TECHNOLOGY FOCUS - ELECTRONICS - Preferred Components: The light emitting element further has substrate. The cathode has light transmittance. The electroconductive material includes metal, metal oxide and carbon material.    TECHNOLOGY FOCUS - ORGANIC CHEMISTRY - Preferred Groups: The ionic group is chosen from 38 groups e.g. groups of formulae: -SM, -C(=O)SM, -CS2M, -OM or -CO2M which are obtained by removing one hydrogen atom from aromatic ring in aromatic compound e.g. of formula (I)-(V).The polar group is chosen from carboxyl group, sulfo group, hydroxyl group, mercapto group, amino group, hydrocarbyl amino group, cyano group, pyrolidinyl group, monovalent heterocyclic group, -O-(R'O)m-R", -S-(R'S)q-R", -C(=O)-(R'-C(=O))q-R", -C(=S)-(R'-C(=S))q-R", -N((R')qR")2, -C(=O)O-(R'-C(=O)O)q-R", -C(=O)-O-(R'O)q-R", -NHC(=O)-(R'NHC(=O))q-R" and group of formula (a).The electron injection layer contains ionic compound of formula: (M"'(power(m'+)))a(X'(power (n'-)))b. The content of ionic compound in the electron injection layer is 0.1-100 parts weight.R = H or optionally substituted hydrocarbyl;M = optionally substituted ammonium cation or metal cation;M' =anion;R' = optionally substituted hydrocarbylene group;R" = H, optionally substituted hydrocarbyl, carboxy, sulfo, hydroxy, mercapto, amino, -NRc, cyano, or -C(=O)NRc;R"' = trivalent hydrocarbyl;m = 1 or more;q = 0 or more;Rc = 6-50C aryl or 1-30C alkyl (both optionally substituted);M"'(power(m'+))=metal cation;X'(power (n'-))=anion;anda,b=1 or more.    TECHNOLOGY FOCUS - POLYMERS - Preferred Composition: The organic compound having ionic group and polar groups is conjugated compound. The conjugated compound has structural units of formulae: -Ar1-(R1-(X1)m1)n1 and -(Ar2(-R2-(X2)m2)n2)-.Ar1 =aromatic group of valence (n1+1), preferably phenyl, naphthyl, fluorenyl or triphenylamino;R1 = direct bond or group having valence of (m1+1);X1, X2 = group containing ionic group or polar group;andm1, n1, m2, n2 = 1 or more.(i) When m1 is 1, R1 is direct bond; and (ii) When m2 is 1, R2 is direct bond.