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.
