Patent ID: 6403236
Filing Date: 2002-06-11
Classification: H01L,Y10S,Y10T

Abstract:
A polymer light emitting device at least having a light emitting layer containing a polymeric fluorescent substance and a charge transporting layer provided adjacent to the light emitting layer between electrodes consisting of a pair of an anode and a cathode, at least one of which electrode is transparent or semitransparent, wherein said polymeric fluorescent substance contains one or more kind of repeating units represented by the following formula (1), the sum of the repeating units being not less than 50% by mol based on the total repeating units, and has a number-average molecular weight of 103 to 107 in terms of polystyreneâ€”Ar1â€”CR1&boxH;CR2â€”â€ƒâ€ƒ(1) (wherein Ar1 represents an arylene group having 4 to 20 carbon atoms taking part in a conjugated bond, or a heterocyclic compound group having 4 to 20 carbon atoms taking part in a conjugated bond; and R1 and R2 independently represent a group selected from the group consisting of hydrogen, an alkyl group having 1 to 20 carbon atoms, an aryl group having 6 to 20 carbon atoms, a heterocyclic compound group having 4 to 20 carbon atoms and a cyano group), and said charge transporting layer contains an organic compound satisfying the following conditions 1 and 2 in an amount of from 1 to 70% by weight, and said organic compound satisfying the above conditions 1 and 2 has two or more condensed polycyclic aromatic compound groups containing three or more rings, in a moleculeEOX2âˆ’0.15&lE;EOX1&lE;EOX2+0.10â€ƒâ€ƒ(condition 1) &lgr;edge2âˆ’30&lE;&lgr;edge1&lE;&lgr;edge2+20â€ƒâ€ƒ(condition 2) wherein EOX1 and &lgr;edge1 respectively represent an electrochemically determined oxidation potential and an absorption edge wavelength of an absorption spectrum of said organic compound; EOX2 and &lgr;edge2 respectively represent an electrochemically determined oxidation potential and an absorption edge wavelength of an absorption spectrum of said polymeric fluorescent substances used in said light emitting layer; and the unit in the condition 1 is V and the unit in the condition 2 is nm).