TECHNOLOGY FOCUS - ORGANIC CHEMISTRY - Preparation: No general preparation given. Preferred Compound: The triarylamine derivative is preferably of formula (2 or 3).Ar11-Ar13,Ar21-Ar23=optionally substituted aryl or heterocyclic group, and may mutually connect to form a cyclic structure, and substituent optionally connecting to form cyclic structure;Ar14,Ar15,Ar24,Ar25,Ar34,Ar35,Ar44,Ar45,Ar54,Ar55=optionally substituted aryl or heterocyclic group, and may mutually connect to form cyclic structure;i+j,m+n,p+q,s+t,v+w=2 or more;X2-X6=organic residue having acidic group;R11,R12,R21,R22,R31,R32,R41,R42,R51,R52=H, halo, optionally substituted alkyl, alkoxy, aryl, alkenyl, amino, cyano, or heterocyclic group;andh,l,o,r,u=1-5.Preferred Components: The oxide semiconductor is titanium oxide. SPECIFIC COMPOUNDS - 150 Triarylamine derivatives are disclosed e.g. (2Z)-3-(5-(5-((E)-2-(4-(bis(4-methylphenyl)amino)phenyl)ethenyl)thiophen-2-yl)thiophen-2-yl)-2-cyanoprop-2-enoic acid of formula (1a), (2Z)-3-(4-(4-((E)-2-(4-(bis(4-methylphenyl)amino)phenyl)ethenyl)phenyl)phenyl)-2-cyanoprop-2-enoic acid, 2-((5E)-5-((4-(4-((E)-2-(4-(diphenylamino)phenyl)ethenyl)phenyl)phenyl)methylidene)-2-((5Z)-3-ethyl-4-oxo-2-sulfanylidene-1,3-thiazolidin-5-ylidene)-4-oxo-1,3-thiazolidin-3-yl)acetic acid, (2Z)-3-(4-(4-((E)-2-(4-((4-((E)-2-(4-(4-((1Z)-2-carboxy-2-cyanoeth-1-en-1-yl)phenyl)phenyl)ethenyl)phenyl)(phenyl)amino)phenyl)ethenyl)phenyl)phenyl)-2-cyanoprop-2-enoic acid, and (2Z)-3-(5-(5-((2E)-3-(4-(bis((4-((2E)-3-(5-(5-((1Z)-2-carboxy-2-cyanoeth-1-en-1-yl)thiophen-2-yl)thiophen-2-yl)but-2-en-2-yl)phenyl))amino)phenyl)but-2-en-2-yl)thiophen-2-yl)thiophen-2-yl)-2-cyanoprop-2-enoic acid.    EXAMPLE - 4,4'-Dimethyl triphenylamine (7.5 g) was dissolved in toluene (22.5 ml), N,N-dimethylformamide (2.53 ml) and phosphorus oxychloride (3.1 ml) were dripped to the reaction mixture at 5 degrees C under ice-cooling, stirring at room temperature for 1 hour, heated at 80 degrees C, cooled, hydrolyzed by injecting the reaction mixture to water (400 ml), organic phase was extracted, washed with water and ethyl acetate, and dried using anhydrous sodium sulfate, to obtain (2Z)-3-(5-(5-((E)-2-(4-(bis(4-methylphenyl)amino)phenyl)ethenyl)thiophen-2-yl)thiophen-2-yl)-2-cyanoprop-2-enoic acid (1a).