A5014905591- Quantum Dots Synthesis And Properties
- Perovskite Materials and Applications
- Chalcogenide Semiconductor Thin Films
- Advanced Chemical Physics Studies
- Solid-state spectroscopy and crystallography
- Crystallization and Solubility Studies
- Radioactive element chemistry and processing
- Nanocluster Synthesis and Applications
- Molecular Junctions and Nanostructures
- X-ray Diffraction in Crystallography
- Optical properties and cooling technologies in crystalline materials
- Luminescence Properties of Advanced Materials
- Nuclear Materials and Properties
- Crystallography and molecular interactions
- Semiconductor Quantum Structures and Devices
- Crystal Structures and Properties
- Gold and Silver Nanoparticles Synthesis and Applications
- Catalytic Processes in Materials Science
- Spectroscopy and Quantum Chemical Studies
- 2D Materials and Applications
- Inorganic Chemistry and Materials
- ZnO doping and properties
- Inorganic Fluorides and Related Compounds
- Advanced Thermoelectric Materials and Devices
- Synthesis and characterization of novel inorganic/organometallic compounds
Basque Center for Materials, Applications and Nanostructures
2022-2025
Ikerbasque
2022-2025
Italian Institute of Technology
2019-2023
Vrije Universiteit Amsterdam
2006-2022
Radboud University Nijmegen
2018
Ghent University
2018
Columbia University
2018
Donostia International Physics Center
2010-2015
University of the Basque Country
2010-2015
University of Wisconsin–Madison
2014
Colloidal lead halide perovskite nanocrystals (NCs) have recently emerged as versatile photonic sources. Their processing and optoelectronic applications are hampered by the loss of colloidal stability structural integrity due to facile desorption surface capping molecules during isolation purification. To address this issue, herein, we propose a new ligand strategy utilizing common inexpensive long-chain zwitterionic such 3-(N,N-dimethyloctadecylammonio)propanesulfonate, resulting in much...
Colloidal lead halide perovskite nanocrystals (NCs) have recently emerged as versatile photonic sources. Their processing and luminescent properties are challenged by the lability of their surfaces, i.e., interface NC core ligand shell. On example CsPbBr3 NCs, we model nanocrystal surface structure its effect on emergence trap states using density functional theory. We rationalize typical observation a degraded luminescence upon aging or recovery postsynthesis treatments. The conclusions...
Abstract The spatial localization of charge carriers to promote the formation bound excitons and concomitantly enhance radiative recombination has long been a goal for luminescent semiconductors. Zero‐dimensional materials structurally impose carrier result in localized Frenkel excitons. Now fully inorganic, perovskite‐derived zero‐dimensional Sn II material Cs 4 SnBr 6 is presented that exhibits room‐temperature broad‐band photoluminescence centered at 540 nm with quantum yield (QY) 15±5 %....
Surface traps are ubiquitous to nanoscopic semiconductor materials. Understanding their atomistic origin and manipulating them chemically have capital importance design defect-free colloidal quantum dots make a leap forward in the development of efficient optoelectronic devices. Recent advances computing power established computational chemistry as powerful tool describe accurately complex chemical species nowadays it became conceivable model with realistic sizes shapes. In this Perspective,...
One of the greatest challenges in field semiconductor nanomaterials is to make trap-free nanocrystalline structures attain a remarkable improvement their optoelectronic performances. In nanomaterials, very high number atoms located on surface and these form main source electronic traps. The relation between atom coordination structure, however, remains largely unknown. Here, we use density functional theory unveil structure/electronic property relations zincblende II–VI CdSe model...
Stable Hg isotope ratios provide a new tool to trace environmental cycling. Thiols (-SH) are the dominant Hg-binding groups in natural organic matter. Here, we report experimental and computational results on equilibrium fractionation between dissolved Hg(II) species thiol-bound Hg. chloride nitrate solutions were equilibrated parallel batches with varying amounts of thiol resin resulting different fractions free Mercury both analyzed by multiple collector inductively coupled plasma mass...
