Modulating chain conformations of polyvinyl alcohol through low cost and nontoxic glyoxal crosslinker: Application in high performance organic transistors

High leakage current and presence of numerous polar hydroxyl groups have often appeared as severe performance obstacles for polyvinyl alcohol (PVA) on its application in organic field effect transistor devices. Herein, we report a facile, yet efficient functionalization and chain structure modification technique to enhance its efficacy as a gate insulating layer. In this work, we have used glyoxal as a cross-linking agent of PVA to modulate its chain conformation and performed a detailed analysis to explore the role of glyoxal crosslinking on the electrical and structural properties of PVA. Applying various amount of glyoxal solution we have properly optimized the dose of the crosslinker to be used in the crosslinking reaction so that minimum amount of leakage can be achieved. Substantial improvement in the insulation properties as well as surface characteristics was observed after the structural modification of the polymer. Correspondingly, organic FETs were fabricated using crosslinked PVA to gauge the effect of crosslinking on the device performance of the transistors. Post-crosslinking improvements in the polymer bulk and surface characteristics were clearly emulated in the device performance parameters. Field-effect mobility as high as 5.4 cm²/V-s and 1.7 cm²/V-s were achieved employing crosslinked PVA as gate dielectric layer in Dinaphtho[2,3-b:2′,3′-f]thieno[3,2-b]thiophene (DNTT) and pentacene based devices, respectively. Thus, our study illustrates the viability of crosslinking PVA using glyoxal and hence, can catalyze the limited use of PVA in electronic applications.