On left: Alan Delahoy, research professor of physics, displays an experimental thin-film cadmium telluride solar cell, with the deposition reactor in the background. On right: Professor Ken Chin, Center director, lectures on cadmium telluride theory.
Earlier this month, NJIT formalized an agreement with Chinese partners that will advance the university’s research on thin-film solar cells, an alternative energy technology with the potential to make buildings and other infrastructure substantially more energy-efficient.With more than $650,000 from the Shanghai-based China National Building Materials Company (CNBM), one of the largest gypsum, cement, and fiber glass producers in the world, NJIT will renovate its solar cell research laboratory and build prototype equipment that will enable manufacturers to produce thin-film cells more cost effectively.
The university’s CNBM New Energy Materials Research Center, directed by physics professor Ken Chin, is focused on thin-film cells based on CIGS (copper indium gallium selenide) and cadmium telluride, which are both potentially lower-cost alternatives to silicon, the industry standard, because they use raw materials more sparingly, take less net energy to produce, and occupy less space on buildings. Compounds such as cadmium telluride and silicon function as the active semiconductor in a solar cell, absorbing sunlight and converting it to electricity.
The CNBM Center has already developed important insights into the physics of the photoelectric behavior of these materials, which suggests that new manufacturing conditions could produce much higher cell efficiencies.
“Cadmium telluride is a promising photovoltaic material, but to date, with the exception of a single company, it has been difficult to produce and deploy on a manufacturing scale,” said Alan Delahoy, Ph.D., research professor and the Center’s general manager. “In terms of the market, the hurdle is making it competitive with crystalline silicon modules. But we see no reason why we can’t meet key efficiency targets by solving some basic scientific questions – and that’s what we aim to do.”
With its new funding, the solar team is building a machine, for example, that will permit manufacturers to deposit thin layers of a transparent conductive material such as zinc oxide on a photovoltaic plate without oxidizing the surface of the source metal in the process.
“Conventional technology performs reactive sputtering to form metal oxides for thin-film solar cells, transistors, and sensors, but this process is notoriously difficult to control,” Delahoy said, adding, “Process control is a big challenge in thin-film production. We are trying to come up with better manufacturing methods.”
The research team is also building sensitive equipment that will allow manufacturers to better detect defects in semiconductors.
CNBM is eager to speed development of inexpensive power production that can be seamlessly incorporated into a range of building materials.
“If just the rooftops of the world’s commercial buildings were equipped with current generation solar panels, it would satisfy ten percent of the global energy need. Imagine if every surface of civil infrastructure and private housing could be generating power,” said Donald Sebastian, senior vice president for research and development at NJIT.