Shape‐Tuned Multiphoton‐Emitting InP Nanotetrapods

Abstract

As the properties of a semiconductor material depend on the fate of the excitons, manipulating exciton behavior is the primary objective of nanomaterials. Although nanocrystals exhibit unusual excitonic characteristics owing to strong spatial confinement, studying the interactions between excitons in a single nanoparticle remains challenging due to the rapidly vanishing multiexciton species. Here, a platform for exciton tailoring using a straightforward strategy of shape‐tuning of single‐crystalline nanocrystals is presented. Spectroscopic and theoretical studies reveal a systematic transition of exciton confinement orientation from 3D to 2D, which is solely tuned by the geometric shape of material. Such a precise shape‐effect triggers a multiphoton emission in single nanotetrapods with arms longer than the exciton Bohr radius of material. In consequence, the unique interplay between the multiple quantum states allows a geometric modulation of the quantum‐confined Stark effect and nanocrystal memory effect in single nanotetrapods. These results provide a useful metric in designing nanomaterials for future photonic applications.

Indium arsenide quantum dots: an alternative to lead-based infrared emitting nanomaterials

“…different types and geometric arrangements of atoms and of broken bonds), often related to anisotropies in the crystal structure. 105,110 The higher affinity of a specific surfactant to some facets than others can affect the corresponding growth rates, leading to QDs featuring non-symmetric shapes, as extensively reported for CdSe [111][112][113] and InP 114 QDs. In the case of InAs QDs, Trentler et al synthesized nanorods(NRs)/nanowires(NWs) for the first time by employing thiophenol.…”

Synthesis of single‐crystalline InP tetrapod nanocrystals via addition of ZnCl2

“…Therefore, InP tetrapods can exhibit multiphoton emitting characteristics when arm lengths are longer than the exciton Bohr radius. 13 [Correction added on 19 April 2023, after first online publication: The second to the last sentence in this paragraph has been updated in this version.] For higher PL quantum yield (PL QY) of III-V NCs, the adoption of epitaxial growth onto the surface of core materials with a wider bandgap as shell materials is a common strategy for increasing the PL QY of III-V nanocrystals (NCs).…”

Impact of Uniform Facets on the Thermodynamics of Ligand Exchanges on Colloidal Quantum Dots

“…Figure A,B depicts the transmission electron microscopy images of the tetrahedrons and cubes, respectively. As previously reported, powder X-ray diffraction patterns, shown in Figure C, indicate that both the tetrahedron- and cube-shaped cadmium selenide quantum dots have a zinc blende crystal structure (ICSD 41528). , The tetrahedrons exhibit primarily triangular two-dimensional projections, which is characteristic of tetrahedron-shaped, zinc blende nanocrystals. ,− Likewise, the cubes exhibit square two-dimensional projections that are characteristic of cube-shaped, zinc blende cadmium selenide nanocrystals. ,,− Due to the isotropic symmetry of the zinc blende crystal structure, both shapes are uniformly faceted . This was confirmed by using high-resolution transmission electron microscopy to identify the lattice spacings for projections aligned along a zone axis (Figure S1).…”