Largely Enhanced Thermoelectric Performance of Flexible Ag2Se Film by Cationic Doping and Dual-Phase Engineering.

Recent studies have shown that silver selenide is a promising thermoelectric material at room temperature. Herein, flexible films with a nominal composition of (Ag1-xCux)2Se are prepared by a simple and efficient one-pot method combined with vacuum-assisted filtration and hot pressing. The thermoelectric properties of the films are regulated by both cationic doping and a dual-phase strategy via a wet chemical method. As the x increases, not only Cu is doped into the Ag2Se, but different new phases (CuAgSe and/or CuSe2) also appear. The (Ag1-xCux)2Se film with x = 0.02 composed of Cu-doped Ag2Se and CuAgSe shows a high PF of ∼2540 µW m-1 K-2 (ZT ∼ 0.90) and outstanding flexibility at room temperature. The high thermoelectric properties of the film are due to the effect of Cu doping and the CuAgSe phase, including the increase in electrical conductivity caused by doping, the enhanced phonon scattering at the Ag2Se/CuAgSe interface, and the interaction between the energy filtering effect and the doping effect. In addition to the high output performance (PDmax = 28.08 W m-2, ΔT = 32.2 K), the flexible device assembled with the (Ag0.98Cu0.02)2Se film also has potential applications as a temperature sensor.

Controllable Design of Metal-Organic Framework-Derived Vanadium Oxynitride for High-Capacity and Long-Cycle Aqueous Zn-Ion Batteries.

Introducing N atoms in vanadium oxides (VOx) of aqueous Zn-ion batteries (ZIBs) can reduce their bandgap energy and enhance their electronic conductivity, thereby promoting the diffusion of Zn2+. The close-packed vanadium oxynitride (VON) generated often necessitates the intercalation of water molecules for restructuring, rendering it more conducive for zinc ion intercalation. However, its dense structure often causes structural strain and the formation of by-products during this process, resulting in decreased electrochemical performance. Herein, carbon-coated porous V2O3/VN nanosheets (p-VON@C) are constructed by annealing vanadium metal-organic framework in an ammonia-contained environment. The designed p-VON@C nanosheets are efficiently converted to low-crystalline hydrated N-doped VOx during subsequent activation while maintaining structural stability. This is because the V2O3/VN heterojunction and abundant oxygen vacancies in p-VON@C alleviate the structural strain during water molecule intercalation, and accelerate the intercalation rate. Carbon coating is beneficial to prevent p-VON@C from sliding or falling off during the activation and cycling process. Profiting from these advantages, the activated p-VON@C cathode delivers a high specific capacity of 518 mAh g-1 at 0.2 A g-1 and maintains a capacity retention rate of 80.9% after 2000 cycles at 10 A g-1. This work provides a pathway to designing high-quality aqueous ZIB cathodes.

Circ_0020887 Silencing Combats Hypoxic-Induced Cardiomyocyte Injury in an MiR-370-3p/CYP1B1-Dependent Manner.

Targeting circular RNA has been a novel approach to preventing and limiting acute myocardial infarction (AMI). Here, we planned to investigate the role and mechanism of circ_0020887 in AMI progression.Hypoxic injury in human cardiomyocytes (AC16) was measured using cell counting kit-8 assay, 5-ethynyl-2'-deoxyuridine assay, flow cytometry, and colorimetric assay kits. RNA and protein expressions were determined using real-time quantitative PCR and western blotting. Direct interplay between RNAs was determined using dual-luciferase reporter, RNA pull-down, and RIP assays.In the plasma and hypoxia-induced AC16 cells of patients with AMI, circ_0020887 and miR-370-3p were upregulated and downregulated, respectively, concomitant with the upregulation of cytochrome P450 1B1 (CYP1B1). Circ_0020887 interference could inhibit hypoxia-induced AC16 cell apoptosis, oxidative stress, and inflammatory response. Circ_0020887 could sponge miR-370-3p, and miR-370-3p could target CYP1B1. The inhibition effect of circ_0020887 knockdown on hypoxia-induced AC16 cell injury could be reversed by the miR-370-3p inhibitor. Besides, CYP1B1 overexpression also overturned the suppressive effect of miR-370-3p on hypoxia-induced AC16 cell apoptosis, oxidative stress, and inflammatory response.In conclusion, circ_0020887 regulated the miR-370-3p/CYP1B1 axis to regulate hypoxia-induced cardiomyocyte injury, confirming that circ_0020887 might promote cardiomyocyte injury.

