A5061296143- Quantum Dots Synthesis And Properties
- Chalcogenide Semiconductor Thin Films
- Perovskite Materials and Applications
- Gold and Silver Nanoparticles Synthesis and Applications
- nanoparticles nucleation surface interactions
- ZnO doping and properties
- Advanced Semiconductor Detectors and Materials
- Solid-state spectroscopy and crystallography
- Gas Sensing Nanomaterials and Sensors
- Crystal Structures and Properties
- Plasmonic and Surface Plasmon Research
- Laser-Ablation Synthesis of Nanoparticles
- Copper-based nanomaterials and applications
- Catalytic Processes in Materials Science
- Optical properties and cooling technologies in crystalline materials
- Surface and Thin Film Phenomena
- Advanced Chemical Physics Studies
- Iron oxide chemistry and applications
- Theoretical and Computational Physics
- Magnetic properties of thin films
- Photonic and Optical Devices
- Chemical and Physical Properties of Materials
- Nanocluster Synthesis and Applications
- Nanomaterials for catalytic reactions
- Nanoparticles: synthesis and applications
Institut Pprime
2022-2023
Centre National de la Recherche Scientifique
2015-2022
Université de Poitiers
2022
University of Antwerp
2020-2021
Center for Nanotechnology Innovation
2020
Italian Institute of Technology
2020
Institut des NanoSciences de Paris
2017-2020
Sorbonne Université
2017-2020
Délégation Paris 6
2020
Institut Lumière Matière
2015-2019
Electron–hole exchange energy,<italic>J</italic>, rules the exciton fine structure splittings in CsPbBr<sub>3</sub>single nanocrystals.
We report the synthesis of colloidal CsPbX3–Pb4S3Br2 (X = Cl, Br, I) nanocrystal heterostructures, providing an example a sharp and atomically resolved epitaxial interface between metal halide perovskite non-perovskite lattice. The CsPbBr3–Pb4S3Br2 nanocrystals are prepared by two-step direct using preformed subnanometer CsPbBr3 clusters. Density functional theory calculations indicate creation quasi-type II alignment at heterointerface as well formation localized trap states, promoting...
We have performed micro-photoluminescence measurements on a single CsPbBr3 nanocrystal (NC) with size comparable to the Bohr diameter (7 nm). When NC has an orthorhombic crystal symmetry, we observe exciton fine structure composed of three peaks linearly polarized. took advantage polarization properties monitor in situ both energy and linewidth individual when increasing temperature. reveal that two regimes exist, at low high temperature, which are dominated by acoustic or longitudinal...
Infrared photodetection based on colloidal nanoparticles is a promising path toward low-cost devices. However, mid-infrared absorption relies interband transitions in heavy metal-based materials, which major flaw for the development mass market. In quest of mercury-free infrared active we here investigate Ag2Se presenting intraband transition between 3 and 15 μm. With photoemission spectroscopy, are able to propose an electronic spectrum material absolute energy scale. We also origin doping...
Homodimers of noble metal nanocubes form model plasmonic systems where the localized plasmon resonances sustained by each particle not only hybridize but also coexist with excitations a different nature: surface polaritons confined within Fabry-Perot cavity delimited facing cube surfaces (i.e., gap plasmons). Destructive interference in strong coupling between one these highly modes and radiating longitudinal dipolar dimer is responsible for formation Fano resonance profile opening spectral...
Nanocrystals are promising materials for the design of low-cost, infrared (IR) detectors. Here we focus on HgTe colloidal quantum dots (CQDs) as an active material detection in extended short-wave (2.5 μm cutoff wavelength). In this paper, propose a strategy to enhance performances previously reported photodiodes. particular, integrate diode unipolar barrier, whose role is reduce dark current injection and subsequently signal-to-noise ratio. We demonstrate that such barrier can be designed...
Abstract Short‐wave infrared (IR) detection is currently driven by InGaAs technology which has limited the perspective of cost effectiveness and consequently slows development IR sensors. Since organic electronics are ineffective in this wavelength range, an alternative to conductive polymers use colloidal quantum dots (CQDs) exhibit strongly tunable absorption. In paper, extended short‐wave (2.5 µm cut‐off) focused on expand capabilities InGaAs, while using HgTe nanocrystals as active...
Various strategies have been proposed to engineer the band gap of metal halide perovskite nanocrystals (NCs) while preserving their structure and composition thus ensuring spectral stability emission color. An aspect that has only marginally investigated is how type surface passivation influences structural/color AMX3 NCs composed two different M2+ cations. Here, we report synthesis blue-emitting Cs-oleate capped CsCdxPb1–xBr3 NCs, which exhibit a cubic phase containing Cd-rich domains...
We report the colloidal synthesis of a series surfactant-stabilized lead chalcohalide nanocrystals. Our work is mainly focused on Pb4S3Br2, phase unknown to date that does not belong ambient-pressure PbS–PbBr2 diagram. The Pb4S3Br2 nanocrystals herein feature remarkably narrow size distribution (with dispersion as low 5%), good tunability (from 7 ∼30 nm), an indirect bandgap, photoconductivity (responsivity = 4 ± 1 mA/W), and stability for months in air. A crystal structure proposed this new...
