Performance enhancement of organic thin-film transistors with improved copper phthalocyanine crystallization by inserting ultrathin pentacene buffer

Organic thin-film transistors (OTFTs) with high crystallization copper phthalocyanine (CuPc) active layers were fabricated by inserting an ultrathin pentacene buffer layer between the dielectric and CuPc layers. Comparing with the OTFTs without a pentacene buffer layer, the charge carrier mobility of the OTFT with a buffer layer presented a much higher value of ∼ 0.20 cm²/V s. Meanwhile, by investigating the morphology of the CuPc active layer with an ultrathin pentacene buffer layer through scanning electron microscopy and X-ray diffraction, the high crystallization of the CuPc film with a larger grain size and less grain boundaries can be observed. As a result, the resistance of the conducting channel was decreased, leading to a performance improvement of the OTFTs.