Solution-processed Fabrication Of High-performance Organic Field-effect Transistors

Solution-processed growth of organic micro/nanocrystal arrays for field-effect transistors(FET)has attracted extensive attention recently.On the one hand,solution-processed method have many advantages of simple operation,suitable for mass production and so on;On the other hand,organic semiconductor materials can dissolve in common organic solvents and be easily deposited on flexible substrates;Moreover,micro/nanocrystal arrays also show a promising potential for the large-scale and high-integration circuits,combining with patterned electrodes.The familiar solution-processed methods are: drop-casting,dip-coating and zone-casting.Aiming at the problems existing in these methods,such as: high requirement for experimental environment and easily leaving solvent residues,making the poor crystal quality and generally low device mobility.In this paper,we propose novel and improve traditional solution-based methods,effectively enhancing the crystal quality of the organic small molecular and polymer semiconductor.Combined with surface modification of the insulating layer,the performance of the FET is absolutely optimized.1.We demonstrate a novel brush-writing method,utilizing the capillary action of brushes,fabricating highly oriented and large-scale TCNQ single-crystal microwire arrays in the direction of perpendicular to brushes.The arrays not only can be grown on conventional rigid substrates,but also unconventional flexible substrates on account of large spread area and small concentration gradient of the organic semiconductor solution.The coverage area of microwire arrays with a consistent orientation can reach 1.5×2.0 mm2 and the success ratio is as high as 93%.Based on these microwire arrays,rigid and flexible FETs can be easily realized.By the Octadecyltrichlorosilane(OTS)modified Si/SiO2 substrate,the device mobility could increase an order of magnitude.2.We utilize the drop-casting method to realize the fabrication of high-quality TIPS-pentacene microribbon arrays by selecting the suitable solvent and substrate temperature,which is unfamiliar in the other literature.By the Trichloro(phenyl)silane(PTS)modified Si/SiO2 substrate,the device mobility increases an order of magnitude,up to 2.22 cm2/Vs that is highest mobility in all TIPS-pentacene crystals FETs by the drop-casting method.3.We use the spin-coating method,obtaining high-quality PCDTPT film by optimizing solution concentration,type of solvents,annealing conditions and insulating layer.The mobility of PCDTPT film FET reaches up to 0.824 cm2/Vs that is highest mobility in all PCDTPT films FETs by the spin-coating method.