Infra-red (IR) absorption results on irradiated and annealed synthetic diamond are presented which confirm an earlier proposal that a component found in the defect-induced one-phonon region of some diamonds arises from positively charged single-substitutional nitrogen . The concentration ratio to neutral substitutional centres may be changed by shining light various energies onto examined samples. By correlating changes IR associated with component, using previously determined relation...

In order to produce polycrystalline oxygen-terminated boron-doped diamond (BDD) electrodes suitable for electroanalysis (i.e., widest solvent window, lowest capacitive currents, stable and reproducible current responses, capable of demonstrating fast electron transfer) outer sphere redox couples, the following factors must be considered. The material contain enough boron that electrode shows metal-like conductivity; electrical measurements demonstrate this is achieved at [B] > 10(20) B atoms...

We report a systematic investigation of orthorhombic perovskite-type RCrO3 powder samples by Raman scattering for nine different rare earth R3+ cations (R = Y, La, Pr, Sm, Gd, Dy, Ho, Yb, Lu). The room-temperature spectra and the associated phonon mode assignment provide reference data structural whole series orthochromites ab-initio calculations. chromite comparison with on other perovskites allows correlating modes distortions in series. In particular, two Ag are identified as octahedra...

We demonstrate, for the first time, electrosynthesis of uniformly dispersed nickel hydroxide nanoparticles (NPs) on polycrystalline boron-doped diamond (pBDD). This has been achieved by electrogenerating OH− at pBDD surface in presence Ni2+ to create local conditions near electrode where highly supersaturated (relative saturation ratio > 105) solutions are generated short periods time (approximately seconds). results deposition NPs directly surface, as confirmed X-ray photoelectron...

Negatively charged Nitrogen-Vacancy (NV$^-$) centers in diamond produced by ion implantation often show properties different from NVs created during the crystal growth. We observe that nitrogen ions with four energies (30-300 keV) much shorter electron spin coherence time $T_2$ compared to "natural" and we could find any dependence of on energy. Moreover, also out about 10% them switching NV$^-$to NV$^0$. develop a method increase single NV$^-$ annealing sample at $t=1200 {\circ}$C whereas...

Atomic defects in wide band gap materials show great promise for development of a new generation quantum information technologies, but have been hampered by the inability to produce and engineer controlled way. The nitrogen-vacancy (NV) color center diamond is one foremost candidates, with single allowing optical addressing electron spin nuclear degrees freedom potential applications advanced sensing computing. Here we demonstrate method deterministic writing individual NV centers at...

One electron at a time: Half-sandwich organometallic cyclopentadienyl–IrIII complexes containing N,N-chelated ligands can catalyze the reduction of quinones (Q), such as vitamin K3, to semiquinones (Q.−) by coenzyme NADH (see picture). DFT calculations suggest that mechanism involves hydride transfer followed two one-electron transfers and unusual IrII oxidation state key transient intermediate.

The octahedral Pt(IV) complex trans,trans,trans-[Pt(N(3))(2)(OH)(2)(py)(2)] (1) is potently cytotoxic to cancer cells when irradiated with visible (blue) light. We show that the acute photocytotoxicity can be switched off by low doses (500 μM) of amino acid l-tryptophan. EPR and NMR spectroscopic experiments using spin traps l-Trp quenches formation azidyl radicals, probably acting as an electron donor. well-known a mediator transfer between distant acceptor/donor centers in proteins, such...

Conducting carbon materials: A multi-microscopy approach shows that local heterogeneous electron-transfer rates at conducting diamond electrodes correlate with the density of electronic states. This model electroactivity is considerable value for rational design electrochemical technologies, and also provides key general insights on electrode structure controls in kinetics (see picture). Detailed facts importance to specialist readers are published as ”Supporting Information”. Such documents...

The development of a novel analytical technique, electrochemical X-ray fluorescence (EC-XRF), is described and applied to the quantitative detection heavy metals in solution, achieving sub-ppb limits (LOD). In EC-XRF, preconcentration species interest onto target electrode achieved here by cathodic electrodeposition. Unambiguous elemental identification quantification metal concentration then made using XRF. This simple step improves LOD energy dispersive XRF over 4 orders magnitude (for...

In electrodeposition the key challenge is to obtain better control over nanostructure morphology. Currently, a lack of understanding exists concerning initial stages nucleation and growth, which ultimately impact physicochemical properties resulting entities. Using identical location scanning transmission electron microscopy (STEM), with boron-doped diamond (BDD) serving as both an electron-transparent TEM substrate electrode, we follow this process, from formation individual metal atom...

