Polymeric fluorescent substance and polymer light-emitting device using the same

A polymeric fluorescent substance exhibiting fluorescence in the solid state and having a polystyrene reduced number average molecular weight of 103 to 108, which is a random copolymer and comprises one or more repeating units represented by formula (1) and one or more repeating units represented by formula (3),

• —Ar1— (1)
• wherein Ar1 represents an arylene group or a divalent heterocyclic compound group and has 1 to 4 substituents, and wherein the substituents are represented by the following formula (2),
• wherein X1 represents a divalent hydrocarbon group;
• Ar2 represents an arylene group or a divalent heterocyclic compound group;
• Ar3 represents an aryl group or a monovalent heterocyclic compound group;
• Ar2 and Ar3 may be mutually connected to form a ring;
• Ar4 represents an aryl group or a monovalent heterocyclic compound group;
• Ar3 and Ar4 may be mutually connected to form a ring;
• k is 0 or 1;
• 1 represents an integer of 1 to 3,
• —Ar5— (3)
• wherein Ar5 represents an arylene group or divalent heterocyclic compound group represented by formula (4) or (5):
• wherein X2 represents a group selected from O, S, SO, SO2, N—R3, CR4R5, SiR6R7;
• R3 to R7 each independently represent a group selected from a hydrogen atom, alkyl group, aryl group and monovalent heterocyclic compound group;
• R1 and R2 each independently represent a group selected from alkyl group, alkoxy group, alkylthio group, alkylsilyl group, alkylamino group, aryl group, aryloxy group, arylsilyl group, arylamino group, arylalkyl group, arylalkoxy group, arylalkylsilyl group, arylalkylamino group, arylalkenyl group, arylalkynyl group, monovalent heterocyclic compound group and cyano group;
• m and n are each independently integers of 0 to 3;
• when m is two or more, a plurality of R1 may be the same or different;
• when n is two or more, a plurality of R2 maybe the same or different;
• R1 to R7 may be connected to form a ring;
• when R1 to R7 is a group containing an alkyl chain, the alkyl chain may be interrupted by a group containing a hetero atom,
• wherein R8 represents a group selected from alkyl group, alkoxy group, alkylthio group, alkylsilyl group, alkylamino group, aryl group, aryloxy group, arylsilyl group, arylamino group, arylalkyl group, arylalkoxy group, arylalkylsilyl group, arylalkylamino group, arylalkenyl group, arylalkynyl group, monovalent heterocyclic compound group and cyano group;
• j is an integer of 0 to 3;
• when j is two or more, a plurality of R8 may be the same or different;
• when R8 is a group containing an alkyl chain, the alkyl chain may be interrupted by a group containing a hetero atom.