Thioacetic-Acid Capped PbS Quantum Dot Solids Exhibiting Thermally Activated Charge Hopping Transport

Dao, Tung Duy; Hafez, Mahmoud Elsayed; Beloborodov, I. S.; Jeong, Hyun‐Dam

doi:10.5012/bkcs.2014.35.2.457

Cited by 7 publications

(9 citation statements)

References 56 publications

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“…There are many examples in the literature of improved conductivity or overall efficiency in QD-based electronic devices by increasing inter-QD coupling via ligand exchange with a shorter or more conjugated ligand. − As hinted at above, another approach to improving device efficiency, however, is to use interfacial dipoles to make charge separation more favorable or to hinder recombination of the exciton. ,,,,− ,− Chuang et al, for example, developed solution-processed PbS QD-based solar cells that were air-stable for over 150 days. The PbS active layer comprised two types of PbS QDs, some treated with EDT and some treated with tetrabutylammonium iodide.…”

Section: Role Of Molecules In the Electronic Structure Of Colloidal Qdsmentioning

confidence: 99%

Electronic Processes within Quantum Dot-Molecule Complexes

et al. 2016

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The subject of this review is the colloidal quantum dot (QD) and specifically the interaction of the QD with proximate molecules. It covers various functions of these molecules, including (i) ligands for the QDs, coupled electronically or vibrationally to localized surface states or to the delocalized states of the QD core, (ii) energy or electron donors or acceptors for the QDs, and (iii) structural components of QD assemblies that dictate QD-QD or QD-molecule interactions. Research on interactions of ligands with colloidal QDs has revealed that ligands determine not only the excited state dynamics of the QD but also, in some cases, its ground state electronic structure. Specifically, the article discusses (i) measurement of the electronic structure of colloidal QDs and the influence of their surface chemistry, in particular, dipolar ligands and exciton-delocalizing ligands, on their electronic energies; (ii) the role of molecules in interfacial electron and energy transfer processes involving QDs, including electron-to-vibrational energy transfer and the use of the ligand shell of a QD as a semipermeable membrane that gates its redox activity; and (iii) a particular application of colloidal QDs, photoredox catalysis, which exploits the combination of the electronic structure of the QD core and the chemistry at its surface to use the energy of the QD excited state to drive chemical reactions.

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Section: Role Of Molecules In the Electronic Structure Of Colloidal Qdsmentioning

confidence: 99%

Electronic Processes within Quantum Dot-Molecule Complexes

et al. 2016

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“… 5,6 Moreover, modification of the semiconductor surfaces either by introducing some molecules to the surface or changing the surface molecules critically enhances the electrons transfer from the valence band (VB) to the conduction band (CB) through shortening the bandgap of the targeted semiconductor. 7 Notably, many efforts have been paid to optimize the structure and morphology of the semiconductor photocatalysts to upgrade their visible–visible light absorption and charge separation efficiency. 8 …”

Section: Introductionmentioning

confidence: 99%

Facile route for C–N/Nb₂O₅ nanonet synthesis based on 2-methylimidazole for visible-light driven photocatalytic degradation of Rhodamine B

et al. 2019

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Herein, we fabricated a C and N co-modified Nb 2 O 5 nanonet structure (C-N/Nb 2 O 5 NNs) from niobium oxalate using 2-methylimidazole (Hmim) as a source for C and N via a simple hydrothermal route. The obtained nanonets are robust and cost-effective with excellent recycling stability. Compared with Ndoped TiO 2 (N-TiO 2 ) and a Nb 2 O 5 control sample (Nb 2 O 5 -CS), the resulting nanonets exhibited the highest performance toward the photocatalytic degradation of Rhodamine B (RhB) upon visible light irradiation (l > 420 nm). Through this study, we revealed that the synergetic effects of C and N on the nanonet surface, which were effectively incorporated into the surface of the Nb 2 O 5 nanonet structure, not only remarkably enhanced the visible light response by decreasing the bandgap to 2.9 eV but also improved the light utilization efficiency and photo-induced electron-hole pair separation efficiency of our nanonet structure. We also proposed that the presence of carbonate species (CO x ) and nitrogen species (NO x ) increased the population of generated holes (h + ) that had the key role in the photodegradation mechanism of RhB, suggesting reasonable importance for the modification of Nb 2 O 5 with C and N. This synergism offers a new view to reveal the origin of photodegradation processes, introducing h + as a key intermediate. Our approach provides a new insight to design 2D nanostructures with potential applications in catalysis, solar energy conversion, and environmental protection.

