THE PHYSICS GRADUATE PROGRAM invites everyone to the seminar:
Colour-tuneable organic light-emitting transistors
Prof. Heinz von Seggern
Electronic Materials, Technische Universität Darmstadt, 64287 Darmstadt, Germany.
Abstract:
The unique property of ambipolar organic light emitting field-effect transistors (OLETs) is the ability to position the light emission zone within the transistor channel through the applied biases. In this talk the basics of the ambipolar OLET will be discussed and two examples for colour conversion will be demonstrated. Both approaches take advantage of the ability of a controlled displacement of the recombination zone through the organic semiconductors. In the first approach two different acenes with different emission colours are employed in a parallel stack in a top-contact bottom-gate FET configuration. It will be demonstrated that due to thermionic emission of electrons at the source, light of one colour can be generated near the source contact even in hole accumulation. Due to the electrically controllable positioning the charge carrier recombination zone can be directed from the top acene layer to in the bottom acene layer. Thereby the emitted light can be continuously shifted by about 50 nm from green to red. A second approach takes advantage of the horizontal displacement of the recombination zone within the channel of the transistor. On top of the semi-transparent gate electrode of a F8BT transistor a colour conversion layer is deposited in a wedge-like shape partially covering the channel. In the ambipolar regime the charge carrier recombination takes place in the F8BT layer, and dependent on the position of the recombination zone either the emitted light of the F8BT layer or the partially absorbed and converted light from the colour conversion layer can be detected. The electroluminescence maximum of the emitted light can be shifted by about 30 nm. The physics and potential applications of such colour tuneable OLETs will be discussed.
Date: 13/September/2013 – (Friday) – Place: Sala 419 – Auditório do Bloco G – Time: 10:00
THE PHYSICS GRADUATE PROGRAM invites everyone to the seminar:
Quark matter under strong magnetic fields
Prof. Norberto Scoccola / Depto. de Fisica, Lab. TANDAR – Argentina
Abstract:
The phase structure of magnetized cold quark matter is analyzed in the framework of the two-flavor Nambu-Jona-Lasinio models paying special attention to its dependence on the model parameters as different values within the phenomenological allowed range are consid- ered. We first discuss the simpler chiral limit case, and then the more realistic situation of finite current masses. We show that in spite of the difference in the nature of some transi- tions, both cases are alike and exhibit a rather rich phase structure for a significant range of acceptable parameters. A simplification of the phase structure is obtained as parameters leading to larger values of the dressed quark mass in the vacuum are considered. Finally, we consider the so-called “inverse catalysis effect” showing that in some phases it implies an actual decrease of the order parameter as the magnetic field increases.
Date: 6/September/2013 – (Friday) – Place: Auditório do Bloco G – Sala 419 – Time: 10:00
The Physics Graduate Program invites everyone to:
Qualifying Examination for Doctoral Thesis
Luiz Laércio Lopes
Estrelas de Nêutrons no Regime da Simetria SU(3)
Defense Committee:
Prof. Dr. Marcus Emmanuel Benghi Pinto – (President) – FSC/UFSC
Prof. Dr. Norberto N. Scoccola – (Membro inglês) – Depto de Física – Lab. TANDAR
Prof. Dr. Sidney dos Santos Avancini – (Local member) – FSC/UFSC
Date: 6/September/2013 – Friday – Time: 2:00 pm – Place: Auditório do Bloco G – Sala 419
