Publications associées à Femtosecond polarization relaxation in CdSe nanocrystals

Investigating Non-equilibrium Physics in Wide Bandgap Semiconductors and Quantum Materials via Ultrafast Spectroscopy

This thesis uses femtosecond laser spectroscopy in studying strong correlation in condensed matters that are pertinent to future technology: a wide bandgap perovskite and a quantum material, with the employment of ultrafast time-resolved spectroscopy in th ...

EPFL2024

Exciton migration in two-dimensional materials

Excitons play an essential role in the optical response of two-dimensional materials. These are bound states showing up in the band gaps of many-body systems and are conceived as quasiparticles formed by an electron and a hole. By performing real-time simu ...

Nature Portfolio2024

Progress and prospects in nonlinear extreme-ultraviolet and X-ray optics and spectroscopy

Majed Chergui

Free-electron lasers and high-harmonic-generation table-top systems are new sources of extreme-ultraviolet to hard X-ray photons, providing ultrashort pulses that are intense, coherent and tunable. They are enabling a broad range of nonlinear optical and s ...

NATURE PORTFOLIO2023

Ultrafast Electron Microscopy of Nanoscale Charge Dynamics in Semiconductors

Fabrizio Carbone, Ivan Madan, Giovanni Maria Vanacore, Francesco Barantani, Ido Kaminer, Kangpeng Wang, Simone Gargiulo

The ultrafast dynamics of charge carriers in solids plays a pivotal role in emerging optoelectronics, photonics, energy harvesting, and quantum technology applications. However, the investigation and direct visualization of such nonequilibrium phenomena re ...

AMER CHEMICAL SOC2023

Ultrafast carrier and quasiparticle dynamics in strongly confined perovskite nanoplatelets

Etienne Christophe Socie

Over the past decade, lead halide perovskites (LHPs) have received considerable attention thanks to their impressive optoelectronic properties. Today, LHP-based devices are one of the most efficient single-junction solar cells, with power-conversion effici ...

EPFL2022

Plasmonic nanobar-on-mirror antenna with giant local chirality: a new platform for ultrafast chiral single-photon emission

Wen Chen, Kai Wang

Providing an additional degree of freedom for binary information encoding and nonreciprocal information transmission, chiral single photons have become a new research frontier in quantum optics. Without using complex external conditions (e.g., magnetic fie ...

ROYAL SOC CHEMISTRY2022

Synthesis and properties of heterostructures in nanowires and 2-D materials

Akshay Balgarkashi

Modern solid-state devices were made possible by the discovery of semiconductor heterostructures. Heterostructures offer the ability to fabricate low-dimensional nanostructures such as quantum dots which can restrain carriers in all three-directions. Quant ...

EPFL2022

Resonant Band-Edge Emissive States in Strongly Confined CsPbBr3 Perovskite Nanoplatelets

Jacques-Edouard Moser, Etienne Christophe Socie, Aaron Tomas Terpstra, Brener Rodrigo De Carvalho Vale

Strongly confined, fully inorganic cesium lead halide perovskite nanocrystals are of great promise for light-emitting devices in the blue spectral range owing to their high photoluminescence quantum yields. A combination of broadband fluorescence up-conver ...

2021

Defect incorporation in In-containing layers and quantum wells: experimental analysis via deep level profiling and optical spectroscopy

Jean-François Carlin, Nicolas Grandjean, Mauro Mosca, Camille Haller

Recent studies demonstrated that the performance of InGaN/GaN quantum well (QW) light emitting diodes (LEDs) can be significantly improved through the insertion of an InGaN underlayer (UL). The current working hypothesis is that the presence of the UL redu ...

IOP PUBLISHING LTD2021

Nano-emitting Heterostructures Violate Optical Reciprocity and Enable Efficient Photoluminescence in Halide-Segregated Methylammonium-Free Wide Bandgap Perovskites

Christophe Ballif, Quentin Thomas Jeangros, Peter Joseph Fiala, Chien-Jen Yang, Pietro Caprioglio, Christian Michael Wolff

This work investigates halide segregation in methylammonium-free wide bandgap perovskites by photoluminescence quantum yield (PLQY) and advanced electron microscopy techniques. Our study reveals how the formation of nano-emitting low-energy domains embedde ...