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“…12, 13 Numerous literature reports studied the effect of length of ligand molecules on charge transport in arrays of NCs, for instance PbS quantum dot, which shows that a strongly-coupled, high mobility can be achieved by replacing bulky, insulating hydrocarbons that are used as ligands during synthesis with shorter ligands, which reduces the interparticle spacing and allows 4 proximal NCs. [14][15][16][17] Here, we demonstrate the use of high-performance In 2 O 3 NC TFTs with short molecules as ligands to reduce interparticle spacing and to improve mobility.…”

Section: Introductionmentioning

confidence: 98%

Newly Observed Temperature and Surface Ligand Dependence of Electron Mobility in Indium Oxide Nanocrystals Solids

Pham

Jeong

2015

ACS Appl. Mater. Interfaces

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We developed a new class of organic surface ligands; 2-aminopyridine (2AP), 4-aminobenzoic acid (4ABA), and benzoic acid (BA); for use in the solution ligand exchange of nanocrystals (NCs) in the presence of nitric acid (HNO3). Here, colloidal NCs synthesis is used for the first time. These short, air-stable, easy-to-model ligands bind to the surface of the indium oxide nanocrystal (In2O3 NC) and provide the electrostatic stabilization of NC semiconductor dispersions in N,N-dimethylformamide, allowing for a solution-based deposition of NCs into thin-film transitors (TFTs). The shorter organic ligands greatly facilitate electronic coupling between the NCs. For example, thin films made from 2AP-capped In2O3 NCs exhibited a high electron mobility of μ≈9.5 cm2/(V·s), an on-off current ratio of about >10(7), and a subthreshold swing of 2.34 V/decade. As the ligand length decreased, the electron mobility increased exponentially. Furthermore, we also report on the temperature-dependent behavior of the electron transport of In2O3 NCs films, in the case in which thin films were cured at 150 °C, as the 2AP, BA, and 4ABA ligand molecules were sustained on the NC. We demonstrated a hopping transport mechanism instead of a band-like transport, and the thermally activated carrier transport process governed the charge transport in our In2O3 NC thin-film solid.

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Thioacetic-Acid Capped PbS Quantum Dot Solids Exhibiting Thermally Activated Charge Hopping Transport

Cited by 7 publications

References 56 publications

Electronic Processes within Quantum Dot-Molecule Complexes

Electronic Processes within Quantum Dot-Molecule Complexes

Facile route for C–N/Nb₂O₅ nanonet synthesis based on 2-methylimidazole for visible-light driven photocatalytic degradation of Rhodamine B

Newly Observed Temperature and Surface Ligand Dependence of Electron Mobility in Indium Oxide Nanocrystals Solids

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Thioacetic-Acid Capped PbS Quantum Dot Solids Exhibiting Thermally Activated Charge Hopping Transport

Cited by 7 publications

References 56 publications

Electronic Processes within Quantum Dot-Molecule Complexes

Electronic Processes within Quantum Dot-Molecule Complexes

Facile route for C–N/Nb2O5 nanonet synthesis based on 2-methylimidazole for visible-light driven photocatalytic degradation of Rhodamine B

Newly Observed Temperature and Surface Ligand Dependence of Electron Mobility in Indium Oxide Nanocrystals Solids

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Facile route for C–N/Nb₂O₅ nanonet synthesis based on 2-methylimidazole for visible-light driven photocatalytic degradation of Rhodamine B