Reduction of the trap density at the organic–organic interface and resultant gate-bias dependency of the mobility in an organic thin-film transistor

We investigate the effect of the thermal treatment on the reduction of the trap density (Nit) at the organic–organic interface together with the mobility dependency to the gate-bias in an organic thin-film transistor (OTFT). The Nit between a poly(4-vinylphenol) layer and a pentacene film is found to be reduced due to the rearranged pentacene molecules during thermal treatment and the resultant mobility is obtained as high as 1.78 cm2/V s. In addition, the mobility dependency to the gate-bias is decreased at the case of thermally-treated OTFT. It can be concluded that the Nit plays an important role on the electrical performances as well as the bias-stability.

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► Effect of the thermal treatment on the reduction of the trap density was studied.
► Gate-bias dependency of the mobility was examined in a viewpoint of the trap density.
► High mobility of 1.78 cm2/V s was obtained in thermally treated transistor.
► Role of the interfacial trap density for bias-stability and performance were described.