Publications

The high-efficiency conversion of water drop mechanical energy into electrical energy has always been an urgent issue in the development and utilization of raindrop energy. In this work, a novel drum-like triboelectric nanogenerator (D-TENG) with robust self-cleaning superhydrophobic features is developed to harvest water drop energy. An elastic superhydrophobic cellulose paper is created by spray-coating nanofumed silica dispersed in a thermoplastic elastomer solution, followed by treatment with triethoxy-1H,1H,2H,2H-tridecafluoro-n-octylsilane. When raindrops hit the D-TENG surface, the superhydrophobic cellulose paper will vibrate and periodic contact and separation with polytetrafluoroethylene will occur to generate electricity. The results demonstrate that when a 6 mm water drop falls from a height of 2.5 m and hits the D-TENG, the generated voltage output can reach a peak of 21.6 V and charge transfer of 10 nC. The output power of the D-TENG can reach 16 µW per droplet, which is more than 13.3 times that generated from the previous TENGs based on the electrostatic induction of water droplets. These results indicate that the superhydrophobic cellulose paper-based D-TENG is potentially a strong candidate for harvesting energy from raindrops, thereby making it a promising sustainable energy source for next-generation electronics.

Because of their special application in photovoltaics, the growth of one-dimensional single-crystalline TiO2 nanostructures on a flexible substrate is receiving intensive attention. Here we present a study of rectangular bunched TiO2 nanorod (NR) arrays grown on carbon fibers (CFs) from titanium by a "dissolve and grow" method. After a corrosion process in a strong acid solution, every single nanorod is etched into a number of small nanowires. Tube-shaped dye-sensitized solar cells are fabricated by using etched TiO2 NRs-coated CFs as the photoanode. An absolute energy conversion efficiency of 1.28% has been demonstrated under 100 mW cm–2 AM 1.5 illumination. This work demonstrates an innovative method for growing bunched TiO2 NRs on flexible substrates that can be applied in flexible devices for energy harvesting and storage.

Abstract The devices based on SiO 2 electret have significant applications in various MEMS sensors. However, the charge stability of SiO 2 electret suffered from the water percolation, which seriously restricts its application. In this work, the long‐term charge stability of the SiO 2 nanoarray electret (SiO 2 NAE) without any water repellent treatment is demonstrated. When the oxidation time is 1.5 h, the potential decay of the SiO 2 NAE is less than 46% during 60 days with an original potential of −120 V. The long‐term charge stability of the SiO 2 NAE is attributed to its unique charge decay process and the large H 2 O diffusion barrier in the SiO 2 NAE: firstly, the charge trapped in the planar part of the SiO 2 NAE decays rapidly. Then, residual charge stored in the SiO 2 nanoarray. Eventually, the large H 2 O diffusion barrier in the interface of Si/SiO 2 effectively hinders the charge decay. In addition, we demonstrate the unique charge stability of nanoelectret, which has a promising application in developing high performance electret‐based devices.

Triboelectric nanogenerators (TENGs) have been investigated for mechanical energy harvesting because of their high-energy conversion efficiency, low cost, ease of manufacturing, and so on. This paper deals with designing a kind of water-fluid-driven rotating TENG (WR-TENG) inspired by the structure of a water meter. The designed WR-TENG is effectively integrated into a self-powered electrostatic scale-preventing and rust protection system. The WR-TENG can generate a constant DC voltage up to about 7.6 kV by using a voltage-doubling rectifier circuit (VDRC) to establish a high-voltage electrostatic field in the water tank. A WR-TENG, a VDRC, and an electric water heating tank are the components of the whole system. The system is convenient to be installed in any waterway system, effectively preventing the rusting of stainless steel and restraining the formation of scale when the water is heated to 65 ± 5 °C. Moreover, the approximately linear relationship between the short-circuit current and the rotation rate of the WR-TENG makes employing it as a self-powered water flow sensor possible. This work enables a facile, safe, and effective approach for electrostatic scale prevention, rust protection, and flow sensing in solar heaters, which will enrich the high-voltage applications of TENGs.

Abstract Contact‐electrification at solid–liquid interfaces (SL‐CE) and contact‐electro‐catalysis (CEC) are two blooming research areas with promising applications in sustainable energy, sensing, and chemical processes. However, prior research has neglected the impact of electronic defects on the ability of high‐performance tribo‐materials, like fluorinated polymers, to perform SL‐CE/CEC. Here, through first‐principle calculations, the addition of surface functional groups to fluorinated ethylene propylene (FEP) enables the tuning of its molecular orbitals' positions, and displacing deep‐level defect states from the HOMO‐LUMO gap is shown. Thereafter, FEP films are modified accordingly by plasma etching; resulting in a significant performance improvement of up to 202% (charge) in SL‐CE experiments, and up to 398% (kinetic rate) in CEC dye degradation. This study provides a theoretical and experimental framework to design high‐performance materials for SL‐CE and CEC, and insights into their physical mechanisms and defect passivation, which are all fundamental for the advancement of these fields.

In this work, polymer-dispersed liquid crystals (PDLCs) under an applied electric field are actuated by a rotary triboelectric nanogenerator (r-TENG). Conventional PDLCs generally rely on high DC voltages for on-off switching, but they can also be effectively switched on and off using an moderate high AC voltage at a frequency of several kHz with a smaller voltage. Here, we use a simple r-TENG to study the optical states of PDLC cells at different low frequencies (2–100 Hz) and simultaneous monitoring of the open-circuit voltage ( <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\text{V}_{\text{oc}}$ </tex-math></inline-formula> ) and short-circuit current ( <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\text{I}_{\text{sc}}$ </tex-math></inline-formula> ) to describe the optical performance of PDLC cells with different thicknesses. The results show that the <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\text{I}_{\text{sc}}$ </tex-math></inline-formula> , provided by a r-TENG with a low <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\text{V}_{\text{oc}}$ </tex-math></inline-formula> (1-2V), inside a PDLC cell is the key factor that determines its performance. Through the application of the r-TENG, we successfully demonstrate the on-off switching of nine PDLC cells connected in series with an area of 15 <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\times15$ </tex-math></inline-formula> mm, and the power consumption is equal to that of a single PDLC cell. This research expands the potential applications of TENGs in photonics and also provides a way to improve the optical properties of PDLCs by connecting TENGs to achieve optimal performance for PDLC-related optoelectronic devices.

