Negative Photoconductive Effect for Novel Photoelectric Sensors: A Review
Huiyao Shi, Si Tang, Jialin Shi, Peng Yu, Tié Yang, Minglin Li, Lianqing Liu
Abstract
Photoelectronic sensors, such as phototransistors, photoelectronic vision sensors, and photoelectronic memory elements based on low-dimensional nanomaterials and their hybrid structures, have received considerable attention for their unique structure and characteristics. Most studies on photoconductance sensors focus on positive photoconductivity (PPC); however, rare cases exist in which the conductivity decreases under light exposure. Such cases are known as negative photoconductivity (NPC). The integration of NPC and PPC has garnered significant interest for its switchable memorized electron transport mechanism, thus paving a novel way for the creation of nonvolatile memories, photoelectric logic gates, and neuromorphic computing systems. To deepen our understanding of NPC-based photoelectric sensors, we focus primarily on the basic mechanics of NPC effects and explore the related materials, structures, properties, and applications. Then, we highlight the modulation techniques for achieving NPC and PPC switching and discuss the most promising logic and memory applications by integrating the NPC and PPC effects. Furthermore, this study addresses key challenges in research on nanomaterials that exhibit NPC effects, aiming to inspire further exploration of novel, high-performance, and stable photoelectric sensors.