Large Red Shift of Emission of PbS Quantum-dot Superlattice with Butylamine Ligands

Mukai, Kazuo; Suetsugu, Fumimasa; Niwa, Koichi

doi:10.2174/1573413713666170619123611

Cited by 6 publications

(7 citation statements)

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“…Considering that the peak wavelength did not change when the excitation intensity was changed, the red shift can be attributed to the overlapping of wave functions between adjacent QDs owing to their approach and the weakening of the quantum size effect. [35][36][37][38][39][40] Even when QDs with the same facet were used, the red shift was larger in the case of sedimentation of 6 days than in that of 20 min. In addition, the wavelength shift of the superlattice film fabricated using spherical QDs was 25 nm, whereas the wavelength shift of the film fabricated using QDs with facets was as large as 40 nm at the maximum.…”

Section: Resultsmentioning

confidence: 99%

Formation of superlattice with aligned plane orientation of colloidal PbS quantum dots

Mukai¹,

Fujimoto²,

Suetsugu³

2018

Jpn. J. Appl. Phys.

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We investigated a method of forming a perfect quantum dot (QD) superlattice, in which each QD has the same plane orientation, by depositing colloidal PbS QDs with clear facets in solution. QD facets were controlled by adjusting the synthesis temperature. X-ray evaluation showed that the crystal orientations of the film with QDs having clear facets were aligned. The slow deposition promoted this crystal alignment. The red shift of photoluminescence wavelength caused by the film formation was larger with QDs having facets than with spherical QDs, suggesting that the connection of the wave function between QDs was better so that the quantum size effect was further reduced.

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Section: Resultsmentioning

confidence: 99%

Formation of superlattice with aligned plane orientation of colloidal PbS quantum dots

Mukai¹,

Fujimoto²,

Suetsugu³

2018

Jpn. J. Appl. Phys.

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“…The third point to be improved is the quality of the QDSL itself. By exchanging the QD ligand for a shorter one, the carrier transport property will be further improved [11,12] and the number of intermediate bands will increase [21]. One would expect that carrier transport would be improved further by matching the crystal orientation of individual QDs.…”

Section: Resultsmentioning

confidence: 99%

“…In organic solar cells, colloidal QD films are prepared by spin coating on a substrate, and the QDs accumulate randomly. We proposed using a superlattice of colloidal QDs in solar cells [10][11][12]. It is known that, after the evaporation of a solvent, colloidal QDs self-assemble and pack densely in the area with electron-microscopic order [13][14][15][16][17].…”

Section: Introductionmentioning

confidence: 99%

Improvement of Solar Cell Characteristics Using PbS Quantum Dot Superlattice Prepared by Sedimentation

Mukai

Ishida

2018

Journal of Nanomaterials

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We report the characteristics of organic solar cells on Si substrates using quantum dot superlattices (QDSLs) prepared by sedimentation. When colloidal quantum dots (QDs) are deposited on a substrate in a solvent, they are closely packed and form multiple grains in a film. We found that the PbS QD grains grew into a large superlattice when the deposition proceeded for a long period of time. A solar cell was fabricated using the QD superlattice film as an absorbing layer. When the deposition was slow, the short-circuit current density of the solar cell doubled compared with that of the rapid deposition case. Simulations based on the superposition model suggest that the superlattice formation process is responsible for the observed change in the cell characteristics.

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“…In PbS QDs, it is reported that the excited state wavefunctions of adjacent QDs are interconnected at a QDs interval of 2.7 nm, and the ground state wavefunctions are also connected at a 1.3 nm interval. 43,44) If QDs are not in close contact, the wavefunction will not be connected due to the wide potential barrier of the solution. As shown in Fig.…”

Section: Methodsmentioning

confidence: 99%

Study on chemical synthesis of SnSSe nanosheets and nanocrystals

Mukai

Nakayama

2022

Jpn. J. Appl. Phys.

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Two kinds of raw material combination for the hot injection method were investigated for the chemical synthesis of SnSSe nanosheets and nanocrystals, which are low-toxic optoelectronic materials. When SnSe quantum dots were synthesized by mainly using oleic acid as Se precursor solvent, the quantum dots changed from spherical to cubic as the size increased. The growth condition dependence of the nanocrystal formation process was discussed. When SnSSe nanocrystals were synthesized by mainly using trioctylphosphine as Se precursor solvent, it was found that the nanocrystal shape changed from dot to rod or sheet by reducing the proportion of S. The bandgap energy did not simply depend on the composition ratio of S but was affected by the change in the nanocrystal shape depending on the quantum confinement effect.

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Large Red Shift of Emission of PbS Quantum-dot Superlattice with Butylamine Ligands

Cited by 6 publications

References 0 publications

Formation of superlattice with aligned plane orientation of colloidal PbS quantum dots

Formation of superlattice with aligned plane orientation of colloidal PbS quantum dots

Improvement of Solar Cell Characteristics Using PbS Quantum Dot Superlattice Prepared by Sedimentation

Study on chemical synthesis of SnSSe nanosheets and nanocrystals

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