Titanium Dioxide Nanomaterials: Synthesis, Properties, Modifications, and Applications

Dye-sensitized solar cells (DSCs) offer the possibilities to design solar cells with a large flexibility in shape, color, and transparency. DSC research groups have been established around the worl ...

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Dye-Sensitized Solar Cells

Photoinduced reactivity of titanium dioxide

A new series of panchromatic ruthenium(II) sensitizers derived from carboxylated terpyridyl complexes of tris-thiocyanato Ru(II) have been developed. Black dye containing different degrees of protonation {(C2H5)3NH}[Ru(H3tcterpy)(NCS)3] 1, {(C4H9)4N}2[Ru(H2tcterpy)(NCS)3] 2, {(C4H9)4N}3[Ru(Htcterpy)(NCS)3] 3, and {(C4H9)4N}4[Ru(tcterpy)(NCS)3] 4 (tcterpy = 4,4‘,4‘ ‘-tricarboxy-2,2‘:6‘,2‘ ‘-terpyridine) have been synthesized and fully characterized by UV−vis, emission, IR, Raman, NMR, cyclic voltammetry, and X-ray diffraction studies. The crystal structure of complex 2 confirms the presence of a RuIIN6 central core derived from the terpyridine ligand and three N-bonded thiocyanates. Intermolecular H-bonding between carboxylates on neighboring terpyridines gives rise to 2-D H-bonded arrays. The absorption and emission maxima of the black dye show a bathochromic shift with decreasing pH and exhibit pH-dependent excited-state lifetimes. The red-shift of the emission maxima is due to better π-acceptor properti...

Engineering of Efficient Panchromatic Sensitizers for Nanocrystalline TiO2-Based Solar Cells

A surface science perspective on TiO2 photocatalysis

MLCT excited states of cuprous bis-phenanthroline coordination compounds

The photophysical and photoelectrochemical properties of Ru(deeb)(bpy)2(PF6)2, where bpy is 2,2‘-bipyridine and deeb is 4,4‘-(COOEt)2-2,2‘-bipyridine, anchored to nanocrystalline TiO2 (anatase) or ZrO2 films are reported. In neat acetonitrile (or 0.1 M tetrabutylammonium perchlorate) long-lived metal-to-ligand charge transfer (MLCT) excited states are observed on both TiO2 and ZrO2. Addition of LiClO4 results in a red shift in the MLCT absorption and photoluminescence, PL, spectra on both TiO2 and ZrO2, and a concentration-dependent quenching of the PL intensity on TiO2. The Li+-induced spectroscopic changes were found to be reversible by varying the electrolyte composition. Time-resolved absorption measurements demonstrate that the presence of lithium cations increases the quantum yield for interfacial charge separation with no discernible influence on the rate of charge recombination. A second-order kinetic model quantified charge recombination transients. A model is proposed wherein Li+ ion adsorption ...

Cation-Controlled Interfacial Charge Injection in Sensitized Nanocrystalline TiO2

In 1974, the metal-to-ligand charge transfer (MLCT) excited state, (Ru(bpy) 3 ) 2+ *, was shown to undergo electron transfer quenching by methylviologen dication (MV 2+ ), inspiring a new approach to artificial photosynthesis based on molecules, molecular-level phenomena, and a "modular approach". In the intervening years, application of synthesis, excited-state measurements, and theory to (Ru(bpy) 3 ) 2+ * and its relatives has had an outsized impact on photochemistry and photophysics. They have provided a basis for exploring the energy gap law for nonradiative decay and the role of molecular vibrations and solvent and medium effects on excited-state properties. Much has been learned about light absorption, excited-state electronic and molecular structure, and excited-state dynamics on timescales from femtoseconds to milliseconds. Excited-state properties and reactivity have been exploited in the investigation of electron and energy transfer in solution, in molecular assem- blies, and in derivatized polymers and oligoprolines. An integrated, hybrid approach to solar fuels, based on dye-sensitized photoelectrosynthesis cells (DSPECs), has emerged and is being actively investigated.

(Ru(bpy) 3 ) 2+ * and other remarkable metal-to- ligand charge transfer (MLCT) excited states*

Background Cardiac surgery is a complex, high-risk procedure with potential vulnerabilities for patient safety. The evidence base describing safety hazards in the cardiovascular operating room is underdeveloped but is essential to guide future safety improvement efforts. Objective To identify and categorise hazards (anything that has the potential to cause a preventable adverse patient safety event) in the cardiovascular operating room. Methods An interdisciplinary team of researchers used prospective methods, including direct observations, contextual inquiry and photographs to collect hazard data pertaining to the cardiac surgery perioperative period, which started immediately before the patient was transferred to the operating room and ended immediately after patient handoff to the post-anaesthesia/intensive care unit. Data were collected between February and September 2008 in five hospitals. An interdisciplinary approach that included a human factors and systems engineering framework was used to guide the study. Results Twenty cardiac surgeries including the corresponding handoff processes from operating room to post-anaesthesia/intensive care unit were observed. A total of 58 categories of hazards related to care providers (eg, practice variations), tasks (eg, high workload), tools and technologies (eg, poor usability), physical environment (eg, cluttered workspace), organisation (eg, hierarchical culture) and processes (eg, non-compliance with guidelines) were identified. Discussion Hazards in cardiac surgery services are ubiquitous, indicating numerous opportunities to improve safety. Future efforts should focus on creating a stronger culture of safety in the cardiovascular operating room, increasing compliance with evidence-based infection control practices, improving communication and teamwork, and developing a partnership among all stakeholders to improve the design of tools and technologies.

https://qualitysafety.bmj.com/content/qhc/21/10/810.full.pdf

David W. Thompson

Papers

MLCT excited states of cuprous bis-phenanthroline coordination compounds

Cation-Controlled Interfacial Charge Injection in Sensitized Nanocrystalline TiO2

(Ru(bpy) 3 ) 2+ * and other remarkable metal-to- ligand charge transfer (MLCT) excited states*

Identifying and categorising patient safety hazards in cardiovascular operating rooms using an interdisciplinary approach: a multisite study

Five years after to err is human