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BEGIN:VEVENT
DTSTAMP:20261021T134804Z
LAST-MODIFIED:20141124T135543Z
DTSTART:20141203T140000Z
DTEND:20141203T150000Z
UID:event1368@bu.edu
URL:http://physics.bu.edu/internal/events/show/1368
SUMMARY:Soft x-ray Spectroscopy Studies of Novel Electronic Materials using
	 Synchrotron Radiation
DESCRIPTION:Featuring David Newby\n\nPart of the PhD Final Oral Exams.\n\nD
	issertation Committee: Kevin Smith\, Karl Ludwig\, Soumendra Basu\, Robert 
	Carey\, David Campbell\n\nAbstract:\n\nSoft x-ray spectroscopy can provide 
	a wealth of information on the electronic structure of solids. In this work
	\, a suite of soft x-ray spectroscopies is applied to organic and inorganic
	 materials with potential applications in electronic and energy generation 
	devices. Using the techniques of x-ray absorption (XAS)\, x-ray emission sp
	ectroscopy (XES)\, and x-ray photoemission spectroscopy (XPS)\, the fundame
	ntal properties of these different materials are explored. \nCycloparapheny
	lenes (CPPs) are a recently synthesized family of cyclic hydrocarbons with 
	very interesting properties and many potential applications. Unusual UV/Vis
	ible fluorescence trends have spurred a number of theoretical investigation
	s into the electronic properties of the CPP family\, but thus far no compre
	hensive electronic structure measurements have been conducted. XPS\, XAS\, 
	and XES data for two varieties\, [8]- and [10]-CPP\, are presented here\, a
	nd compared with the results of relevant DFT calculations.\nTurning towards
	 more application-centered investigations\, similar measurements are applie
	d to two materials commonly used in solid oxide fuel cell (SOFC) cathodes: 
	La1-xSrxMnO3 (LSMO) and La1-xSrxCo1-yFeyO3 (LSCF).  Both materials are stru
	cturally perovskites\, but they exhibit strikingly different electronic pro
	perties.  SOFC systems very efficiently produce electricity by catalyzing r
	eactions between oxygen and petroleum-based hydrocarbons at high temperatur
	es (>800ºC). Such systems are already utilized to great effect in many ind
	ustries\, but more widespread adoption could be had if the cells could oper
	ate at lower temperatures.  Understanding the electronic structure and oper
	ational evolution of the cathode materials is essential for the development
	 of better low-temperature fuel cells.\nLSCF is a mixed ion-electron conduc
	tor which holds promise for low-temperature SOFC applications. XPS spectra 
	of LSCF thin films are collected as the films are heated and gas-dosed in a
	 controlled environment. The surface evolution of these films is discussed\
	, and the effects of different gas environments on oxygen vacancy concentra
	tion are elucidated. \nLSMO is commonly used in commercial fuel cell device
	s. Here the resonant soft x-ray emission (RIXS) spectrum of LSMO is examine
	d\, and it is shown that the inelastic x-ray emission structure \n\n\n\n![D
	avid Newby](/resources/event-image/1368/88cb767_small)
LOCATION:PRB 365\, 3 Cummington Mall\, 02215
STATUS:CONFIRMED
CLASS:PUBLIC
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