Rodrigo Fernando Bianchi

Design and characterization of a novel indicator dosimeter for blue-light radiation.

Optical absorption and fluorescence measurements have been done on poly[2-methoxy-5-(2-ethyl-hexyloxy)-1,4-phenylene vinylene]/[aluminum-tris(8-hydroxyquinoline)] solutions. The authors show that there is a visible response that covers the electronic absorption of bilirubin (350-500 nm), and hence, this material is applicable for managing the radiation doses planning before treatment of jaundice of neonates, which is one of the most common reasons of hospital readmission of newborns infants. The results show that the material presents a gradation of color from orange to yellow clearly, while its peak position emission shifts from orange-red (lambda(max) = 571 nm) to green (lambda(max) = 540 nm) with the radiation exposure time. The rate of these changes can be altered by manipulations of organic solution concentration and they are usually slow (from 2 to 8 h), suggesting these color and emission changes can be used to design an easy to make, easy to read, easy to operate, low cost (< US

A Novel and Low-Cost Disposable Device for Phototherapy of Neonatal Jaundice

0.50) and accuracy for individual monitoring indicator dosimeter in order to represent easily the radiation exposure time usually used in management of neonatal jaundice.

Comparison of V2O5 and WO3 sandwicheds, via sol-gel, to development as photovoltaics cells

The present work details, to our knowledge, the first examination of the influence of blue-light radiation on the optical properties of organic luminescent films in attempting to develop an indicator dosimeter for phototherapy of neonatal jaundice. Jaundice is the most common problem encountered in newborns due to immature functioning in the liver. The operating principle of the device is based on the optical response of poly[2-methoxy-5-(2-ethylhexyloxy)-p-phenylene (MEH-PPV) and tris(8-hydroxyquinolinato) aluminum (Alq 3 ) materials dispersed in polystyrene (PS) matrix (denoted as PS/MEH-PPV/Alq 3 ). It is observed a blue-shift on the photoluminescence of PS/MEH-PPV/Alq 3 system from red to orange-yellow, and then to green as function of the blue-light radiation exposure time. The result is attributed to the spectral overlap between emission of Alq 3 and absorption of MEH-PPV. The optical response of PS/MEH-PPV/Alq 3 to radiation was investigated to design a low-cost (

Chemical Treatment Influence on the Glass Substrate to the Growth of V2O5/PANI Thin Film

In this work, a new type of WO₃ and V₂O₅ photovoltaic cell were fabricated. The oxides were obtained by sol-gel route. Both V₂O₅ and WO₃ presented a lamellar structure with d = 1.17 nm and 0.69 nm, respectively. From SEM of V₂O₅ was observed ribbons and for WO₃ noted a presence of platelets. For WO₃, increasing the distance of lamp was observed a decreasing of light intensity: 164 mV in 44000 lux to 42 mV in 60 lux. For V₂O₅, in 1700 lux it was observed a voltage of 1418 mV and in 15000 lux a value of 1572 mV.

Influence of intensive light exposure on the complex impedance of polymer light-emitting diodes

Growth of the vanadium pentoxide xerogel in the presence of the polyaniline thin film (V 2O5/PANI) in different chemical treatment on substrate are presented. The in situ characterization studies revealed the presence of a lamellar structure for the V 2O5/PANI hybrid material. The intercalation reaction was evidenced on the basis of the increase in the d-spacing as well as the displacement of the absorption bands toward lower energy levels. The growth of V 2O5/PANI thin film, from direct reaction, on glasses substrate using pre-treated with cationic surfactant cetyl pyridinium chloride (CPC) and cetyl trimethylammonium bromide (CTAB) presented layers with a surface homogeneous. The UV/ozone and RCA treatment showed that the film had low adhesion on substrate compared with CPC and CTAB treatment. Furthermore, these results suggests that the CTAB and CPC treatment can be used, further, for V 2O5/PANI LbL films using V 2O5 gel as first layer as well as a promising candidate for applications as sensor for ammonia detection in poultry shed.

A blue-light dosimeter which indicates the dose accumulation by a multicoloured change of photodegraded polymer.

In this work we investigated the effect of visible radiation on the electrical properties of poly[(2-methoxy-5-hexyloxy)-p-phenylenevinylene]- MH-PPV films and light emitting diodes. Complex impedance measurements of (Au or ITO)/MH-PPV/(Au or Al) samples were carried out at room temperature and exposed to white light. Over the frequency range from 100 mHz to 2 MHz, the electrical results of Au/MH-PPV/Au was dominated by the Cole-Cole approach, where the electrode influence is negligible. However, some additional influence of the interface was observed to occur when Al was used as electrode. These effects were observed under both dark and visible-light illumination conditions. A simple model based on resistor-capacitor parallel circuits was developed to represent the complex impedance of the samples, thereby separating bulk and interface contributions. We observed that the polymer electrical resistivity decreased while the dielectric constant of the polymer and the thickness of the Al/MH-PPV layer were almost constant with increasing light intensity. The decrease of the polymer layer resistance comes from a better charge injection due to a light induced dissociation of positive charge carriers at the electrode.