Colloidal 3-Mercaptopropionic Acid Capped Lead Sulfide Quantum Dots in a Low Boiling Point Solvent

Reinhart, Chase C.; Johansson, Erik M. J.

doi:10.1021/jacs.7b00158

Cited by 13 publications

(12 citation statements)

References 55 publications

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“…Notably, a red shift of ∼2 nm in the absorption and PL spectra are observed after ligand treatment. Considering the unchanged size and morphology, the red-shifting phenomenon could be due to the ligand replacement of the CsPbBr 3 NPL surface by the shorter DDA + ligand, which facilitates the overlap of NPL wave functions. − Obviously, the treated CsPbBr 3 NPLs showed a remarkable increase of the PL intensity and PLQY (from 45.1% to over 69.4%) and emitted a much stronger blue light under UV lamp irradiation (Figure b).…”

Section: Resultsmentioning

confidence: 99%

Surface Ligand Engineering toward Brightly Luminescent and Stable Cesium Lead Halide Perovskite Nanoplatelets for Efficient Blue-Light-Emitting Diodes

et al. 2019

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Recently, two-dimensional colloidal perovskite nanoplatelets (NPLs) have attracted great attention as one of the most promising candidate blue emitters due to their large exciton binding energy and precisely tunable thickness. However, the lack of techniques to simultaneously obtain highly emissive and stable perovskite NPLs has limited the successful exploitation of highly efficient perovskite NPL-based optoelectronic devices. Herein, we report the surface ligand-engineering strategy to enhance the photoluminescence quantum yields and stability of perovskite NPLs using a short-chain halide ion-pair ligand. Benefits from the shorter-chain ligand treatment, the electronic conductivity, and carrier injection of perovskite NPL films have also been improved significantly, enabling us to realize highly efficient blue (469 nm) electroluminescence devices with a peak external quantum efficiency of 1.42%, which is among the highest efficiencies of colloidal pure-bromide perovskite NPL-based light-emitting diodes.

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Section: Resultsmentioning

confidence: 99%

Surface Ligand Engineering toward Brightly Luminescent and Stable Cesium Lead Halide Perovskite Nanoplatelets for Efficient Blue-Light-Emitting Diodes

et al. 2019

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“…Recently, an assortment of nanomaterial-based fluorophores has been engineered to efficiently emit light at wavelengths spanning two infrared spectral windows, − typically denoted as the first near-infrared window (NIR-I, 700–950 nm) and the second near-infrared window (NIR-II, 950–2000 nm), with the latter also known as the short-wave infrared (SWIR). There is some variability in the literature over the nomenclature and spectral ranges of these windows, and it is noteworthy that the IUPAC defines the infrared A spectrum (IR-A) as 780–1400 nm.…”

Section: Introductionmentioning

confidence: 99%

“…The vast majority of studies to date exploring the SWIR window have focused on the enhanced penetration depth of SWIR photons through biological tissue deriving from reduced scattering. Compared with images collected at shorter wavelengths, SWIR images of thick tissues exhibit higher resolution and higher contrast, with particularly impressive outcomes for optical vascular imaging in living animals. − The diversity of SWIR-emitting nanomaterials is rapidly expanding and now includes carbon nanotubes, rare-earth-doped nanocrystals, and semiconductor QDs composed of InAs, PbS, PbSe, Ag 2 S, Ag 2 Se, Cd 3 P 2 , CuInSe 2 , and HgCdTe. − …”

Section: Introductionmentioning

confidence: 99%

Short-Wave Infrared Quantum Dots with Compact Sizes as Molecular Probes for Fluorescence Microscopy

Sarkar

Geng

et al. 2020

J. Am. Chem. Soc.

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Materials with short-wave infrared (SWIR) emission are promising contrast agents for in vivo animal imaging, providing high-contrast and high-resolution images of blood vessels in deep tissues. However, SWIR emitters have not been developed as molecular labels for microscopy applications in the life sciences, which require optimized probes that are bright, stable, and small. Here, we design and synthesize semiconductor quantum dots (QDs) with SWIR emission based on Hg x Cd 1−x Se alloy cores red shifted to the SWIR by epitaxial deposition of thin Hg x Cd 1−x S shells with a small band gap. By tuning alloy composition alone, the emission can be shifted across the visible-to-SWIR (VIR) spectra while maintaining a small and equal size, allowing direct comparisons of molecular labeling performance across a broad range of wavelength. After coating with click-functional multidentate polymers, the VIR-QD spectral series has high quantum yield in the SWIR (14−33%), compact size (13 nm hydrodynamic diameter), and long-term stability in aqueous media during continuous excitation. We show that these properties enable diverse applications of SWIR molecular probes for fluorescence microscopy using conjugates of antibodies, growth factors, and nucleic acids. A broadly useful outcome is a 10−55-fold enhancement of the signal-to-background ratio at both the single-molecule level and the ensemble level in the SWIR relative to visible wavelengths, primarily due to drastically reduced autofluorescence. We anticipate that VIR-QDs with SWIR emission will enable ultrasensitive molecular imaging of low-copy number analytes in biospecimens with high autofluorescence.

