By monitoring opioid metabolites, wastewater-based epidemiology (WBE) could be an excellent tool for real-time information on the consumption of illicit drugs. A key limitation of WBE is the reliance on costly laboratory-based techniques that require substantial infrastructure and trained personnel, resulting in long turnaround times. Here, we present an aptamer-based graphene field effect transistor (AptG-FET) platform for simultaneous detection of three different opioid metabolites. This platform provides a reliable, rapid, and inexpensive method for quantitative analysis of opioid metabolites in wastewater. The platform delivers a limit of detection 2–3 orders of magnitude lower than previous reports, but in line with the concentration range (pg/mL to ng/mL) of these opioid metabolites present in real samples. To enable multianalyte detection, we developed a facile, reproducible, and high-yield fabrication process producing 20 G-FETs with integrated side gate platinum (Pt) electrodes on a single chip. Our devices achieved the selective multianalyte detection of three different metabolites: noroxycodone (NX), 2-ethylidene-1,5-dimethyl-3,3-diphenylpyrrolidine (EDDP), and norfentanyl (NF) in wastewater diluted 20× in buffer.

Due to its outstanding safety and high energy density, all-solid-state lithium-sulfur batteries (ASLSBs) are considered as a potential future energy storage technology. The electrochemical reaction pathway in ASLSBs with inorganic solid-state electrolytes is different from Li-S batteries with liquid electrolytes, but the mechanism remains unclear. By combining operando Raman spectroscopy and ex situ X-ray absorption spectroscopy, we investigated the reaction mechanism of sulfur (S 8 ) in ASLSBs. Our results revealed that no Li 2 S 8, Li 2 S 6, and Li 2 S 4 were formed, yet Li 2 S 2 was detected. Furthermore, first-principles structural calculations were employed to disclose the formation energy of solid state Li 2 S n (1 � n � 8), in which Li 2 S 2 was a metastable phase, consistent with experimental observations. Meanwhile, partial S 8 and Li 2 S 2 remained at the full lithiation stage, suggesting incomplete reaction due to sluggish reaction kinetics in ASLSBs.

By monitoring opioid metabolites, wastewater-based epidemiology (WBE) could be an excellent tool for real-time information on consumption of illicit drugs. A key limitation of WBE is the reliance on costly laboratory-based techniques that require substantial infrastructure and trained personnel, resulting in long turnaround times. Here, we present an aptamer-based graphene field effect transistor (AptG-FET) platform for simultaneous detection of three different opioid metabolites. This platform provides a reliable, rapid, and inexpensive method for quantitative analysis of opioid metabolites in wastewater (WW). The platform delivers a limit of detection (LOD) 2-3 orders of magnitude lower than previous reports, but in line with the concentrations range (pg/ml to ng/ml) of these opioid metabolites present in real samples. To enable multianalyte detection we developed a facile, reproducible, and high yield fabrication process producing twenty G-FETs with integrated side gate platinum (Pt) electrodes on a single chip. Our devices achieved the simultaneous and selective multianalyte detection of three different metabolites: Noroxycodone (NX), 2-ethylidene-1,5-dimethyl-3,3-diphenylpyrrolidine (EDDP), and Norfentanyl (NF) in wastewater.

Integrating different two-dimensional (2D) crystals is highly demanded for advancing their application in nextgeneration electronics. 2D transition metal carbides, nitrides, and carbonitrides (MXenes), as new members in the 2D family, are promising candidates for 2D electrodes because of their high conductivity and stability. However, integrating MXenes with other 2D semiconductors has been underdeveloped due to the limitation of top-down etching synthesis of MXenes. Our recent development of atomic substitution synthesis achieved ultrathin non-van der Waals (non-vdW) transition metal nitrides (TMNs) through the conversion of vdW transition metal dichalcogenides (TMDs), opening opportunities of combining TMDs with TMNs via controllable partial conversion. Here, we perform an in-depth study of the atomic substitution process from semiconducting MoS 2 to metallic MoN and realize both lateral and vertical MoN− MoS 2 heterostructures via edge and surface epitaxial conversion, respectively. The structural evolution investigation from MoS 2 to MoN using high-resolution transmission electron microscopy suggests atomically bonded interface for lateral heterostructures and moirépattern in vertical heterostructures. Moreover, mask-assisted atomic substitution is applied to create patterned MoN−MoS 2 − MoN lateral heterostructures. Electrical measurements reveal a Schottky barrier height of meV for a three-layer MoS 2 −MoN interface, showcasing the potential of atomically bonded lateral heterostructures for MoS 2 electronics with MoN as contact electrodes.

