Synthesis and characterization of PbS nanoparticles in block copolymer micelles

Schneider, Thomas; Haase, Markus; Kornowski, Andreas; Naused, Sabine; Weller, Horst; Förster, Beate; Antonietti, Markus

doi:10.1002/bbpc.19971011119

Cited by 36 publications

(38 citation statements)

References 12 publications

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“…This is in contrast to a previous report that only needle-shaped particles would show a distinct band gap absorption around 580 nm and spherical and cubic shaped particles would show an absorption spectrum similar to that of the PbS nanoparticles stabilized with PVP. 43 The discrepancies noticed from the optical absorption and previous work will require further investigation.…”

Section: Discussionmentioning

confidence: 91%

“…37 Later work by Schneider and co-workers reported that the spectrum of needle-shaped PbS particles prepared using amphiphilic block copolymer micelles exhibits the excitonic peak at 580 nm. 43 The excitonic peak disappeared for spherical particles prepared with higher lead concentration and lower temperature. No explanation was provided as to why the peak disappeared.…”

Section: Discussionmentioning

confidence: 98%

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Synthesis, Optical Spectroscopy and Ultrafast Electron Dynamics of PbS Nanoparticles with Different Surface Capping

et al. 2000

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Lead sulfide, PbS, nanoparticles have been synthesized using a number of surface capping agents including poly(vinyl-alcohol) (PVA), poly(vinyl-pyrrolidone) PVP, gelatin, DNA, polystyrene (PS), and poly(methylmethacrylate) (PMMA). The electronic absorption spectra and particle shapes have been found to depend on the capping molecules used. An excitonic feature at 580 nm was observed for capping with PVA and DNA, while no such excitonic feature was observed for PVP, PS or PMMA. A weak excitonic feature was observed for gelatin. The particle shape varied from cubic, needle to spherical as controlled by the capping agents. For the DNA-capped PbS nanocrystals, HRTEM demonstrated the presence of oval crystals with a diameter of 3-8 nm. Powder X-ray diffraction of the PbS-DNA nanocrystals showed the characteristic peaks for PbS at 2.97, 3.43, and 2.10 Å. The XRD suggested the size of the nanoparticles to be approximately 4 nm. The dynamics of photoinduced electrons in PbS nanoparticles have been determined using femtosecond laser spectroscopy. For all the samples studied the electronic relaxation has been found to be very similar and follow a double exponential decay with time constants of 1.2 and 45 ps. The fast decay can be attributed to trapping from the conduction band to shallow traps or from shallow traps to deep traps while the slower decay is most likely due to electron-hole recombination mediated by a high density of surface trap states that lie within the band gap. The decay profiles are independent of particle size, shape, surface capping, probe wavelength, and excitation intensity. The results seem to indicate a high density of surface states, consistent with no detectable fluorescence signal at room temperature.

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Section: Discussionmentioning

confidence: 91%

Section: Discussionmentioning

confidence: 98%

Synthesis, Optical Spectroscopy and Ultrafast Electron Dynamics of PbS Nanoparticles with Different Surface Capping

et al. 2000

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“…The small size of the micelle core opens an avenue to employ micelle nanoreactors for the synthesis of narrowly distributed semiconductors with marked quantum-size (Q-size) effects. This micellar approach has been demonstrated in a number of papers where Q-sized semiconductors (ZnSe, [24] CdS, [25] CdSe, [26] CdTe, [25b,27] PbS, [28] ZnS [29] ) were fabricated inside AOT (sodium bis(2-ethylhexyl)sulfosuccinate) reverse micelles using ion-exchange reactions. This anionic surfactant has received particular attention because of its ability to solubilize relatively large amounts of water in a variety of hydrophobic organic solvents.…”

Section: Micellar Systemsmentioning

confidence: 98%

Nanoparticle Synthesis in Engineered Organic Nanoscale Reactors

Shchukin

Sukhorukov²

2004

Advanced Materials

360

253

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In this review, the recent achievements in the synthesis of inorganic nanomaterials inside the spatially confined volume of individual micro‐ and submicroreactors (emulsions, micelles, organized thin films, polyelectrolyte capsules, etc.) are presented. The advantages and shortcomings of each type of microreactor are discussed. Particular attention is paid to polyelectrolyte capsules as confined microreactors with controlled shell permeability and the possibility of shell engineering on the nanolevel, thus tailoring different functionalities. Nanomaterials synthesized inside a confined multifunctional microreactor have several advantages: i) absence of particle aggregates, ii) amorphous or metastable crystal phases, and iii) unique composite inorganic/inorganic and inorganic/organic structures.

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“…At the nucleation stage, the microemulsion droplet may play a role in confining the size and shape of the crystal nucleus [23], which would eventually affect the shape formation of the final products [24]. This growth pattern was also observed by Weller and coworkers for PbS needles in amphiphilic block copolymer micelles [25] and by Yan and co-workers for the growth of the ZnO nanowires in a solvothermal colloid system [26].…”

Section: Resultsmentioning

confidence: 66%