Solution-processed low-voltage organic phototransistors based on an anthradithiophene molecular solid

Low-voltage organic phototransistors (OPTs) are attractive candidates for optoelectronic applications such as photodetectors and memory devices. Here we describe a solution-processed low-voltage organic phototransistor based on a triethylgermylethynyl-substituted anthradithiophene (diF-TEG ADT). Two kinds of dielectric materials were used: 80-nm-thick potassium alumina (PA) and 300-nm-thick thermally grown SiO₂. To investigate its application in a moist environment, the performance at different humidities was characterized. Results showed that the device was very stable in high humidity. A major change in drain current (I_DS) was observed when connecting or disconnecting the gate electrode to the device. This feature may motivate the application of diF-TEG ADT-based phototransistors as multistage photo-controlled memory devices.