| abstract |
The present invention pertains to a composition which contains a compound having a perovskite crystal structure, wherein the composition includes constituent components A, B, X, and M, and the value of a molar ratio [M/(M+B)] obtained by dividing the number of moles of M by the total number of moles of M and B is 0.7 or less. ("A" represents a cesium ion, an organic ammonium ion, or an amidinium ion positioned at each vertex of a hexahedron in which B is positioned at the center in the perovskite crystal structure. B represents a lead ion. M represents at least one cation selected from the group consisting of the cations of monovalent metal elements, except for a cesium ion. X represents a component positioned at each vertex of an octahedron in which B is positioned at the center in the perovskite crystal structure, the component being at least one anion selected from the group consisting of Cl-, Br-, F-, I-, and SCN-.) |