Nitrogenous Interlayers for ITO S/D Electrodes in N‐Type Organic Thin Film Transistors

The commercialization of organic thin film transistors (OTFTs) is partly hindered by the high cost and stubborn work function (WF) common Au source/drain (S/D) electrodes. In this work, indium tin oxide (ITO) S/D electrodes modified with three different nitrogenous interlayers including 1,4-bis(2-hydroxyethyl) piperazine (HEP), polyethylenimine ethoxylated (PEIE), branched (PEI) are adopted to fabricate n-type OTFTs. WF bare ITO 4.7 eV, whereas exhibits WFs ranging from 4.1 3.6 eV. By first-principle calculation element analysis, protonated amines critical for reduction surface WF. Besides, higher nitrogen contents more likely improve wettability octadecyltrichlorosilane (OTS) substrates, help gain continuous oriented poly[2,5-bis(4-tetradecyloctadecyl)pyrrolo[3,4-c]pyrrole-1,4(2H,5H)-dione-alt-5,5′-di(thiophen-2-yl)-2,2′-(E)-1,2-bis(3,4-difluorothien-2-yl)-ethene] (P4FTVT-C32) semiconductor films. Therefore, P4FTVT-C32 based OTFTs maximum electron field-effect mobility 1.95 cm2 V−1 s−1 achieved PEI treatments. These results indicate that can greatly slash costs promote