Organic Compound, Light-Emitting Element, Light-Emitting Device, Electronic Device, and Lighting Device

Abstract

A novel organic compound with which the emission characteristics, emission efficiency, and reliability of a light-emitting element can be improved is provided. The organic compound has an imidazo[1,2-f]phenanthridine skeleton and a dibenzothiophene skeleton or a dibenzofuran skeleton bonded through an arylene group. The light-emitting element including the organic compound in a light-emitting layer shows high efficiency and low power consumption.

What is claimed is: 
     
         1 . An organic compound comprising:
 an imidazo[1,2-f]phenanthridine skeleton; and   one of a dibenzothiophene skeleton and a dibenzofuran skeleton,   wherein the imidazo[1,2-f]phenanthridine skeleton is bonded to the one of the dibenzothiophene skeleton and the dibenzofuran skeleton through an arylene group.   
     
     
         2 . The organic compound according to  claim 1 ,
 wherein the arylene group is a substituted or unsubstituted phenylene group or a substituted or unsubstituted biphenyldiyl group.   
     
     
         3 . The organic compound according to  claim 1 ,
 wherein the arylene group is a substituted or unsubstituted m-phenylene group.   
     
     
         4 . An organic compound represented by a formula (G1): 
       
         
           
           
               
               
           
         
         wherein: 
         R 1  to R 9  and R 21  to R 27  separately represent hydrogen, an alkyl group having 1 to 4 carbon atoms, or a substituted or unsubstituted aryl group having 6 to 13 carbon atoms; 
         Ar represents a substituted or unsubstituted arylene group having 6 to 13 carbon atoms; and 
         Z represents a sulfur atom or an oxygen atom. 
       
     
     
         5 . The organic compound according to  claim 4 ,
 wherein Ar represents a phenylene group.   
     
     
         6 . The organic compound according to  claim 4 ,
 wherein Ar represents a biphenyldiyl group.   
     
     
         7 . The organic compound according to  claim 4 ,
 wherein the organic compound is represented by a formula (G2):   
       
         
           
           
               
               
           
         
         wherein R 11  to R 14  separately represent hydrogen, an alkyl group having 1 to 4 carbon atoms, or a substituted or unsubstituted aryl group having 6 to 13 carbon atoms. 
       
     
     
         8 . The organic compound according to  claim 4 ,
 wherein Z represents a sulfur atom.   
     
     
         9 . The organic compound according to  claim 4 ,
 wherein the organic compound is represented by any one of the following formulae:   
       
         
           
           
               
               
           
         
       
     
     
         10 . A light-emitting device comprising:
 a first electrode;   an EL layer over the first electrode; and   a second electrode over the EL layer,   wherein the EL layer comprises an organic compound represented by a formula (G1):   
       
         
           
           
               
               
           
         
       
       and
 wherein: 
 R 1  to R 9  and R 21  to R 27  separately represent hydrogen, an alkyl group having 1 to 4 carbon atoms, or a substituted or unsubstituted aryl group having 6 to 13 carbon atoms; 
 Ar represents a substituted or unsubstituted arylene group having 6 to 13 carbon atoms; and 
 Z represents a sulfur atom or an oxygen atom. 
 
     
     
         11 . The light-emitting device according to  claim 10 ,
 wherein Ar represents a phenylene group or a biphenyldiyl group.   
     
     
         12 . The light-emitting device according to  claim 10 ,
 wherein the organic compound is represented by a formula (G2):   
       
         
           
           
               
               
           
         
         wherein R 11  to R 14  separately represent hydrogen, an alkyl group having 1 to 4 carbon atoms, or a substituted or unsubstituted aryl group having 6 to 13 carbon atoms. 
       
     
     
         13 . The light-emitting device according to  claim 10 ,
 wherein Z represents a sulfur atom.   
     
     
         14 . The light-emitting device according to  claim 10 ,
 wherein the organic compound is represented by any one of the following formulae:   
       
         
           
           
               
               
           
         
       
     
     
         15 . The light-emitting device according to  claim 10 ,
 wherein the EL layer comprises a light-emitting layer, and   wherein the organic compound is included in the light-emitting layer.   
     
     
         16 . The light-emitting device according to  claim 15 ,
 wherein the light-emitting layer further comprises a second compound and a third compound,   wherein the second compound is capable of emitting phosphorescence, and   wherein the third compound forms an exciplex with the organic compound.   
     
     
         17 . The light-emitting device according to  claim 16 ,
 wherein emission of the excimer overlaps with an absorption band of the second compound on the longest wavelength side.   
     
     
         18 . The light-emitting device according to  claim 15 ,
 wherein the EL layer further comprises:
 a second light-emitting layer over and in contact with the light-emitting layer; and 
 an electron-transport layer over and in contact with the second light-emitting layer, and 
   wherein the second light-emitting layer and the electron-transport layer each comprise the organic compound.   
     
     
         19 . An electronic device comprising the light-emitting device according to  claim 10 . 
     
     
         20 . A lighting device comprising the light-emitting device according to  claim 10 .