Roles of alcohols and existing metal ions in surface chemistry and photoluminescence of InP cores

Chen, Pin‐Ru; Lai, Kuo‐Yang; Chen, Hsueh‐Shih

doi:10.1039/d1ma00408e

Cited by 11 publications

(6 citation statements)

References 66 publications

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“…Furthermore, QD surface ligand exchange after metal oleate treatment is verified by N 1s and Cl 2p spectra, as displayed in Figure 5 c,d. The pristine InP QDs feature an oleylammonium chloride ([OAmH + ]-Cl − ) ion pair surface ligand, as reported in our previous work [ 51 , 52 ]. The ZnOA- and CdOA-InP QDs show vastly decreased peak intensities in both N 1s and Cl 2p spectra, implying removal of [OAmH + ]-Cl − ligands.…”

Section: Resultsmentioning

confidence: 98%

Bifunctional Metal Oleate as an Alternative Method to Remove Surface Oxide and Passivate Surface Defects of Aminophosphine-Based InP Quantum Dots

et al. 2022

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The optical properties of indium phosphide (InP) quantum dots (QDs) are significantly influenced by their surface native oxides, which are generally removed by treating InP cores with hydrofluoric acid (HF). Besides the harmful health effects of HF, its etching may cause over-etching or QD size broadening, and surface oxidation can also reoccur rapidly. In the present study, a safer bifunctional metal oleate treatment was developed to simultaneously remove the surface oxide layer and passivate the surface defects for aminophosphine-based InP QDs. Compared to conventional HF etching, the bifunctional metal oleate was able to more efficiently remove the surface oxide of InP cores and effectively preserve the oxide-free surface, leading to a 20% narrower photoluminescence (PL) bandwidth after growing a ZnSe/ZnS shell. The metal oleate treatment is thus considered a greener and safer post-synthetic method to remove InP surface oxide and provide additional passivation to improve the optical properties of aminophosphine-based InP QDs, which could have potential in industrial mass production.

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Section: Resultsmentioning

confidence: 98%

Bifunctional Metal Oleate as an Alternative Method to Remove Surface Oxide and Passivate Surface Defects of Aminophosphine-Based InP Quantum Dots

et al. 2022

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“…The absorption around 3260 and 3238 cm −1 corresponding to N−H and N−H 3 + may be attributed to oleylamine (OAm) and oleylammonium (OAmH + ). 50,51 In the present case, we suppose that the native OA ligands are replaced by the OAm/OAmH + ligands in OAm/toluene after the light irradiation process instead of negatively charged OA ligands, 52,53 the positively charged OAm/OAmH + ligands are thought to have a higher affinity to the QD surface for light-radiated QDs with negatively charged surface, as schematically shown in Figure 8b. Therefore, the OAm/OAmH + ligands might provide better protection for QDs against photo-oxidation, which is supported by a relatively weak Zn−OH peak (∼618 cm −1 , blue curve, Figure 8a).…”

Section: Photostability Of Qds With Different Thickness and Additivesmentioning

confidence: 99%

Enhanced Photostability of Core/Shell Quantum Dots under Intense Blue Light Irradiation through Positive Photoaging Mechanism

Chen,

Lin

et al. 2023

ACS Appl. Mater. Interfaces

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Photostability of semiconductor core/shell quantum dots (QDs) has historically been perceived as intricate and unpredictable. Notably, the long-term luminescence stability of QDs under light exposure does not seem to consistently correspond with their characteristics in the absence of light. In this study, we propose a positive photoaging mechanism of QDs, integrating both ligand/shell-induced photobrightening and surface photo-oxidation, to deal with the photostability nuances. When QDs are subjected to higher energy light, their photobrightening and photodarkening conjointly determine the photostability. Enhanced photostability may not be simply attributed to a thicker shell or the presence of ligands. When adjusted with an optimal shell thickness and supplemented with negatively charged ligands, QDs exhibit enhanced photostability in both solvents and polymers.

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“…The second T peak appears at ∼525 °C, suggesting new forming bonds after QDs surface oxidation, as considering the only organic in QD is oleate ligands. 69 According to the IR spectrum and thermogravimetric results, it is clear that the coordinated ligands easily detach from the QD surface after photoaging, and the exposed surface is thus oxidized.…”

Section: Discolorization Of Qdcc Caused Bymentioning

confidence: 99%

Macroscopic Discolorization in Quantum Dot Color Converters for Microdisplay Applications

Lin,

Chen

2024

ACS Appl. Nano Mater.

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Quantum dot color converters (QDCCs) currently have the unsolved problems of photostability and discolorization in appearance after long-term operation in microdisplays. Instead of polymer-to-carbon conversion and/or impurity precipitation, the macroscopic bright-yellow-to-dark-brown discolorization is determined by microscopic interfacial chemical reactions of the QDligand-polymer system. The phenomenon has been confirmed to be related to multiple factors, including chemical transformation of the QD shell and partial degradation of the polymer, resulting in increased optical reflectance and reduced photoluminescence (PL) intensity in QDCCs. Our finding suggests that the photoexcitation of QDs in the polymer matrix should lead to detached surface ligands along with photocatalytic reactions, oxidizing the QD shell together with degrading the polymer chains.

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Roles of alcohols and existing metal ions in surface chemistry and photoluminescence of InP cores

Abstract: Surface oxidation and chemistry determine the optical properties of indium phosphide (InP) nanocrystals (NCs). In this study, existing metal ions from the reaction residuals and alcohols normally used in the...

Cited by 11 publications

References 66 publications

Bifunctional Metal Oleate as an Alternative Method to Remove Surface Oxide and Passivate Surface Defects of Aminophosphine-Based InP Quantum Dots

Bifunctional Metal Oleate as an Alternative Method to Remove Surface Oxide and Passivate Surface Defects of Aminophosphine-Based InP Quantum Dots

Enhanced Photostability of Core/Shell Quantum Dots under Intense Blue Light Irradiation through Positive Photoaging Mechanism

Macroscopic Discolorization in Quantum Dot Color Converters for Microdisplay Applications

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