Electrode buffer layer has been extensively studied to improve the performance of organic field-effect transistor (OFET). Here, poly(methylmethacrylate) (PMMA) was employed as an electrode buffer layer between poly(3-hexylthiophene) (P3HT) layer and gold electrodes in OFETs. These OFETs exhibited nearly five-fold enhancement of hole mobility. Through atomic force microscope and grazing-incidence X-ray diffraction analyses, the performance enhancement was attributed to the uniformity and hydrophobicity of PMMA surface, which led to a remarkable reduction of contact resistance at P3HT/electrode interface. This study provides a facile strategy for the performance enhancement of OFET and insights into the essentiality of buffer layers.

High mobility organic field-effect transistors (OFETs) by inserting water-soluble deoxyribonucleic acid (DNA) buffer layer between electrodes and pentacene film through spray coating process were fabricated. Compared with the OFETs incorporated with DNA in the conventional organic solvents of ethanol and methanol: water mixture, the water-soluble DNA based OFET exhibited an over four folds enhancement of field-effect mobility from 0.035 to 0.153 cm²/Vs. By characterizing the surface morphology and the crystalline structure of pentacene active layer through atomic force microscope and X-ray diffraction, it was found that the adoption of water solvent in DNA solution, which played a key role in enhancing the field-effect mobility, was ascribed to both the elimination of the irreversible organic solvent-induced bulk-like phase transition of pentacene film and the diminution of a majority of charge trapping at interfaces in OFETs.