NOVELTY - The solar cell has a front sub-cell (SC1) provided on a first side of a transparent substrate (110), where the front sub-cell includes a first electrode, a first photoactive layer (220), and a second electrode. A rear sub-cell (SC2) is provided on a second side of the substrate, where the rear sub-cell includes a third electrode, a second photoactive layer (320), and a fourth electrode. One of the third electrode and the fourth electrode is a reflection electrode, where the reflection electrode comprises an area of about 50 to 95 % relative to an area of the second photoactive layer.    USE - Light transmission type two-sided solar cell for being installed on a window or exterior wall of a building as a smart curtain for transforming solar energy into electrical energy and simultaneously transmitting solar light to adjust inflowing light from an outside.    ADVANTAGE - The reflection electrode is patterned and formed on a part of the second photoactive layer, so that light transmittance of the solar cell can be controlled according to the area of the reflection electrode. The solar cell realizes a highly efficient light transmission type solar cell controlling greater than or equal to about 5 % of light transmittance and securing absorbance since the area of the reflection electrode is about 50 to 95 % relative to the total area of the second photoactive layer, and avoids need for a separate interlayer as a recombination site and a structure in which the front sub-cell and the rear sub-cell are stacked, so that performance degradation due to damage to a lower layer is avoided during stacking process, and additional control for matching current among the sub-cells is avoided.    DETAILED DESCRIPTION - The first, second, third and fourth electrodes are finger electrodes (210a, 230a, 310a, 330a).    DESCRIPTION OF DRAWING(S) - The drawing shows a cross-sectional view of a light transmission type two-sided solar cell.    Front sub-cell (SC1)    Rear sub-cell (SC2)    Transparent substrate (110)    Finger electrodes (210a, 230a, 310a, 330a)    Photoactive layers (220, 320)