MIXED CATION PEROVSKITE SOLID STATE SOLAR CELL AND FABRICATION THEREOF

The present invention provides a perovskite material comprising an organic-inorganic perovskite structure of formula (1), A n MX 3 (I), n being the number of cation A and an integer ‰¥ 4, A being a monovalent cation selected from inorganic cations Ai and/or from organic cations Ao, M being a divalent metal cation or a combination thereof, X being a halide and/or pseudohalide anion or a combination thereof, wherein at least one cation A is selected from organic cations Ao, the inorganic cations Ai are independently selected from Li + , Na + , K + , Rb + , Cs + , or Tl + and the organic cations Ao are independently selected from ammonium (NH 4 + ), methyl ammonium (MA) (CH 3 NH 3 + ), ethyl ammonium (CH 3 CH 2 NH 3 ) + , formamidinium (FA) (CH(NH 2 ) 2 + ), methylformamidinium (CH 3 C(NH 2 ) 2 + ), guanidium (C((NH) 2 ) 3 + ), tetramethylammonium ((CH 3 ) 4 N + ), dimethylammonium ((CH 3 ) 2 NH 2 + ) or trimethylammonium ((CH 3 ) 3 NH + ).