A Stable Matrix Assisting Highly Compatible and Maintainable Lithium-Garnet Interface for Solid-State Batteries.

Solid-state Li metal batteries (SSLMBs) are attractive due to their capability to simultaneously offer high energy density and high-level safety when combining Li metal anodes, solid-state electrolytes (SSEs), and high-voltage cathodes together. However, SSLMBs may well incur short circuits caused by Li dendrites penetrations, which mainly originate from the instability and poor contact between Li metal and SSEs. Herein, by taking full advantage of the reaction products of Li and Li1.3Al0.3Ti1.7(PO4)3 (LATP), a lithium-LATP composite anode (Li-LATP) is obtained, in which a stable matrix is formed to enhance the contact between Li and the garnet-type SSEs, alleviating the volume change and preserving an intact interface during the charge/discharge process. Consequently, the Li-LATP/garnet/Li-LATP symmetric cell displays a fairly low interfacial resistance of 6 Ω cm2 and stable cycling performance for over 2500 h with a low overpotential. Furthermore, the LiCoO2/garnet/Li-LATP full cell also shows a high discharge capacity of 159 mAh g-1 and great cycling performance.

Largely Enhanced Thermoelectric Power Factor of Flexible Cu2-xS Film by Doping Mn.

Copper-sulfide-based materials have attracted noteworthy attention as thermoelectric materials due to rich elemental reserves, non-toxicity, low thermal conductivity, and adjustable electrical properties. However, research on the flexible thermoelectrics of copper sulfide has not yet been reported. In this work, we developed a facile method to prepare flexible Mn-doped Cu2-xS films on nylon membranes. First, nano to submicron powders with nominal compositions of Cu2-xMnyS (y = 0, 0.01, 0.03, 0.05, 0.07) were synthesized by a hydrothermal method. Then, the powders were vacuum-filtrated on nylon membranes and finally hot-pressed. Phase composition and microstructure analysis revealed that the films contained both Cu2S and Cu1.96S, and the size of the grains was ~20-300 nm. By Mn doping, there was an increase in carrier concentration and mobility, and ultimately, the electrical properties of Cu2-xS were improved. Eventually, the Cu2-xMn0.05S film showed a maximum power factor of 113.3 µW m-1 K-2 and good flexibility at room temperature. Moreover, an assembled four-leg flexible thermoelectric generator produced a maximum power of 249.48 nW (corresponding power density ~1.23 W m-2) at a temperature difference of 30.1 K, and had good potential for powering low-power-consumption wearable electronics.

High-Performance Ag2Se Film by a Microwave-Assisted Synthesis Method for Flexible Thermoelectric Generators.

Flexible Ag2Se thermoelectric (TE) films are promising for wearable applications near room temperature (RT). Herein, a Ag2Se film on a nylon membrane with high TE performance was fabricated by a facile method. First, Ag2Se powders were prepared by a microwave-assisted synthesis method using Ag nanowires as a template. Second, the Ag2Se powders were deposited onto nylon via vacuum filtration followed by hot pressing. Through modulating the Ag/Se molar ratio for synthesizing the Ag2Se powders, an optimized Ag2Se film demonstrates a high power factor of 1577.1 µW m-1 K-2 and good flexibility at RT. The flexibility of the Ag2Se film is mainly attributed to the flexible nylon membrane. In addition, a six-leg flexible TE generator (f-TEG) fabricated with the optimized Ag2Se film exhibits a maximum power density of 18.4 W m-2 at a temperature difference of 29 K near RT. This work provides a new solution to prepare high-TE-performance flexible Ag2Se films for f-TEGs.

Nanoengineering Approach toward High Power Factor Ag2Se/Se Composite Films for Flexible Thermoelectric Generators.

Herein, a flexible Ag2Se/Se composite film with a high power factor has been fabricated on a nylon membrane. The film has a high density and contains well-crystallized Ag2Se grains and embedded Se nanoinclusions, which exhibits not only excellent flexibility but also a comparably large room-temperature power factor and Seebeck coefficient of up to 2023 µW m-1 K-2 and -155 µV K-1, respectively. The high Seebeck coefficient is ascribed to the energy-filtering effect as caused by the Se/Ag2Se heterointerface. The assembled flexible thermoelectric generator (4-leg) exhibits a maximum output power of 1135 nW and a power density of up to 16.4 W m-2 when the applied temperature difference is 30 K. This work offers a feasible method to design high-performance and low-cost flexible thermoelectric generators used for wearable electronics.

