A Perovskite solar cell, comprising: a first electrode including a transparent conductive substrate; a recombination-preventing layer formed on the first electrode; a photoactive layer formed on the recombination-preventing layer; a hole transport layer formed on the photoactive layer; and a second electrode formed on the hole transport layer, wherein the photoactive layer consists of a Perovskite double layer consisting of a layer of a first Perovskite represented by the following Chemical Formula 1 and a layer of a second Perovskite represented by the following Chemical Formula 2 formed on the layer of the first Perovskite: [Chemical Formula 1] RMX 3 wherein, in Chemical Formula 1, R includes a +1 cation selected from the group consisting of C n H 2n+1 NH 3 + wherein n is an integer of from 1 to 9, NH 4 +, HC(NH 2) 2 +, Cs +, NF 4 +, NCl 4 +, PF 4 +, PCl 4 +, CH 3 PH 3 +, CH 3 AsH 3 +, CH 3 SbH 3 +, PH 4 +, AsH 4 +, SbH 4 +, and combinations thereof, M includes a +2 metal cation selected from the group consisting of Pb 2+, Sn 2+, Ge 2+, and combinations thereof, and X is a halogen anion; [Chemical Formula 2] R'M'X' 3 wherein, in the Chemical Formula 2, R' includes a +1 cation selected from the group consisting of C n H 2n+1 NH 3 + wherein n is an integer of from 1 to 9, NH 4 +, HC(NH 2) 2 +, Cs +, NF 4 +, NCl 4 +, PF 4 +, PCl 4 +, CH 3 PH 3 +, CH 3 AsH 3 +, CH 3 SbH 3 +, PH 4 +, AsH 4 +, SbH 4 +, and combinations thereof, M' includes a +2 metal cation selected from the group consisting of Pb 2+, Sn 2+, Ge 2+, and combinations thereof, and X' is a halogen anion; characterized in that the cation R included in the Chemical Formula 1 and the cation R' included in the Chemical Formula 2 are different from each other and the metal cation M' is the same as M. a first electrode including a transparent conductive substrate; a recombination-preventing layer formed on the first electrode; a photoactive layer formed on the recombination-preventing layer; a hole transport layer formed on the photoactive layer; and a second electrode formed on the hole transport layer, wherein the photoactive layer consists of a Perovskite double layer consisting of a layer of a first Perovskite represented by the following Chemical Formula 1 and a layer of a second Perovskite represented by the following Chemical Formula 2 formed on the layer of the first Perovskite: [Chemical Formula 1] RMX 3 wherein, in Chemical Formula 1, R includes a +1 cation selected from the group consisting of C n H 2n+1 NH 3 + wherein n is an integer of from 1 to 9, NH 4 +, HC(NH 2) 2 +, Cs +, NF 4 +, NCl 4 +, PF 4 +, PCl 4 +, CH 3 PH 3 +, CH 3 AsH 3 +, CH 3 SbH 3 +, PH 4 +, AsH 4 +, SbH 4 +, and combinations thereof, M includes a +2 metal cation selected from the group consisting of Pb 2+, Sn 2+, Ge 2+, and combinations thereof, and X is a halogen anion; [Chemical Formula 2] R'M'X' 3 wherein, in the Chemical Formula 2, R' includes a +1 cation selected from the group consisting of C n H 2n+1 NH 3 + wherein n is an integer of from 1 to 9, NH 4 +, HC(NH 2) 2 +, Cs +, NF 4 +, NCl 4 +, PF 4 +, PCl 4 +, CH 3 PH 3 +, CH 3 AsH 3 +, CH 3 SbH 3 +, PH 4 +, AsH 4 +, SbH 4 +, and combinations thereof, M' includes a +2 metal cation selected from the group consisting of Pb 2+, Sn 2+, Ge 2+, and combinations thereof, and X' is a halogen anion; characterized in that the cation R included in the Chemical Formula 1 and the cation R' included in the Chemical Formula 2 are different from each other and the metal cation M' is the same as M. R includes a +1 cation selected from the group consisting of C n H 2n+1 NH 3 + wherein n is an integer of from 1 to 9, NH 4 +, HC(NH 2) 2 +, Cs +, NF 4 +, NCl 4 +, PF 4 +, PCl 4 +, CH 3 PH 3 +, CH 3 AsH 3 +, CH 3 SbH 3 +, PH 4 +, AsH 4 +, SbH 4 +, and combinations thereof, M includes a +2 metal cation selected from the group consisting of Pb 2+, Sn 2+, Ge 2+, and combinations thereof, and X is a halogen anion; R' includes a +1 cation selected from the group consisting of C n H 2n+1 NH 3 + wherein n is an integer of from 1 to 9, NH 4 +, HC(NH 2) 2 +, Cs +, NF 4 +, NCl 4 +, PF 4 +, PCl 4 +, CH 3 PH 3 +, CH 3 AsH 3 +, CH 3 SbH 3 +, PH 4 +, AsH 4 +, SbH 4 +, and combinations thereof, M' includes a +2 metal cation selected from the group consisting of Pb 2+, Sn 2+, Ge 2+, and combinations thereof, and X' is a halogen anion; characterized in that the cation R included in the Chemical Formula 1 and the cation R' included in the Chemical Formula 2 are different from each other and the metal cation M' is the same as M.