Wide range highly sensitive relative humidity sensor based on series combination of MoS2 and PEDOT:PSS sensors array

Hierarchical Self‐Assembly of Tetrakis(1‐pyrenyl)porphyrins into Microscopic Petals and Flowers with Ultrasensitive Room‐Temperature NO2 Sensing in a Broad Humidity Range

“…As can be seen from Figure , along with increase in relative humidity (RH) from 45% to 75%, the conductivity increases from 1.9×10 −4 S cm −1 (RH=45%) to 8.3×10 −4 S cm −1 (RH=75%) for 1 , and from 4.3×10 −4 S cm −1 (RH=45%) to 9.2×10 −4 S cm −1 (RH=75%) for 2 , respectively, Figure (dashed and dotted lines). This humidity‐induced increase in conductivity should be attributed the adsorption of water vapors at the air/porphyrin interface and at grain boundaries of the nanopetals and ball‐flower‐like microstructure of 1 and 2 , which offered the possibility for charge‐transfer interactions from electron‐donating H 2 O to the porphyrin semiconducting layer and injection of electron charge carriers into the bulk aggregates . Meanwhile the increased conductivity of the aggregates of 1 and 2 upon the H 2 O absorption also indicated the n‐type semiconducting behavior of 1 and 2 .…”

“…This humidity-induced increase in conductivity should be attributed the adsorption of water vapors at the air/porphyrin interface and at grain boundaries of the nanopetals and ballflower-like microstructure of 1 and 2, which offered the possibility for charge-transfer interactions from electron-donating H 2 O to the porphyrin semiconducting layer and injection of electron charge carriers into the bulk aggregates. [37][38] Meanwhile the increased conductivity of the aggregates of 1 and 2 upon the H 2 O absorption also indicated the n-type semiconducting behavior of 1 and 2. It should be noted that, the degree of increase in conductivity of 2 is more obvious from 0% RH to 45% RH by compared to that of 1, inset of Figure 5.…”

Fabrication and Characterization of Humidity Sensors Based on Graphene Oxide–PEDOT:PSS Composites on a Flexible Substrate

“…As the PSS absorbed the water molecules, the distance between adjacent PEDOT chains increased, leading to a decrease in electrical conduction [42]. Once the absorption of water molecules by the PSS chains saturated, the impedance decreased drastically due to the physisorption of the water molecules, which facilitated the ionic current and provides better current flow paths within the PEDOT structure [43]. This occurred up to ~70% RH, where the impedance modulus started decreasing more softly, since this point is defined as a maximum detection limit of the PEDOT [13].…”

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.…”