Synthesis and Optical Properties of Thiol-Stabilized PbS Nanocrystals

Zhao, Xusheng; Gorelikov, Ivan; Musikhin, S. F.; Cauchi, Sam; Sukhovatkin, Vlad; Sargent, Edward H.; Kumacheva, Eugenia

doi:10.1021/la048730y

Cited by 98 publications

(99 citation statements)

References 26 publications

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“…Similar observations have previously been made in other aqueous-synthesized PbS nanocrystals. [14,15] Increasing absorption at higher energies and strong photoluminescence peaking near 1100 nm suggests quantum confinement and band-edge luminescence consistent with 4 nm PbS nanocrystals. [16] Figure 3b shows additional photoluminescence spectra for four samples under excitation at 830 nm.…”

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confidence: 88%

Efficient Infrared‐Emitting PbS Quantum Dots Grown on DNA and Stable in Aqueous Solution and Blood Plasma

et al. 2005

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Quantum-dot nanocrystals have been used to label single molecules during living-cell assays [1] and provide direct visual guidance and real-time confirmation of complete resection during cancer surgery in an animal model. [2] The use of quantum dots for deep-tissue imaging accompanied by low autofluorescence in vivo requires emission in the second infrared biological window of 1000±1200 nm combined with stability in biological media. Surface chemistry determines the chemical and optical stability of quantum dots. A stabilizing outer shell minimizes diffusion of oxygen to the surface of the core of the nanoparticle, as demonstrated using a high-bandgap semiconductor shell [3] and a dielectric shell.[4] Silanized nanoparticles have been shown to be water soluble and to retain the absorption and emission spectra of the original particles; however, the nanoparticles lost 60±80 % of their original quantum efficiency in this process. Recently, oligomeric phosphines [5] have been employed to form three thin concentric sublayers around quantum dots: an inner phosphine layer for dot-surface passivation, a linking layer for protection, and an outer functionalized layer for miscibility and subsequent chemical modification or conjugation to biomolecules. In the infrared, the application of this multistep synthetic method to type-II core±shell nanoparticles has resulted in quantum dots that show modest degradation in 37 C plasma over the course of half an hour.[3]Here we adopt an entirely different strategy: we report the first growth of efficient infrared photoluminescent quantum dots directly on a DNA template. Our infrared-emitting quantum dots grown on the biomolecular template are efficient and stable in water, serum, and blood plasma.DNA has previously been decorated with metal nanoparticles 5±10 nm in diameter through the use of thiol linkages. [6] DNA has also been used as a long-term stabilizer and template in the growth of CdS nanocrystals, but with no reports of a photoluminescence quantum efficiency.[7±10] Related progress has also been made in synthesizing CdS nanoparticles in which growth was carried out at room temperature followed by annealing at 80 C to improve photoluminescent properties; quantum efficiencies of 10 ±4 were estimated.[11] The only previous report of DNA-templated growth on PbS has yielded materials with no detectable luminescence in the infrared.[12]We worked instead at a synthesis temperature at which chemical interaction was possible between the metal cations used in PbS growth and at least two classes of sites on DNA: the phosphate backbone, and also DNA's purine and pyrimidine bases. The bases provide an additional opportunity for control over the growth of nanoparticles and the passivation of their surface states. The synthesis reported herein is simple, reproducible, and yields PbS nanoparticles with exceptional stability and photoluminescence quantum efficiency. Energyfiltered transmission electron microscopy (EFTEM) reveals cubic-latticed PbS quantum dots 4 nm in diameter on a network...

