Organic-inorganic perovskite, film, light-emitting film, delayed fluorescence-emitting film, light-emitting element, and method for producing light-emitting element

An electroluminescent device having an anode, a cathode, and a light-emitting layer between the anode and the cathode, wherein the light-emitting layer is composed of an organic-inorganic perovskite satisfying the following requirements (1) and (2) and represented by the formula (10) below:

• ET<ET1 (1)
• ES-ET≤0.1 eV (2)
• wherein ES represents an excited singlet energy level in emission of an inorganic component constituting the organic-inorganic perovskite, ET represents an excited triplet energy level in emission of an inorganic component constituting the organic-inorganic perovskite, Rn represents an excited triplet energy level in emission of an organic component constituting the organic-inorganic perovskite
• R2An−1BnX3n+1 (10)
• wherein R represents a monovalent organic cation represented by the formula (11) below, A represents a formamidinium, B represents a divalent metal ion selected from the group consisting of Cu2+, Ni2+, Mn2+, Fe2+, Co2+, Pd2+, Ge2+, Sn2+, Pb2+, and Eu2+, X represents a halide ion, and n represents an integer of 2 or more,
• and wherein an inorganic layer having a composition represented by BX4n, in the formula (10) constitutes the inorganic component, and the organic cation represented by R in the formula (10) constitutes the organic component
• Ar(CH2)n1NH3+ (11)
• wherein Ar represents an aromatic ring, and n1 represents an integer of 1 to 20.