Prof Tony Cafolla

Biography

1975B.Sc. in Experimental Physics, Trinity College Dublin 1977M.Sc. in Nuclear Instrumentation Physics, Trinity College Dublin 1985Ph.D. in Solid State Physics, University of Virginia. 1985 – 1990: Research Associate in Atomic and Molecular Physics, University of Manchester. 1990 – 1992: Research Associate in Surface Physics, University of Wales, College of Cardiff. 1992- present: Lecturer in Applied Physics, Dublin City University. 1999 – present: Member of HEA-funded National Centre for Sensor Research

Research Expertise

PhD Students

  • PhD Student #1
  • PhD Student #2
  • PhD Student #3

Select Publications

Phase fluorometric dissolved oxygen sensor
  C McDonagh, C Kolle, AK McEvoy, DL Dowling, AA Cafolla, SJ Cullen, BD MacCraith      2001      Sensors and Actuators B: Chemical
Polyoxometalate (POM) based supramolecular assemblies have received significant attention over recent years because of their unique and diverse redox and photochemical behaviour and their potential value across a range of important light driven applications such as photo-driven synthesis and photocatalysis. This review explores the dominant approaches to assembly of polyoxometalates into supramolecular materials, both covalent and electrostatic, with particular focus on charge transfer materials and those capable of sensitized photoelectrocatalysis. The integration of POMs as components in devices such as dye sensitized solar cells, electrocatalytic photoanodes, sensing and waste remediation are considered.

The design and performance of a ruggedised dissolved oxygen (DO) probe, which is based on phase fluorometric detection of the quenched fluorescence of an oxygen-sensitive ruthenium complex, is reported. The complex is entrapped in a porous hydrophobic sol–gel matrix that has been optimised for this application. The LED excitation and photodiode detection are employed in a dipstick probe configuration, with the oxygen-sensitive film coated on a disposable PMMA disc, which in turn is designed to guide light into the film by total internal reflection. A key element of the design is the common mode rejection of phase between the signal and reference channels, requiring careful selection of the relevant optoelectronic components. The advantages of the phase fluorometric approach over intensity measurement are highlighted. The phase detection electronics exhibits excellent long-term stability with a temperature coefficient of 0.00087. The sensor response exhibits excellent signal-to-noise ratio (SNR) and reversibility and has been corrected for both temperature and pressure. The limit of detection (LOD) is typically 0.15 hPa or 6 ppb. The sensor has many potential applications but it has been designed primarily for application in waste-water monitoring.

 

Homolytic cleavage of molecular oxygen by manganese porphyrins supported on Ag (111)
  Barry E Murphy, Sergey A Krasnikov, Natalia N Sergeeva, Attilio A Cafolla, Alexei B Preobrajenski, Alexander N Chaika, Olaf Lübben, Igor V Shvets      2014      ACS nano
In electrogenerated chemiluminescence, also known as electrochemiluminescence (ECL), electrochemically generated intermediates undergo a highly exergonic reaction to produce an electronically excited state that then emits light. These electron-transfer reactions are sufficiently exergonic to allow the excited states of luminophores, including polycyclic aromatic hydrocarbons and metal complexes, to be created without photoexcitation. For example, oxidation of [Ru(bpy)3]2+ in the presence of tripropylamine results in light emission that is analogous to the emission produced by photoexcitation. This review highlights some of the most exciting recent developments in this field, including novel ECL-generating transition metal complexes, especially ruthenium and osmium polypyridine systems; ECL-generating monolayers and thin films; the use of nanomaterials; and analytical, especially clinical, applications.

Oxygen binding and cleavage are important for both molecular recognition and catalysis. Mn-based porphyrins in particular are used as catalysts for the epoxidation of alkenes, and in this study the homolytic cleavage of O2 by a surface-supported monolayer of Mn porphyrins on Ag(111) is demonstrated by scanning tunneling microscopy, X-ray absorption, and X-ray photoemission. As deposited, {5,10,15,20-tetraphenylporphyrinato}Mn(III)Cl (MnClTPP) adopts a saddle conformation with the average plane of its macrocycle parallel to the substrate and the axial Cl ligand pointing upward, away from the substrate. The adsorption of MnClTPP on Ag(111) is accompanied by a reduction of the Mn oxidation state from Mn(III) to Mn(II) due to charge transfer between the substrate and the molecule. Annealing the Mn(II)ClTPP monolayer up to 510 K causes the chlorine ligands to desorb from the porphyrins while leaving the monolayer intact. The Mn(II)TPP is stabilized by the surface acting as an axial ligand for the metal center. Exposure of the Mn(II)TPP/Ag(111) system to molecular oxygen results in the dissociation of O2 and forms pairs of Mn(III)OTPP molecules on the surface. Annealing at 445 K reduces the Mn(III)OTPP complex back to Mn(II)TPP/Ag(111). The activation energies for Cl and O removal were found to be 0.35 ± 0.02 eV and 0.26 ± 0.03 eV, respectively.

 

Plasma surface modification of cyclo-olefin polymers and its application to lateral flow bioassays
  MM Dudek, RP Gandhiraman, C Volcke, AA Cafolla, S Daniels, AJ Killard      2009      Langmuir

The modification of cyclo-olefin polymer Zeonor by plasma-enhanced chemical vapor deposition to form a silica-like surface and evaluation of its application for lateral flow bioassays applications are discussed in this study. The SiOx layer was extensively characterized using contact angle measurements, atomic force microscopy, and Fourier transform infrared spectroscopy in attenuated total internal reflectance mode where the presence of a uniform SiOx film was clearly identified. The SiOx modification resulted in a surface with enhanced wettability and excellent fluidic properties when combined with a hot-embossed micropillar capillary fill-based substrate. The SiOx surface also had the ability to accelerate the clotting of human plasma, which may have application in certain types of blood coagulation assays.

 

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