AMER CHEMICAL SOC2021

Luminescent, porous, metal-organic crystals: Design, synthesis, and applications

Fatmah Ebrahim

The work presented in this thesis is focused on the design and discovery of new luminescent, porous, crystalline materials for targeted applications. In particular, we focus on luminescent Metal-Organic Frameworks (MOFs) and Organic Molecules of Intrinsic ...

EPFL2020

Dark-level trapping, lateral confinement, and built-in electric field contributions to the carrier dynamics in c-plane GaN/AlN quantum dots emitting in the UV range

Nicolas Grandjean, Raphaël Butté, Sebastian Pascal Tamariz Kaufmann

c-plane GaN/AlN quantum dots (QDs) are promising zero-dimensional quantum nanostructures that exhibit single photon emission properties up to room temperature and even above. In this context, it is of prime interest to gain a deeper insight into the recomb ...

AMER INST PHYSICS2021

Photo- and thermally-induced electronic and structural dynamics in perovskites and transition metal oxides

Oliviero Cannelli

In this thesis, we exploited optical and X-ray pump-probe methods in a synergistic approach to study the interplay of the electronic, spin and structural degrees of freedom in two class of complex systems relevant for solar energy conversion applications: ...

EPFL2021

Enhanced Room-Temperature Photoluminescence Quantum Yield in Morphology Controlled J-Aggregates

Frank Nüesch, Surendra Babu Anantharaman, Jakob Heier

Supramolecular assemblies from organic dyes forming J-aggregates are known to exhibit narrowband photoluminescence with full-width at half maximum of approximate to 9 nm (260 cm(-1)). Applications of these high color purity emitters, however, are hampered ...

2021

Integrated photonics enables continuous-beam electron phase modulation

Rui Ning Wang, Tobias Kippenberg, Junqiu Liu, Arslan Sajid Raja, Guanhao Huang, Yujia Yang

Integrated photonics facilitates extensive control over fundamental light-matter interactions in manifold quantum systems including atoms(1), trapped ions(2,3), quantum dots(4) and defect centres(5). Ultrafast electron microscopy has recently made free-ele ...

NATURE PORTFOLIO2021

Spectroscopic view of ultrafast charge carrier dynamics in single- and bilayer transition metal dichalcogenide semiconductors

Jens Christian Johannsen

The quasiparticle spectra of atomically thin semiconducting transition metal dichalcogenides (TMDCs) and their response to an ultrafast optical excitation critically depend on interactions with the underlying substrate. Here, we present a comparative time- ...

ELSEVIER2021

Physics of optically driven nanojunctions

Philippe Andreas Rölli

Recent years have seen spectacular developments in the domain of nano-optics. Alongside the well-known techniques of super-resolution microscopy progress in nanofabrication has enabled important improvements in the fields of optical imaging and spectros ...

EPFL2020

Direct Observation of Shallow Trap States in Thermal Equilibrium with Band‐Edge Excitons in Strongly Confined CsPbBr 3 Perovskite Nanoplatelets

Jacques-Edouard Moser, Etienne Christophe Socie, Andrés Burgos Caminal, Brener Rodrigo De Carvalho Vale

Lead halide perovskites exhibit great potential for light-emitting devices. Enhanced photoluminescence (PL) is obtained in perovskite materials of reduced dimensionalities due to the large exciton binding energy. However, as the nanocrystal size is reduced ...

2021

Ultra-broadband time-resolved THz spectroscopy of perovskites and nanomaterials

Andrés Burgos Caminal

The fundamental study of charge carrier dynamics has been shown to be of great interest for optoelectronics, paving the way forward for future developments. Often, some of the key processes that determine the photophysics of a material occur on very short ...

EPFL2020

Solution Processing and Self-Organization of PbS Quantum Dots Passivated with Formamidinium Lead Iodide (FAPbI(3))

Frank Nüesch, Roland Hany

Solution-processed lead sulfide quantum dots (PbS QDs) are very attractive as NIR-active semiconductors for the fabrication of cost-efficient optoelectronic devices. To control the thin film carrier transport, as well as stability, surface passivation is o ...

2020