B. Cichy

Field-emission light sources utilizing carbon nanotubes and composite phosphor made of SiO2 nanospheres covered with Y2O3:Eu

A new concept of field-emission light sources (FELS) with electrophoretically deposited carbon nanotubes and newly discovered nanocomposite phosphor is presented. The vacuum micromachined devices were fabricated from silicon and glass wafers. Two types of miniature devices were tested. The first consisted of the silicon cathode covered with indium-tin oxide (ITO) layer and carbon nanotubes. The anode was made of glass wafer covered with ITO contact layer and nanocomposite core-shell phosphor. Nanocrystalline composite phosphor was made of silica core spheres covered with europium doped yttrium oxide Y2O3:Eu shell. For this model structure bright and uniform light emission was obtained. The second type of light source consisted of SiO2∕Y2O3:Eu phosphor deposited onto cathode, directly on carbon nanotubes layer. For this device successful but nonuniform luminescence was observed. Fabricated FELS are technologically compatible with microsystem technology and can be integrated with microfluidic systems.

Miniature field emission light sources associated with silicon-glass microcytometer for measurements of quality of oocytes

New micro-cytometric chip for qualitative, parametrical measurement of living oocytes/embryos of cows and pigs is proposed. The idea of measurement (Figure 1) is based on positioning of oocyte/embryo inside a micromachined glass-silicon or glass-PDMS chip with fluidic channel and set of micro-optical devices allowing spectrophotometric (absorption/transmission VIS/NIR spectra) and/or fluorimetric (fixed wavelength) measurements. Our preliminary work showed that cow embryos at different stage of maturity might be characterized by characteristic points of absorption spectra shifted toward longer wavelengths (Figure 2a). The another qualification factor might be a time-dependent decreasing of fluorescence intensity of dye labeled embryo. “Better” oocytes may tend to do not flourish whereas apoptic or necrotic oocytes marked by fluorescent dye are going to flourish at characteristic emission lines (Figure 2b).

Miniature field emission light sources for bio-chips

A concept based on preparation of miniature field emission light sources (FELS) for integration with bio-chips is presented. Glass and silicon-glass micro-fluidic systems (biochips) with spectrofluorometric detection are designated for this solution. Planar, miniature silicon-glass field emission light sources were designed and fabricated for this conception. Carbon nanotubes (CNTs) have been used as a low-voltage electron emissive layer. Nanocrystalline yttria matrices doped with rare earth (Re) ions (Re: Eu3+, Tb3+) have been synthesized and utilized as phosphor layers. Light emission spectral characteristics of fabricated sources allow to couple them with typical fluorescent markers as e.g. Alexa, Fluorescein or TO-PRO, used on the wide scale in biochemical researches. Fabricated FELSs are characterized by the intensive and homogenous light emission with well defined sharp emission lines. The efficient and stable field emission from carbon nanotubes has also been noticed. Fabricated FELS are technologically compatible with highly developing micromachined fluidic systems and are able to direct on-chip integration with these microsystems.

A New Concept of "Tuned" Light Sources for Microfluidic Applications

In the paper, a new idea of utilizing of the field-emission miniature light sources in microfluidics has been presented. We used YAG and Y2O3 based nanocrystalline phosphors fabricated by sol-gel method. Very good agreement of spectral characteristics of light emitted by field sources with very narrow absorption peaks of fluorophors used in biochemical analyses has been obtained

Green/White Light Sources utilizing Nanocrystalline YAG Phosphores and MWNT Field-Emission Cathodes

In the paper, a new field-emission miniature light source has been presented. Fabrication process of the nanopowdered phosphors and cleaning method of the multi-walls carbon nanotubes has been described. XRD spectrum of carbon nanotubes, cathodoluminescence spectra of nanocrystalline phosphors, and current-voltage characteristics of field emission from carbon nanotubes cathodes have been presented