The goal of artificial photosynthesis is to use the energy of the sun to make high-energy chemicals for energy production. One approach, described here, is to use light absorption and excited-state electron transfer to create oxidative and reductive equivalents for driving relevant fuel-forming half-reactions such as the oxidation of water to O2 and its reduction to H2. In this “integrated modular assembly” approach, separate components for light absorption, energy transfer, and long-range electron transfer by use of free-energy gradients are integrated with oxidative and reductive catalysts into single molecular assemblies or on separate electrodes in photelectrochemical cells. Derivatized porphyrins and metalloporphyrins and metal polypyridyl complexes have been most commonly used in these assemblies, with the latter the focus of the current account. The underlying physical principleslight absorption, energy transfer, radiative and nonradiative excited-state decay, electron transfer, proton-coupled elec...

Chemical approaches to artificial photosynthesis

Coordination complexes exhibiting room-temperature phosphorescence: Evaluation of their suitability as triplet emitters in organic light emitting diodes

Room-temperature phosphorescent materials that emit light in the visible (red, green, and blue; from 400 to 700 nm) have been a major focus of research and development during the past decades, due to their applications in organic light-emitting diodes (OLEDs), light-emitting electrochemical cells, photovoltaic cells, chemical sensors, and bio-imaging. In recent years, near-infrared (NIR) phosphorescence beyond the visible region (700–2500 nm) has emerged as a new, promising, and challenging research field with potential applications toward NIR OLEDs, telecommunications, night vision-readable displays. Moreover, NIR phosphorescence holds promise for in vivo imaging, because cells and tissues exhibit little absorption and auto-fluorescence in this spectral region. This review describes the overall progress made in the past ten years on NIR phosphorescent transition-metal complexes including Cu(I), Cu(II), Cr(III), Re(I), Re(III), Ru(II), Os(II), Ir(III), Pt(II), Pd(II), Au(I), and Au(III) complexes, with a primary focus on material design complemented with a selection of optical, electronic, sensory, and biologic applications. A critical comparison of various NIR phosphorescent materials reported in the literature and a blueprint for future development in this field are also provided.

Near-infrared phosphorescence: materials and applications

Luminescent metal complexes of d6, d8 and d10 transition metal centres

High quality brookite TiO2 nanorods have been obtained by the thermal hydrolysis of commercially available aqueous solutions of titanium bis(ammonium lactate) dihydroxide in the presence of high concentrations of urea (≥6.0 M) as an in situ OH− source. Biphasial anatase/brookite mixtures are obtained at lower urea concentrations. The ratios between anatase and brookite can readily be tailored by the control of the urea concentration. The obtained powders have been characterized by X-ray diffraction, Raman spectroscopy, field emission-scanning electron microscopy, high-resolution transmission electron microscopy, UV−vis diffuse reflectance spectra, and nitrogen adsorption. The photocatalytic activity of pure anatase nanoparticles, of anatase/brookite mixtures, and of pure brookite nanorods has been assessed by hydrogen evolution from aqueous methanol solution as well as by the degradation of dichloroacetic acid (DCA) in aqueous solution. The results indicate that the photocatalytic hydrogen evolution activ...

Tailored Titanium Dioxide Nanomaterials: Anatase Nanoparticles and Brookite Nanorods as Highly Active Photocatalysts

Photochemistry and Photophysics of Chromium(III) Complexes.

Erreurs dans les mesures actinometriques dans le developpement lent de la coloration dues a l'inhibition de la formation du complexe Fe(phen) 3 2+ par le ferrioxalate lui-meme. Elimination de ces erreurs par 1) addition d'exces de phenanthroline, 2) addition d'exces d'oxalate libre pour empecher la dissociation de [Fe(OX) 3 3− ], 3) addition d'agents complexants pour Fe 3+ ], 3) addition d'agents complexants pour Fe 3+

Alexander D. Kirk

Papers

Photochemistry and Photophysics of Chromium(III) Complexes.

Errors in ferrioxalate actinometry

Picosecond flash photolysis and spectroscopy: Transition metal coordination compounds

Chromium(iii) photochemistry and photophysics

Luminescence of chromium(III) complexes