ASU’s photovoltaics program earns 6 Energy Department SunShot Awards

Arizona State University has earned six prestigious U.S. Department of Energy SunShot Awards, totaling $4.3 million, ranking it first among recipients in the Photovoltaics Research category for 2017.  

This year’s awards, which come with grants totaling $20.5 million overall for 28 projects, supports the development of new commercial photovoltaics technologies that improve product performance, reliability and manufacturability. In this round, ASU’s Ira A. Fulton Schools of Engineering placed ahead of other leading solar research centers — the University of Central Florida ($3.18 million), Stanford ($1.59 million) and Colorado State ($1.28 million) each earned two awards. Last year, ASU photovoltaics researchers also received the majority of SunShot PV awards, taking six of 19 and $3.75 million in funding.

SunShot was launched in 2011 with a goal of making solar cost-competitive with conventional energy sources by 2020; the program is now at 90 percent of its goal of $0.06 per kilowatt-hour and recently expanded its target to $0.03 per kilowatt-hour by 2030.

ASU’s Quantum Energy and Sustainable Technologies (QESST) NSF-DOE research center and testbed in Tempe has established ASU’s engineering program as a powerhouse in photovoltaics, playing a key role in SunShot objectives. QESST is the largest university solar research facility in the United States, drawing researchers from around the world in the mission to advance photovoltaic technologies. QESST will continue to play a major role in the photovoltaics industry as SunShot moves to double the amount of national electricity demand provided by solar.

“ASU receiving six DOE SunShot Initiative grants — many more than any academic institution on the awardee list — is a testimony to our faculty’s excellence in building innovative solutions that help power the future in a reliable and cost-effective way,” said Sethuraman “Panch” Panchanathan, executive vice president of Knowledge Enterprise Development and chief research and innovation officer at ASU.

“For the second year in a row, our faculty won more SunShot awards than any other institution in the country, reaffirming our leadership in the research, development and advancement of photovoltaic science and technology,” said Kyle Squires, dean of the Ira A. Fulton Schools of Engineering. “Photovoltaics are a key component of tomorrow’s energy solutions, and this recognition from the Department of Energy highlights not only our faculty’s research excellence and the inherent value of their ideas, but also the breadth and depth of research in the Fulton Schools of Engineering.”

This year’s award recipients include:

Mariana Bertoni, assistant professor in the School of Electrical, Computer and Energy Engineering, was granted two awards. 

Award 1: Spalling, or the process of exfoliating a wafer from a silicon block, has shown promise as an efficient, waste-reducing production method for wafers. Bertoni’s first study is exploring a new spalling technique that relies on sound waves and low temperatures, to mitigate contamination of the wafers, while achieving industry relevant thickness and surface planarity.

“During our previous DOE award we have shown that the technique works; now we need to fine-tune the parameters to evaluate the potential for upscaling,” Bertoni said. “This could be a disruptive technology with applications well beyond silicon.”

Award 2: Bertoni’s second project will be studying the correlation between electrical properties, structure and composition at the nanoscale in thin film modules of cadmium telluride and copper indium gallium selenide. The team will be designing a multimodal hard X-ray microscopy approach to probe non-destructively different regions of modules under operating conditions. Detailed characterization could lead the way to improved module efficiency, lower degradation rates and longer warranties. Additionally, Bertoni is serving as co-principal investigator on Assistant Professor Owen Hildreth’s award (see below), and is co-PI on a fourth award, working in conjunction with Assistant Professor David Fenning of the University of California San Diego to develop a way to detect water present in photovoltaic modules. Using this methodology, the pair hopes to model performance degradation from water exposure.

“Understanding the origin of performance loses and how variations in illumination or temperature affect thin film modules will help us engineer high efficiency, long lasting devices,” Bertoni said.

Stuart Bowden, associate research professor in the School of Electrical, Computer and Energy Engineering, is designing a novel photovoltaic cell architecture known as M-CELL. This structure is a single silicon wafer, which allows integration and interconnection of multiple cells in series to enable higher voltage and lower current than existing modules.

Owen Hildreth, assistant professor in the School for Engineering of Matter, Transport and Energy, is researching ways to drastically reduce solar cell cost through the reduction of silver consumption. His project is investigating the how material and growth properties of reactive metal inks impact the reliability of solar cells metallized using these new inks. Hildreth’s work has potential for use both traditional silicon wafer technologies and next-generation heterojunction architectures, which currently employ costly metallization techniques due to temperature sensitivity.

“The solar cell industry currently spends more than $14 billion per year screen printing silver electrodes on the top of solar cells; this project aims to reduce those costs by a factor of 10 and reduce solar cell wafer production costs by 27 percent — making solar energy even more affordable to consumers,” said Hildreth.

Govindasamy Tamizhmani, associate research professor at the Polytechnic School, is investigating new methods for rapid and accurate characterization of photovoltaic modules in operation. Current methods are time-consuming and costly and lack the ability to account for differences between lab and field conditions — a vital component to understand the physical causes of performance variation in the field.

“Obtaining string and module I-V curves simultaneously is of great importance to plant owners and service providers to identify the underperforming modules and to determine the degradation rates and module mismatch losses,” Tamizhamani said.

Meng Tao, professor in the School of Electrical, Computer and Energy Engineering, is working on a two-layer aluminum electrode to replace its silver counterpart currently used in silicon photovoltaic cells. This could reduce processing expenses and improve device lifetime and reliability while maintaining high efficiency.