Publications

Abstract The simultaneous achievement of multiple functional attributes, such as flexibility, stretchability, transparency, comfortability, biodegradability, and self‐powered ability into electronic skins (e‐skins) is vital to their long‐term practical applications. Due to the internal contradiction between functional material combination and simple structural design, this kind of multifunctional e‐skin has rarely been fabricated or even reported. To this end, chitosan (CS), a natural material with remarkable biocompatibility, biodegradability, and electron‐donating ability, is integrated with a single‐mode triboelectric nanogenerator (TENG) to develop a multifunctional e‐skin, which includes sweat permeability, controllable biodegradability, high transparency, and self‐powered sensing ability. In addition, a facile, efficient, and large‐scale fabrication strategy is proposed to construct stretchable, ultrathin, transparent, and shape‐adaptable gold nanofibers (Au NFs) electrodes. Furthermore, the e‐skin can achieve a voltage response pressure sensitivity of 0.012 kPa −1 in the pressure range of 0–70 kPa and a fast response time of 70 ms. Finally, it shows controllable and excellent degradability in various solutions. It is believed that the proposed e‐skin based on the design and integration of CS and Au NFs will provide a paradigm shift for the next‐generation self‐powered transient electronics.

A branched ZnO-CdS double-shell NW array on the surface of a carbon fiber (CF/ZnO-CdS) was successfully synthesized via a facile two-step hydrothermal method. Based on a single CF/ZnO-CdS wire on a polymer substrate, a flexible photodetector was fabricated, which exhibited ultrahigh photon responsivity under illuminations of blue light (1.11 × 10(5) A/W, 8.99 × 10(-8) W/cm(2), 480 nm), green light (3.83 × 10(4) A/W, 4.48 × 10(-8) W/cm(2), 548 nm), and UV light (1.94 × 10(5) A/W, 1.59 × 10(-8) W/cm(2), 372 nm), respectively. The responsivity of this broadband photon sensor was enhanced further by as much as 60% when the device was subjected to a -0.38% compressive strain. This is because the strain induced a piezopotential in ZnO, which tunes the barrier height at the ZnO-CdS heterojunction interface, leading to an optimized optoelectronic performance. This work demonstrates a promising application of piezo-phototronic effect in nanoheterojunction array based photon detectors.

Endocrine fibroblast growth factors (FGFs) require Klotho transmembrane proteins as necessary co-receptors to activate FGF receptor (FGFR) signaling. In particular, FGF19 and FGF21 function through β-Klotho to regulate glucose and lipid metabolism. Recent research has focused on elucidating how these two FGFs interact with β-Klotho and FGFRs to activate downstream signaling. In this study, using hydrogen deuterium exchange coupled to mass spectrometry (HDX-MS), we identified regions on the β-Klotho protein that likely participate in ligand interaction, and vice versa. Alanine and arginine mutagenesis were carried out to further probe the contributions of individual residues to receptor/ligand interactions. Using biochemical and cell-based signaling assays with full-length proteins, we show that both the KL1 and KL2 domains of β-Klotho participate in ligand interaction, and these binding sites on β-Klotho are shared by FGF19 and FGF21. In addition, we show that two highly conserved regions in the C-terminal tail of FGF19 and FGF21 are responsible for interaction with the co-receptor. Our results are consistent with recent publications on the crystal structures of the Klotho proteins and provide insight into how endocrine FGFs interact with co-receptors for signal transduction.

Tremendous work has been made recently to improve the power conversion efficiencies (PCEs) of perovskite solar cells (PSCs); the best reported value is now over 23%. However, further improving the PCEs of PSCs is challenged by material properties, device stability, and packaging technologies. Here, we report a new approach to increase the PCEs of flexible PSCs via introducing the piezo-phototronic effect in the PSCs by growing an array of ZnO nanowires on flexible plastic substrates, which act as the electron-transport layer for PSCs. From the piezo-phototronic effect, the absolute PCE was improved from 9.3 to 12.8% for flexible perovskite solar cells under a static mechanical strain of 1.88%, with a ∼40% enhancement but no change in the components of materials and device structure. A corresponding working model was proposed to elucidate the strategy to boost the performance of the PSCs. These findings present a general approach to improve PCEs of flexible PSCs without changing their fundamental materials.

