High-resolution unpixelated smart patches with antiparallel thickness gradients of nanoparticles.

A new concept for high-resolution sensing of touch/load and location in which the number of pixels can be significantly diminished is presented. The technology is based on a flexible substrate with two parallel gold-nanoparticle strips with antiparallel sensitivity gradients for an unpixelated skin strip. The approach exhibits high location and load resolutions.

Flexible sensors based on nanoparticles.

Flexible sensors can be envisioned as promising components for smart sensing applications, including consumer electronics, robotics, prosthetics, health care, safety equipment, environmental monitoring, homeland security and space flight. The current review presents a concise, although admittedly nonexhaustive, didactic review of some of the main concepts and approaches related to the use of nanoparticles (NPs) in flexible sensors. The review attempts to pull together different views and terminologies used in the NP-based sensors, mainly those established via electrical transduction approaches, including, but, not confined to: (i) strain-gauges, (ii) flexible multiparametric sensors, and (iii) sensors that are unaffected by mechanical deformation. For each category, the review presents and discusses the common fabrication approaches and state-of-the-art results. The advantages, weak points, and possible routes for future research, highlighting the challenges for NP-based flexible sensors, are presented and discussed as well.

Tunable touch sensor and combined sensing platform: toward nanoparticle-based electronic skin.

In this paper, we present touch (or pressure) flexible sensors based on monolayer-capped nanoparticles (MCNPs) that are potentially inexpensive, could allow low-voltage operation, and could provide a platform for multifunctional applications. We show that modifying the mechanical and geometrical properties of the flexible substrates, on which the MCNP films are deposited, allows measuring a large span of loads ranging between tens of mg to tens of grams. All flexible sensors exhibited repeatable responses even after a large number of bending cycles. In addition, we show that modified platforms of those touch (or pressure) sensors allow precise detection and monitoring of environmental temperature and humidity. Relying on their superior characteristics, we were able to build an MCNP-based prototype allowing simultaneous detection and monitoring of multiple environmental parameters of touch (or pressure), humidity, and temperature. The excellent temperature (resolution higher than 1 °C and average error of ~5%) and relative humidity (resolution higher than 1% RH and average error of ~9%) sensitivities and the possibility to integrate those sensing abilities makes the suggested platform interesting for potentially inexpensive and low-voltage multifunctional electronic-skin applications.