High Thermoelectric Performance and Ultrahigh Flexibility Ag2S1-xSex film on a Nylon Membrane.

Flexible thermoelectric (TE) generators have recently attracted increasing attention as they have the potential to power wearable devices using the temperature difference between the human body and the environment. Ag2S is recently reported to have plasticity near room temperature; however, it has very low electrical conductivity, leading to its poor TE property. Here, to improve the TE property, different amounts of Se (Se/Ag2S molar ratios being 0.4, 0.5, and 0.6) solid solution-substituted Ag2S films on a nylon membrane are prepared by combing wet-chemical synthesis, vacuum filtration, and hot-pressing. The film (Se/Ag2S molar ratio = 0.6) exhibits a better TE performance with a power factor of 477.4 ± 15.20 µW m-1 K-2 at room temperature, which is comparable to that of bulk Ag2S1-xSex. In addition, the film possesses excellent flexibility (only ∼5.4% decrease in electrical conductivity after 2000 times bending along a rod with a radius of 4 mm). The power density of a 6-leg TE generator assembled with the film is 6.6 W/m2 under a temperature difference of 28.8 K. This work provides a facile new route to Ag2S-based TE films with low cost, high TE performance, and ultrahigh flexibility.

YTH Domain Proteins Play an Essential Role in Rice Growth and Stress Response.

As the most prevalent epi-transcriptional modification, m6A modifications play essential roles in regulating RNA fate. The molecular functions of YTH521-B homology (YTH) domain proteins, the most known READER proteins of m6A modifications, have been well-studied in animals. Although plants contain more YTH domain proteins than other eukaryotes, little is known about their biological importance. In dicot species Arabidopsis thaliana, the YTHDFA clade members ECT2/3/4 and CPSF30-L are well-studied and important for cell proliferation, plant organogenesis, and nitrate transport. More emphasis is needed on the biological functions of plant YTH proteins, especially monocot YTHs. Here we presented a detailed phylogenetic relationship of eukaryotic YTH proteins and clustered plant YTHDFC clade into three subclades. To determine the importance of monocot YTH proteins, YTH knockout mutants and RNAi-induced knockdown plants were constructed and used for phenotyping, transcriptomic analysis, and stress treatments. Knocking out or knocking down OsYTHs led to the downregulation of multicellular organismal regulation genes and resulted in growth defects. In addition, loss-of-function ythdfa mutants led to better salinity tolerance whereas ythdfc mutants were more sensitive to abiotic stress. Overall, our study establishes the functional relevance of rice YTH genes in plant growth regulation and stress response.

Construction of hierarchical polypyrrole coated copper-catecholate grown on poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) fibers for high-performance supercapacitors.

Fiber-shaped supercapacitors (FSCs) are considered as the optimal candidate for wearable energy devices, due to their high safety, excellent electrochemical stability, workability and body adaptability. However, the specific capacitances of today's FSCs such as carbon nanotube fibers and graphene fibers, are still not high enough for practical applications due to the limitation of their energy storage mode. So, we design a ternary composite fiber-shaped electrode: First, a kind of metal organic framework (MOF), copper-catecholate (Cu-CAT) nanorods, are in-situ grown on a wet-spun poly(3,4-ethylenedioxythiophene): poly(styrenesulfonate) (PEDOT:PSS) fiber at the ambient temperature. Second, polypyrrole (PPy) is electrodeposited on the surface of the Cu-CAT/PEDOT:PSS fiber to obtain PPy@Cu-CAT@PEDOT:PSS fiber (PPy@Cu-CAT@PF). The growing Cu-CAT with high porosity anchored on the fiber surface provides electrochemical activate sites and the encapsulation of PPy effectively provides a continuous charge transfer path and improve its cycling stability. Notably, the PPy@Cu-CAT@PF electrode exhibits a satisfactory areal capacitance of 669.93 mF cm-2 at 2 mA cm-2, which remains 61.66% even at a high current density of 20 mA cm-2. Furthermore, the assembled symmetric FSC displays excellent electrochemical properties and outstanding mechanical flexibility, demonstrating its feasibility as a wearable supercapacitor.

Prognostic Value of Serum Galectin-3 in Chronic Heart Failure: A Meta-Analysis.

