Thermoelectric properties of individual single-crystalline PbTe nanowires grown by a vapor transport method

We report the thermoelectric performance of individual PbTe nanowires with sizes ranging from 76 to 436 nm grown from a vapor transport method that synthesizes high-quality, single-crystalline PbTe nanowires. Independent measurements of temperature-dependent Seebeck coefficient (S), thermal conductivity (κ) and electrical conductivity (σ) of individual PbTe nanowires were investigated. By varying the nanowire size, the simultaneous increase and decrease of S (-130 μV K(-1)) and κ (1.2 W m(-1) K(-1)), respectively, are achieved at room temperature. Our results demonstrate the enhanced thermoelectric properties of individual single-crystalline PbTe nanowires, compared to that of bulk PbTe, and can provide guidelines for future work on nanostructured thermoelectrics based on PbTe.     

High Efficiency Solid‐State Dye‐Sensitized Solar Cells Assembled with Hierarchical Anatase Pine Tree‐like TiO2 Nanotubes

A facile and effective method to prepare hierarchical pine tree‐like TiO₂ nanotube (PTT) arrays with an anatase phase directly grown on a transparent conducting oxide substrate via a one‐step hydrothermal reaction. The PTT arrays consist of a vertically oriented long nanotube (NT) stem and a large number of short nanorod (NR) branches. Various PTT morphologies are obtained by adjusting the water/diethylene glycol ratio. The diameter of the NTs and the size of the NR branches decreases from 300 to100 nm and from 430 to 230 nm, respectively, with increasing water content. The length of the PTT arrays could be increased up to 19 μm to significantly improve the charge transport and specific surface area. The solid‐state dye‐sensitized solar cells (ssDSSC) assembled with the 19 μm long PTT arrays exhibit an outstanding energy‐conversion efficiency of 8.0% at 100 mW/cm², which is two‐fold higher than that of commercially available paste (4.0%) and one of the highest values obtained for N719 dye‐based ssDSSCs. The high performance is attributed to the larger surface area, improved electron transport, and reduced electrolyte/electrode interfacial resistance, resulting from the one‐dimensional, well‐aligned structure with a high porosity and large pores.     

Proteomic Analysis Reveals PGAM1 Altering cis‐9, trans‐11 Conjugated Linoleic Acid Synthesis in Bovine Mammary Gland

cis‐9, trans‐11 Conjugated linoleic acid (CLA) is one of the most extensively studied CLA isomers due to its multiple isomer‐specific effects. However, the molecular mechanisms of cis‐9,trans‐11 CLA synthesis in ruminant mammary gland are still not clearly understood. This process may be mediated, to a certain extent, by trans‐11 C18:1 regulated by stearoyl‐CoA desaturase‐1 (SCD1) and/or its syntrophic proteins. This study aimed to investigate the effects of TVA on SCD1‐mediated cis‐9,trans‐11 CLA synthesis in MAC‐T cells and its potential molecular mechanism. Results showed that trans‐11 C18:1 was continually taken up and converted into cis‐9,trans‐11 CLA in MAC‐T cells during the 4‐h incubation of 50 μM trans‐11 C18:1. SCD1 protein expression increased more than twofold at 2 h (P < 0.01) and 2.5 h (P < 0.05) before decreasing to less than half of the normal level at 4 h (P < 0.05). One up‐regulated (RAS guanyl releasing protein 4 isoform 1 [RASGRP4]) and six down‐regulated proteins (glucosamine‐6‐phosphate deaminase 1 [GNPDA1], triosephosphate isomerase [TPI1], phosphoglycerate mutase 1 [PGAM1], heat shock protein beta‐1 [HSPB1], annexin A3 [ANXA3], thiopurine S‐methyltransferase [TPMT]) were found in MAC‐T cells treated with trans‐11 C18:1. Of these seven identified proteins, the presence of GNPDA1 and PGAM1 was verified in several models. More trans‐11 C18:1 was taken up after PGAM1 knockdown by small interfering RNA (siRNA). In conclusion, our data suggested that PGAM1 may have a negative relationship with SCD1 and seemed to be involved in cis‐9, trans‐11 CLA synthesis by facilitating the absorption of trans‐11 C18:1 in the bovine mammary gland.     

