Charge transport ink composition

Abstract

This invention provides a charge-transfer ink composition that exhibits excellent dispersibility of metal oxide nanoparticles in organic solvents and provides a charge-transfer thin film with excellent charge transport properties. The ink composition comprises: metal oxide nanoparticles: oxides of metals selected from the group consisting of Zn, Mg, Ti, Zr, Sn, Ga, Fe, Ta, Nb, Y, Mo, W, Pb, In, Bi, and Sr; and at least one metal oxide nanoparticle from the group consisting of a complex of at least two of the aforementioned metals, a salt consisting of a cation represented by formula (A2-3) and an anion represented by formula (B1-1), wherein the salt has a topological polar surface area (TPSA) of 1 or more, and the difference in MolLogP between the cation and anion represented by "MolLogP(cation)-MolLogP(anion)" (ΔMolLogP) is greater than -3.0, and an organic solvent.