A combination of high-resolution electrical and electrochemical imaging techniques, in conjunction with cathodoluminescence (CL), is used to investigate the behavior oxygen-terminated highly doped polycrystalline boron diamond (BDD). The BDD has a dopant density approximately 5 x 10(20) atoms cm(-3), grain size ca. 5-40 microm, thickness 500 microm. CL demonstrates that uptake nonuniform across surface BDD, conducting atomic force microscopy (C-AFM) highlights how this impacts on local...

Pt nanoparticle (NP)-modified polycrystalline boron-doped diamond (pBDD) disk electrodes have been fabricated and employed as amperometric sensors for the determination of dissolved oxygen concentration in aqueous solution. pBDD columns were cut using laser micromachining techniques sealed glass, order to make which then characterized electrochemically. Electrodeposition onto was optimized so give maximum reduction peak current with lowest background signal. NPs, >0-10 nm diameter, found...

Despite the numerous experimental and theoretical studies on negatively charged nitrogen vacancy center $({\mathrm{NV}}^{\ensuremath{-}})$ in diamond predictions that neutral $({\mathrm{NV}}^{0})$ should have an $S=\frac{1}{2}$ ground state, ${\mathrm{NV}}^{0}$ has not previously been detected by electron paramagnetic resonance (EPR). We report new EPR data a trigonal nitrogen-containing defect with $S=\frac{3}{2}$ excited state populated via optical excitation. Analysis of spin Hamiltonian...

We demonstrate optical spin polarization of the neutrally charged silicon-vacancy defect in diamond (SiV^{0}), an S=1 which emits with a zero-phonon line at 946 nm. The is found to be most efficient under resonant excitation, but nonzero below-resonant energies. measure ensemble coherence time T_{2}>100 μs low-temperature, and relaxation limit T_{1}>25 s. Optical spin-state initialization around nm allows independent SiV^{0} NV^{-} within same optically addressed volume, telecoms...

Electron paramagnetic resonance (EPR) and optical spectroscopy have been used to determine the structure electronic state of nickel-nitrogen centres in natural diamonds synthetic enriched 13C. The latter were grown an Fe-Ni-C solvent/catalyst system at 1750 K, under stabilizing pressure, by temperature gradient method afterwards treated high pressure. parameters directions 13C hyperfine (HFS) tensors for NE1 centre found confirm previously proposed model this defect, with a nickel ion double...

A novel tomographic imaging technique is described based on the energy analysis, at fixed angle, of coherent X-ray scatter excited in an object by polychromatic radiation. The authors term their 'energy-dispersive diffraction tomography' (EXDT). It permits properties small voxels extended to be measured vivo. Tomographic information obtained directly without need reconstruct from projections. EXDT images a simple test comprising water and various plastic materials are presented illustrate...

We report wide-ranging studies to elucidate the factors and issues controlling stripping voltammetry of metal ions on solid electrodes using well-known Pb/Pb(2+) couple polycrystalline boron doped diamond (pBDD) as an exemplar system. Notably, high-resolution microscopy techniques have revealed new insights into features observed in differential pulse anodic (DPV-ASV) which provide a deeper understanding how best utilize this technique. DPV-ASV was employed impinging wall-jet configuration...

A novel electrochemical approach to the direct detection of hydrogen sulfide (H2S), in aqueous solutions, covering a wide pH range (acid alkali), is described. In brief, dual band electrode device employed, hydrodynamic flow cell, where upstream used controllably generate hydroxide ions (OH(-)), which flood downstream detector and provide correct environment for complete conversion H2S electrochemically detectable, (HS(-)) ion. All-diamond, coplanar conducting diamond electrodes, insulated...

The development of a voltammetric boron doped diamond (BDD) pH sensor is described. To obtain sensitivity, laser micromachining (ablation) utilized to introduce controlled regions sp(2) carbon into high quality polycrystalline BDD electrode. resulting activated produce electrochemically reducible quinone groups using temperature acid treatment, followed by anodic polarization. Once activated, no further treatment required. show linear (R(2) = 0.999) and Nernstian (59 mV/(pH unit))...

X-band room temperature spectra obtained by rapid-scan, continuous wave, field-swept echo-detected and Fourier transform electron paramagnetic resonance (FTEPR) were compared for three samples with long spin relaxation times: amorphous hydrogenated silicon (T1 = 11 μs, T2 3.3 μs), 0.2% N@C60 solid 120–160 2.8 μs) neutral single substitutional nitrogen centres (NS0) in diamonds 2300 230 μs). For each technique, experimental parameters selected to give less than 2% broadening of the lineshape....