Effect of PMMA polymer matrix on optical properties of CdSe nanoplatelets

Saidzhonov, Bedil M.; Зайцев, В. Б.; Vasiliev, R. B.

doi:10.1016/j.jlumin.2021.118175

Cited by 14 publications

(10 citation statements)

References 45 publications

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“…Such optical feature shifts are not observed in QDs of similar bandgap energy and composition . Similar effects have been observed in wurtzite CdSe quantum belts exchanged with thiols or thiolates, in two-dimensional wurtzite CdSe and CdS nanostructures exchanging metal oleates or halides (or other pseudohalides such as hydroxide or nitrate) for amine termination, − and even in NPLs embedded in poly(methyl methacrylate) …”

Section: Synthesis and Structure Of Nplsmentioning

confidence: 99%

2D II–VI Semiconductor Nanoplatelets: From Material Synthesis to Optoelectronic Integration

Diroll

Güzeltürk

et al. 2023

Chem. Rev.

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The field of colloidal synthesis of semiconductors emerged 40 years ago and has reached a certain level of maturity thanks to the use of nanocrystals as phosphors in commercial displays. In particular, II−VI semiconductors based on cadmium, zinc, or mercury chalcogenides can now be synthesized with tailored shapes, composition by alloying, and even as nanocrystal heterostructures. Fifteen years ago, II−VI semiconductor nanoplatelets injected new ideas into this field. Indeed, despite the emergence of other promising semiconductors such as halide perovskites or 2D transition metal dichalcogenides, colloidal II−VI semiconductor nanoplatelets remain among the narrowest room-temperature emitters that can be synthesized over a wide spectral range, and they exhibit good material stability over time. Such nanoplatelets are scientifically and technologically interesting because they exhibit optical features and production advantages at the intersection of those expected from colloidal quantum dots and epitaxial quantum wells. In organic solvents, gram-scale syntheses can produce nanoparticles with the same thicknesses and optical properties without inhomogeneous broadening. In such nanoplatelets, quantum confinement is limited to one dimension, defined at the atomic scale, which allows them to be treated as quantum wells. In this review, we discuss the synthetic developments, spectroscopic properties, and applications of such nanoplatelets. Covering growth mechanisms, we explain how a thorough understanding of nanoplatelet growth has enabled the development of nanoplatelets and heterostructured nanoplatelets with multiple emission colors, spatially localized excitations, narrow emission, and high quantum yields over a wide spectral range. Moreover, nanoplatelets, with their large lateral extension and their thin short axis and low dielectric surroundings, can support one or several electron−hole pairs with large exciton binding energies. Thus, we also discuss how the relaxation processes and lifetime of the carriers and excitons are modified in nanoplatelets compared to both spherical quantum dots and epitaxial quantum wells. Finally, we explore how nanoplatelets, with their strong and narrow emission, can be considered as ideal candidates for pure-color light emitting diodes (LEDs), strong gain media for lasers, or for use in luminescent light concentrators.

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Section: Synthesis and Structure Of Nplsmentioning

confidence: 99%

2D II–VI Semiconductor Nanoplatelets: From Material Synthesis to Optoelectronic Integration

Diroll

Güzeltürk

et al. 2023

Chem. Rev.

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“…Compared to aqueous dispersions, interactions such as homo-FRET and energy transfer between individual CdSe/CdS NPLs have to be considered and have been observed for closely packed stacks of NPLs. − , However, e.g., homo-FRET is most efficient in NPL stacks of reduced disorder and NPLs arranged next to each other in a single layer have shown significantly less efficient FRET. , With a large estimated Förster radius of 13.5 nm, homo-FRET between CdSe/CdS NPLs could be responsible for decreased PLQY and photoluminescence lifetimes even through a polymer layer. ,, On the other hand, resonant energy transfer to the polymer in our case is very unlikely due to a lack of spectral overlap between the NPL photoluminescence and the PEL absorption . Saidzhonov et al have reported on the influence of incorporating hydrophobic CdSe NPLs stabilized with oleic acid by a PMMA matrix . Their results show a red shift of the optical properties and significant trap state emission of the nanocomposites, which the authors explain by the removal of surface ligands and the occurrence of mid-gap states by the process .…”

Section: Resultsmentioning

confidence: 99%

“…75 Saidzhonov et al have reported on the influence of incorporating hydrophobic CdSe NPLs stabilized with oleic acid by a PMMA matrix. 76 Their results show a red shift of the optical properties and significant trap state emission of the nanocomposites, which the authors explain by the removal of surface ligands and the occurrence of mid-gap states by the process. 76 We do not observe trap state emission in our PEL/ LbL NPL nanocomposites and conclude that the MUA ligands are less likely to be removed from the CdSe/CdS NPL surface than the original carboxylate ligands by the dip-coating process.…”

Section: T H I S C O N T E N T Imentioning

confidence: 94%

“…76 Their results show a red shift of the optical properties and significant trap state emission of the nanocomposites, which the authors explain by the removal of surface ligands and the occurrence of mid-gap states by the process. 76 We do not observe trap state emission in our PEL/ LbL NPL nanocomposites and conclude that the MUA ligands are less likely to be removed from the CdSe/CdS NPL surface than the original carboxylate ligands by the dip-coating process. The measured photoluminescence quantum yield of ∼5% for NPL/PEL nanocomposites is in line with PLQY values typically reported for solid-state thin films.…”

