Thin Film Protected Flexible Nanoparticle Strain Sensors: Experiments and Modeling

Abstract

In this work, the working performance of Platinum (Pt), solvent-free nanoparticle (NP)-based strain sensors made on a flexible substrate has been studied. First, a new model has been developed in order to explain sensor behaviour under strain in a more effective manner than what has been previously reported. The proposed model also highlights the difference between sensors based on solvent-free and solvent-based NPs. As a second step, the ability of atomic layer deposition (ALD) developed Al2O3 (alumina) thin films to act as protective coatings against humidity while in adverse conditions (i.e., variations in relative humidity and repeated mechanical stress) has been evaluated. Two different alumina thicknesses (5 and 11 nm) have been tested and their effect on protection against humidity is studied by monitoring sensor resistance. Even in the case of adverse working conditions and for increased mechanical strain (up to 1.2%), it is found that an alumina layer of 11 nm provides sufficient sensor protection, while the proposed model remains valid. This certifies the appropriateness of the proposed strain-sensing technology for demanding applications, such as e-skin and pressure or flow sensing, as well as the possibility of developing a comprehensive computational tool for NP-based devices.

High-Performance Flexible Humidity Sensor Based on MoOx Nanoparticle Films for Monitoring Human Respiration and Non-Contact Sensing

“…It has been previously demonstrated that the performance of the NP assembly-based sensors is governed by interparticle electron tunneling, ,,,− which implies that the NP coverage, plays a crucial role in the sensing performance. In order to evaluate the effect of NP coverage on the sensitivity of the sensor, three samples were prepared with varying deposition times of 200, 310, and 650 s (designated as samples a, b, and c, respectively) at a deposition rate of 1.4 ± 0.05 Å/s, as shown in Figure S7a in the Supporting Information.…”

Nanomaterial-based flexible sensors for metaverse and virtual reality applications

“…The spatial characteristics of NPs can be exploited to fabricate high-performance flexible strain sensors using various strategies, for example, binding to conductive hydrogels [109,110], cross-linking with molecules [111], ligand exchange [112], self-assembly [113], atomic layer deposition [114], drop-casting [115], dip coating, and spin-coating [116]. Zhao et al demonstrated that lignin-coated silica NPs can enhance the elasticity of conductive hydrogels to prepare flexible sensors with high stability and repeatability [99].…”

Highly sensitive stretchable sensor combined with low-power memristor for demonstration of artificial mechanoreceptor properties

“…. From previous research on NPbased sensors realized either on a silicon substrate [58] or a polyimide flexible substrate [59], we know that GF lies in the range of 30-40 for small strain values (silicon substrate) while it can reach 50-70 for higher strains applied to flexible substrates. Limitation of the GF value is a result of the tunneling mechanism governing charge transport through the NP network; this has been theoretically investigated [60].…”