Negative Photoconductivity in 2D Materials: Revolutionizing Adaptive Optoelectronic Intelligence and Secure...

2D materials feature atomically thin layers with strong in-plane covalent bonds and weak out-of-plane van der Waals interactions. This unique structure endows them with unique physical and chemical properties, making them highly promising for photodetector applications. Traditionally, photodetectors have mainly relied on positive photoconductivity (PPC) for their operation. However, recent research has shed light on the importance of anomalous negative photoconductivity (NPC), revealing its significant implications and innovative applications in the field. This review comprehensively summarizes the advancements made in understanding NPC within 2D material photodetectors. It highlights not only the physical mechanisms involved but also their promising applications. Currently, numerous applications of switchable positive-negative photoconductivity, ranging from dynamic perception, image processing, neuromorphic, and bio-inspired systems, information processing, secure encoding, optoelectronic storage, and logic operations, are also included. By delving into these underlying mechanisms and proposing novel application paradigms, the frontiers of 2D material photodetectors are being redefined within the realm of intelligent information electronics. This review delivers not only transformative insights for photodetection technology but also highlights opportunities for next-generation neuromorphic vision systems and cryptophotonic architectures. These breakthroughs provide an innovative hardware foundation crucial for the advancement of future artificial intelligence.