Enhancing the light absorption in ultrathin-film silicon solar cells is important for improving efficiency and reducing cost. In this paper, we report a highly effecient cosine periodic nanostructure as light trapping texture. The design and fabrication as well as measurement of cosine nanotextures were presented. The optimized structure yields an average reflectance of 7.07% at an equivalent silicon thickness of 10μm, much better than planar and random pyramid structures. The measurements demonstrate that the absorptions in ultrathin film solar cells are very close to the Yablonovitch limit for the entire solar spectrum and insensitive to the angle of the light. This approach is applicable to various thicknesses and promising in future glass-based thin film solar cells.
When solar radiation transmits in the atmosphere, radiation wave band from 240nm to 280nm is strongly absorbed by the
ozone layer, which makes the ultraviolet radiation in this wave band difficult to reach the near earth surface. It forms the
solar radiation blind region on the near earth surface that is usually called solar blind region. Because of the strong
absorption, the solar blind ultraviolet detecting system works in wee background noise condition. In this paper, we
design a set of ultraviolet detecting experiment system. From the radiometry, we establish an improved estimate of the
operating range model based on the target signal, background signal difference and noise of detector. Using the improved model, we can calculate the operating range for point target in solar blind ultraviolet detecting system. For the special ultraviolet target, the calculated values are consistent with the practically measured values in the experiment system designed in the paper.