TECHNOLOGY FOCUS - ORGANIC CHEMISTRY - Preferred Method: The non-solvent is added to the composition including an organic material and a good solvent, and the mixture is applied to the substrate to form the thin film. The composition including an organic material and a good solvent is applied to the substrate, and the non-solvent is applied to form the thin film. The non-solvent is applied to the substrate, and the composition including an organic material and a good solvent is applied to form the thin film. The surface of the substrate is pretreated. The surface-treatment is carried out by a method using a self-assembled monolayer, a method using a buffer layer, or a method for varying surface physical properties. The thin film is annealed at 50-200degrees C for 1 minute to 1 hour. The volume ratio of the good solvent to the non-solvent added is 1:1-1.000:1. Preferred Component: The organic material is an organic semiconductor material or an organic insulating material. The organic semiconductor material is anthracene, tetracene, pentacene, melocyanine, copper phthalocyanine, perylene, rubrene, coronene, anthradithiophene, oligothiophene, or their derivatives. The organic insulating material is benzocyclobutene, parylene, and/or their derivatives. Preferred Composition: The good solvent is a solvent having a solubility of 0.05-20 (preferably 1-10) wt.% for the organic material and the non-solvent is a solvent having a solubility of 0.001 wt.% to less than 0.05 (preferably 0.01-0.03) wt.% for the organic material. The composition includes 0.1-50 wt.% of the organic material and 50-99.9 wt.% of the good solvent.    TECHNOLOGY FOCUS - POLYMERS - Preferred Component: The organic semiconductor material is polyfluorene, polyacetylene, polydiacetylene, polypyrrole, polythiophene, polyselenophene, polyisothianaphthene, polyarylenevinylene, polyaniline, polyazulene, polypyrene, polycarbazole, polyfuran, polyphenylene, polyindole, polypyridazine, polyacene, polythienylthiazole, or their derivatives. The organic insulating material is polyimide, benzocyclobutene, parylene, polyacrylate, polyvinyl alcohol, polyvinylphenol, and/or their derivatives. EXAMPLE - About 1 wt.% poly(3-hexylthiophene) was dissolved in chlorobenzene at 45degrees C, and 10 pbv acetonitrile was added to the solution. The mixture was dispersed by sonication for 3 hours to prepare an organic semiconductor composition. A molybdenum/tungsten alloy was deposited to a thickness of 1000 Angstrom on a clean glass substrate by sputtering to form a gate electrode. Then a mixture of the methacryloxypropyltrimethoxysilane polymer and tetrabutoxy titanate was dissolved in butanol a concentration of 10 wt.%. The solution was spin-coated to a thickness of 7000 Angstrom to form a gate insulating layer. The organic semiconductor composition was spin-cast at 1000 rpm to a thickness of 800 Angstrom on the gate insulating layer, and baked under a nitrogen atmosphere at 100degrees C for 10 minutes to form a semiconductor layer. Gold was deposited to a thickness of 700 Angstrom on the semiconductor layer by metal vapor deposition to form source-drain electrodes, completing fabrication of an organic thin film transistor with a top contact structure. The organic thin film transistor showed increased charge carrier mobility (0.02614) and increased on-current (3.2x 10-7) compared to comparative sample of the transistor (0.00723 and 1.09x 10-7, respectively).