Brennan James Walder

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The nature of the dynamics and structural changes that take place at the ferroelectric phase transition in lead oxides is a rich field of study. Solid-state nuclear magnetic resonance (NMR) of Pb-207 is well suited to study the local structure and disorder ...

We investigate changes in the local environment of Pb-207 sites in the relaxor ferroelectric 0.67PbMg(1/3)Nb(2/3)O(3)-0.33PbTiO(3) using variable temperature magic angle spinning nuclear magnetic resonance. We observe a Gaussian distribution of Pb-207 chem ...

Despite use of blended cements containing significant amounts of aluminum for over 30 years, the structural nature of aluminum in the main hydration product, calcium aluminate silicate hydrate (C-A-S-H), remains elusive. Using first-principles calculations ...

It has recently been shown how dynamic nuclear polarization can be used to hyperpolarize the bulk of proton-free solids. This is achieved by generating the polarization in a wetting phase, transferring it to nuclei near the surface and relaying it towards ...

Determining atomic-level characteristics of molecules on two-dimensional surfaces is one of the fundamental challenges in chemistry. High-resolution nuclear magnetic resonance (NMR) could deliver rich structural information, but its application to two-dime ...

Isotopic enrichment of Si-29 and DNP-enhanced NMR spectroscopy are combined to determine the detailed surface structure of a silicated alumina catalyst. The significant sensitivity enhancement provided by DNP is vital to the acquisition of multinuclear and ...

Efforts to tune the bulk physical properties of concrete are hindered by a lack of knowledge related to the atomic-level structure and growth of calcium silicate hydrate phases, which form about 50-60% by volume of cement paste. Here we describe the first ...

Ligand exchange and CdS shell growth onto colloidal CdSe nanoplatelets (NPLs) using colloidal atomic layer deposition (c-ALD) were investigated by solid-state nuclear magnetic resonance (NMR) experiments, in particular, dynamic nuclear polarization (DNP) e ...

Cadmium doping has recently emerged as an efficacious strategy for defect suppression and band gap tuning in hybrid as well as all-inorganic halide perovskites. However, the cadmium speciation in these materials is unknown. Here, we use high-field cadmium- ...

The residual broadening observed in H-1 spectra of rigid organic solids at natural abundance under 111 kHz magic angle spinning (MAS) is typically a few hundred Hertz. Here we show that refocusable and non-refocusable interactions contribute roughly equall ...

Dynamic nuclear polarization can be used to hyperpolarize the bulk of proton-free inorganic materials in magic angle spinning NMR experiments. The hyperpolarization is generated on the surface of the material with incipient wetness impregnation and from th ...

Understanding the surface of semiconductor nanocrystals (NCs) prepared using colloidal methods is a long-standing goal of paramount importance for all their potential optoelectronic applications, which remains unsolved largely because of the lack of site-s ...

The study of hydration and crystallization processes involving inorganic oxides is often complicated by poor long-range order and the formation of heterogeneous domains or surface layers. In solid-state NMR, H-1-H-1 spin diffusion analyses can provide info ...

The high conversion efficiency has made metal halide perovskite solar cells a real break-through in thin film photovoltaic technology in recent years. Here, we introduce a straight-forward strategy to reduce the level of electronic defects present at the i ...

Brennan James Walder

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Chemical exchange at the ferroelectric phase transition of lead germanate revealed by solid state Pb-207 nuclear magnetic resonance

Lead-Oxygen Bond Length Distributions of the Relaxor Ferroelectric 0.67PbMg(1/3)Nb(2/3)O(3)-0.33PbTiO(3) from Pb-207 Nuclear Magnetic Resonance

The Atomic-Level Structure of Cementitious Calcium Aluminate Silicate Hydrate

Maximizing nuclear hyperpolarization in pulse cooling under MAS

One- and Two-Dimensional High-Resolution NMR from Flat Surfaces

Determining the Surface Structure of Silicated Alumina Catalysts via Isotopic Enrichment and Dynamic Nuclear Polarization Surface-Enhanced NMR Spectroscopy

The Atomic-Level Structure of Cementitious Calcium Silicate Hydrate

Colloidal-ALD-Grown Core/Shell CdSe/CdS Nanoplatelets as Seen by DNP Enhanced PASS-PIETA NMR Spectroscopy

Cd-113 Solid-State NMR at 21.1 T Reveals the Local Structure and Passivation Mechanism of Cadmium in Hybrid and All-Inorganic Halide Perovskites

Line narrowing in H-1 NMR of powdered organic solids with TOP-CT-MAS experiments at ultra-fast MAS

Hyperpolarization transfer pathways in inorganic materials

Resolving the Core and the Surface of CdSe Quantum Dots and Nanoplatelets Using Dynamic Nuclear Polarization Enhanced PASS-PIETA NMR Spectroscopy

Measurement of Proton Spin Diffusivity in Hydrated Cementitious Solids

Atomic-level passivation mechanism of ammonium salts enabling highly efficient perovskite solar cells

Characterization of semiconductor nanocrystals using advanced NMR spectroscopy

207Pb NMR of ferroelectric perovskite lead germanate at and below the paraelectric phase transition

Using 207Pb NMR to investigate temperature dependent nuclear spin relaxation and Pb-O bond covalency in relaxor ferroelectrics