OBJECTIVE: To evaluate the association between serum galectin-3 and all-cause death (ACD) and cardiovascular death (CVD) in patients with chronic heart failure (CHF). METHODS: The PubMed and Embase databases and Clinical Trials Registry (www.clinicaltrials.gov) were searched for studies with data on serum galectin-3 and ACD and CVD in CHF patients. The hazard ratios (HRs) of ACD and CVD were calculated and presented with 95% CIs. HRs were pooled using fixed effects or random effects models when appropriate. Sensitivity analysis, meta-regression and subgroup analysis were applied to find the origin of heterogeneity. Visual inspection of Begg's funnel plot and Egger's test were performed to assess the possibility publication bias. RESULTS: Pooled data included the results from 6,440 patients from 12 studies in the meta-analysis. Higher serum galectin-3 was associated with a higher risk of ACD (HR, 1.38; 95% CI, 1.14-1.67) and CVD (HR, 1.13; 95% CI, 1.02-1.25) in CHF patients. In the subgroup analyses, higher serum galectin-3 was associated with an increased risk of ACD in all subgroups. The pooled HR of the shorter follow-up group (1.78; 95% CI, 1.50-2.11) was significantly higher than the pooled HR of the longer follow-up group (1.15; 95% CI, 1.05-1.25). Sensitivity analysis of eliminating one study in each turn indicated that Koukoui et al.'s study had the largest influence on the risk of all-cause death. All-cause death publication bias was not detected (Pr>|z| = 0.35 for Begg's test and P>|t| = 0.15 for Egger's test). CONCLUSIONS: Serum galectin-3 has prognostic value of both all-cause death and cardiovascular death in CHF. Serum galectin-3 could be useful for risk classification in patients with CHF. SYSTEMATIC REVIEW REGISTRATION: https://www.crd.york.ac.uk/prospero/display_record.php?RecordID=193399.

Ultraflexible and High-Thermoelectric-Performance Sulfur-Doped Ag2Se Film on Nylon for Power Generators.

In this work, we developed a facile method to fabricate low-cost, flexible, and high-thermoelectric-performance n-type Ag2Se1-xSx@(Ag2S1-ySey/S) composite film on a nylon membrane. The composite film was prepared by first performing wet-chemical synthesis of the S-doped Ag2Se powder, then vacuum-assisted filtration of the powder on a nylon membrane, and finally hot-pressing. Transmission electron microscopy (TEM) observation and energy-dispersive system (EDS) analysis of the film revealed that the film had a porous network-like microstructure, in which Ag2Se1-xSx sub-micron grains formed the skeleton and are coated by a ∼15 nm thick layer of S-rich Ag2S1-ySey nanograins mixed with an S amorphous phase. The film showed a power factor of ∼954.7 µW·m-1·K-2 at 300 K and superior flexibility (94.4% of the original electrical conductivity was preserved after bending 2000 times around a rod with a radius of 4 mm). Moreover, a six-leg flexible thermoelectric generator was assembled with the film and produced a maximum power of 6.67 µW (corresponding power density ∼14.8 W/m2) at a temperature difference of 38.7 K. This work reveals a novel approach to explore high-performance and low-cost flexible thermoelectric devices suitable for room-temperature applications.

High Power Factor Ag/Ag2Se Composite Films for Flexible Thermoelectric Generators.

Herein, we fabricated an Ag/Ag2Se composite film on a flexible nylon membrane with a high power factor and excellent flexibility. First, Ag nanoparticles and multiscale Ag2Se nanostructure composite powders were prepared by wet chemical synthesis using Se nanowires, silver nitrate, and l-ascorbic acid as raw materials, followed by vacuum-assisted filtration of the composite powders on a porous nylon membrane and then hot pressing. The optimized composite film shows a very high power factor of 1860.6 µW m-1 K-2 (with a corresponding electrical conductivity of 3958 S cm-1) at room temperature. The composite film retains 93.3% of the original electrical conductivity after 1000 bending cycles around a rod with a diameter of 8 mm. At a temperature difference of 27 K, an 8-leg thermoelectric prototype device assembled with the optimized composite film generates a maximum power of 7.14 µW with a corresponding power density of 8.74 W m-2. This work provides a new strategy to synthesize flexible thermoelectric films with both a high power factor and high electrical conductivity.

Enhanced-Performance PEDOT:PSS/Cu2Se-Based Composite Films for Wearable Thermoelectric Power Generators.

