Driving oxygen coordinated ligand exchange at nanocrystal surfaces using trialkylsilylated chalcogenides

Caldwell, Marissa A.; Albers, Aaron E.; Levy, Seth C.; Pick, Teresa E.; Cohen, Bruce E.; Helms, Brett A.; Milliron, Delia J.

doi:10.1039/c0cc02220a

Cited by 34 publications

(34 citation statements)

References 26 publications

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“…26–28 Polymers were synthesized from 2 kDa polyacrylic acid and optimized for non-aggregation with a 3:5:1 ratio of octyl, carboxylate, and ammonium groups (PAOA polymers; Figure S3). Dynamic light scattering (DLS), negative-stain electron microscopy, and fluorescence correlation spectroscopy (FCS) measurements of aqueous QDs show that the combination of surface ligands and polymer adds ~6 nm to the inorganic diameters measured by TEM (Figures 1 and S2), consistent with measurements for other QDs 24 (Table S1). Aqueous CdSe/CdS QDs showed no measurable change in quantum yield compared to their hydrophobic counterparts (Table S3).…”

Section: Resultssupporting

confidence: 74%

Covalent Protein Labeling and Improved Single-Molecule Optical Properties of Aqueous CdSe/CdS Quantum Dots

Wichner¹,

Mann

Powers

et al. 2017

ACS Nano

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Semiconductor quantum dots (QDs) have proven to be superior probes for single molecule imaging compared to organic or genetically encoded fluorophores, but they are limited by difficulties in protein targeting, their larger size and on-off blinking. Here, we report compact aqueous CdSe/CdS QDs with significantly improved bioconjugation efficiency and superior single-molecule optical properties. We have synthesized covalent protein labeling ligands (i.e., SNAP tags) that are optimized for nanoparticle use, and QDs functionalized with these ligands label SNAP-tagged proteins ~10-fold more efficiently than existing SNAP ligands. Single-molecule analysis of these QDs shows 99% of time spent in the fluorescent on state, ~4-fold higher quantum efficiency than standard CdSe/ZnS QDs, and 350 million photons detected before photobleaching. Bright signals of these QDs enable us to track the stepping movement of a kinesin motor in vitro and the improved labeling efficiency enables tracking of single kinesins in live cells.

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Section: Resultssupporting

confidence: 74%

Covalent Protein Labeling and Improved Single-Molecule Optical Properties of Aqueous CdSe/CdS Quantum Dots

Wichner¹,

Mann

Powers

et al. 2017

ACS Nano

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“…[57] Excellent field-effect mobilities (1-10 cm 2 /V s range) have been reported, as have promising photoluminescence behavior. The absence of reports of high-performance bipolar devices, such as photodiodes, photodetectors, or electroluminescent devices, suggests that excellent transport and minimal excess recombination have yet to be combined within a single QD solid of this novel and highly promising class of materials.…”

Section: Pathways To Improvementmentioning

confidence: 95%

Materials processing strategies for colloidal quantum dot solar cells: advances, present-day limitations, and pathways to improvement

