Hierarchical Self-Assembled SnS₂ Nanoflower/Zn₂SnO₄ Hollow Sphere Nanohybrid for Humidity-Sensing Applications

Abstract

At present, humidity sensors have promising prospects in disease monitoring, family life, environmental protection, and so on. Flexible humidity sensor is more and more popular because of its flexibility and portability. In our work, a flexible humidity sensor based on a tin disulfide (SnS) nanoflower and a zinc stannate (ZnSnO) hollow sphere film was fabricated though layer-by-layer self-assembly technique. The humidity performance showed that the SnS/ZnSnO hybrid film sensor was ultrasensitive to humidity at room temperature. The test results demonstrated superior response, fast response/recovery behavior, and excellent repeatability. Moreover, compared to the single SnS and single ZnSnO nanomaterials, the SnS/ZnSnO hybrid film sensor exhibited great improvement in humidity sensing. In addition, complex impedance spectroscopy was adopted to further explore the sensing mechanisms of the SnS/ZnSnO hybrid to various humidities. Human respiration, palm sweat, urine, and water droplets were delicately detected by the SnS/ZnSnO humidity sensor, indicating its great potential in multifarious application fields.

Flexible Smart Noncontact Control Systems with Ultrasensitive Humidity Sensors

“…In addition, the sensor also has fast response (<0.4 s) and recovery (<2 s) over the full RH range (0–100%) (Figure S3, Supporting Information). Different types of humidity sensors have been compared in Table S2 (Supporting Information), showing that our sensors have much surpassed the reported humidity sensors in terms of the sensitivity, speed, and detection range . In addition, we compared the state‐of‐the‐art commercial humidity sensors (such as Sensirion SHT35, Humidlcon HIH7000, TE HM1500LF) with our work in terms of detection range, sensitivity, accuracy tolerance, flexibility, transparency, and noncontact control applications.…”

“…However, direct contact sensing not only brings inevitable mechanical wear but limits their use in a broader range of applications such as remote sensing and sensing in toxic or harmful environments. In this case, a noncontact humidity sensor can be a noteworthy candidate to the existing sensors . Compared to the direct contact sensors, the humidity sensor can be controlled in a noncontact way through the humidity changes, thus avoiding the mechanical touch and bacteria transmission.…”

“…In this case, a noncontact humidity sensor can be a noteworthy candidate to the existing sensors. [15][16][17][18][19][20] Compared to the direct contact sensors, the humidity sensor can be controlled in a noncontact way through the humidity changes, thus avoiding the mechanical touch and bacteria transmission. Importantly, moisture is distributed on all humid surfaces such as fingers, thus the humidity sensor can effectively utilize the human body's sweat as an information source to realize long-range and noncontact control, which would be a novel control approach in advanced HMI interface.So far, a variety of sensing materials, such as graphene oxide (GO), [20][21][22][23] carbon nanotubes, [24,25] 2D materials, [19,[26][27][28] and porous membrane [29,30] have been studied for the use in humidity sensors, but there still exists some limitations in terms of stability and performance.…”

“…In this case, a noncontact humidity sensor can be a noteworthy candidate to the existing sensors. [15][16][17][18][19][20] Compared to the direct contact sensors, the humidity sensor can be controlled in a noncontact way through the humidity changes, thus avoiding the mechanical touch and bacteria transmission. Importantly, moisture is distributed on all humid surfaces such as fingers, thus the humidity sensor can effectively utilize the human body's sweat as an information source to realize long-range and noncontact control, which would be a novel control approach in advanced HMI interface.…”

“…Different types of humidity sensors have been compared in Table S2 (Supporting Information), showing that our sensors have much surpassed the reported humidity sensors in terms of the sensitivity, speed, and detection range. [16,18,[27][28][29]32,[37][38][39] In addition, we compared the state-of-the-art commercial humidity sensors (such as Sensirion SHT35, Humidlcon HIH7000, TE HM1500LF) with our work in terms of detection range, sensitivity, accuracy tolerance, flexibility, transparency, and noncontact control applications. The corresponding content is shown in Table S3 (Supporting Information).…”