Full-Spectrum Solar Light–Activated Chemiresistive Sensors Based on W18O49/Ag2S S-Scheme Heterostructure for Highly Sensitive Room-Temperature NO2 Detection

en This link goes to a English section zh This link goes to a Chinese section Light-activated gas sensors hold significant potential in environmental monitoring and smart Internet of Things (IoT) owing to their advantage in room temperature operation. Nevertheless, due to a narrow light absorption range, high photocarrier recombination rate, and weak redox activity of the sensing material, the performance enhancement of the current light-activated gas sensors is still impeded. Herein, a full-spectrum solar light–activated gas sensor is designed based on W 18 O 49 /Ag 2 S nanocomposites with an S-scheme heterostructure for the highly sensitive detection of NO 2 at room temperature. Under solar light illumination, the gas sensor exhibits a high response of 430.84% to 1 ppm NO 2 , which is over 11 times higher than that based on pristine W 18 O 49 or Ag 2 S components. Moreover, the sensor demonstrates excellent repeatability fast response/recovery times (5/3 s), low limit of detection (50 ppb), high selectivity, and satisfactory long-term stability. The enhanced sensing performance might arise from the broadened light-harvesting capability and the unique charge carrier transfer mechanism in the S-scheme heterostructure. A Bluetooth-enabled portable monitoring system is further developed to achieve real-time NO 2 monitoring and wireless visualization. This work provides theoretical insights and experimental validation for the effectiveness of S-scheme heterostructure in enhancing room-temperature gas-sensing performance, demonstrating the prospective application potential for IoT-related environmental monitoring. 摘要 en This link goes to a English section zh This link goes to a Chinese section 光激活气体传感器因其室温工作的优势 , 在环境监测和智能物联网 领域具有重要潜力。然而 , 由于传感材料的光吸收范围窄、光生载流子复合速率高以及氧化还原活性较弱 , 目前光激活气体传感器的性能提升仍受到阻碍。本研究设计了一种基于W 18 O 49 /Ag 2 S纳米复合材料的全光谱太阳光激活气体传感器 , 该材料具有S型异质结构 , 可在室温下高灵敏检测NO 2 。在太阳光照射下 , 该气体传感器对1 ppm NO 2 的响应高达430.84% , 是纯W 18 O 49 或Ag 2 S组分的11倍以上。此外 , 该传感器展现出优异的可重复性、快速的响应/恢复时间 ( 5/3 s ) 、低检测限 ( 50 ppb ) 、高选择性以及令人满意的长期稳定性。 理论分析表明传感性能的增益源于S型异质结构中拓宽的光捕获能力和独特的载流子传输机制。在此基础上, 进一步开发了一套蓝牙便携式监测系统 , 实现了NO 2 的实时监测和无线可视化。本研究为S型异质结构有效增强气体传感性能提供了理论指导 和实验验证 , 为发展面向物联网应用的高灵敏室温气体传感器提供了重要技术支撑。