New approach promises to smooth out silicon texture characterization in solar cells
New approach promises to smooth out silicon texture characterization in solar cells lead image
As solar cells become more efficient, understanding the interplay between the textures and flow of current in these devices has become increasingly important. This kind of analysis, however, has often relied on slow, computationally intensive methods to characterize the textures of the crystalline silicon (c-Si) solar cells. A new analytical method employing optical simulation provides a way to learn about these textures in a matter of seconds.
As they report in the Journal of Applied Physics, a research team developed an approach to directly evaluate the optical and recombination losses in c-Si solar cells that can be used on a variety of c-Si textures. They used perfectly flat optical models to perform the external quantum efficiency (EQE) analysis on the textured silcon structures.
Micron-sized pyramid textures are added to many silicon-based solar cells to suppress light reflection and enhance absorption. Adding this texture, however, makes it difficult to study how the materials lose electric current. EQE analysis allows researchers to explore these questions, relying on reflectance spectra produced when light strikes the cell.
EQE analysis often involves ray tracing techniques to characterize different solar cell textures. By instead comparing the reflectance spectra to flat optical models, finding current loss mechanisms was simpler. After testing this on previously characterized solar cells, they report that their technique provides fast, accurate results for various textured c-Si solar cells, including c-Si heterojunction solar cells, a dopant-free c-Si solar cell with a MoOx layer, and an n-type passivated emitter with rear locally diffused (PERL) solar cell.
Source: “Fast determination of the current loss mechanisms in textured crystalline Si-based solar cells,” by Akihiro Nakane, Shohei Fujimoto, and Hiroyuki Fujiwara, Journal of Applied Physics (2017). The article can be accessed at https://doi.org/10.1063/1.4997063 .
