A Self‐Powered Portable Nanowire Array Gas Sensor for Dynamic NO₂ Monitoring at Room Temperature

Abstract

The fast development of the Internet of Things (IoT) has driven an increasing consumer demand for self‐powered gas sensors for real‐time data collection and autonomous responses in industries such as environmental monitoring, workplace safety, smart cities, and personal healthcare. Despite intensive research and rapid progress in the field, most reported self‐powered devices, specifically NO2 sensors for air pollution monitoring, have limited sensitivity, selectivity, and scalability. Here, a novel photovoltaic self‐powered NO2 sensor is demonstrated based on axial p–i–n homojunction InP nanowire (NW) arrays, that overcome these limitations. The optimized innovative InP NW array device is designed by numerical simulation for insights into sensing mechanisms and performance enhancement. Without a power source, this InP NW sensor achieves an 84% sensing response to 1 ppm NO2 and records a limit of detection down to the sub‐ppb level, with little dependence on the incident light intensity, even under <5% of 1 sun illumination. Based on this great environmental fidelity, the sensor is integrated into a commercial microchip interface to evaluate its performance in the context of dynamic environmental monitoring of motor vehicle exhaust. The results show that compound semiconductor nanowires can form promising self‐powered sensing platforms suitable for future mega‐scale IoT systems.

High-Performance Ni3(HHTP)2 Film-Based Flexible Field-Effect Transistor Gas Sensors

“…For example, they can be affixed to road traffic signs and advertising boards for monitoring NO 2 on traffic roads. 70 Sensors mounted on face masks, fabrics, etc. can be well applied to monitor gas pollutants in daily life, providing new ideas for healthcare monitoring.…”

Analytical Gas‐Sensing Responses for Single‐Crystalline Semiconducting Gas Sensors

“…This is why we need to develop nanoscale gas sensors, consistent with the experimental observations in literature. [8][9][10][11][12][13][14][15][16][17][18][19][20] Figure 3c depicts the experimental sensitivities. Overall, the sensitivity decreases at higher analyte concentration.…”

“…Chemical gas sensors have found a wide range of applications in defense, [1][2][3] safety, and disease diagnosis. [4][5][6][7] To enhance sensitivity, low-dimensional materials such as nanoparticles, [8][9][10][11] polycrystalline thin films, [12][13][14] chemical-vapor-deposited nanowires (NWs) [15][16][17] and 2D atomically thin materials [18][19][20] are often used as gas sensors due to their high surface-to-volume ratio (SVR) compared with bulk material. Although the sensing mechanism of chemiresistive gas sensor has been extensively investigated, [21][22][23][24] an analytical gas-sensing formula that allows for designing gas sensors and predicting sensor responses has yet to be established due to the challenges to control the dimensionality, surface states, and crystal quality of these lowdimensional materials.…”

Towards Highly Efficient Nitrogen Dioxide Gas Sensors in Humid and Wet Environments Using Triggerable-Polymer Metasurfaces

“…The selection of this spectral window was made for two reasons: firstly, the laser beam is not attenuated by the water droplets in high-humidity conditions, and, secondly, the telecom C band around 1550 nm has a multitude of off-the-shelf components which can be used to create low-cost gas sensors. Recent reports [ 37 ], in which InP nanowire arrays are used to monitor NO at room temperature by measuring an electrical signal have provided a significant level of insight in the realization of NO gas sensors in typical ambient environments. Our method differs from the former due to the fact that our sensor is designed for use in humid and wet environments, where the recording of small-level electrical signals can become challenging.…”