Flexible Wearable Humidity Sensor Based on Nanodiamond With Fast Response

Yu, Xiang; Chen, Xinpeng; Yu, Xiang; Chen, Xinpeng; Ding, Xing; Zhao, Xuan

doi:10.1109/ted.2019.2897142

Cited by 13 publications

(9 citation statements)

References 34 publications

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“…These results indicate that the humidity sensitivity of the fabricated sensors can be significantly enhanced by reducing the resonator's bending radius under the limitation that the bending radius of the substrate can reach the minimum value. The possible reasons can be explained as follows: the interspaces between ND particles will expand due to the stretching of the bending sensing films, thus forming wider sensing channels [41]. Among the three sensors, sensor C with the smallest bending radius can absorb more water molecules to diffuse through the sensing films due to the largest interspaces and the widest channels between ND particles, thus producing a higher frequency shift than that of sensors A and B.…”

Section: Resultsmentioning

confidence: 99%

“…Therefore, the electromagnetic characteristics of the resonator rely on the dielectric properties of the air surrounding the resonator. When the ND films are coated on the sensing region, due to the PI substrate's insensitivity to humidity [41], ɛ eff will strongly depend on the dielectric properties of the ND films ( ɛ r , ND ) in the case of humidity change. Obviously, the presence of the ND material within the sensing region will increase the effective dielectric constant.…”

Section: Theory and Designmentioning

confidence: 99%

See 1 more Smart Citation

Flexible SIW humidity sensors based on nanodiamond sensing films

Chen

Chen²,

Yao

et al. 2023

Int. J. Microw. Wireless Technol.

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In this paper, flexible substrate integrated waveguide (SIW) resonators have been designed and fabricated on polyimide substrates for humidity sensing applications. The proposed SIW resonant cavity allows the resonator to obtain the maximum humidity sensitivity and meet the demand for flexible microwave sensing detection. Meanwhile, the humidity response performance can be further significantly enhanced by introducing nanodiamond (ND) sensing material. Three prototypes of ND-coated SIW sensors with different bending radii are measured to analyze their humidity sensing performance. The experimental results demonstrate that the proposed ND-coated SIW sensor with the minimum bending radius can achieve a maximum humidity sensitivity of 1.09 MHz/% relative humidity (RH) in the high RH region (>75.3% RH) and a low humidity hysteresis of 1.8% in the range of 11.3–97.3% RH. This study provides a promising candidate to realize flexible microwave sensors with excellent sensing performance.

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Section: Resultsmentioning

confidence: 99%

Section: Theory and Designmentioning

confidence: 99%

Flexible SIW humidity sensors based on nanodiamond sensing films

Chen

Chen²,

Yao

et al. 2023

Int. J. Microw. Wireless Technol.

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“…In order to meet the needs of humidity sensors in novel applications, it is necessary to develop flexible, nontoxic, and fast response humidity sensors. So far, many humidity sensors based on organic substrates have been reported, but they suffer from some shortcomings like flexible gas sensors. − The definitions (response, sensitivity, and response/recovery times) of humidity sensing parameters of the humidity sensor are basically consistent with that of gas sensor. It should be noted that the hysteresis phenomenon of the humidity sensor is obvious, which needs to be defined and studied separately.…”

Section: Applications Of Pb Gas Humidity and Strain Sensorsmentioning

confidence: 92%

Paper-Based Sensors for Gas, Humidity, and Strain Detections: A Review

Tai

Duan

Wang

et al. 2020

ACS Appl. Mater. Interfaces

353

184

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Paper, as a flexible, low-cost, lightweight, tailorable, environmental-friendly, degradable, and renewable material, is emerging in electronic devices. Especially, many kinds of paper-based (PB) sensors have been reported for wearable applications in recent years. Among them, the PB gas, humidity, and strain sensors are widely studied for monitoring gas, humidity, and strain from the human body and the environment. However, gas, humidity, and strain often coexist and interact, and the paper itself is hydrophilic and flexible, resulting in that it is still challenging to develop high-performance PB sensors specialized for gas, humidity, and strain detections. Therefore, it is necessary to summarize and discuss them systematically. In this review, we focus on summarizing the state-of-art studies of the PB gas, humidity, and strain sensors. Specifically, the fabrications (electrodes and sensing materials) and applications of PB gas, humidity, and strain sensors are summarized and discussed. The current challenges and the potential trends of PB sensors for gas, humidity, and strain detections are also outlined. This review not only can help readers to understand the development status of the PB gas, humidity, and strain sensors but also is helpful for readers to find out and solve the problems in this field through comparative reading.

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“…[32][33][34]. Among these types of materials, one can mention, inter alia, graphene oxide [35][36][37], carbon nanotubes [38][39][40], amorphous carbon [41], nanodiamond [42,43], nanocones [44], fullerenes and their derivatives [45,46], carbon nanocoils [47], holey carbon nanohorns (CNHox) and their nanocomposites [48][49][50][51][52][53][54][55], hydrogenated amorphous carbon [56], oxidized carbon nanoonions [57][58][59][60], carbon quantum dots [61].…”

Section: Methodsmentioning

confidence: 99%

Quaternary Holey Carbon Nanohorns/SnO2/ZnO/PVP Nano-Hybrid as Sensing Element for Resistive-Type Humidity Sensor

et al. 2021

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In this study, a resistive humidity sensor for moisture detection at room temperature is presented. The thin film proposed as a critical sensing element is based on a quaternary hybrid nanocomposite CNHox//SnO2/ZnO/PVP (oxidated carbon nanohorns–tin oxide–zinc oxide–polyvinylpyrrolidone) at the w/w/w/w ratios of 1.5/1/1/1 and 3/1/1/1. The sensing structure consists of a Si/SiO2 dielectric substrate and interdigitated transducers (IDT) electrodes, while the sensing film layer is deposited through the drop-casting method. Morphology and composition of the sensing layers were investigated through scanning electron microscopy with energy-dispersive X-ray spectroscopy (SEM-EDX), X-ray diffraction, and Raman spectroscopy. Each quaternary hybrid nanocomposite-based thin film’s relative humidity (RH) sensing capability was analyzed by applying a direct current with known intensity between two electrodes and measuring the voltage difference when varying the RH from 0% to 100% in a humid nitrogen atmosphere. While the sensor with CNHox/SnO2/ZnO/PVP at 1.5/1/1/1 as the sensing layer has the better performance in terms of sensitivity, the structure employing CNHox//SnO2/ ZnO/PVP at 3/1/1/1 (mass ratio) as the sensing layer has a better performance in terms of linearity. The contribution of each component of the quaternary hybrid nanocomposites to the sensing performance is discussed in relation to their physical and chemical properties. Several alternative sensing mechanisms were taken into consideration and discussed. Based on the measured sensing results, we presume that the impact of the p-type semiconductor behavior of CNHox, in conjunction with the swelling of the hydrophilic polymer, is dominant and leads to the overall increasing resistance of the sensing film.

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Flexible Wearable Humidity Sensor Based on Nanodiamond With Fast Response

Cited by 13 publications

References 34 publications

Flexible SIW humidity sensors based on nanodiamond sensing films

Flexible SIW humidity sensors based on nanodiamond sensing films

Paper-Based Sensors for Gas, Humidity, and Strain Detections: A Review

Quaternary Holey Carbon Nanohorns/SnO2/ZnO/PVP Nano-Hybrid as Sensing Element for Resistive-Type Humidity Sensor

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