Phone: (509) 963-2818
Fax: (509) 963-1050
Office: Science Building 302C
Dr. Diaz’s research involves the study of electron-hole (e-h) pair transport and trapping in doped luminescent materials under vacuum ultraviolet (VUV) excitation. Excitation by VUV radiation leads to the formation of an e-h pair in the host. In order for luminescence to occur this e-h pair must be trapped by the rare earth dopant. However, the electron may also be trapped by bulk killers (impurities or defects), or it may be lost to surface states. In this figure YBO3 is the host and Eu3+ is the dopant. The purpose of our research is to quantify the fate of the e-h pair after absorption of a VUV photon takes place. This work is funded by the National Science Foundation Division of Materials Research (DMR 0906992).
Developing a detailed understanding of electron transport processes in solids is important to a wide variety of fields within materials science, including the study of scintillators, two-photon phosphors, dye-sensitized solar cells and transparent conductors. Functioning devices based on these technologies often require the transport of electrons through an oxide insulator. Although a fairly large number of useful materials have been developed for these applications, relatively little is known about the fundamental factors governing these processes. In particular, basic structure/property relationships for efficient VUV excitation are not well developed, and knowledge of such processes is inherently valuable to the study of electron transport in insulators in general.
1) K. Olsen, A. Lawler, and A. L. Diaz, "Quantitative Assessment of Surface Loss in Nanocrystalline YBO3:Eu3+ from Measurements of Host-to-Activator Transfer Efficiency," Journal of Physical Chemistry C, 115 17136 – 17146 (2011).
2) R. L. Rabinovitz, K. J. Johnston, and A. L. Diaz, "Investigation of the Effect of Gd3+ on Host-to-Europium Transfer Efficiency in (Y,Gd)BO3:Eu3+ Under VUV Excitation," Journal of Physical Chemistry C, 114 13884 – 13889 (2010).
3) T. Watrous-Kelley, A. L. Diaz and T. A. Dang, "Quantitative Determination of Non-Radiative Host-to-Activator Energy Transfer Efficiencies in YBO3:Eu3+ and Y2O3:Eu3+ Under VUV Excitation", Chemistry of Materials, 18 3130 – 3136 (2006).
4) B. Dawson, M. Ferguson, G. Marking and A. L. Diaz, “Mechanisms of VUV Damage in BaMgAl10O17:Eu2+”, Chemistry of Materials, 16 5311 – 5317 (2004).
5) B. Howe and A. L. Diaz, “Characterization of Host Lattice Emission and Energy Transfer in BaMgAl10O17,” Journal of Luminescence, 109 51 – 59 (2004).
6) D. B. Bolstad and A. L. Diaz, “Synthesis and Characterization of Nanocrystalline Y2O3:Eu3+ Phosphor: An Upper-Division Inorganic Chemistry Laboratory,” Journal of Chemical Education, 79 1101 - 1104 (2002).