Fluorescence and delayed fluorescence-type organic light-emitting material and element

Abstract

Fluorescence-emitting material which improves luminous efficiency of an organic light-emitting element such as an organic EL element or an organic PL element and an organic light-emitting element using the fluorescence-emitting material. The fluorescence-emitting material includes a compound having an indolocarbazole skeleton represented by the following general formula (1), as defined in the specification. The organic light-emitting element includes an organic EL element including: a substrate; an anode; a cathode; and a light-emitting layer, the anode and the cathode being laminated on the substrate and the light-emitting layer being sandwiched between the anode and the cathode, in which the light-emitting layer includes: the organic light-emitting material; and as a host material, an organic compound having excited triplet energy higher than that of the organic light-emitting material.

1 . An organic light-emitting material which emits fluorescence and delayed fluorescence, the organic light-emitting material having a difference between excited singlet energy (S1) and excited triplet energy (T1) of 0.2 eV or less. 
     
     
         2 . The organic light-emitting material of  claim 1 , wherein the organic light-emitting material comprises a compound represented by formula (1): 
       
         
           
           
               
               
           
         
       
       wherein:
 a ring A represents an aromatic ring represented by the formula (1a) to be fused with an adjacent ring at an arbitrary position; 
 a ring B represents a heterocycle represented by the formula (1b) to be fused with an adjacent ring at an arbitrary position; 
 Ar's in the formulae (1) and (1b) each independently represent an aromatic hydrocarbon group or an aromatic heterocyclic group selected from the group consisting of groups each produced by removing one hydrogen atom from benzene, pentalene, indene, naphthalene, azulene, heptalene, octalene, indacene, acenaphthylene, phenalene, phenanthrene, anthracene, trindene, fluoranthene, acephenanthrylene, aceanthrylene, triphenylene, pyrene, chrysene, tetraphene, tetracene, pleiadene, picene, perylene, pentaphene, pentacene, tetraphenylene, cholanthrylene, helicene, hexaphene, rubicene, coronene, trinaphthylene, heptaphene, pyranthrene, ovalene, corannulene, fulminene, anthanthrene, zethrene, terylene, naphthacenonaphthacene, truxene, furan, benzofuran, isobenzofuran, xanthene, oxanthrene, dibenzofuran, perixanthenoxanthene, thiophene, thioxanthene, thianthrene, phenoxathiin, thionaphthene, isothianaphthene, thiophthene, thiophanthrene, dibenzothiophene, pyrrole, pyrazole, tellurazole, selenazole, thiazole, isothiazole, oxazole, furazan, pyridine, pyrazine, pyrimidine, pyridazine, triazine, indolizine, indole, isoindole, indazole, purine, quinolizine, isoquinoline, carbazole, imidazole, naphthyridine, phthalazine, quinazoline, benzodiazepine, quinoxaline, cinnoline, quinoline, pteridine, phenanthridine, acridine, perimidine, phenanthroline, phenazine, carboline, phenotellurazine, phenoselenazine, phenothiazine, phenoxazine, anthyridine, thebenidine, quindoline, quinindoline, acrindoline, phthaloperine, triphenodithiazine, triphenodioxazine, phenanthrazine, anthrazine, benzothiazole, benzoimidazole, benzooxazole, benzisooxazole, benzisothiazole, or an aromatic compound having a plurality of these aromatic rings linked together; 
 R's in the formulae (1) and (1a) each independently represent hydrogen or a monovalent substituent selected from the group consisting of an alkyl group having 1 to 10 carbon atoms, an alkoxy group having 1 to 10 carbon atoms, an alkylthio group having 1 to 10 carbon atoms, an alkylamino group having 1 to 10 carbon atoms, an acyl group having 2 to 10 carbon atoms, an aralkyl group having 7 to 20 carbon atoms, a substituted or unsubstituted aromatic hydrocarbon group having 6 to 30 carbon atoms, and a substituted or unsubstituted aromatic six-membered heterocyclic group having 3 to 30 carbon atoms, provided that adjacent substituents may together form a ring; and 
 n represents an integer of 1 or more and 4 or less. 
 
     
     
         3 . The organic light-emitting material of  claim 2 , wherein n in formula (1) represents 1. 
     
