Here, we report on the fabrication of low-voltage-operating pentacene-based organic field-effect transistors (OFETs) that utilize crosslinked cyanoethylated poly(vinyl alcohol) (CR-V) gate dielectrics. The crosslinked CR-V-based OFET could be operated successfully at low voltages (below 4 V), but abnormal behaviour during device operation, such as uncertainty in the field-effect mobility (μ) and hysteresis, was induced by the slow polarization of moieties embedded in the gate dielectric (e.g. polar functionalities, ionic impurities, water and solvent molecules). In an effort to improve the stability of OFET operation, we measured the dependence of μ and hysteresis on dielectric thickness, CR-V crosslinking conditions and sweep rate of the gate bias. The influence of the CR-V surface properties on μ, hysteresis, and the structural and morphological features of the pentacene layer grown on the gate dielectric was characterized and compared with the properties of pentacene grown on a polystyrene surface.

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Recently, organic light-emitting diodes (OLEDs) have widely been used as one of the information display techniques. We synthesized 2-(2-hydroxyphenyl)benzoxazole [Zn(HPB)2], (1,10-phenanthroline)(8-hydroxyquinoline) [Zn(phen)q] and (2-(2-hydroxyphenyl)benzoxazole)(8-hydoxyquinoline) [Zn(HPB)q]. The ionization potential (IP) and electron affinity (EA) of Zn complexes were investigated by cyclic voltammetry (CV). The EAs of Zn(HPB)2, Zn(HPB)q, and Zn(phen)q were determined to be 2.8, 3.5, and 3.2 eV, respectively. Moreover, the IPs of Zn(HPB)2, Zn(HPB)q, and Zn(phen)q are 6.5, 6.8, and 7.3 eV, respectively. The EL spectra of Zn(HPB)2, Zn(HPB)q, and Zn(phen)q were observed at the wavelengths of 455, 532, and 535 nm, respectively. We used Zn(HPB)2 and Zn(HPB)q as hole-blocking materials and Zn(phen)q as an electron-transporting material. The efficiency of the device with Zn(HPB)2 increased compared with that of the device without it. The device with Zn(phen)q exhibited an improved performance Alq3 as an electron-transporting material.