Organic Field-Effect Transistors with Macroporous Semiconductor Films as High-Performance Humidity Sensors

In this study, we designed and fabricated a high-performance humidity sensor based on a donor-acceptor polymer transistor. To improve its sensing performance, a polymeric semiconductor film with macroporous structure was prepared using a facilitated phase-separation method. The relationship between the sensing performance and the pore size was systematically investigated by testing the humidity-sensing performance. The results suggested that the sensitivity of the sensor was improved with increasing pore size within a certain range. The sensor based on the macroporous film with an average pore size of 154 nm exhibited a sensitivity of 415 and a response time of 0.68 s, as the low relative humidity (RH) changed from 32% RH (9146 ppm) to 69% RH (20 036 ppm). These sensitivity values are better than those obtained by other reported humidity sensors based on organic field-effect transistors.