As narrow band gap nanocrystals become a considerable building block for the design of infrared sensors, device needs to match their actual operating conditions. While in near and shortwave infrared, room-temperature operation has been demonstrated, longer wavelengths still require low-temperature operations thus specific design. Here, we discuss how field-effect transistors (FETs) can be compatible with detection. To reach this goal, two key developments are proposed. First, report gating...
HgTe nanocrystals (NCs) enable broadly tunable infrared absorption, now commonly used to design light sensors. This material tends grow under multipodic shapes and does not present well-defined size distributions. Such point generates traps reduces the particle packing, leading a reduced mobility. It is thus highly desirable comprehensively explore effect of shape on their performance. Here, we show, using combination electron tomography tight binding simulations, that charge dissociation...
The optical properties of small Cu–Ag bimetallic clusters have been experimentally and theoretically investigated in relation to their chemical structure analyzed by high resolution transmission electron microscopy (HRTEM). Cu (1–x)Agx about 5 nm diameter are produced a laser vaporization source with well-defined stoichiometry (x = 0, 25, 50, 75, 100%) dispersed an alumina matrix. Absorption spectra dominated broad strong surface plasmon resonance whose shape location dependent on both...
Now that colloidal nanocrystals (NCs) have been integrated as green and red sources for liquid crystal displays, the next challenge quantum dots is their use in electrically driven light-emitting diodes (LEDs). Among various NCs, nanoplatelets (NPLs) appeared promising candidates devices because two-dimensional shape allows a narrow luminescence spectrum, directional emission, high light extraction. To reach efficiency, it critical to grow core/shell structures. High temperature growth of...
Intraband absorption in doped nanocrystals offers an interesting alternative to narrow-band-gap materials explore mid-infrared optoelectronic device designs. However, the performance of such a clearly lags behind ones relying on intrinsic materials. Livache et al. proposed dye-sensitized approach overcome limitations observed from intraband (high dark current, slow response, low activation energy), where absorber is coupled with undoped material, which takes care charge conduction. Here, we...
After the use of nanocrystals as light downconverters, infrared sensing appears to be one first market applications where they can used while being both electrically and optically active. Over recent years, tremendous progress has been achieved, leading an apparent rise in technological-readiness level (TRL). So far, efforts have focused on PbS for operation near-infrared. Here, we focus HgTe since its narrower band gap offers more flexibility explore extended short-wave midwave infrared. We...
Nanocrystals are often described as interesting materials for the design of low-cost optoelectronic devices, especially in infrared range. However, driving reaching absorption generally contain heavy metals (Pb and Hg) with a high toxicity. An alternative strategy to achieve transition is use doped semiconductors presenting intraband or plasmonic short-, mid-, long-wave infrared. This may offer more flexibility regarding range possible candidate materials. In particular, significant progress...
The gating of nanocrystal films is currently driven by two approaches: either the use a dielectric such as SiO2 or electrolyte. allows fast bias sweeping over broad range temperatures but requires large operating bias. Electrolytes, thanks to capacitances, lead significant reduction are limited slow and quasi-room-temperature operation. None these conditions optimal for narrow-band-gap nanocrystal-based phototransistors, which necessary large-capacitance gate has be combined with...
Infrared spectra of CdTe, HgTe and HgTe/CdS nanoplatelets.
Mercury chalcogenide nanocrystals generate a lot of interest as active materials for low-cost infrared sensing. Device improvement requires building deeper understanding their electronic structure, which combines inverted band ordering, quantum confinement, and dependence on surface chemistry. This is particularly true with the development mercury colloidal heterostructures (HgSe/HgTe, HgTe/CdS...). In this case, lattice mismatch induces strain, affects significantly gap, given narrow gap...
We study the effect of nitrogen on morphological evolution thin silver (Ag) films deposited weakly-interacting amorphous carbon (a-C) and silicon oxide (SiOx) surfaces. Films are synthesized at a deposition rate 0.1nm·s-1 by direct current magnetron sputtering (DCMS), high power impulse (HiPIMS), electron-beam evaporation (EBE). monitor growth in situ real time measuring film stress optical properties, complemented ex analyses discontinuous-layer morphologies, crystal structure, composition....
The generic optical absorption band of core–shell M@Ag nanoparticles observed in many experiments is rationalized through the formation a Fano-like profile originating from coupling between silver shell LSPR and core interband continuum.
Nanocrystal-based solar cell technologies currently have two materials competing for the highest performances: PbS and perovskites. The latter benefit from a defect-tolerant electronic structure, while benefits mature diode fabrication techniques its near-infrared absorption. Here we choose to revisit potential of photodiodes detection more precisely active imaging. This mode combines an eye-invisible source with detector. Such is used surveillance, industrial sorting, LIDAR, etc. use...
Lead sulfide (PbS) colloidal quantum dot-based photodiodes are remarkable structures because of their outstanding optoelectronic performances obtained via engineering. They combine surface ligand engineering to design a p–n junction with all-solution processability. Here, we investigate the electronic structure PbS diode combining static and dynamic photoemissions transport measurements. We show that n-type nature I– capped CQDs shifts valence band away from Fermi level compared thiol-capped...
Multimetallic nano-alloys display a structure and consequently physicochemical properties evolving in reactive environment.