Due to its outstanding safety and high energy density, all-solid-state lithium-sulfur batteries (ASLSBs) are considered as a potential future energy storage technology. The electrochemical reaction pathway in ASLSBs with inorganic solid-state electrolytes is different from Li-S batteries with liquid electrolytes, but the mechanism remains unclear. By combining operando Raman spectroscopy and ex situ X-ray absorption spectroscopy, we investigated the reaction mechanism of sulfur (S 8 ) in ASLSBs. Our results revealed that no Li 2 S 8, Li 2 S 6, and Li 2 S 4 were formed, yet Li 2 S 2 was detected. Furthermore, first-principles structural calculations were employed to disclose the formation energy of solid state Li 2 S n (1 � n � 8), in which Li 2 S 2 was a metastable phase, consistent with experimental observations. Meanwhile, partial S 8 and Li 2 S 2 remained at the full lithiation stage, suggesting incomplete reaction due to sluggish reaction kinetics in ASLSBs.

Lithium-metal (Li0) anode is considered the holy grail of all-solid-state batteries owing to their exceedingly high energy density; in practice, their stability remains unsatisfactory because of the incompatibility between Li0 and solid-state electrolytes (SEs). One strategy is introducing an interlayer, which often consists of the mixed ionic-electronic conductor (MIEC), to stabilize the Li0. However, how Li ions (Li+) transport within MIEC remains unknown. Herein, we investigate the Li, including Li0 and Li+, dynamics in a graphite interlayer, a typical MIEC, using operando neutron imaging and Raman spectroscopy. Our study reveals the Li evolution during mechano-chemistry and mechano-electrochemistry reactions. During cell assembly, intercalation–extrusion-dominated mechano-chemical reactions transform the graphite into a Li-graphite interlayer consisting of SE, Li0, and diluted graphite-intercalation compounds. During battery operation, dictated by the lowest nucleation energy, Li0 plating preferentially occurred at the Li-graphite|SE interface and then transferred into the Li-graphite interlayer without intercalation. Upon further plating, Li0-dendrites formed, inducing short circuits and reverse immigration of Li0 from the anode to the cathode during charging. Continuum modeling was conducted to explain the Li dynamics. We concluded that with the MIEC interlayer, a lowest nucleation barrier at the Li0 side is necessary to drive the Li+ to transport across MIEC and preferentially deposit onto the Li0.

All-solid-state lithium-sulfur batteries (ASLSBs) have been considered a promising next-generation energy storage technology due to their remarkable safety and high energy density. In ASLSBs, the electrochemical pathways are intrinsically different from conventional Li-S batteries using liquid electrolytes. However, the mechanism still lacks clear identification and deep understanding. Herein, for the first time, we investigated the chemistries and explored the electrochemical reaction mechanism and kinetic in ASLSBs through coupling operando Raman spectroscopy and ex-situ X-ray absorption spectroscopy. We proved no long-chain lithium polysulfides (Li2Sn, 4≤n≤8) were formed during the redox reactions, but a short-chain polysulfide (Li2S2) intermediate phase formation was identified in the conversion between active material S8 and reduction product Li2S. The existence of intermediate phase Li2S2 results in low sulfur utilization and poor battery performance. In comparison to liquid cells, ASLSBs exhibit sluggish reaction kinetics due to the higher conversion barrier and slower charger transfer in solid-solid reactions. This study revealed the generation of Li2S2 intermediates in ASLSBs, inspiring future research to further improve the performance of ASLSBs through completing the conversions and promoting reaction kinetics in ASLSBs.