Organic thin-film transistors

A method for forming a semiconductor layer, comprising:

• depositing a liquid composition onto a substrate to form the semiconducting layer;
• wherein the liquid composition comprises a semiconducting material selected from Formula (I) or Formula (II):
• wherein X is independently selected from S and Se in Formula (I) and X is independently selected from S, Se, and O in Formula (II);
• R1 is independently selected from hydrogen, alkyl, substituted alkyl, aryl, substituted aryl, heteroaryl, halogen, —CN, —NO2, and ethynylsilane;
• R2, R3, R4, and R5 are independently selected from hydrogen, alkyl, substituted alkyl, aryl, substituted aryl, heteroaryl, halogen, —CN, and —NO2;
• Ar and Ar′ are independently a conjugated divalent moiety;
• a and b are independently integers from 1 to about 10;
• and
• n is an integer and is at least 2.