Energy transfer and charge transfer between semiconducting nanocrystals and transition metal dichalcogenide monolayers.

Nowadays, as a result of the emergence of low-dimensional hybrid structures, the scientific community is interested in their interfacial carrier dynamics, including charge transfer and energy transfer. By combining the potential of transition metal dichalcogenides (TMDs) and nanocrystals (NCs) with low-dimensional extension, hybrid structures of semiconducting nanoscale matter can lead to fascinating new technological scenarios. Their characteristics make them intriguing candidates for electronic and optoelectronic devices, like transistors or photodetectors, bringing with them challenges but also opportunities.

Optical Modeling of Plasmonic Nanoparticles with Electronically Depleted Layers.

Doped metal oxide (MO) nanocrystals (NCs) are well-known for the localized surface plasmon resonance in the infrared range generated by free electrons in the conduction band of the material. Owing to the intimate connection between plasmonic features and the NC's carrier density profile, proper modeling can unveil the underlying electronic structure. The carrier density profile in MO NCs is characterized by the presence of an electronically depleted layer as a result of the Fermi level pinning at the surface of the NC.

Alloying Bi-Doped CsAgNaInCl Nanocrystals with K Cations Modulates Surface Ligands Density and Photoluminescence Efficiency.

We show how, in the synthesis of yellow-emissive Bi-doped CsAgNaInCl double perovskite nanocrystals (NCs), preventing the transient formation of Ag particles increases the photoluminescence quantum yield (PLQY) of the NCs from ∼30% to ∼60%. Calculations indicate that the presence of even a single Ag species on the surface of a NC introduces deep trap states. The PL efficiency of these NCs is further increased to ∼70% by partial replacement of Na with K ions, up to a 7% K content, due to a lattice expansion that promotes a more favorable ligands packing on the NC surface, hence better surface passivation.

Near-Infrared Plasmon-Induced Hot Electron Extraction Evidence in an Indium Tin Oxide Nanoparticle/Monolayer Molybdenum Disulfide Heterostructure.

In this work, we observe plasmon-induced hot electron extraction in a heterojunction between indium tin oxide nanocrystals and monolayer molybdenum disulfide. We study the sample with ultrafast differential transmission, exciting the sample at 1750 nm where the intense localized plasmon surface resonance of the indium tin oxide nanocrystals is and where the monolayer molybdenum disulfide does not absorb light. With the excitation at 1750 nm, we observe the excitonic features of molybdenum disulfide in the visible range, close to the exciton of molybdenum disulfide.

Liquid-Phase Exfoliation of Bismuth Telluride Iodide (BiTeI): Structural and Optical Properties of Single-/Few-Layer Flakes.

Bismuth telluride halides (BiTeX) are Rashba-type crystals with several potential applications ranging from spintronics and nonlinear optics to energy. Their layered structures and low cleavage energies allow their production in a two-dimensional form, opening the path to miniaturized device concepts. The possibility to exfoliate bulk BiTeX crystals in the liquid represents a useful tool to formulate a large variety of functional inks for large-scale and cost-effective device manufacturing.