A Camel Nose-Inspired Highly Durable Neuromorphic Humidity Sensor with Water Source Locating Capability

Abstract

Numerous emerging applications in modern society require humidity sensors that are not only sensitive and specific but also durable and intelligent. However, conventional humidity sensors do not have all of these simultaneously because they require very different or even contradictory design principles. Here, inspired by camel noses, we develop a porous zwitterionic capacitive humidity sensor. Relying on the synergistic effect of a porous structure and good chemical and thermal stabilities of hygroscopic zwitterions, this sensor simultaneously exhibits high sensitivity, discriminability, excellent durability, and, in particular, the highest respond speed among reported capacitive humidity sensors, with demonstrated applications in the fast discrimination between fresh, stale, and dry leaves, high-resolution touchless human-machine interactive input devices, and the real-time monitoring humidity level of a hot industrial exhaust. More importantly, this sensor exhibits typical synapse behaviors such as paired-pulse facilitation due to the strong binding interactions between water and zwitterions. This leads to learning and forgetting features with a tunable memory, thus giving the sensor artificial intelligence and enabling the location of water sources. This work offers a general design principle expected to be applied to develop other high-performance biochemical sensors and the nextgeneration intelligent sensors with much broader applications.

Progress and Perspectives of Single‐Atom Catalysts for Gas Sensing

“…[ 6 ] Currently, the internet of things (IoTs) and human–machine interactions attract extensive attention; the development of high‐performance gas sensors with low power consumption become imperative for the construction of artificial neural networks. [ 7,8 ] The widespread usages of sensors for monitoring and ensuring our normal work and life are indispensable. The gas sensor market is one of the biggest ones across the entire sensor technology which is estimated to reach $1.34 billion by 2027.…”

Humidity-Independent Artificial Olfactory Array Enabled by Hydrophobic Core–Shell Dye/MOFs@COFs Composites for Plant Disease Diagnosis

“…Volatile organic compounds (VOCs) monitoring and detection is of great importance and applied in diverse fields such as disease diagnosis, − environmental monitoring, and the quality assessment of food and beverages. , Among a variety of VOCs detection technologies, the colorimetric sensor array has been one of the most emerging ways due to rapidity, cost-effectiveness, and portability. − Inspired by the mammalian olfactory system, the colorimetric sensor arrays take advantage of the cross-reaction between colorants and analyte mixtures to generate a visual fingerprint pattern. − While colorimetric sensor arrays have been extensively studied, few have been commercialized for some limitations, such as humidity-dependent sensitivity. , Humidity refers to the amount of water vapor in the air, ranging from 6280 ppm (20% relative humidity, RH) to 25 740 ppm (80% RH) in ambient air. , In general, the concentration of water vapor is much higher than that of gas analytes at the ppm or ppb level in ambient air. Thus, the humidity interference is a huge challenge to the colorimetric sensor arrays for VOCs detection in the field of practical application.…”

“…11,15 Humidity refers to the amount of water vapor in the air, ranging from 6280 ppm (20% relative humidity, RH) to 25 740 ppm (80% RH) in ambient air. 16,17 In general, the concentration of water vapor is much higher than that of gas analytes at the ppm or ppb level in ambient air. Thus, the humidity interference is a huge challenge to the colorimetric sensor arrays for VOCs detection in the field of practical application.…”

SrTiO3/CuNi‐Heterostructure‐Based Thermopile for Sensitive Human Radiation Detection and Noncontact Human–Machine Interaction

“…The active sensors, such as optical [ 4–6 ] and capacitive [ 7–9 ] proximity switches, comprise a continuous transmitter and a receiver, which typically require high power consumption. In contrast, the passive sensors which directly detect human‐related physical properties, such as spontaneous thermal radiation, [ 10,11 ] humidity, [ 12–15 ] and accumulated electric charges, [ 16,17 ] are known for their low‐power characteristic. For example, Tang et al.…”

“…The active sensors, such as optical [4][5][6] and capacitive [7][8][9] proximity switches, comprise a continuous transmitter and a receiver, which typically require high power consumption. In contrast, the passive sensors which directly detect human-related physical properties, such as spontaneous thermal radiation, [10,11] humidity, [12][13][14][15] and accumulated electric charges, [16,17] are known for their low-power characteristic. For example, Tang et al [16] utilized the electric charges gathered at the fingertip to induce the charge redistribution on the graphene surface, based on which a touchless screen sensor was constructed.…”