An organic water-gated ambipolar transistor with a bulk heterojunction active layer for stable and tunable photodetection

Organic water-gatedtransistors (OWGTs) have emerged as promising sensing architectures for biomedical applications and environmental monitoring due to their ability ofin-situ detection of biological substances with high sensitivity and low operation voltage, as well as compatibility with various read-out circuits. Tremendous progress has been made in the development of p-type OWGTs. However, achieving stable n-type operation in OWGTs due to the presence of solvated oxygen in water is still challenging. Here, we report an ambipolar OWGT based on a bulkheterojunction active layer, which exhibits a stable hole and electrontransport when exposed to aqueous environment. The device can be used as aphotodetector both in the hole and electron accumulation regions to yield a maximum responsivity of 0.87  A W−1. More importantly, the device exhibited stable static and dynamicphotodetection even when operated in the n-type mode. These findings bring possibilities for the device to be adopted for future biosensing platforms, which are fully compatible with low-cost and low-power organic complementary circuits.
Source: Applied Physics Letters - Category: Physics Authors: Source Type: research