, NQDs are characterized by significant fluorescence intermittency (blinking) that hinders applications as single-photon light sources for quantum informatics and biolabels for real-time monitoring of single biomolecules. Furthermore, while NQDs are significantly more photostable than their organic dye counterparts, traditional NQDs photobleach over periods of seconds to many minutes. Here, we demonstrate for the first time that by encapsulating the NQD core in a sufficiently thick inorganic shell, we are able to divorce NQD function from NQD surface chemistry and chemical environment. We show that our giant NQDs (g-NQDs) are functionally distinct from standard core-only, core/shell and even core/multishell NQDs. g-NQDs are substantially less sensitive to changes in surface chemistry. They do not photobleach under continuous laser excitation over periods of several hours repeated over several days, and they exhibit markedly different blinking behavior; >20\% of the g-NQDs do not blink, while >40\% have on-time fractions of >80\%. All of these observations are in stark contrast with control samples comprising core-only and standard, thinner core/multishell NQDs.}, address = {Chemistry Division, Los Alamos National Laboratory, Los Alamos, New Mexico 87545}, author = {Chen, Yongfen and Vela, Javier and Htoon, Han and Casson, Joanna L. and Werder, Donald J. and Bussian, David A. and Klimov, Victor I. and Hollingsworth, Jennifer A. }, citeulike-article-id = {2568128}, doi = {http://dx.doi.org/10.1021/ja711379k}, journal = {J. Am. Chem. Soc.}, month = {March}, posted-at = {2008-05-06 21:39:24}, priority = {2}, title = {\&\#x201c;Giant\&\#x201d; Multishell CdSe Nanocrystal Quantum Dots with Suppressed Blinking}, url = {http://dx.doi.org/10.1021/ja711379k}, year = {2008} }

TY - JOUR ID - citeulike:2568128 L3 - citeulike-article-id:2568128 TI - “Giant” Multishell CdSe Nanocrystal Quantum Dots with Suppressed Blinking JF - J. Am. Chem. Soc. AD - Chemistry Division, Los Alamos National Laboratory, Los Alamos, New Mexico 87545 N2 - Abstract: Semiconductor nanocrystal quantum dots (NQDs) comprise an important class of inorganic fluorophores for applications from optoelectronics to biology. Unfortunately, to date, NQD optical properties (e.g., their efficient and particle-size-tunable photoluminescence) have been susceptible to instabilities at the bulk and single-particle levels. Specifically, ensemble quantum yields (QYs) in emission are dependent upon NQD surface chemistry and chemical environment, while at the single-particle level, NQDs are characterized by significant fluorescence intermittency (blinking) that hinders applications as single-photon light sources for quantum informatics and biolabels for real-time monitoring of single biomolecules. Furthermore, while NQDs are significantly more photostable than their organic dye counterparts, traditional NQDs photobleach over periods of seconds to many minutes. Here, we demonstrate for the first time that by encapsulating the NQD core in a sufficiently thick inorganic shell, we are able to divorce NQD function from NQD surface chemistry and chemical environment. We show that our giant NQDs (g-NQDs) are functionally distinct from standard core-only, core/shell and even core/multishell NQDs. g-NQDs are substantially less sensitive to changes in surface chemistry. They do not photobleach under continuous laser excitation over periods of several hours repeated over several days, and they exhibit markedly different blinking behavior; >20% of the g-NQDs do not blink, while >40% have on-time fractions of >80%. All of these observations are in stark contrast with control samples comprising core-only and standard, thinner core/multishell NQDs. AU - Chen, Yongfen AU - Vela, Javier AU - Htoon, Han AU - Casson, Joanna AU - Werder, Donald AU - Bussian, David AU - Klimov, Victor AU - Hollingsworth, Jennifer PY - 2008/03/20/ UR - http://dx.doi.org/10.1021/ja711379k ER -