New insight could lead to better silicon solar panels

Researchers astatine the U.S. Department of Energy's National Renewable Energy Laboratory (NREL) and Colorado School of Mines are applying a caller method to place defects successful silicon star cells that origin a driblet successful efficiency. The lessons learned astatine the atomic level could pb to improvements successful the mode manufacturers fortify their products against what is known arsenic light-induced degradation.

Light-induced degradation, oregon LID, shaves the ratio of silicon solar cells by astir 2%, which adds up to a important driblet successful powerfulness output implicit the 30- to 40-year lifespan of the exertion deployed successful the field. Solar cells made from silicon relationship for much than 96% of the global market, and the astir commonly utilized semiconductor utilized successful the manufacture of these cells is made from boron-doped silicon. But boron-doped silicon is susceptible to LID, truthful manufacturers person developed methods to stabilize the star modules.

Without an knowing of the defects astatine the atomic level, the researchers said it is intolerable to foretell the stableness of those modules.

"Some of the modules are stabilized completely. Some of them are lone half-stabilized," said Abigail Meyer, a Ph.D. campaigner astatine Mines and a researcher astatine NREL. She is the pb writer of a caller insubstantial detailing efforts to pinpoint the root of the LID phenomenon. The article, "Atomic Structure of Light-Induced Efficiency-Degrading Defect successful Boron-Doped Czochralski Silicon Solar Cells," appears successful the diary Energy & Environmental Science.

Her co-authors are Vincenzo LaSalvia, William Nemeth, Matthew Page, David Young, Paul Stradins, each from NREL; Sumit Agarwal, Michael Venuti, and Serena Eley, who are from Mines; and P. Craig Taylor, a retired Mines prof who consulted connected the research.

Stradins, a main idiosyncratic and a task person successful silicon photovoltaic probe astatine NREL, said the occupation of LID has been studied for decades but the nonstop microscopic quality of what causes the degradation has not been determined. Researchers person concluded, done indirect experimentation and theory, that the occupation decreases erstwhile little boron is utilized oregon erstwhile little oxygen is contiguous successful the silicon.

The collaboration betwixt NREL and Mines researchers relied connected electron paramagnetic resonance (EPR) to place defects liable for the LID. For the archetypal time, the microscopic examination revealed a chiseled defect signature arsenic the illustration star cells became much degraded by light. The defect signature disappeared erstwhile the scientists applied the empirical "regeneration" process to cure the LID that manufacture has adopted. To their surprise, the researchers besides recovered a second, "broad" EPR signature affected by airy exposure, involving galore much dopant atoms than determination are LID defects. They hypothesized that not each atomic changes induced by airy pb to the LID.

The techniques developed to survey LID tin beryllium extended to uncover different types of degrading defects successful silicon star cells and successful different semiconductor materials utilized successful photovoltaics including cadmium telluride and perovskites, the scientists noted.

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