NOVELTY - A composition comprises a charge-transporting substance comprising an aryl diamine derivative (I), an electron-accepting dopant substance, and an organic solvent.    USE - Composition is used for forming anode buffer layer of organic thin-film solar cell (all claimed).    ADVANTAGE - The composition economically provides anode buffer layer of organic thin-film solar cell having high photoelectric conversion efficiency.    DETAILED DESCRIPTION - A composition comprises a charge-transporting substance comprising an aryl diamine derivative of formula (I), an electron-accepting dopant substance, and an organic solvent.    R1-R4=H, halo, nitro, cyano, hydroxy, thiol, phosphoric acid group, sulfonic acid group, carboxy, 1-20C alkoxy, 1-20C thioalkoxy, 1-20C alkyl, 1-20C haloalkyl, 3-20C cycloalkyl, 6-20C bicycloalkyl, 2-20C alkenyl, 2-20C alkynyl, 6-20C aryl, 7-20C aralkyl, or 1-20C acyl;    R5-R8=H, or phenyl, naphthyl, pyridyl, pyrimidinyl, pyridazinyl, pyrazinyl, furanyl, pyrrolyl, pyrazolyl, imidazolyl or thienyl (all optionally substituted by substituent (S1) chosen from halo, nitro, cyano, hydroxy, thiol, phosphoric acid group, sulfonic acid group, carboxy, 1-20C alkoxy, 1-20C thioalkoxy, 1-20C alkyl, 1-20C haloalkyl, 3-20C cycloalkyl, 6-20C bicycloalkyl, 2-20C alkenyl, 2-20C alkynyl, 6-20C aryl, 7-20C aralkyl, or 1-20C acyl), or group of formula (i), in which at least 1 of R5-R8 is H;    R9-R12=H, halo, nitro, cyano, hydroxy, thiol, phosphoric acid group, sulfonic acid group, carboxy, 1-20C alkoxy, 1-20C thioalkoxy, 1-20C alkyl, 1-20C haloalkyl, 3-20C cycloalkyl, 6-20C bicycloalkyl, 2-20C alkenyl, 2-20C alkynyl, 6-20C aryl, 7-20C aralkyl, or 1-20C acyl;    R13,R14=phenyl, naphthyl, anthryl, pyridyl, pyrimidinyl, pyridazinyl, pyrazinyl, furanyl, pyrrolyl, pyrazolyl, imidazolyl or thienyl (all optionally substituted by substituent (S1));    R13+R14=ring;and    n=2-5.    An INDEPENDENT CLAIM is included for organic thin-film solar cell, which comprises an anode buffer layer produced from the composition, and an active layer in contact with the anode buffer layer.