Quinacridone organic field effect transistors with significant stability by vacuum sublimation

Quinacridone (QA), a highly stable red dye, was investigated for the fabrication of organic field effect transistors (OFETs) by vacuum sublimation. Field effect mobilities for holes of 10−6 to 10−3 cm2/Vs were found, depending on the purity of the QA and the substrate temperature during the sublimation. The latter influences the structural phase composition of the films. The temperature dependence of the mobilities exhibits a maximum (μ = (1.5 ± 0.2) × 10−3 cm2/Vs) at ∼270 K. Over a period of 50 days, the mobilities are stable and even slightly increase, although the OFETs were exposed to air between measurements.