利用1,6-二(三氯甲硅烷基)己烷(C6-Si)交联的聚甲基丙烯酸甲酯(C-PMMA)修饰聚乙烯醇(PVA)绝缘层(C-PMMA/PVA), 并研究了修饰前后绝缘层的表面性质和电学性能。结果表明: 经C-PMMA修饰后, 虽然绝缘层表面粗糙度从0.386 nm增加到0.532 nm, 电容由14.2 nF/cm2减小到11.5 nF/cm2, 但绝缘层的水接触角显著变大, 从36°增加到68°, 表明修饰后表面极性显著下降; 此外, C-PMMA修饰的绝缘层的漏电流密度降低了约2个数量级。用纯PVA和C-PMMA修饰的PVA两种绝缘层制备了具有底栅顶接触结构的3-己基噻吩(P3HT)有机薄膜场效应晶体管, C-PMMA修饰PVA后器件性能显著提高, 开关比提高了约20倍, 迁移率增大了约4倍, 分别达到~102 cm2·V-1·s-1和3.3×10-2 cm2·V-1·s-1, 而且回滞现象明显降低。

The surface and electrical characteristics of the bare poly(vinyl alcohol)(PVA) and PVA modified with cross-linked poly(methyl methacrylate)(C-PMMA) by 1,6-bis(trichlorosilyl)hexane(C6-Si)(C-PMMA/PVA) were studied. The surface roughness increases from 0.386 nm to 0.532 nm, and the capacitance drops to 11.5 nF/cm2 from 14.2 nF/cm2 by the cross linking, however, the contact angle of water is greatly raised from 36° to 68°, indicating that the surface polarity of PVA is remarkably decreased by the modification of C-PMMA . Additionally, the leakage current of the C-PMMA- modified PVA layer is reduced by about 2 orders of magnitude. The C-PMMA/PVA as well as bare PVA insulating layers are utilized to fabricate organic field-effect transistors(OFETs) based on 3-hexyl thiophene (P3HT) with a bottom gate/top contact configuration. The performance of the device with the C-PMMA/PVA insulating layer is significantly improved, with the on/off ratio increased by 20 times and the mobility increased by 4 times, reaching ~102 cm2·V-1·s-1and 3.3×10-2 cm2·V-1·s-1, respectively. Furthermore, the hysteresis of the P3HT OFET, which mainly originates from the high surface polarity of the PVA insulating layer, is reduced dramatically by the modification of a very thin C-PMMA film.