et al. 2013

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Colloidal quantum dot photovoltaic devices have improved from initial, sub-1% solar power conversion efficiency to current record performance of over 7%. Rapid advances in materials processing and device physics have driven this impressive performance progress. The highestefficiency approaches rely on a fabrication process that starts with nanocrystals in solution, initially capped with long organic molecules. This solution is deposited and the resultant film is treated using a solution containing a second, shorter capping ligand, leading to a cross-linked, non-redispersible, and dense layer. This procedure is repeated, leading to the widely employed layer-by-layer solid-state ligand exchange. We will review the properties and features of this process, and will also discuss innovative pathways to creating even higher-performing films and photovoltaic devices.The most abundant and cleanest source of energy available on Earth, solar energy, is also the most underutilized. Its peak intensity is 1000 W/m 2 which, averaged over space and time, provides vastly more energy daily than the global population consumes. Solar energy thus offers, in principle, a compelling option to power a sustainable and increasingly electricitycentric future.[1] While a substantial photovoltaic industry is beginning to take shape worldwide, driven by early generation solar technology based on silicon and compound semiconductors such as cadmium telluride, the fact remains that, in order to compete with traditional energy sources, particularly with cheap and plentiful natural gas, solar photovoltaic systems must cost, fully installed, no more than $1 per watt-peak, which translates to a levelized cost of electricity of approximately $0.05/kWh over a system lifetime.[2] This is noticeably less than current first-and second-generation commercially available solar products, which are held back by higher materials and manufacturing costs; combined with installation costs influenced by the bulky, heavy, and rigid nature of the solar panels themselves.Third-generation photovoltaic systems, including organic, dye-sensitized, and colloidal quantum dot (CQD) solar cells, offer a path to low-weight, low-cost, and prospectively highefficiency solar energy capture and conversion. While thirdgeneration technologies currently function at lower efficiency than commercial first-generation modules, significant pathways exist to reach and surpass the conversion efficiencies required to be commercially feasible.CQD solar cells are of particular interest among the mentioned technologies due to the size tunability of these nanometer-scale semiconductor particles, pictured in Fig. 1(a). The optimal bandgap for a single-junction solar cell as reported by Shockley and Queisser [4] is 1.1 eV; while this offers a limited selection of bulk semiconductors, the quantum confinement effect allows the fabrication of quantum dots (QDs) with reasonable properties [5] using bulk small bandgap semiconductor compounds such as lead sulfide (PbS) and lead selenide (PbSe)...

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“…In particular, the use of TMS 2 S as the S precursor could play a role in silylating carboxylate- and phosphonate-based ligands 30 and thereby deprotecting the nanocrystal surface in a manner analogous to that recently noted for the use of trimethylsilyl groups in driving ligand exchange reactions at nanocrystal surfaces. 31 While TMS 2 S is well known as a precursor for sulphide shells on QDs under simultaneous addition alongside alkylated metal sources, its use in SILAR is atypical. 11–13 We chose to apply doses equivalent to approximately 0.8 ML incremental shell thickness (= 0.27 nm) in each SILAR cycle.…”

Section: Experimental Designmentioning

confidence: 99%

Alternating layer addition approach to CdSe/CdS core/shell quantum dots with near-unity quantum yield and high on-time fractions

et al. 2012

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We report single-particle photoluminescence (PL) intermittency (blinking) with high on-time fractions in colloidal CdSe quantum dots (QD) with conformal CdS shells of 1.4 nm thickness, equivalent to approximately 4 CdS monolayers. All QDs observed displayed on-time fractions > 60% with the majority > 80%. The high-on-time-fraction blinking is accompanied by fluorescence quantum yields (QY) close to unity (up to 98% in an absolute QY measurement) when dispersed in organic solvents and a monoexponential ensemble photoluminescence (PL) decay lifetime. The CdS shell is formed in high synthetic yield using a modified selective ion layer adsorption and reaction (SILAR) technique that employs a silylated sulfur precursor. The CdS shell provides sufficient chemical and electronic passivation of the QD excited state to permit water solubilization with greater than 60% QY via ligand exchange with an imidazole-bearing hydrophilic polymer.

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Driving oxygen coordinated ligand exchange at nanocrystal surfaces using trialkylsilylated chalcogenides

Cited by 34 publications

References 26 publications

Covalent Protein Labeling and Improved Single-Molecule Optical Properties of Aqueous CdSe/CdS Quantum Dots

Covalent Protein Labeling and Improved Single-Molecule Optical Properties of Aqueous CdSe/CdS Quantum Dots

Materials processing strategies for colloidal quantum dot solar cells: advances, present-day limitations, and pathways to improvement

Alternating layer addition approach to CdSe/CdS core/shell quantum dots with near-unity quantum yield and high on-time fractions

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