NOVELTY - Thin film solar cell includes front electrode (110) positioned on substrate (100), and including a first front electrode layer (110a) and a second front electrode layer (110b), each containing a conductive material with light transmissivity. The first front electrode layer is formed on the substrate and contacts the substrate. A hole exposing a portion of the substrate is formed in a portion of the first front electrode layer. The second front electrode layer contacts the first front electrode layer and covers the hole of the first front electrode layer.    USE - Thin film solar cell i.e. tandem solar cell e.g. double or triple junction solar cell having p-type intrinsic n-type (p-i-n)/p-i-n structure.    ADVANTAGE - Because the second front electrode layer contacts and covers the first front electrode layer, the photoelectric conversion unit is prevented from directly contacting the substrate in the porous pin holes of the first front electrode layer. Hence, the unstable combination of carriers in the photoelectric conversion unit is reduced or prevented. The generation of cracks in the photoelectric conversion unit is prevented. Thus, the photoelectric efficiency of the thin film solar cell is improved.    DETAILED DESCRIPTION - Thin film solar cell comprises front electrode (110) positioned on substrate (100), and including a first front electrode layer (110a) and a second front electrode layer (110b), each containing a conductive material with light transmissivity; back electrode (130) positioned on the front electrode; and photoelectric conversion unit positioned between the front and back electrodes, where photoelectric conversion unit receives light and converts light into electricity. The first front electrode layer is formed on the substrate and contacts the substrate. A hole exposing a portion of the substrate is formed in a portion of the first front electrode layer. The second front electrode layer contacts the first front electrode layer and covers the hole of the first front electrode layer.    DESCRIPTION OF DRAWING(S) - The drawing is a cross-sectional view of thin film solar cell.    Substrate (100)    Front electrode (110)    First front electrode layer (110a)    Second front electrode layer (110b)    Back electrode (130)