A water‐soluble micropatterned MoS2 quantum dots/polyvinyl alcohol film as a transient contact (pressure) and non‐contact (humidity) as touch and proximity sensor

Abstract Water‐soluble electronics have become increasingly popular due to their potential applications in various fields such as biodegradable and wearable‐stretchable electronics. Flexible polymers such as polydimethylsiloxane are hydrophobic. Hence, water‐soluble polymers like polyvinyl alcohol (PVA) have been extensively utilized as substrates for water‐soluble electronics. However, the patterning of the PVA has never been achieved to enhance the sensing capabilities for such devices. Herein we report for the first time the micro‐pyramid patterning of PVA film embedded with MoS 2 quantum dots (QDs) for improved pressure‐sensing capabilities. The fabricated sensor displayed superior sensitivity of 1.44 kPa −1 compared to the sensitivity of 0.51 kPa −1 unpatterned PVA films. This enhanced performance can be attributed to the easier transport of the charge carriers from QD‐PVA‐QD film and the decrement in the tunneling resistance between adjacent MoS 2 QDs due to localized stress on the micropattern. Further, the fabricated sensor was tested for real‐time application as a touch sensor in both contact (pressure) and noncontact mode (humidity), which finds potential application in security and personal healthcare, and so forth. The fabricated film is subjected to ~1200 stimulus cycles to manifest good reproducibility of sensor responses. Moreover, the device dissolves in water within ~300 s exhibiting magnificent transient behavior.