     
         4 . The organic light-emitting material of  claim 2 , wherein at least one of Ar in formula (1) represents an aromatic heterocyclic group. 
     
     
         5 . The organic light-emitting material of  claim 2 , wherein at least one of Ar in formula (1) represents a group of formula (2): 
       
         
           
           
               
               
           
         
       
       wherein: X's each independently represent N, C—H, or C—Ar 1  and at least one of X's represents N; and Ar 1 's each independently represent an aromatic hydrocarbon group or an aromatic heterocyclic group, provided that when X represents C—Ar 1 , Ar 1  and a ring comprising X may have a side in common to form a fused ring. 
     
     
         6 . An organic light-emitting material which emits fluorescence and delayed fluorescence, the organic light-emitting material having a difference between excited singlet energy (A1) and excited triplet energy, (T1) of 0.2 ev or less, provided that when said organic light-emitting material comprises a compound represented by formula (1): 
       
         
           
           
               
               
           
         
       
       then:
 a ring A represents an aromatic ring represented by the formula (1a) to be fused with an adjacent ring at an arbitrary position; 
 a ring B represents a heterocycle represented by the formula (1b) to be fused with an adjacent ring at an arbitrary position; 
 Ar's in the formulae (1) and (1b) each independently represent an aromatic hydrocarbon group or an aromatic heterocyclic group selected from the group consisting of groups each produced by removing one hydrogen atom from benzene, pentalene, indene, naphthalene, azulene, heptalene, octalene, indacene, acenaphthylene, phenalene, phenanthrene, anthracene, trindene, fluoranthene, acephenanthrylene, aceanthrylene, triphenylene, pyrene, chrysene, tetraphene, tetracene, pleiadene, picene, perylene, pentaphene, pentacene, tetraphenylene, cholanthrylene, helicene, hexaphene, rubicene, coronene, trinaphthylene, heptaphene, pyranthrene, ovalene, corannulene, fulminene, anthanthrene, zethrene, terylene, naphthacenonaphthacene, truxene, furan, benzofuran, isobenzofuran, xanthene, oxanthrene, dibenzofuran, perixanthenoxanthene, thiophene, thioxanthene, thianthrene, phenoxathiin, thionaphthene, isothianaphthene, thiophthene, thiophanthrene, dibenzothiophene, pyrrole, pyrazole, tellurazole, selenazole, thiazole, isothiazole, oxazole, furazan, pyridine, pyrazine, pyrimidine, pyridazine, triazine, indolizine, indole, isoindole, indazole, purine, quinolizine, isoquinoline, carbazole, imidazole, naphthyridine, phthalazine, quinazoline, benzodiazepine, quinoxaline, cinnoline, quinoline, pteridine, phenanthridine, acridine, perimidine, phenanthroline, phenazine, carboline, phenotellurazine, phenoselenazine, phenothiazine, phenoxazine, anthyridine, thebenidine, quindoline, quinindoline, acrindoline, phthaloperine, triphenodithiazine, triphenodioxazine, phenanthrazine, anthrazine, benzothiazole, benzoimidazole, benzooxazole, benzisooxazole, benzisothiazole, or an aromatic compound having a plurality of these aromatic rings linked together; 
 R's in the formulae (1) and (1a) each independently represent hydrogen or a monovalent substituent selected from the group consisting of an alkyl group having 1 to 10 carbon atoms, an alkoxy group having 1 to 10 carbon atoms, an alkylthio group having 1 to 10 carbon atoms, an alkylamino group having 1 to 10 carbon atoms, an acyl group having 2 to 10 carbon atoms, an aralkyl group having 7 to 20 carbon atoms, a substituted or unsubstituted aromatic hydrocarbon group having 6 to 30 carbon atoms, and a substituted or unsubstituted aromatic six-membered heterocyclic group having 3 to 30 carbon atoms, provided that adjacent substituents may together form a ring; and 
 n represents an integer of 1 or more and 4 or less. 
 
     
     
         7 . The organic light-emitting material of  claim 1 , wherein the organic light-emitting material has no metal atom in its molecule. 
     
     
         8 . An organic light-emitting material for a fluorescence and delayed fluorescent type organic light-emitting element, which emits fluorescence and delayed fluorescence, the organic light-emitting material having difference between excited singlet energy (S1) and excited triplet energy (T1) of 0.2 eV or less.