Graduate Program in Physics at UFSC, Florianópolis

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The Physics Graduate Program invites everyone to:

Qualifying Examination for Doctoral Thesis

 Daniel Salvador

 TRANSIÇÕES DE FASE NO MODELO DE POTTS COM MODULAÇÃO APERIÓDICA

Defense Committee:

 Prof. Dr. Nilton da Silva Branco – (president) – FSC/UFSC

Prof. Dr. Jürgen Fritz Stilck – (external member) – UFF/IF

Prof. Dr. Wagner Figueiredo – (local member) – UFSC/FSC

Prof. Dr. Daniel Girardi – (local member) – UFSC/Blumenau

Prof. Dr. Marcelo Henrique Romano Tragtenberg – (supplementary member) – UFSC/FSC

Date: 31/March/2015 – tuesday – Time: 4:20 pm – Place: Auditório do LAED – (piso térreo do Departamento de Matemática)

The Physics Graduate Program invites everyone to:

 Defence of M.Sc. dissertation

 Luiza Gomes Ferreira

 UM MODELO SIMPLIFICADO PARA A DINÂMICA DE MOTORES MOLECULARES

Defense Commitee

Prof. Dr. Wagner Figueiredo – (president) – UFSC/FSC

Profª. Drª. Carla Goldman – (external member) – USP/IF

Prof. Dr. Nilton da Silva Branco – (local member) – UFSC/FSC

Prof. Dr. Lucas Nicolao – (local member) – UFSC/FSC

Prof. Dr. Eduardo Cerutti Mattei – (supplementary member) – UFSC/FSC

 Date: 31/March/2015 – tuesday – Time: 10:00 am – Place: Sala 212 – Auditório do Departamento de Física

The Physics Graduate Program invites everyone to:

Defence of M.Sc. dissertation

 Rodrigo Sergio Tiedt

 EFEITO DA RADIAÇÃO ULTRAVIOLETA NA FORMAÇÃO DE NÚCLEOS DE CONDENSAÇÃO DE NUVENS EM MISTURAS DE ÁGUA E DIMETILSULFETO

Defense Commitee

 Prof. Dr. Manoel Gustavo Petrucelli Homem – (president) – UFSCar/QMC

Prof. Dr. Reinaldo Luiz Cavasso Filho – (external member) – UFABC/CCNH

Prof. Dr. Renato Ramos da Silva – (local member) – UFSC/Meteorologia

Prof. Dr. Danilo de Paiva Almeida – (local member) – UFSC/FSC

Prof. Dr. Wendell Rondinelli Gomes Farias – (supplementary member) – UFSC/FSC

Date: 31/March/2015 – tuesday – Time: 2:00 pm – Place: Sala 212 – Auditório do Departamento de Física

 THE PHYSICS GRADUATE PROGRAM invites everyone to the seminar: 

   Hydrogen from Sunlight – Photoelectrochemical Water Splitting with Li-doped TiO2 Nanotubes 

Prof. Dr. Giovanni Zangari

Department of Materials Science and Engineering, University of Virginia – Charlottesville, VA, USA

Abstract:

While solar energy is one of the few energy sources capable of meeting the world’s energy demands,¹ the transient nature of sunlight necessitates the development of technologies to store that energy for on-demand use to supplement photovoltaics.² Photoelectrochemical solar cells use sunlight to electrolyze water to produce hydrogen as a storable fuel, which can then be converted to electricity by a fuel cell. TiO₂ nanotubes formed by the anodization of titanium foils in electrolytes containing fluoride ions produce aligned arrays of tube-like structures 70-100 nm in width and tunable length on the order of microns as shown in Figure 1(a, b). These structures are a promising architecture for photoelectrochemical applications³ because of their high stability in solution and under irradiation, high surface area, and 1-dimensional charge transport for efficient movement of photogenerated charges. While hundreds of microns long nanotubes in principle may be grown, one major limitation on the performance of TiO₂ nanotubes is the presence of defects in the crystal structure which facilitate the recombination of photogenerated electron-hole pairs;⁴ the best photoelectrochemical performance of TiO₂ nanotubes for water splitting has been observed in Nb-doped TiO₂ with a length of 7 mm and an associated photocurrent of 1.0 mA/cm².⁵ Electrochemical Li doping was demonstrated to passivate the trap states in TiO₂ nanotubes, suppressing recombination. This process resulted in up to a 2 fold increase in the photoelectrochemical performance of 1 mm long TiO₂ nanotubes compared to the undoped samples.⁶ For long TiO₂ nanotubes, a new optimum length of 15 mm was achieved, resulting in 1.5 mA/cm² of photocurrent at 1.0 V_SCE under simulated sunlight as seen in Figure 1(c). These results demonstrate the ability to produce high performance TiO₂ nanotubes for photoelectrochemical solar energy devices using simple electrochemical techniques.

