Low-temperature solution-processed high-k ZrTiOx dielectric films for high-performance organic thin film transistors

• A 200 °C hotplate annealing in ambient air was develpoed to prepare ZrTiOx dielectric films with a high-k value of 27.
• Organic transistor with 200 °C annealed ZrTiOx dielectric films can achieve a high carrier mobility of 0.51 cm2/Vs, highly comparable to those with 500 °C annealed ZrTiOx gate dielectrics.
• Organic transistor with 200 °C annealed ZrTiOx dielectric films also realized high hystersis and aging stability, important for the actual applications.

Solution-processed high-k oxide dielectrics, significant for low-voltage organic thin film transistors (OTFTs), mostly rely on the high-temperature annealing process. Here, we report a simple 200 °C hotplate-annealed zirconium titanium oxide (ZrTiOx) films with excellent dielectric properties for low-voltage OTFTs. The high dielectric constant of 27 and low leakage current of 1.5 × 10−6 A/cm2 were achieved. Moreover, the pentacene-based OTFT with 200 °C annealed ZrTiOx gate dielectrics realize high performances, such as the charge carrier mobility of 0.51 cm2/Vs, on/off current ratio of 104, threshold voltage about −1.4 V, and subtheshold voltage of 0.64 V/dec at the low operating voltage of 6 V. These performances are highly comparable to those with 500 °C annealed ZrTiOx gate dielectrics. Moreover, our OTFTs show high hysteresis and aging stability, important for pratical applications. These results indicate that a simple low-temperature hotplate annealing can offer high-performance dielectrics for OTFTs, and provide a promising approach for low-power organic electronics at a low cost.