The complex tetrapod shape of zinc oxide nanostructure, which is constructed from four one-dimensional arms interconnected together via a central core, is a special 3D geometry with multifunctional applications in advanced technologies. The ZnO hexagonal wurtzite crystal lattice with a non-centrosymmetric structure introduces interesting piezoelectric property in nanorods in the bent state, which has been well reported and utilized in piezo- and tribo-electric nanogenerator applications. Considering the broad technological relevance of tetrapods, it is important to understand the piezoelectric response of zinc oxide tetrapods under different conditions. In this study, we explicate the fundamental mechanical and electrical properties of ZnO nanotetrapods (ZnO NTs) through a detailed finite element method analysis. On this basis, the effects of shape factors (including length, height, and aspect ratio) as well as connection strength and packing density on the deformation and piezoelectric potential of ZnO NTs are examined, offering guidance for the fabrication of ZnO NTs. This theoretical model and numerical simulation provide an avenue for further piezoelectric and piezotronic research of ZnO NTs.

Abstract Objectives To identify the SPINK1 or SPINK1‐based model as a more reliable biomarker for the diagnosis of hepatocellular carcinoma (HCC). Methods Serum samples and related laboratory parameters were collected from 540 subjects (119 healthy donors, 113 patients with chronic hepatitis B, 122 patients with liver cirrhosis, and 186 patients with HCC). SPINK1 was determined by ELISA assay. Differences in each variable were compared by one‐way ANOVA or Kruskal‐Wallis test. ROC (receiver operating characteristic) curve analysis was conducted to compare the diagnostic efficiency of alpha‐fetoprotein (AFP), SPINK1, and a SPINK1‐based combine model constructed by binary Logistic regression. Results In detecting HCC using the other three groups as control, ROC curve analysis revealed that SPINK1 alone reached AUC of 0.899 (0.866–0.933), with the sensitivity of 0.812 of and specificity of 0.953. The combined model increased the AUC to 0.945 (0.926–0.964) with the sensitivity and specificity of 0.860 and 0.910, respectively. For AFP, significantly lower AUC ( p &lt; 0.0001) was shown, which was 0.695 (0.645–0.745) with the sensitivity and specificity of 0.634 and 0.718, respectively. In discriminating HCC from liver disease control, AUC of SPINK1 was 0.863(0.826–0.894), the sensitivity and specificity were 0.823 and 0.906, respectively. For combined model, the AUC, sensitivity, and specificity were 0.915 (0.884–0.940), 0.863, and 0.916, respectively. For detecting early‐stage HCC, SPINK1 and combined model achieved the sensitivity of 0.788 and 0.818, respectively, much higher than AFP of 0.485 ( p &lt; 0.05); however, the difference between SPINK1 and combined model was not statistically significant ( p = 1). Conclusion We provided solid evidence for SPINK1 as a robust serological tool for HCC diagnosis.

BACKGROUND: The endocannabinoid system (ECS) is involved in appetite, body weight regulation and metabolism and is a promising target for novel pharmacologic treatments for obesity.Central and peripheral effects of endocannabinoids are mediated through CBI, a G-protein coupled receptor.In adipocytes CBI appears to playa role in regulating lipolysis.We have previously demonstrated that CBl expression is upregulated in visceral (V) compared to subcutaneous (S) adipose tissue (AT) and adipocytes (AC) in animal models of obesity.We therefore tested the hypothesis that CBI was also upregulated in VAT and VAC in obese humans.METHODS: Twenty-two morbidly obese subjects (20F12M, Age 40 ± 8 y, BMI S2 ± 9 kg/m 2 ) provided informed consent for the collection of subcutaneous and visceral adipose tissue samples at the time of elective roux-en-Y gastric bypass surgery.CBI mRNA expression levels were determined using quantitative RT-PCR and normalized to the expression of GAPDH.RESULTS: CB I mRNA expression was significantly higher in VAT compared to SAT (91 ± 2S vs. 74 ± 22 relative units, P < O.OS) and in V AC compared to SAC (30 ± 18 vs.IS ± 11, P < 0.01).CBl mRNA expression levels correlated with CD68 expression levels (a macrophage cell surface marker) in SAT (R = 0.S4, P = 0.01) but not in VAT (R = 0.27, P = 0.22).CBI expression levels also correlated with expression levels of monocyte chemotactic protein-I (MCP-I) and interleukin-6 (1L-6) in SAC (R = 0.74, P < 0.001 and R = 0.S9, P = om, respectively), but did not correlate significantly with MCP-I or 1L-6 in V AC (R = -0.20,P = 0.46 and R = O.4S, P = 0.08).CONCLUSIONS: These results indicate that expression of the endocannabinoid receptor CB I is upregulated in VAT and VAC relative to SAT and SAC in morbidly obese individuals.The beneficial effects of pharmacological CB I blockade to reduce abdominal obesity may be mediated.in part, by direct CB I mediated actions of these drugs on visceral adipocytes.In SAT, but not VAT, CBI expression appears related to the inflammatory phenotype.The effects of pharmacological CB I blockade to reduce markers of low-grade systemic inflammation may occur primarily through CB I mediated actions in this depot.