Figure 1. (a) Cross section and (b) surface view of TiO₂ nanotubes grown by anodization. (c) Lithium intercalation enhances the photocurrent by trap state passivation, resulting in up to 1.5 mA/cm² of photocurrent at 15 m.

References

(1)            Lewis, N. S.; Nocera, D. G. Proc. Natl. Acad. Sci. U. S. Amer. 2006, 103, 15729.
(2)            Cook, T. R.; Dogutan, D. K.; Reece, S. Y.; Surendranath, Y.; Teets, T. S.; Nocera, D. G. Chem. Rev. 2010, 110, 6474.
(3)            Tsui, L. -k.; Zangari, G. J. Electrochem. Soc. 2014, 161, D3066
(4)            Tsui, L.; Zangari, G. Electrochim. Acta 2014, 121, 203.
(5)            Das, C.; Roy, P.; Yang, M.; Jha, H.; Schmuki, P. Nanoscale 2011, 3, 3094.
(6)            Tsui, L.; Saito, M.; Homma, T.; Zangari, G. J. Mater. Chem. A 2015, 3, 360.

 Date: 27/March/2015 – (friday) – Place: Sala 212 – Auditório do Departamento de Física- Time: 10h15min

The Physics Graduate Program invites everyone to:

Qualifying Examination for Doctoral Thesis

 Paulo Roberto Innocente

 Estudo da Geração de H2 com Fotocatodo de Cu2O

Defense Committee:

 Prof. Dr. André Avelino Pasa – (president) – FSC/UFSC

Prof. Dr. Andre Santarosa Ferlauto – (external member) – UFMG/FSC

Prof. Dr. Rafael Gallina Delatorre – (local member) – UFSC – Joinville

Prof. Dr. Kleber Ersching – (local member) – IFC/Camboriú

Drª Silvia Pelegrini – (supplementary member) – UFSC/FSC

Date: 13/March/2015 – friday – Time: 10:00 am – Place: Sala 114 – Sala de Reuniões do Departamento de Física

The Physics Graduate Program invites everyone to:

Qualifying Examination for Doctoral Thesis

 Juan Camilo Macias Ramirez

 Confinamento e Susceptibilidade da Matéria Hadrônica em Teoria de Perturbação Otimizada

Defense Committee:

 Prof. Dr. Marcus Emmanuel Benghi Pinto – (president) – FSC/UFSC

Prof. Dr. Sidney dos Santos Avancini – (external member) – UFSC/FSC

Prof. Dr. Celso de Camargo Barros Junior – (Local member) – UFSC/FSC

Prof. Dr. Paulo Juliano Liebgott – (local member) – UFSC/FSC

Date: 20/March/2015 – friday – Time: 10:00 am – Place: Sala de Aula 206 – Departamento de Física

The Physics Graduate Program invites everyone to:

 Defense of Doctoral Thesis

 Robson Lourenço Cavalcanti

  Caracterização impedimétrica do crescimento de camadas porosas em ITO

Defense Committee:

 Profª. Drª. Maria Luisa Sartorelli – (president) – FSC/UFSC

Prof. Dr. Antonio Riul Júnior – (external member) – IF/UNICAMP

Drª Edna Regina Spada – (external member) – USP/IFSC

Prof. Dr. Lucas Natálio Chavero – (membro titular) – UFSC/Blumenau

Profª. Drª. Françoise Toledo Reis – (local member) – UFSC/FSC

Profª. Drª. Marta Elisa Rosso Dotto – (local member) – UFSC/FSC

 Date: 19/March/2015 – thursday – Times: 2:00 pm – Place: Sala 212 – Auditório do Departamento de Física