Herein, we report the preparation and thermoelectric (TE) properties of flexible PEDOT:PSS/Cu2Se-based nanocomposite films on a nylon membrane using facile vacuum filtration and then hot pressing. The main composition of the composite film changed during hot pressing, causing the change of the carrier transport and TE performance intensively. Consequently, the optimized film shows a high power factor of 820 µW/mK2 at 400 K, which is 3 times as high as that of the nonhot-pressed one. The film shows excellent flexibility with 85% retention of the power factor after 1000 bending cycles around a 5 mm diameter rod. The outstanding flexibility results from a good combination between the nylon membrane and the Cu2Se-based nanoporous structured film. By pairing with n-type PEDOT/Ag2Se/CuAgSe films, a ten-legged flexible TE generator outputs maximum voltage and power of 50 mV and 1.55 µW, respectively, at a temperature difference of 44 K. Our research opens up a promising avenue to design high property flexible TE films for energy conversion.

DSCAM-AS1 mediates pro-hypertrophy role of GRK2 in cardiac hypertrophy aggravation via absorbing miR-188-5p.

Sustained cardiac hypertrophy, as previously clarified, serves as a critical initiator of heart failure and therefore is acknowledged as an important factor for heart failure treatment. The broadly demonstrated function and participation of long non-coding RNAs (lncRNAs) in tumors are well accepted. However, the underlying mechanism implicating lncRNAs in cardiac hypertrophy is mostly unexplored and deserves to be specifically studied. The devised work was aimed to disclose the function of lncRNA DS cell adhesion molecule antisense RNA 1 (DSCAM-AS1) in angiotensin II (AngII)-induced cardiac hypertrophy. In this study, we discovered the upregulation of DSCAM-AS1 in cardiomyocytes treated with AngII by quantitative real-time polymerase chain reaction (qRT-PCR). Western blot and qRT-PCR suggested that DSCAM-AS1 silencing attenuated the highly expressed hypertrophic biomarkers including ß-myosin heavy chain (ß-MHC), brain natriuretic peptide (BNP), and atrial natriuretic peptide (ANP) at mRNA and protein levels. The expanded cell surface in the presence of AngII treatment area was also shrunk by DSCAM-AS1 silencing. Mechanical analysis manifested that DSCAM-AS1 sponged microRNA-188-5p to boost the pro-hypertrophy gene G protein-coupled receptor kinase 2 (GRK2) expression. Rescue experiments unveiled miR-188-5p and GRK2 managed to reverse the anti-hypertrophy impact of DSCAM-AS1 silencing. In summary, DSCAM-AS1 was identified as a positive modulator in cardiac hypertrophy through miR-188-5p decoying and GRK2 augmentation, giving rise to an enriched theoretical basis for finding a promising target in cardiac hypertrophy regulation.

Ultrahigh Performance of n-Type Ag2Se Films for Flexible Thermoelectric Power Generators.

Due to the limited thermoelectric (TE) performance of conducting polymers and rigidity of inorganic materials, it is still a huge challenge to prepare low-cost, highly flexible, and high-performance TE materials. Herein, we fabricated n-type Ag2Se films using a porous nylon membrane as a flexible substrate by vacuum-assisted filtration, followed by hot pressing. A very high power factor of ∼1882 µW m-1 K-2 at room temperature is obtained. The high power factor is mainly the result of the high density of the Ag2Se film and the tuned grain orientation, which is realized by the synthesis of multisized Ag2Se nanostructures. The film also exhibits excellent flexibility with 90.7% retention of the power factor after bending around a rod of 4 mm radius for 1000 times. A four-leg TE generator is assembled with the Ag2Se film, and its maximum output power is up to 3.2 µW at a temperature difference of 30 K, corresponding to the maximum power density of 22.0 W m-2 and a normalized maximum power density of 408 µW m-1 K-2. This work provides an effective route to achieve high-power-factor, high-flexibility, and low-cost TE films.

MiR-625-5p Inhibits Cardiac Hypertrophy Through Targeting STAT3 and CaMKII.

