Charge-transporting material and charge-transporting varnish

A charge-transporting thin film produced from a charge-transporting varnish consisting of a charge-transporting material and an organic solvent,

• wherein the charge-transporting material contains a heteropolyacid compound as a charge-transporting substance, and
• the heteropolyacid compound is uniformly dissolved in the organic solvent,
• wherein the organic solvent contains one or more good solvent selected from the group consisting of N,N-dimethylformamide, N,N-dimethylacetamide, N-methylpyrrolidone, 1,3-dimethyl-2-imidazolidinone, dimethyl sulfoxide, N-cyclohexyl-2-pyrrolidinone, cyclohexanol, ethylene glycol, 1,3-octylene glycol, diethylene glycol, dipropylene glycol, triethylene glycol, tripropylene glycol, 1,3-butanediol, 2,3-butanediol, 1,4-butanediol, propylene glycol, hexylene glycol, o-cresol, m-cresol, p-cresol, methyl isopropyl ketone, diethyl ketone, methyl isobutyl ketone, methyl n-butyl ketone, cyclohexanone, ethyl n-amyl ketone, isopropanol, t-butanol, allyl alcohol, 2-methyl-2-butanol, isobutanol, 2-methyl-1-butanol, 1-pentanol, 2-methyl-1-pentanol, 2-ethylhexanol, 1-octanol, 1-methoxy-2-butanol, diacetone alcohol, furfuryl alcohol, tetrahydrofurfuryl alcohol, benzyl alcohol, propylene glycol monomethyl ether, ethylene glycol monomethyl ether, ethylene glycol monobutyl ether, propylene glycol monoethyl ether, ethylene glycol monoethyl ether, ethylene glycol monoisopropyl ether, propylene glycol monobutyl ether, dipropylene glycol monomethyl ether, diethylene glycol monomethyl ether, dipropylene glycol monoethyl ether, diethylene glycol monoethyl ether, and triethylene glycol dimethyl ether, and
• wherein the organic solvent further contains a high-viscosity solvent having a viscosity at 25° C. of 10 to 200 mPa·s.