Towards a Structured Framework for Techno-Economic Analyses of Chemical Recycling Technologies

The role of chemical recycling (CR) as a valuable complementary strategy to mechanical recycling in closing the carbon cycle for carbon-containing waste is currently being discussed in political, economic, and social spheres. However, CR deployment is hindered by uncertainties regarding its environmental impacts and costs compared to conventional waste treatment and chemical production routes. While methods for assessing CR's environmental impacts are the focus of socio-political debates and investigations, techno-economic analyses (TEA) to evaluate costs of CR remain scarce. To contribute to a standardized framework for assessing the economic viability of CR technologies, this article draws on life cycle assessment and TEA literature to develop a six-stage TEA process for CR. A checklist is also presented to support transparent and comprehensive analyses.     

Beyond Plastics-to-Plastics to Waste-to-Products: Opportunities for Closing the Carbon Cycle via Chemical Recycling

The plastic crisis is a key driver for chemical recycling (CR), with focus placed on plastics circularity via Plastics-to-Plastics. This neglects its potential in enabling circularity for a wide range of carbon-containing waste and hinders a critical discussion of its broader contributions to decarbonizing the chemical sector. To address this gap, four CR routes and their integration in the conventional waste treatment and chemical production value chains are briefly reviewed, and reasons proposed for a focus expansion to Waste-to-Products to realize opportunities for closing the carbon cycle via chemical recycling.     

Block and Random Living,Ring‐Opening Metathesis Copolymerization of Functionally Differentiated Carbazole‐Containing Norbornene Monomers

The synthesis of novel diblock polymers containing both a potential charge transport and a non‐linear optic block has been accomplished. The synthesis exploits the living, ring‐opening metathesis block copolymerization of two norbornene type monomers, one of which contains an unsubstituted N‐carbazolyl ring while the other has a bromo substituent at the 3‐position of the carbazole ring. Conversion of the bromo functionality to a 2,2‐dicyanovinyl group introduces the non‐linear optic property. The first monomer was prepared by the previously reported efficient cation radical Diels–Alder cycloaddition of N‐trans‐1‐propenylcarbazole to 1,3‐cyclopentadiene, while the second was obtained by N‐bromosuccinimide bromination of the first monomer. For purposes of comparison, the corresponding random copolymer was also synthesized.     

Unraveling Polymer–Ion Interactions in Electrochromic Polymers for their Implementation in Organic Electrochemical Synaptic Devices

Owing to low-power, fast and highly adaptive operability, as well as scalability, electrochemical random-access memory (ECRAM) technology is one of the most promising approaches for neuromorphic computing based on artificial neural networks. Despite recent advances, practical implementation of ECRAMs remains challenging due to several limitations including high write noise, asymmetric weight updates, and insufficient dynamic ranges. Here, inspired by similarities in structural and functional requirements between electrochromic devices and ECRAMs, high-performance, single-transistor and neuromorphic devices based on electrochromic polymers (ECPs) are demonstrated. To effectively translate electrochromism into electrochemical ion memory in polymers, this study systematically investigates polymer–ion interactions, redox activity, mixed ionic–electronic conduction, and stability of ECPs both experimentally and computationally using select electrolytes. The best-performing ECP-electrolyte combination is then implemented into an ECRAM device to further explore synaptic plasticity behaviors. The resulting ECRAM exhibits high linearity and symmetric conductance modulation, high dynamic range (≈1 mS or ≈6x), and high training accuracy (>84% within five training cycles on a standard image recognition dataset), comparable to existing state-of-the-art ECRAMs. This study offers a promising approach to discover and design novel polymer materials for organic ECRAMs and demonstrates potential applications, taking advantage of mature knowledge basis on electrochromic materials and devices.     

An Efficient Synthesis of Ring‐Opening Metathesis Monomers and Polymers Containing Carbazole and Other Electron‐Rich Moieties

An efficient synthesis of ring‐opening metathesis monomers and polymers containing ionizable moieties such as N‐carbazolyl, 2‐dibenzofuranyl, 2‐dibenzothiophenyl, and 4‐anisyl functionalities has been developed, using cation radical Diels‐Alder cycloaddition chemistry to generate the appropriate norbornene‐type monomers.