Flexible capacitive sensor based on 2D-titanium dioxide nanosheets/bacterial cellulose composite film

Abstract

In this paper, titanium dioxide nanosheets (Ti0.91O2 NSs) were incorporated into bacterial cellulose (BC) film for dielectric property tuning while maintaining the flexibility of the resulting composite paper. By taking advantage of the improved dielectric constant, the nanosheets/BC composites were employed as capacitive sensors. The fabricated devices showed the highest sensing performance of ∼2.44 × 10−3 kPa−1 from 0 to 30 N when incorporating as little as 3 vol% of Ti0.91O2 NSs (or ∼2 wt% Ti). Stable operation and high robustness of the sensor were demonstrated, where simple human motions could be efficiently monitored. This study provided a route for preparing flexible and low-cost BC composite paper for capacitive sensor. The strategy for enhancing the dielectric properties as well as sensing performances of the BC demonstrated herein will be essential for the future development of biocompatible, low-cost, and eco-friendly wearable electronics.

Effect of Adsorbed Water and Temperature on the Universal Power Law Behavior of Lepidocrocite-Type Alkali Titanate Ceramics

“…It is well known that alkali-containing ceramics are prone to atmospheric water adsorption. Among these, several members of the alkali titanate family have received increasing attention thanks to their superionic conduction, giant/colossal dielectric permittivity, ,, and water-induced transport properties. − The alkali titanates show rich structural chemistry and compositional flexibility, as exemplified by the layered or tunnel-structured Andersson–Wadsley-type A 2 O· n TiO 2 (A = alkali; 1 ≤ n ≤ 6) and the lepidocrocite-type layered A x Ti 2– y M y O 4 (M = transition metals of the first row). − In particular, the layered alkali titanates can undergo exfoliation into nanosheets, which are an important component in nanoelectronics or triboelectric nanogenerators. − In these cases, water can be incorporated either as (i) crystalline hydrates at the interlayer space, , (ii) noncrystalline hydrates at the grain boundary/porosity/external surfaces, ,, or (iii) the combination of these two. , Investigating the effects of noncrystalline water will widen our fundamental understanding of water-induced conductions, complementing extensive works on the crystalline hydrated (i.e., protonic) titanates ,,, and the nanosheet analogues, , offering ways to enhance the sensing performances, and so on.…”

Highly Sensitive and Flexible Capacitive Pressure Sensors Based on Vertical Graphene and Micro-Pyramidal Dielectric Layer

“…Among these sensors, capacitive sensors with a dielectric layer sandwiched between two electrodes exhibit the advantages of a simple structure, facile manufacturing, low energy consumption, and static/dynamic detection. Therefore, flexible capacitive pressure sensors have attracted extensive attention in tactile sensing [ 16 , 17 ], environmental detection [ 18 , 19 ], and human motion monitoring [ 20 , 21 , 22 ]. High sensitivity is key to achieving high-pressure resolution, which is essential for simplifying signal processing [ 23 ].…”

Recent Progress in Piezoelectric-Triboelectric Effects Coupled Nanogenerators

“…Currently, artificial intelligence technology and Internet of Things (IoTs) are playing important roles in industry and people’s lives, from managing inventories to improving personalized shopping experiences and assisting in data mining, even transforming how people do business today [ 1 ]. Intelligent electronic devices such as wearable devices [ 2 , 3 , 4 , 5 ], implantable devices [ 6 , 7 , 8 ], medical robots, and other products are showing explosive growth and helping people control and detect various aspects of the surrounding environment [ 9 ], human health, and energy harvesting [ 10 , 11 , 12 ]. However, because the composition of artificial intelligence and IoTs require numerous sensors with high performance, low power consumption, and especially, stable and sustainable operation, which is the key to realize the full power of IoTs, traditional electrochemical sensor power sources are facing challenges in this era due to their limited endurance and energy storage capacity [ 13 , 14 , 15 ].…”