Solution-Processed Fabrication Of Polymer Organic Field-Transistors

Liquid phase method as one of widely used methods for preparing semiconductor layers in organic thin-film field-effect transistors?OTFTs?,which owns the advantages of low cost,low energy consumption,simple equipment and process requirements,and is suitable for industrial large-scale production,hasattracted a lot of attention.The liquid phase method is now mostly used to grow organic small molecule single crystal arrays or films,but it is often difficult to meet the requirements of flexible electronic devices due to the poor stretchability and flexibility of these materials.In contrast,OTFTs based on organic polymer semiconductor has the advantages of light weight,low cost,and solution processing compatible with flexible substrate,which makes it have unique advantages in constructing large-area flexible electronics.However,due to the structural differences of polymer macromolecular chains,the film formation law is very different from that of small molecule materials,and it is difficult to obtain high-quality polymer films by conventional preparation methods.Therefore,the optimization of thin film growth methods and the preparation of high performance polymer field effect transistors have become the research hotspots in recent years.In this paper,the electrical properties of PCDTPT thin-film transistors are effectively enhanced by improving the traditional film-forming methods of drop coating and spin coating.Based on this,flexible devices were prepared,as follows:1.We designed a novel lamination method to octadecyltrichlorosilane?OTS?modify the top surface of substrate,resulting in the difference in surface tension between the top and bottom substrates in the laminated structure.The orientation of the solution from the inside out is achieved on the bottomsubstrate.This method can completely eliminate the coffee ring effect in the traditional drop coating,thereby obtaining a large-area uniform high-quality PCDTPT polymer film.Based on this,we have prepared a field-effect transistor with a mobility of 0.97 cm²V^-1s^-1,which is the highest performance of the material obtained by the drop coating method.2.Using a simple spin coating method,by modifying the insulating layer,adjusting the solution concentration,optimizing the annealing conditions and the kind of solvent,a high quality PCDTPT polymer film was obtained,and the device mobility was up to 0.42cm²V^-1s^-1.3.We use the optimized lamination method to grow PCDTPT polymer film,and use organic solvent-resistant c-PVA as the insulating layer to construct ultra-thin flexible field-effect transistor.The device has excellent conformability,which demonstrates the application prospects in future wearable electronics.