The development of flexible pressure sensors has attracted increasing research interest for potential applications such as wearable electronic skins and human healthcare monitoring. Herein, we demonstrated a piezoresistive pressure sensor based on AgNWs-coated hybrid architecture consisting of mesoscaled dome and microscaled pillar arrays. We experimentally showed that the key three-dimensional component for a pressure sensor can be conveniently acquired using a vacuum application during the spin-coating process instead of a sophisticated and expensive approach. The demonstrated hybrid structure exhibits dramatically improved sensing capability when compared with the conventional one-fold dome-based counterpart in terms of the sensitivity and detectable pressure range. The optimized sensing performance, by integrating D1000 dome and D50P100 MPA, reaches a superior sensitivity of 128.29 kPa–1 (0–200 Pa), 1.28 kPa–1 (0.2–10 kPa), and 0.26 kPa–1 (10–80 kPa) and a detection limit of 2.5 Pa with excellent durability. As a proof-of-concept, the pressure sensor based on the hybrid configuration was demonstrated as a versatile platform to accurately monitor different kinds of physical signals or pressure sources, e.g., wrist pulse, voice vibration, finger bending/touching, gas flow, as well as address spatial loading. We believe that the proposed architecture and developed methodology can be promising for future applications including flexible electronic devices, artificial skins, and interactive robotics.

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Polydimethysiloxane (PDMS)-based materials are emerging as an ideal category of flexible multifunctional membranes that are expected to be used for wearable and skin-attachable pressure sensors. Here, we report a simple and effective fabrication strategy to construct a highly sensitive and robust wearable pressure sensor device based on interlocked connection structure (ILCS), which formed from silver nanowires (AgNW)-coated PDMS pillar arrays sheets. Two pieces of PDMS thin layers that manufactured with AgNW-coated pillar arrays were assembled face to face as the pressure sensing device. The interlocked structures enable a pressure sensitive variation in the contact area between AgNW-coated PDMS pillars under different pressure loading. Therefore, the electrical resistance changes according to the degree of interconnection and pillar deformation when different magnitudes of pressures were applied. The pressure sensor exhibits ultrahigh pressure sensitivity of ∼20.08 kPa–1 up to 0.8 kPa, and sensor response is highly reproducible and repeatable for more than 10000 cycles. Additionally, all the results demonstrate that the pressure sensor can be used as the device for the monitoring of the signals ranging from epidermis movements to air flows, such as mimic swallowing action, gently touching, bending, and torsion. We believe that the presented sensor can be used in many potential applications fields, such as flexible electronics, artificial e-skin, wearable sensor devices, and so on.

Side-chain polymers have the potential to be excellent dopant-free hole-transporting materials (HTMs) for perovskite solar cells (PSCs) because of their unique characteristics, such as tunable energy levels, high charge mobility, good solubility, and excellent film-forming ability. However, there has been less research focusing on side-chain polymers for PSCs. Here, two side-chain polystyrenes with triphenylamine substituents on carbazole moieties were designed and characterized. The properties of the side-chain polymers were tuned finely, including the photophysical and electrochemical properties and charge mobilities, by changing the positions of triphenylamine substituents on carbazole. Owing to the higher mobility and charge extraction ability, the polymer P2 with the triphenylamine substituent on the 3,6-positions of the carbazole unit showed higher performance with power conversion efficiency (PCE) of 18.45%, which was much higher than the PCE (16.78%) of P1 with 2,7-positions substituted. These results clearly demonstrated that side-chain polymers can act as promising HTMs for PSC applications and the performance of side-chain polymers could be optimized by carefully tuning the structure of the monomer, which provides a new strategy to design new kinds of side-chain polymers and obtain high-performance dopant-free HTMs.

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