CISSEM’s Principal Investigators (PIs) have spent much of the last three decades developing expertise in interface science, and acquiring the state-of-the-art facilities and equipment to enable basic and applied research in interface science/engineering and the creation of new materials. A key strength of CISSEM is our ability to integrate materials synthesis, surface and interface analysis, and device science for the same heterojunction in organic photovoltaic solar cells (OPVs). Current facilities and equipment have been enhanced further by new equipment developed and procured under our EFRC award Number DE-SC0001084. This infrastructure – at the five institutions participating in CISSEM – positions us to pursue our mission and to be a national resource for the development of new thin-film photovoltaic technologies. These facilities, equipment, expertise, and instrumental approaches represent outstanding training opportunities for future energy scientists.
Some of the specialized analytical equipment and resources available at the CISSEM member institutions to support our basic research includes:
Thin-film metal oxide deposition platforms: NREL facilities include pulsed laser deposition systems and a collection of sputtering systems to create tailored metal oxides, paired with a suite of high throughput characterization tools. CISSEM researchers also use a thermal-Atomic Layer Deposition (ALD) system and a plasma-enhanced ALD (PE-ALD) tool at Georgia Tech, the latter in the Marcus Nanotechnology Building clean room. Both thermal- and PE-ALD are used for thin-film, metal oxide preparation, including new nanolaminates.
Photoelectron and photoemission spectroscopies: CISSEM researchers use state-of-the-art X-ray and UV-photoelectron spectroscopy (XPS and UPS) instruments at Georgia Tech, Princeton University, and The University of Arizona (UA), and inverse photoemission spectroscopy (IPES) at Princeton University, to characterize the surface composition and energetics of metal oxides, metals, and carbon-based materials. Through CISSEM funding, the UA system was upgraded in 2010 with a new multi-array detector achieving unprecedented resolution and sensitivity. In 2012, a new fully integrated glovebox sample handling system and additional high vacuum, thin-film deposition and sample handling enhancements were added to the UA XPS/UPS instrument through CISSEM funding. UA also provides unique two-photon UHV photoemission spectroscopies to study the energetics of organic semiconductor/metal or semiconductor (e.g. ZnO) interfaces, and ultra-fast spectroscopies for the study of charge injection at interfaces.
Spectroelectrochemical platforms: Spectroelectrochemical waveguide platforms (e.g., potential modulated attenuated total reflectance spectroscopy, PM-ATRS) at UA provide characterization of electron-transfer rates and orientation of molecular modifiers attached to oxide surfaces, with sub-monolayer sensitivity. CISSEM EFRC funding has extended this capability at UA to planar waveguide-based transient absorbance spectroscopy studies and extended the time domain down to sub-microsecond regimes.
Time-resolved electrostatic force microscopy (trEFM): CISSEM researchers at the University of Washington are developing new scanning-probe-based tools to characterize interfaces in thin-film PV structures at nanometer to sub-micron length scales, to dramatically improve resolution in trEFM, and enable measurements of heterogeneity in interfacial charge transfer rates in diode and OPV platforms.
Reflectance FT-IR and ultra-high vacuum (UHV) Raman spectroscopies: CISSEM researchers at UA use UHV Raman spectroscopy to provide compositional information about both organic/metal and organic/metal oxide interfaces. CISSEM funding, made available a Raman spectrometer fully dedicated to studies in UHV. Polarization modulation infrared reflection absorption spectroscopy (PM-IRRAS) experiments are being performed at UA to obtain detailed orientation and bonding information of oxide interface modifiers, with unprecedented sensitivity and resolution.
Laboratory-scale diode and OPV samples: We use sophisticated equipment at UA, Georgia Tech, and at NREL to prepare and test laboratory-scale diode structures and OPVs. NREL‘s equipment is located in its Process Development and Integration Laboratory (PDIL) with extensive and unique combinations of glovebox and atmospheric processing tools. The equipment at UA has been enhanced and expanded though CISSEM funding to provide thin-film deposition and glovebox sample handling capabilities integrated with the XPS/UPS instrument, in order to couple diode and OPV preparation with surface characterization environment for sample transfer without atmospheric exposure.
SLAC National Accelerator Laboratory: CISSEM researchers have made extensive use of the DOE SLAC facility to perform Near-edge X-ray absorption fine structure spectroscopy (NEXAFs) studies.