“Interface Science of Emerging Solar Cell Technologies and Their Potential Role at the Nexus of Energy/Water/Food (A View from Arid and Hyper-Arid Environments)”

The U.S. has entered a new phase of how energy generation portfolios are determined, driven by an abundance of low-cost natural gas and explosive growth and dramatically falling prices for electricity generation from renewable energy sources such as utility scale photovoltaics (PV) and wind.  Regions of the southwestern U.S. with a combined population of ca. 70M people (Texas to California) may produce up to 50% of their electricity. from PV and wind by 2030, in parallel with the retirement of older fossil fuel generating stations. These dramatic changes, however, come at a time of unprecedented “water stress” to these same communities.  Low cost thin film solar cells have entered the picture as one potential pathway to electricity generation that provides for their integration into buildings and even greenhouses. In these “controlled environment greenhouses” food can be grown in energy efficient environments, with low water and energy use, possibly using semi-transparent solar cells as both a window and an energy source. For the beginning of this talk we’ll consider life in the “Living Laboratory” (Arizona) and then focus the remainder of the talk on some of the recent interface science that supports the development of new inexpensive and scalable organic and perovskite-based thin film solar cell technologies. For organic active layers, charge transfer reactions occur with both high and low work function contacts that can, if understood and controlled, actually aid in charge harvesting and improved efficiencies.  For perovskite active layers, which may promise higher energy conversion efficiencies, there is a much richer portfolio of Brønsted and Lewis acid/base chemistries that need to be considered for active layers in contact with semi-transparent oxide or even some organic thin film contacts, i.e. it is not just about control of work function.  Modification of these contacts needs to consider those chemistries in designing compositional and energetic gradients that we believe will lead to high-energy conversion efficiencies and improved device stabilities, that actually “move the needle” at the Energy/Water Nexus.

About the Speaker

Neal Armstrong is a Regents Professor of Chemistry/Biochemistry/Optical Sciences, and an Assoc. VP for Research at the University of Arizona.  His program has focused on the interface science of emerging technologies such as organic light emitting diodes (OLEDs), thin film solar cells (OPVs and perovskites), and photoactive nanocrystalline materials.  He has recently been “drawn” into the science, systems and policy underpinning the Energy/Water/(Food) nexus at UA and various other research development activities including new programs in quantum information science.