Energy levels in the band gap arising from surface states can dominate optical and electronic properties of semiconductor nanocrystal quantum dots (QDs). Recent theoretical work has predicted that such trap II-VI III-V QDs arise only two-coordinated anions on QD surface, offering hypothesis Lewis acid (Z-type) ligands should be able to completely passivate these anionic states. In this work, we provide experimental support for by demonstrating Z-type ligation is primary cause PL QY increase...
We report the composition-dependent optical properties of Bi-doped Cs2Ag1–xNaxInCl6 nanocrystals (NCs) having a double perovskite crystal structure. Their photoluminescence (PL) was characterized by large Stokes shift, and PL quantum yield increased with amount Na up to ∼22% for Cs2Ag0.4Na0.6InCl6 stoichiometry. The presence Bi3+ dopants crucial achieve high yields (PLQYs) as nondoped NC systems were not emissive. Density functional theory calculations revealed that substitution Ag+ Na+...
Colloidal cesium lead halide perovskite nanocrystals (CsPbX3 PNCs, X = Cl, Br, I) exhibit important optoelectronic properties that make them amenable for a plethora of applications. However, the origin these properties, even as-synthesized and unpurified is largely unknown. Electronic structure calculations are therefore essential to understand with atomistic detail nanomaterials; however, finding model PNCs resembles experiments challenging task. Essentially, main problem how correctly...
Postsynthesis ligand exchange has been employed extensively on lead halide perovskite (LHP) nanocrystals (NCs), but the complex shell composition of starting NCs prevented a clear understanding process, and surface chemistry final remained poorly characterized. Here, we describe strategy involving displacement both cationic anionic ligands native model systems CsPbBr3 NCs, which are exclusively coated with Cs-oleate. These exchanged various quaternary ammonium bromides (R4NBr), complete is...
Optoelectronic devices require tailored ligands that stabilize nanocrystals and promote charge transport
Although solvent–ligand interactions play a major role in nanocrystal synthesis, dispersion formulation, and assembly, there is currently no direct method to study this. Here we examine the broadening of 1H NMR resonances associated with bound ligands turn this poorly understood descriptor into tool assess interactions. We show that line has both homogeneous heterogeneous component. The former nanocrystal-size dependent, latter results from Our model supported by experimental theoretical...
We devised a colloidal approach for the synthesis of CsPbBr3 nanocrystals (NCs) in which only ligands employed are alkyl phosphonic acids. Compared to more traditional syntheses NCs, present scheme delivers NCs with following distinctive features: (i) The do not have cubic but truncated octahedron shape enclosed by Pb-terminated facets. This is consequence strong binding affinity phosphonate groups toward Pb2+ ions. (ii) near unity photoluminescence quantum yields (PLQYs), no need...
Semiconductor quantum dots have long been considered artificial atoms, but despite the overarching analogies in strong energy-level quantization and single-photon emission capability, their spectrum is far broader than typical atomic lines. Here, by using ab-initio molecular dynamics for simulating exciton-surface-phonon interactions structurally dynamic CsPbBr3 dots, followed single dot optical spectroscopy, we demonstrate that line-broadening these primarily governed coupling of excitons...
We synthesize colloidal nanocrystals (NCs) of Rb3InCl6, composed isolated metal halide octahedra ("0D"), and Cs2NaInCl6 Cs2KInCl6 double perovskites, where all share corners are interconnected ("3D"), with the aim to elucidate compare their optical features once doped Sb3+ ions. Our computational analyses evidence that photoluminescence quantum yield (PLQY) these systems is consistently lower than corresponding bulk materials due presence deep surface traps from under-coordinated Also,...
Abstract Halide perovskites, in the form of thin films and colloidal nanocrystals, have recently taken semiconductor optoelectronics research by storm, emerged as promising candidates for high‐performance solar cells, light‐emitting diodes (LEDs), lasers, photodetectors, radiation detectors. The impressive optical optoelectronic properties, along with rapid increase efficiencies cells LEDs, greatly attracted researchers across many disciplines. However, most advances made so far terms...
