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

Abstract

An organic-inorganic perovskite satisfying E T <E T1 and E S −E T ≤0.1 eV has a high emission efficiency. E S represents the excited singlet energy level in emission of an inorganic component, E T represents the excited triplet energy level in emission of an inorganic component, E T1 represents the excited triplet energy level in emission of an organic component.

1 . An organic-inorganic perovskite satisfying the following requirements (1) and (2):
   E T <E T1    (1)
       E   S   −E   T ≤0.1 eV   (2)
   wherein E S  represents an excited singlet energy level in emission of an inorganic component constituting the organic-inorganic perovskite, E T  represents an excited triplet energy level in emission of an inorganic component constituting the organic-inorganic perovskite, E T1  represents an excited triplet energy level in emission of an organic component constituting the organic-inorganic perovskite.   
     
     
         2 . The organic-inorganic perovskite according to  claim 1 , which emits delayed fluorescence. 
     
     
         3 . The organic-inorganic perovskite according to  claim 1 , which is a quasi-two-dimensional perovskite. 
     
     
         4 . The organic-inorganic perovskite according to  claim 1 , which is represented by the following formula (10):
   R 2 A n−1 B n X 3+1    (10)
   wherein R represents a monovalent organic cation, A represents a monovalent cation, B represents a divalent metal ion, X represents a halide ion, and n represents an integer of 2 or more,   and wherein an inorganic layer having a composition represented by BX 4n  in the formula (10) constitutes the inorganic component, and the organic cation represented by R in the formula (10) constitutes the organic component.   
     
     
         5 . The organic-inorganic perovskite according to  claim 4 , wherein R in the formula (10) is an ammonium represented by the following formula (11):
   Ar(CH 2 ) n1 NH 3   +   (11)
   wherein Ar represents an aromatic ring, and n1 represents an integer of 1 to 20.   
     
     
         6 . The organic-inorganic perovskite according to  claim 4 , wherein A in the formula (10) is a formamidinium or a methylammonium. 
     
     
         7 . The organic-inorganic perovskite according to  claim 4 , wherein B in the formula (10) is Pb 2+ . 
     
     
         8 . The organic-inorganic perovskite according to  claim 4 , wherein X in the formula (10) is Br − . 
     
     
         9 . An organic-inorganic perovskite represented by the following formula (A) or the following formula (B):
   PEA 2 FA n−1 Pb n Br 3n+1    (A)
     PEA 2 MA n−1 Pb n Br 3n+1    (B)
   wherein PEA represents a phenylethylammonium, FA represents a formamidinium, MA represents a methylammonium, and n represents an integer of 2 or more.   
     
     
         10 . A film comprising an organic-inorganic perovskite of  claim 1 . 
     
     
         11 . A light-emitting film comprising an organic-inorganic perovskite of  claim 1 . 
     
     
         12 . A delayed fluorescence-emitting film comprising an organic-inorganic perovskite of  claim 1 . 
     
     
         13 . A light-emitting device having a film of  claim 10 . 
     
     
         14 . The light-emitting device according to  claim 13 , which emits delayed fluorescence at 300 K. 
     
     
         15 . A method for producing a light-emitting device wherein an organic-inorganic perovskite is so planned as to satisfy the following requirements (1) and (2), and a light-emitting device is produced using an organic-inorganic perovskite satisfying the following requirements:
   E T <E T1    (1)
       E   S   −E   T ≤0.1 eV   (2)
   wherein E S  represents an excited singlet energy level in emission of an inorganic component constituting the organic-inorganic perovskite, E T  represents an excited triplet energy level in emission of an inorganic component constituting the organic-inorganic perovskite, E T1  represents an excited triplet energy level in emission of an organic component constituting the organic-inorganic perovskite.