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Efficient Infrared‐Emitting PbS Quantum Dots Grown on DNA and Stable in Aqueous Solution and Blood Plasma

et al. 2005

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“…The crystal growth of hydrothermally treated PbS nanoparticles, for instance, is reported to occur through the Ostwald ripening mechanism. 29 The synthesis conditions are similar for both QDs and NPs in terms of the temperature, duration of the reaction, surface adsorption of anions (Ch 3 COO − ), capping ligands, and concentration. The difference is in the source of sulfur, which seems to be the crucial factor for OA during crystal growth.…”

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confidence: 99%

Role of surface states and defects in the ultrafast nonlinear optical properties of CuS quantum dots

2014

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We report facile preparation of water dispersible CuS quantum dots (2–4 nm) and nanoparticles (5–11 nm) through a nontoxic, green, one-pot synthesis method. Optical and microstructural studies indicate the presence of surface states and defects (dislocations, stacking faults, and twins) in the quantum dots. The smaller crystallite size and quantum dot formation have significant effects on the high energy excitonic and low energy plasmonic absorption bands. Effective two-photon absorption coefficients measured using 100 fs laser pulses employing open-aperture Z-scan in the plasmonic region of 800 nm reveal that CuS quantum dots are better ultrafast optical limiters compared to CuS nanoparticles.

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“…The former is based on the reaction between molecular or ionic precursors in solution phase and is more familiar to chemists [76][77][78]. However, the latter method which is more familiar to engineers includes carving of bulk semiconductor lithographically or electrochemically into particles with sizes in the range of 1-10 nm [4].…”

Section: Synthesis Of Quantum Dots and Deposition Techniquesmentioning

confidence: 99%

Recent Developments in Quantum Dots/CNT Co-Sensitized Organic Solar Cells

Soltani¹,

Katbab²,

Ameri³

2017

J Material Sci Eng

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Polymer solar cells (PSCs) are emerging alternative candidates to the standard silicone technology for green and renewable energy generation owing to their flexibility and solution processability. Bulk heterojunction (BHJ) organic solar cells (OSCs) based on conjugated semiconducting polymers as donor (D) and fullerene derivatives as acceptor (A) offer large D/A interfacial area, which overcomes the short exciton diffusion length. Although, recent advances in narrow band gap semiconducting polymers have led to the improvement in power conversion efficiency of organic photovoltaics (OPVs) beyond 10%, inefficient charge separation and low carrier mobility as well as negligible photon harvesting in near-infrared (NIR) and/or infrared (IR) region of the solar spectrum have still remained as bottle neck for ultimate performance of OPVs. Most PSCs only absorb the UV-visible part of the solar spectrum, leading to the low light harvesting efficiency. Hence, solution processed photoactive materials comprising nanostructured semiconducting inorganic quantum dots (QDs) as sensitizer have attracted great attention to improve energy conversion efficiency of the OPVs. This is attributed to the outstanding optoelectronic properties of QDs such as band gap tunability, potential NIR photons harvesting and multi exciton generation (MEG). However, the main shortcoming of inorganic QDs based OSCs is randomly hopping charge transport among discrete QD particles, which can be tackled through hybridization with one dimensional (1D) electrically conductive nanostructured materials such as carbon nanotube (CNT). By this way, CNT particles would behave as support for anchoring the light harvesting semiconductor QDs, leading to the enhancement of the exciton dissociation and charge transport towards the corresponding electrodes. Recently, manufacturing PSCs co-sensitized by QD loaded CNT has been shown as a promising direction to maximize performance of the device. This article reviews the recent developments in enhancement of OPVs" performance by utilization of high efficient light harvesting QDs and/or their hybrid with 1D CNTs.

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Synthesis and Optical Properties of Thiol-Stabilized PbS Nanocrystals

Cited by 98 publications

References 26 publications

Efficient Infrared‐Emitting PbS Quantum Dots Grown on DNA and Stable in Aqueous Solution and Blood Plasma

Efficient Infrared‐Emitting PbS Quantum Dots Grown on DNA and Stable in Aqueous Solution and Blood Plasma

Role of surface states and defects in the ultrafast nonlinear optical properties of CuS quantum dots

Recent Developments in Quantum Dots/CNT Co-Sensitized Organic Solar Cells

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