A p ‐Type Ladder‐Polymer Photoelectrochemical Transistor Enabling Integrated Optical Sensing and Adaptive Computing

ABSTRACT The integration of optical sensing, signal amplification, memory, and computation in compact devices is important for artificial visual systems, neuromorphic electronics, and robotics. Organic photoelectrochemical transistors (OPECTs) offer a promising platform, as their photonic–ionic–electronic coupling enables low‐voltage operation and intrinsic amplification. However, most single‐component OPECTs rely on n ‐type mixed ionic–electronic conductors, while high‐performing p ‐type devices remain scarce. Advancing p ‐type photoactive materials is crucial for complementary circuits with reconfigurable responses. We report a high‐performance p ‐type OPECT based on the ladder‐type organic conductor, PBBT‐Me, serving as both light‐sensitive channel and gate electrode. Under illumination, the device achieves a photocurrent of ∼640 µA, and a photoinduced transconductance modulation ratio of 35, combining strong photoresponse with transistor amplification. The effect arises from light‐induced gate potential modulation that enhances electrochemical channel doping and increases drain current. Beyond photodetection, the OPECT emulates optical synaptic functions such as short‐term plasticity, paired‐pulse facilitation, and rehearsal learning, enabling neuromorphic preprocessing for digit recognition. A complementary, light‐controlled inverter operates as a voltage‐to‐voltage photoamplifier with gain of 120 V/V, supporting optically switchable OR/NOR logic. Integration with robotic platforms further demonstrates light‐controlled gestures and motion, establishing p ‐type ladder‐polymer OPECTs as versatile building blocks for compact optoelectronic and neuromorphic systems.