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A Zintl compound was identified as a candidate that is based on barium, cadmium and phosphorus.
The movement to using renewable energy for power generation is leading to the growing use of solar power. While progress has been made, research is ongoing to find new materials that can increase power conversion efficiency while remaining stable during use.
Geoffrey Hautier, Hodgson Family associate professor of engineering at Dartmouth College in Hanover, N.H., says, "The main solar material in use is silicon, which only achieves a certain efficiency level but has limitations including energy needs for production. Research has been conducted to identify different materials that could be used alone or even combined with silicon to improve performance."
Some of these alternative materials are cadmium telluride, CIGS (prepared from copper, indium, gallium and selenium) and perovskites. Hautier says, "One concern with
CIGS is the sourcing of the various materials used in its preparation. Lead halide perovskites have emerged as another option but are not stable. They degrade when exposed to oxygen and water. There is no clear approach for overcoming these issues."
A previous TLT article1 addressed the issue of perovskite solar cell stability by discussing work conducted by researchers to change the architecture from a n-i-p to an inverted p-i-n structure. The difference between the two orientations is the positioning of the electron transportation and hole transportation layers with respect to each other and to the perovskite. The surface modification was accomplished through treating a p-i-n perovskite thin film with an amine-based pyridine derivative. Performance testing at 55°C in ambient air led to an 87% maximum power conversion efficiency after 2,428 hours of sunlight exposure. A conventional perovskite solar cell only attained a 76% efficiency after less than half the sunlight exposure. Better resistance from moisture also was obtained with the cell maintaining 94% of its efficiency after being exposed to 85% relative humidity at 85°C for 850 hours.
Hautier says, "Alternative solar cell materials are needed that meet the criteria of...