An optimized photolithography recipe for Cu(In1-x,Gax)(Sy,Se1-y)2(CIGSSe) solar cells

In order to characterize solar cell modules, patterning a sub-module into small-sized devices by photolithography are required. For CIGSSe sub-modules fabricated by sulfurization-after-selenization (SAS), the small-size device performance was considerably deteriorated (from 19.3 % to 11.3 % for power conversion efficiency (PCE)) as compared to the sub-module after traditional photolithography process. We found that, undesirable Cu
_2-x
Se phase was introduced into the film by the traditional photolithography process. By utilizing an optimized photolithograph recipe, the PCE as high as 19.5 % (nearly the same as the sub-module) for the patterned small-size unit cells were achieved. This allows us to perform specific characterizations to the small-size device in order to evaluate the properties of the sub-modules.