The development of lightweight, superportable, and sustainable power sources has become an urgent need for most modern personal electronics. Here, we report a cut-paper-based self-charging power unit (PC-SCPU) that is capable of simultaneously harvesting and storing energy from body movement by combining a paper-based triboelectric nanogenerator (TENG) and a supercapacitor (SC), respectively. Utilizing the paper as the substrate with an assembled cut-paper architecture, an ultralight rhombic-shaped TENG is achieved with highly specific mass/volume charge output (82 nC g-1/75 nC cm-3) compared with the traditional acrylic-based TENG (5.7 nC g-1/5.8 nC cm-3), which can effectively charge the SC (∼1 mF) to ∼1 V in minutes. This wallet-contained PC-SCPU is then demonstrated as a sustainable power source for driving wearable and portable electronic devices such as a wireless remote control, electric watch, or temperature sensor. This study presents a potential paper-based portable SCPU for practical and medical applications.

Harvesting biomechanical energy in vivo is an important route in obtaining sustainable electric energy for powering implantable medical devices. Here, we demonstrate an innovative implantable triboelectric nanogenerator (iTENG) for in vivo biomechanical energy harvesting. Driven by the heartbeat of adult swine, the output voltage and the corresponding current were improved by factors of 3.5 and 25, respectively, compared with the reported in vivo output performance of biomechanical energy conversion devices. In addition, the in vivo evaluation of the iTENG was demonstrated for over 72 h of implantation, during which the iTENG generated electricity continuously in the active animal. Due to its excellent in vivo performance, a self-powered wireless transmission system was fabricated for real-time wireless cardiac monitoring. Given its outstanding in vivo output and stability, iTENG can be applied not only to power implantable medical devices but also possibly to fabricate a self-powered, wireless healthcare monitoring system.

'Pseudoelasticity' published in 'Encyclopedia of Nanotechnology'

Abstract Pulse wave carries comprehensive information regarding the human cardiovascular system (CS), which is essential for directly capturing CS parameters. More importantly, cuffless blood pressure (BP) is one of the most critical markers in CS. Accurately measuring BP via the pulse wave for continuous and noninvasive diagnosis of a disease associated with hypertension remains a challenge and highly desirable. Here, a flexible weaving constructed self‐powered pressure sensor (WCSPS) is reported for measurement of the pulse wave and BP in a noninvasive manner. The WCSPS holds an ultrasensitivity of 45.7 mV Pa −1 with an ultrafast response time of less than 5 ms, and no performance degradation is observed after up to 40 000 motion cycles. Furthermore, a low power consumption sensor system is developed for precisely monitoring pulse wave from the fingertip, wrist, ear, and ankles. A practical measurement is performed with 100 people with ages spanning from 24 to 82 years and different health statuses. The discrepancy between the measured BP results using the WCSPS and that provided by the commercial cuff‐based device is about 0.87–3.65%. This work demonstrates an efficient and cost‐effective way for human health monitoring, which would be a competitive alternative to current complex cardiovascular monitoring systems.

The development of stretchable energy generation devices is indispensable for achieving stretchable, self-powered electronic systems. In this paper, a type of highly stretchable triboelectric nanogenerators made from conventional, inelastic materials such as paper is presented. It exploits a rationally designed interlocking kirigami structure and is capable of harvesting energy from various types of motions such as stretching, pressing, and twisting owing to the shape-adaptive thin film design. Energy harvested from the as-fabricated devices has been used for powering an LCD screen and lighting LED arrays. Furthermore, the paper-based devices have also been demonstrated for self-powered acceleration sensing and self-powered sensing of book opening and closing. This work introduces traditional kirigami into the development of stretchable triboelectric nanogenerators and verifies its promising applications in both power generation and self-powered sensing.