Cardiac hypertrophy is an adaptive cardiac response to heart stress. Sustained cardiac hypertrophy indicates higher risk of heart failure. Ca2+/calmodulin-dependent protein kinase II (CaMKII) has been proved to be a key regulator of cardiac hypertrophy, but its mechanism remains largely unknown. Our study proposed to explore the regulatory mechanism of CaMKII in cardiac hypertrophy. We validated that CaMKII was upregulated in cardiac hypertrophy models in vivo and in vitro and that knockdown of CaMKII attenuated Ang II-induced cardiac hypertrophy in vitro. Furthermore, we demonstrated that signal transducer and activator of transcription 3 (STAT3) was highly expressed in cardiac hypertrophy and could stimulate the transactivation of CaMKII. Moreover, we predicted through TargetScan and confirmed that miR-625-5p targeted and inhibited STAT3 so as to reduce the expression of CaMKII. Interestingly, we also found that miR-625-5p directly targeted CaMKII and inhibited its expression. Rescue assays suggested that miR-625-5p attenuated Ang II-induced cardiac hypertrophy through CaMKII/STAT3. Consequently, this study elucidated that miR-625-5p inhibited cardiac hypertrophy through targeting STAT3 and CaMKII, suggesting miR-625-5p as a novel negative regulator of cardiac hypertrophy. Graphical abstract [Figure: see text].

High Performance and Flexible Polyvinylpyrrolidone/Ag/Ag2Te Ternary Composite Film for Thermoelectric Power Generator.

In this work, polyvinylpyrrolidone (PVP) coated Ag-rich Ag2Te nanowires (NWs) were synthesized by a wet chemical method using PVP coated Te NWs as templates, and a flexible PVP/Ag/Ag2Te ternary composite film on a nylon membrane was prepared by vacuum assisted filtration, followed by heat treatment. TEM and STEM observations of the focused ion beam prepared sample reveal that the composite film shows a porous network-like structure and that the Ag and Ag2Te exist as nanoparticles and NWs, respectively, both bonded with PVP. The Ag nanoparticles are formed by separation of the Ag-rich Ag2Te NWs during the heat treatment. For the composite film starting from a Ag/Te initial molar ratio of 6:1, a high power factor of 216.5 µW/mK2 is achieved at 300 K, and it increases to 370.1 µW/mK2 at 393 K. Bending tests demonstrate excellent flexibility of the hybrid film. A thermoelectric (TE) prototype composed of five legs of the hybrid film is assembled, and a maximum output power of 469 nW is obtained at a temperature gradient of 39.6 K, corresponding to a maximum power density of 341 µW/cm2. This work provides an effective route to a composite film with high TE performance and excellent flexibility for wearable TE generators.

Good Performance and Flexible PEDOT:PSS/Cu2Se Nanowire Thermoelectric Composite Films.

Herein, poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) coated Cu xSe y (PC-Cu xSe y) nanowires are prepared by a wet-chemical method, and PEDOT:PSS/Cu xSe y nanocomposite films on flexible nylon membrane are fabricated by vacuum assisted filtration and then cold-pressing. XRD analysis reveals that the Cu xSe y with different compositions can be obtained by adjusting the nominal Cu/Se molar ratios of their sources. For the composite film starting from a Cu/Se nominal molar ratio of 3, an optimized power factor of ∼270.3 µW/mK2 is obtained at 300 K. Moreover, the film exhibits a superior flexibility with 85% of the original power factor retention after bending for 1000 cycles around a rod with a diameter of 5 mm. TEM and STEM observations of the focused ion beam (FIB) prepared sample reveal that it is mainly attributed to a synergetic effect of the nylon membrane and the composite film with nanoporous structure formed by the intertwined nanowires, besides the intrinsic flexibility of nylon. Finally, a thermoelectric prototype composed of nine legs of the optimized hybrid film generates a voltage and a maximum power of 15 mV and 320 nW, respectively, at a temperature gradient of 30 K. This work offers an effective approach for high TE performance inorganic/polymer composite film for flexible TE devices.

High performance n-type Ag2Se film on nylon membrane for flexible thermoelectric power generator.

Researches on flexible thermoelectric materials usually focus on conducting polymers and conducting polymer-based composites; however, it is a great challenge to obtain high thermoelectric properties comparable to inorganic counterparts. Here, we report an n-type Ag2Se film on flexible nylon membrane with an ultrahigh power factor ~987.4 ± 104.1 µWm-1K-2 at 300 K and an excellent flexibility (93% of the original electrical conductivity retention after 1000 bending cycles around a 8-mm diameter rod). The flexibility is attributed to a synergetic effect of the nylon membrane and the Ag2Se film intertwined with numerous high-aspect-ratio Ag2Se grains. A thermoelectric prototype composed of 4-leg of the Ag2Se film generates a voltage and a maximum power of 18 mV and 460 nW, respectively, at a temperature difference of 30 K. This work opens opportunities of searching for high performance thermoelectric film for flexible thermoelectric devices.