The Physics Graduate Program invites everyone to:
Defense of Doctoral Thesis
Iuri Stefani Brandt
PROPRIEDADES RELACIONADAS ÀS VACÂNCIAS DE Cu EM FILMES ELETRODEPOSITADOS DE Cu2O E EMISSÃO DE PARES PÓSITRON-ELÉTRON CORRELACIONADOS DE SUPERFÍCIES
Defense Committee:
Prof. Dr. André Avelino Pasa – (President) – FSC/UFSC
Prof. Dr. Marcelo Knobel – (External member) – UNICAMP
Prof. Dr. Jandir Miguel Hickmann – (External member) – UFRGS
Prof. Dr. Alexandre da Cas Viegas – (Membro titular) – FSC/UFSC
Prof. Dr. Márcio Santos – (Local member) – FSC/UFSC
Dr. Vinicius Claudio Zoldan – (Local member) – FSC/UFSC
Dr. Jonathan Israel Avila Osses – (Supplementary member)-FSC/UFSC
Dr. Mohmmad Khalid – (Supplementary member) – FSC/UFSC
Date: 02/September/2013 – Monday – Times: 2:00 pm – Place: Auditório do Bloco G – Sala 419
The Physics Graduate Program invites everyone to:
Qualifying Examination for Doctoral Thesis
Rodrigo Pereira Rocha
Difusão e Localização em Sistemas Desordenados Descritas por uma Equação Mestra Estocástica
Defense Committee:
Prof. Dr. Wagner Figueiredo – (President) – FSC/UFSC
Prof. Dr. Mario Jose de Oliveira – (External member) – IF/USP
Prof. Dr. Nilton da Silva Branco – (Local member) – FSC/UFSC
Prof. Dr. Jeferson de Lima Tomazelli – (Local member) – FSC/UFSC
Date: 30/August/2013 – Friday – Time: 10:00 am – Place: Meeting room Block G – room 11
THE PHYSICS GRADUATE PROGRAM invites everyone to the seminar:
J-PAS: The Javalambre-Physics of the Accelerated Universe Astrophysical Survey
Narciso Benitez Lozano
Instituto de Astrofísica de Andalucía (CSIC)
Abstract:
The Javalambre-Physics of the Accelerated Universe Astrophysical Survey (J-PAS) is a very wide field Cosmological Survey to be carried out from the Javalambre Observatory in Spain with a purpose-built, dedicated 2.5m telescope, using a set of 54 narrow band and 5 broad band filters over a 1.2Gpix, 4.7deg2 camera. Starting in 2015, J-PAS will image 8500deg2 of Northern Sky and obtain 0.003(1 + z) precision photometric redshifts for 9 × 107 galaxies, about 50 times more than the largest current spectroscopic survey, sampling an effective volume of ∼ 14 Gpc3. In addition J-PAS will also carry out a SNIe survey, a cosmic shear survey (thanks to the superb seeing at Javalambre) and a cluster survey, exploring the four main Dark Energy probes. In fact, and thanks to its innovative design, J-PAS will be the first experiment capable of reaching Stage IV according to the Dark Energy Task Force classification, several years before other projects like Euclid or LSST start their operations. The instrumental development of this project involves a small fraction of the cost and complexity of a high multiplexing spectrograph, yet it will produce data which enable a much wider range of Astrophysical applications: J-PAS effectively uses a 4.7deg2 “IFU” which will produce a low resolution 3D image of the Extragalactic Northern sky. Our survey will have a lasting legacy value, serving as a fundamental dataset for future cosmological projects.
Date: 30/August/2013 – (Friday) – Place: Sala 419 – Auditório do Bloco G – Time: 10:00
The Physics Graduate Program invites everyone to:
Defence of M.Sc. dissertation
Graziâni Candiotto
Método potenciodinâmico aplicado ao estudo da difusão iônica limitada por camada porosa em substratos de ITO
Defense Commitee
Profª. Drª. Maria Luisa Sartorelli – (President) – FSC/UFSC
Prof. Dr. Lucas Fugikawa Santos – (External member) – Unesp – São José do Rio Preto
Prof. Dr. Osvaldo Frederico Schilling Neto – (Local member) -FSC/UFSC
Profª. Drª. Marta Elisa Rosso Dotto – (Local member) – FSC/UFSC
Date: 28/August/2013 – Wednesday – Time: 10:00 am – Place:Auditório do Bloco G – Sala 419
