Subcategory: Physics (not Nanoscience)
Yannik Palmer-Tesema - Alabama A&M
Co-Author(s): B. Rami Reddy, Alabama A&M, Huntsville Al.
Abstract Now-a-days there is a great demand for LED bulbs which are replacing incandescent light bulbs. LED bulbs are compact, rugged, and free from pollution. Diodes emit a single wavelength. However, phosphor coated diodes generate white light on exposure to blue or violet light. Global research is ongoing to design phosphor coatings which emit high intensity in a broad spectral wavelength region. We are also investigating different phosphor materials to address this issue. We are investigating the suitability of europium doped crystals and glasses for this purpose. Crystals used for this study were procured from commercial sources and the glasses were made in our laboratory. Appropriate quantities of the chemicals were measured, ground and then mixed for an hour. The chemicals were poured into an aluminum crucible and heated in a box furnace above the melting point for an hour. The resulting melt was poured into a mold and allowed to cool to room temperature, naturally. The glass samples were polished with sand papers of different grades. Detailed spectroscopy measurements were performed to characterize the materials. Absorption spectral measurements of the materials were performed using a Cary 3E spectrophotometer. Emission was stimulated from the samples by exposing them to blue diode lasers. Sample glow was white for blue laser excitation, along the beam path. A compact spectrometer was used for fluorescence spectral measurements. Emission spectral data and lifetime measurements were used for unambiguous spectroscopic assignments. From the emission spectral measurements color co-ordinates and color temperature were derived. All these results will be presented in detail.
Funder Acknowledgement(s): Alabama A&M University
Faculty Advisor: Dr. Rami Bommareddi, firstname.lastname@example.org
Role: My portion of this research is finding and using spectroscopy characteristics of glass to help emit white light.