New materials for photonic devices - hybrid systems and nanoscience

NEW MATERIALS FOR PHOTONIC DEVICES - HYBRID SYSTEMS AND NANOSCIENCE

PETRUS A. SANTA-CRUZ

Laboratório de Materiais Vítreos e Cerâmicas - LVC

Grupo de Arquitetura de Dispositivos Optoeletrônicos - ADOPE

Departamento de Química Fundamental/CCEN-UFPE, 50740-540 Recife-PE, Brazil

Presented by GILBERTO F. DE SÁ

We have developed a wide class of new materials for photonic device applications using lanthanide ions in complex, thin films complex, oxides, fluorides and metallic thin films and nanoparticles, conjugated with glasses, glassceramics, ceramics, hydrogels and enamels, characterizing hybrid systems for photonic and optoelectronic devices.

Some precursors of those materials, like oxyfluoride glasses with silver nanoparticles, were developed by our group more than 15 years ago (Malta OL et al. 1985. Chem Phys Lett 116:396), in the time that nanoscience was not fashionable. Nowadays we are developing devices for applications in pollution, toxins using immunoassay, up-conversion tracking of medical drugs in body and radiation dosimeters. A personal low-cost ultraviolet dosimeter of high sensitivity and selectivity to UV-A, B and C was developed using photonic process, resulting in a molecular device to skin cancer prevention (Santa-Cruz PA and Gameiro CG 1999. Patent # PI9705743-6 Brazil, RPI 1490:187). Two kinds of materials were used as the active part of the device: a thermoevaporated thin film of Eu^{3 +} complex or the complex powder dispersed in an enamel-like medium by spin-coating. In both systems that use glass substrates, the Eu^{3 +} red emission (⁵D₀

⁷F₂ transition) decreases as a function of UV dose. This reduction is irreversible, giving it a memory effect which allows dosimetry measurements. All measurements may be related to the MED (minimum erythemal dose) of 28 mJ/cm², because a calibration curve, from an integration sphere/radiometer, provides absolute dose measurements. A ligand-dependent process justifies the selectivity presented by the dosimeter, and explains the mechanism of the complex photodegradation at molecular level. We conclude that hybrid systems have large potential for use as active parts of photonic and integrated optoelectronic devices for sensors and dosimetry applications. — ( May 18, 2001 )

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Publication Dates

• Publication in this collection
  05 Oct 2001
• Date of issue
  Sept 2001