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- Arias, A.C., et al.
(author)
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Use of tin oxide thin films as a transparent electrode in PPV based light-emitting diodes
- 2000
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In: Thin Solid Films. - 0040-6090 .- 1879-2731. ; 371:1, s. 201-206
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Journal article (peer-reviewed)abstract
- Tin oxide (TO) thin films, nominally undoped, have been used as electrodes in poly(p-phenylene vinylene) (PPV) based organic electroluminescent devices. The evolution of the crystallinity and the electrical resistance of TO films submitted to the PPV thermal conversion conditions, have been investigated. It has been found that the electrical resistance is decreased whereas the crystallinity of the film is increased. It is shown in this work, that the photoluminescence of PPV converted on top of TO substrates is not as quenched as it is when converted on top of indium-tin oxide (ITO) substrates. The quantum efficiency of light-emitting diode is 0.07% at 17 V forward bias. It is also shown that the work function of TO films is very stable to different cleaning procedures, in contrast with previous results obtained for ITO films.
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| 2. |
- Arias, M R, et al.
(author)
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An approach of the geometrical-based single bounce elliptical channel model for mobile environments
- 2002
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In: 8th International Conference on Communication Systems. ICCS 2002 (Cat. No.02EX585). - 0780375106 ; 1, s. 11-16
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Conference paper (peer-reviewed)abstract
- The simulation approach is an important tool used for the design and implementation of mobile radio systems with an emphasis on the propagation modeling for wireless channel. We carried out simulations for three different street positions scenarios of the receiver, (mobile station), using the geometrical-based single bounce elliptical channel model, as might be appropriate for microcellular applications and mobile-to-mobile communication. From the simulation results we use the parameters time-of-arrival (TOA) and angle-of-arrival (AOA), (delay and angular domain, respectively), to estimate the higher order channel statistics, such as the delay spread (DS) and the angle spread (AS), respectively
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| 5. |
- Roman, LS, et al.
(author)
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Photovoltaic devices based on photo induced charge transfer in polythiophene : CN-PPV blends
- 2003
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In: Brazilian journal of physics. - 0103-9733 .- 1678-4448. ; 33:2, s. 376-381
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Journal article (peer-reviewed)abstract
- We have investigated the photovoltaic properties of polymer devices based on a blend of two polymers, (poly(3-(2'-methoxy-5'-octylphenyl) thiophene) (POMeOPT) and poly(2,5,2',5'-tetrahexyloxy-7,8'-dicyanodi-p-phenylenevinylene) (CN-PPV), where photo induced charge transfer takes place at the interfaces formed by the interpenetrating network of the donor and the acceptor. The polymer blend films resulting from the spin coating were phase separated and the photo response of the devices depended on the morphology of the segregation. We have studied different blend ratios by photoluminescence quenching, scanning force microscopy and photovoltaic measurements. External quantum efficiencies of 4.5% at 500nm were achieved for the less segregated polymer blend.
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