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“…Short molecules, similar to those used in the fabrication of the early CQD solar cells, allow for achieving charge transport while retaining the quantum confinement. For example, aryl‐ or alkyl‐thiols have been shown to stabilize PbS CQDs in chlorinated organic solvents . However, only partial investigations are available, and at this stage it is not possible to evaluate their performances in devices.…”

Section: Assembly Of Cqd Thin Filmsmentioning

confidence: 99%

Lead‐Chalcogenide Colloidal‐Quantum‐Dot Solids: Novel Assembly Methods, Electronic Structure Control, and Application Prospects

Balazs

Loi

2018

Advanced Materials

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Colloidal particles are formed and stabilized by surrounding the core with a surfactant shell that keeps the CQDs isolated and prevents charge transport though the arrays. [6] Replacing this shell by shorter molecules, so-called ligands, decreases the interparticle distance and increases the electronic coupling. This is thus a crucial step in forming conductive, practically relevant assemblies.Most early studies relied on a repetitive, layer-by-layer deposition and ligand exchange of CQDs to achieve thick conductive films, a method that resulted in the demonstration of field effect transistors and solar cells of noteworthy performances. [7][8][9][10][11][12][13][14][15] However, this technique only allows for limited control of the nanostructure and is not suitable for upscaling. The last few years brought several improvements in controlling the properties of CQD thin films with focus on both applications and the underlying science. [16,17] Current solar cells and transistors based on CQD arrays are on par with or better than the semiconducting polymer-based devices, showing the true prospects of these materials. [18][19][20] The most interesting feature of CQD solids is their enormous specific surface area; around one third of the atoms of a few nanometer CQDs are located at the surface, experiencing lower coordination than in bulk. Changing the dielectric or chemical environment thus has a significant effect on the overall properties. Much research has been conducted into this direction as well, leading to the ability to design the properties for applications.Here, we aim to show the most recent developments, put these results in perspective, and identify the limiting factors that limit further improvement in device performance. We focus on lead chalcogenides as they have been the subject of a variety of approaches to form solids, mainly because of their prospects in solar cell applications. However, the fundamental findings reported are valid for CQDs in general, and most methods can be used for other types of semiconductor nanocrystals as well. Although, numerous studies discuss the unique optical properties of CQDs, we have chosen to avoid their discussion here to be able to focus on the fabrication, electronic properties, and applications of CQD assemblies. In Section 2, two novel directions in sample fabrication of lead-chalcogenide CQD assemblies are discussed. The first one, the solution-phase ligand exchange, is relevant for mass production of devices, while the other, the self-assembly, is important for creating arrays with controlled nanostructure and order. Related to the difference in The quest for novel semiconductors with easy, cheap fabrication and tailorable properties has led to the development of several classes of materials, such as semiconducting polymers, carbon nanotubes, hybrid perovskites, and colloidal quantum dots. All these candidates can be processed from the liquid phase, enabling easy fabrication, and are suitable for different electronic and optoelectronic applications. Here, rece...

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Colloidal 3-Mercaptopropionic Acid Capped Lead Sulfide Quantum Dots in a Low Boiling Point Solvent

Cited by 13 publications

References 55 publications

Surface Ligand Engineering toward Brightly Luminescent and Stable Cesium Lead Halide Perovskite Nanoplatelets for Efficient Blue-Light-Emitting Diodes

Surface Ligand Engineering toward Brightly Luminescent and Stable Cesium Lead Halide Perovskite Nanoplatelets for Efficient Blue-Light-Emitting Diodes

Short-Wave Infrared Quantum Dots with Compact Sizes as Molecular Probes for Fluorescence Microscopy

Lead‐Chalcogenide Colloidal‐Quantum‐Dot Solids: Novel Assembly Methods, Electronic Structure Control, and Application Prospects

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