Section: T H I S C O N T E N T Imentioning

confidence: 99%

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Layer-by-Layer Deposition of 2D CdSe/CdS Nanoplatelets and Polymers for Photoluminescent Composite Materials

Klepzig

Keppler

et al. 2022

Langmuir

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semiconductor nanoplatelets (NPLs) are strongly photoluminescent materials with interesting properties for optoelectronics. Especially their narrow photoluminescence paired with a high quantum yield is promising for light emission applications with high color purity. However, retaining these features in solid-state thin films together with an efficient encapsulation of the NPLs is a challenge, especially when trying to achieve high-quality films with a defined optical density and low surface roughness. Here, we show photoluminescent polymer-encapsulated inorganic−organic nanocomposite coatings of 2D CdSe/CdS NPLs in poly(diallyldimethylammonium chloride) (PDDA) and poly(ethylenimine) (PEI), which are prepared by sequential layer-by-layer (LbL) deposition. The electrostatic interaction between the positively charged polyelectrolytes and aqueous phase-transferred NPLs with negatively charged surface ligands is used as a driving force to achieve self-assembled nanocomposite coatings with a well-controlled layer thickness and surface roughness. Increasing the repulsive forces between the NPLs by increasing the pH value of the dispersion leads to the formation of nanocomposites with all NPLs arranging flat on the substrate, while the surface roughness of the 165 nm (50 bilayers) thick coating decreases to R a = 14 nm. The photoluminescence properties of the nanocomposites are determined by the atomic layer thickness of the NPLs and the 11-mercaptoundecanoic acid ligand used for their phase transfer. Both the full width at half-maximum (20.5 nm) and the position (548 nm) of the nanocomposite photoluminescence are retained in comparison to the colloidal CdSe/CdS NPLs in aqueous dispersion, while the measured photoluminescence quantum yield of 5% is competitive to state-of-the-art nanomaterial coatings. Our approach yields stable polymer-encapsulated CdSe/CdS NPLs in smooth coatings with controllable film thickness, rendering the LbL deposition technique a powerful tool for the fabrication of solid-state photoluminescent nanocomposites.

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“…Polymethylmethacrylate (PMMA) is a highly transparent polymer with a non-crystalline nature. Bedil et al realized the tunability of absorption and emission for CdSe and core/shell CdSe/CdS nanoplatelets by introducing them into PMMA polymer matrix, whose dielectric screening and strain effect induced the red-shift of emission peak [43]. Due to its good weather resistance and high transparency in the visible spectral region, PMMA also has been employed to encapsulate perovskite QDs by either modifying the dot film in one and two faces, or blend with QDs to fabricate composite films as color-converter for lighting or display [44][45][46][47][48].…”

Section: Stability Investigationmentioning

confidence: 99%

Investigation on the stability improvement of hybrid halide all-inorganic perovskite quantum dots

Cheng¹,

Li²,

Fang³

et al. 2022

Nanotechnology

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Perovskite quantum dots (QDs) with stable luminous properties are crucial to for the construction of corresponding light-emitting diodes (LEDs). Hybrid halide perovskite QDs, especially those contain iodine element emitting red light, usually demonstrate poor emission stability owing to the halide segregation. Moreover, red component is indispensable for the construction of white LEDs (WLEDs). Hence, it is essential to improve the luminous stability of hybrid halide perovskite QDs containing iodine element. Here, magnesium dopant and silica matrix were employed to improve the stability of hybrid halide CsPb(IBr)3 QDs. Red, green and blue are three primary colors for constructing WLEDs. Therefore, silica-coated CsPbBr3 QDs emitting green light were also synthesized. The fabricated silica-coated Mn:CsPb(IBr)3/PMMA film delivered good emission stability during a 42-day observation period, exhibiting the improved stability compared with the corresponding Mn:CsPb(IBr)3 QDs in solution. WLEDs were fabricated by integrating the mixture of silica-coated Mn:CsPb(IBr)3 QDs, silica-coated CsPbBr3 QDs and silicon sealant with a blue-emission LED chip. The as fabricated device exhibited a longer lifetime to be lit than that of those reported previously. During the 36-day observation period for the as fabricated device, the red emission from the silica-coated Mn:CsPb(IBr)3 QDs experienced a peak-emission shift of 34 nm, which is much less than that in Mn:CsPb(IBr)3 QDs solution. Their overall intensity downtrend combined the peak-emission shift are responsible for the spectrum shape change, so as to the fluctuation of color correlated temperature (CCT) and color rendering index (CRI). Our study provides a good starting point for the further improvement of the stability of the hybrid halide perovskites QDs and the corresponding light-emitting devices. With deep studies on the synthesis method and luminous mechanism for hybrid halide CsPb(IBr)3 QDs, red-emission perovskite QDs with satisfied properties are expected to be obtained.

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Effect of PMMA polymer matrix on optical properties of CdSe nanoplatelets

Cited by 14 publications

References 45 publications

2D II–VI Semiconductor Nanoplatelets: From Material Synthesis to Optoelectronic Integration

2D II–VI Semiconductor Nanoplatelets: From Material Synthesis to Optoelectronic Integration

Layer-by-Layer Deposition of 2D CdSe/CdS Nanoplatelets and Polymers for Photoluminescent Composite Materials

Investigation on the stability improvement of hybrid halide all-inorganic perovskite quantum dots

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