Consequence of shape elongation on emission asymmetry for colloidal CdSe/CdS nanoplatelets

Feng, Fu; Nguyen, Linh Thuy; Nasilowski, Michel; Nadal, Brice; Dubertret, Benoît; Coolen, Laurent; Maître, Agnès

doi:10.1007/s12274-017-1926-3

Cited by 28 publications

(60 citation statements)

References 39 publications

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“…1(c)). Such spatial asymmetry induces a dielectric antenna effect due to the high optical index contrast between the nanoemitter material and the surrounding dielectric environment 27 which can be at the origin of the small degree of polarization for horizontal platelets 28 .…”

Section: Experimental Protocolmentioning

confidence: 99%

Probing the Fluorescence Dipoles of Single Cubic CdSe/CdS Nanoplatelets with Vertical or Horizontal Orientations

et al. 2018

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Measuring the orientation of a single fluorescent nano-emitter and obtaining emitters with a desired orientation is of highest importance for nanophotonics, especially in plasmonics where an emitting dipole close to a metallic surface will couple efficiently to plasmonic modes only if it is deposited vertically. Control of the orientation of a nano-object remains a challenge. Achieving vertical orientation, or having an information on the dipole orientation are key steps for efficient plasmonic excitation. We consider here cubic-shaped nanoplatelets with a thin CdSe core sandwiched in a thick CdS shell. By a combination of polarization measurement and radiation pattern Fourier analysis, we show that each single platelet behaves with excellent precision as a 2D dipole (sum of 2 orthogonal incoherent dipoles) and having only two possible orientations: either they lie horizontally on the substrate or they stand vertically on the edge. The cubic shape allows some platelets to deposit vertically so that they present a deterministic vertical dipole component.

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Section: Experimental Protocolmentioning

confidence: 99%

Probing the Fluorescence Dipoles of Single Cubic CdSe/CdS Nanoplatelets with Vertical or Horizontal Orientations

et al. 2018

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“…The real part of this refractive index is the effective refractive index for the optical mode propagating along the CQW plane, across which the CQW dipoles are isotropic. [23,29] On the other hand, ellipsometry measurements on the spin-coated films of the same CQWs yield a refractive index of about 1.80, due to more sparse packing of CQWs compared to the self-assembly deposited CQWs. Our self-assembly approach therefore forms very uniform, tightly packed CQW film with a negligible amount of voids and sparse imperfections, reducing optical scattering ( Figure S2, Supporting Information), and increasing the effective refractive index of the resulting film compared to spincoated films of the same CQWs.…”

Section: Resultsmentioning

confidence: 99%

Optical Gain in Ultrathin Self‐Assembled Bi‐Layers of Colloidal Quantum Wells Enabled by the Mode Confinement in their High‐Index Dielectric Waveguides

Foroutan-Barenji

Erdem

Gheshlaghi

et al. 2020

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This study demonstrates an ultra‐thin colloidal gain medium consisting of bi‐layers of colloidal quantum wells (CQWs) with a total film thickness of 14 nm integrated with high‐index dielectrics. To achieve optical gain from such an ultra‐thin nanocrystal film, hybrid waveguide structures partly composed of self‐assembled layers of CQWs and partly high‐index dielectric material are developed and shown: in asymmetric waveguide architecture employing one thin film of dielectric underneath CQWs and in the case of quasi‐symmetric waveguide with a pair of dielectric films sandwiching CQWs. Numerical modeling indicates that the modal confinement factor of ultra‐thin CQW films is enhanced in the presence of the adjacent dielectric layers significantly. The active slabs of these CQW monolayers in the proposed waveguide structure are constructed with great care to obtain near‐unity surface coverage, which increases the density of active particles, and to reduce the surface roughness to sub‐nm scale, which decreases the scattering losses. The excitation and propagation of amplified spontaneous emission (ASE) along these active waveguides are experimentally demonstrated and numerically analyzed. The findings of this work offer possibilities for the realization of ultra‐thin electrically driven colloidal laser devices, providing critical advantages including single‐mode lasing and high electrical conduction.

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“…[ 149,150 ] Polarization of light could be influenced by various factors such as dielectric environment, orientation of emitter, and the symmetry of the electronic states of emitters. [ 151 ] Realized polarized emission from low‐dimensional anisotropic HP nanostructures could be beneficial in many electronic devices including laser, photodetectors and displaying technologies to produce high energy efficient polarized light sources. In this respect, utilization of 1D polarized light source greatly enhances energy efficiency by replacing conventional polarizers, which causes high optical loss, used in front of backlight unit of LCD panels.…”

Section: Photonic and Optoelectronic Applications Of Luminous Perovskmentioning

confidence: 99%

Nano–Micro Dimensional Structures of Fiber‐Shaped Luminous Halide Perovskite Composites for Photonic and Optoelectronic Applications

Ercan

Chen

2020

Macromol. Rapid Commun.

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Perovskite nanomaterials have been revealed as highly luminescent structures regarding their dimensional confinement. In particular, their promising potential lies behind remarkable luminescent properties, including color tunability, high photoluminescence quantum yield, and the narrow emission band of halide perovskite (HP) nanostructures for optoelectronic and photonic applications such as lightning and displaying operations. However, HP nanomaterials possess such drawbacks, including oxygen, moisture, temperature, or UV lights, which limit their practical applications. Recently, HP‐containing polymer composite fibers have gained much attention owing to the spatial distribution and alignment of HPs with high mechanical strength and ambient stability in addition to their remarkable optical properties comparable to that of nanocrystals. In this review, the fabrication methods for preparing nano–microdimensional HP composite fiber structures are described. Various advantages of the luminescent composite nanofibers are also described, followed by their applications for photonic and optoelectronic devices including sensors, polarizers, waveguides, lasers, light‐down converters, light‐emitting diode operations, etc. Finally, future directions and remaining challenges of HP‐based nanofibers are presented.

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Consequence of shape elongation on emission asymmetry for colloidal CdSe/CdS nanoplatelets

Cited by 28 publications

References 39 publications

Probing the Fluorescence Dipoles of Single Cubic CdSe/CdS Nanoplatelets with Vertical or Horizontal Orientations

Probing the Fluorescence Dipoles of Single Cubic CdSe/CdS Nanoplatelets with Vertical or Horizontal Orientations

Optical Gain in Ultrathin Self‐Assembled Bi‐Layers of Colloidal Quantum Wells Enabled by the Mode Confinement in their High‐Index Dielectric Waveguides

Nano–Micro Dimensional Structures of Fiber‐Shaped Luminous Halide Perovskite Composites for Photonic and Optoelectronic Applications

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