Combining multiple species working in tandem for different hydrogen evolution reaction (HER) steps is an effective strategy to design HER electrocatalysts. Here, we engineered a hierarchical electrode the composed of amorphous-TiO2/Cu nanorods (NRs) decorated with cost-effective Ru-Cu nanoheterostructures (Ru mass loading = 52 μg/cm2). Such exhibits stable, over 250 h, low overpotential 74 mV at -200 mA/cm2 1 M NaOH. The high activity attributed, by structural analysis, operando X-ray...
ConspectusThe surface chemistry of lead halide perovskite nanocrystals (NCs) plays a major role in dictating their colloidal and structural stability as well governing optical properties. A deep understanding the nature ligand shell, ligand-NC, ligand-solvent interactions is therefore utmost importance. Our recent studies have revealed that such knowledge can be harnessed following multidisciplinary approach comprising chemical, structural, spectroscopic analyses coupled with atomistic...
Alkaline electrolyzers generally produce hydrogen at current densities below 0.5 A/cm2. Here, we design a cost-effective and robust cathode, consisting of electrodeposited Ru nanoparticles (mass loading ~ 53 µg/cm2) on vertically oriented Cu nanoplatelet arrays grown metallic meshes. Such cathode is coupled with an anode based stacked stainless steel meshes, which outperform NiFe hydroxide catalysts. Our exhibit as high 1 A/cm2 1.69 V 3.6 2 V, reaching the performances proton-exchange...
The nature of the chemical bond between gold and noble gases in simplest prototype Au(I) complexes (NgAuF NgAu+, where Ng = Ar, Kr, Xe), has been theoretically investigated by state art all-electron fully relativistic DC-CCSD(T) DFT calculations with extended basis sets. main properties molecules, including dipole moments polarizabilities, have computed a detailed study electron density changes upon formation Ng-Au made. Ar-Au dissociation energy is found to be nearly same both Argon...
Colloidal quantum dots (QDs) stand among the most attractive light-harvesting materials to be exploited for solution-processed optoelectronic applications. To this aim, quantitative replacement of bulky electrically insulating ligands at QD surface coming from synthetic procedure is mandatory. Here we present a conceptually novel approach design nanomaterials demonstrating that modification with suitable short conjugated organic molecules permits us drastically enhance light absorption QDs,...
We report an amine-free synthesis of lead halide perovskite (LHP) nanocrystals, using trioctylphosphine oxide (TOPO) instead aliphatic amines, in combination with a protic acid (e.g., oleic acid). The overall scheme bears many similarities to the chemistry behind preparation LHP thin films and single crystals, terms ligand coordination chemical precursors. acidity environment hence extent protonation TOPO molecules tune reactivity PbX2 precursor, regulating size nanocrystals. On other hand,...
While the surface termination of quasi-spherical metal chalcogenide nanocrystals or quantum dots has been widely investigated, it remains unclear whether ensuing chemistry models apply to similar with anisotropic shapes. In this work, we report on surface-chemistry 2D CdSe nanoplatelets, where make use an improved synthesis strategy that yields stable and aggregation free nanoplatelet suspensions a photoluminescence yield as high 55%. We confirm such nanoplatelets are enriched in Cd and, by...
Fully inorganic cesium lead halide perovskite (CsPbX3) nanocrystals (NCs) have been extensively studied due to their excellent optical properties, especially high photoluminescence quantum yield (PLQY) and the ease with which PL can be tuned across visible spectrum. So far, most strategies for synthesizing CsPbX3 NCs are highly sensitive processing conditions ligand combinations. For example, in synthesis of nanocubes different sizes, it is not uncommon samples that contain various other...
Nanocrystal–ligand interactions and ligand exchange processes are usually described by a uniform distribution of equal binding sites. Here, we analyze this assumption quantitative study the displacement Z-type cadmium oleate ligands from CdSe nanocrystals addition L-type ligands. First, determined stoichiometry reaction analyzing equilibrium upon dilution using solution nuclear magnetic resonance spectroscopy. We found that 1 equiv tetramethylethylene-1,2-diamine (TMEDA) or 2 n-butylamine...