ABSTRACT
The total collection efficiency of the solar cell consists of four distinct components, namely, the fundamental collection efficiency, reflection efficiency or reflection loss factor, inactive area, and internal collection efficiency and its expression can be written as
ηcoll.= [inactive area (percent)][reflection efficiency][fundamental collection efficiency][internal collection efficiency] (4.2)
The impact of bulk carrier lifetime and sunlight concentration factor on internal collection efficiency will be discussed under solar illumination intensity or concentration factors. The overall conversion efficiency is dependent on several factors, such as interaction area of the solar cell device (typically 98 percent), reflection efficiency (typically 95 percent), fundamental collection efficiency (typically 95 percent), contact efficiency (typically 96 percent), internal collection efficiency (typically 98 percent), voltage factor (typically 0.9), fill factor (typically 0.75), and bulk carrier lifetime (ranging from 230 µsec at 1 sun to 5 µsec at 100 suns, where sun represents the sunlight concentration factor). The total collection efficiency, also known as the fundamental collection efficiency, is the major contributing source, which is a function of silicon cell thickness and the sunlight illumination factor. Typical values of fundamental collection efficiency for a one-dimensional silicon solar cell under AM1 sunlight illumination are summarized in Table 4.1.
