Organic phototransistors with all-polymer bulk heterojunction layers of p-type and n-type sulfur-containing conjugated polymers

All-polymer phototransistors were fabricated using both glass and flexible plastic film substrates by employing bulk heterojunction channel layers of p-type polymer (P3HT) and n-type polymer (THBT-ht). The devices could detect the entire visible light because the n-type polymer could sense photons in the deep red parts (>650 nm). The responsivity of devices was higher at the lower light intensity, while it could be controlled by varying the gate and/or drain voltages. Similar performances were measured for flexible all-polymer phototransistors with a bottom-source/drain and top-gate electrode configuration.