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The ion-sensitive field effect transistor (ISFET) has emerged as a crucial sensor device, owing to its numerous benefits such as label-free operation, miniaturization, high sensitivity, and rapid response time. Currently, ISFET technology excels in detecting ions, nucleic acids, proteins, and cellular components, with widespread applications in early disease screening, condition monitoring, and drug analysis. Recent advancements in sensing techniques, coupled with breakthroughs in nanomaterials and microelectronics, have significantly improved sensor performance. These developments are steering ISFETs toward a promising future characterized by enhanced sensitivity, seamless integration, and multifaceted detection capabilities. This review explores the structure and operational principles of ISFETs, highlighting recent research in ISFET biosensors for biomarker detection. It also examines the limitations of these sensors, proposes potential solutions, and anticipates their future trajectory. This review aims to provide a valuable reference for advancing ISFETs in the field of biomarker measurement. [ABSTRACT FROM AUTHOR]

The direct electrosynthesis of hydrogen peroxide (H2O2) through a two-electron oxygen reduction reaction (2e− ORR) under ambient conditions has emerged as a promising solution for on-site applications, aiming to replace the energy-intensive, waste-generating, and indirect anthraquinone process. Recent advancements have focused on developing catalysts to enhance their activity and efficiency. However, the dynamic evolution and in situ construction behavior of electrocatalysts during operation have often been overlooked. Herein, we investigate the in situ electrochemical reconstruction process of oxygen-deficient TiO2, which forms on the surface of Ti2O3 during the ORR process. The reconstructed catalyst exhibits a complete transition from a 4e− ORR pathway to a 2e− pathway, exhibiting exceptional performance in synthesizing H2O2 with a faradaic efficiency exceeding 90%. Furthermore, by cross-confirmation with density functional calculations, we validate the transition process of the phase and ORR pathway by in situ electrochemical Raman and infrared spectroscopy. [ABSTRACT FROM AUTHOR]

Electrochemical CO2 reduction into value-added chemicals represents an attractive and promising approach to capitalize on the abundant CO2 present in the atmosphere. This reaction, however, is hampered by low energy efficiency and selectivity owing to competition from hydrogen evolution reaction and multiple-electron transfer processes. Therefore, there is a pressing need to develop efficient yet cost-effective electrocatalysts to facilitate practical applications. Sn-based electrocatalysts have gained increasing attention in this active field due to their outstanding merits such as abundance, non-toxicity, and environmental friendliness. This review provides a comprehensive overview of recent advances in Sn-based catalysts for the CO2 reduction reaction (CO2RR), beginning with a brief introduction to the CO2RR mechanism. Subsequently, the CO2RR performance of various Sn-based catalysts with different structures is discussed. The article concludes by addressing the existing challenges and offering personal perspectives on the future prospects in this exciting research area. [ABSTRACT FROM AUTHOR]

Solution‐processed organic–inorganic metal halide perovskites have recently attracted tremendous attention in the photodetector community due to their excellent optoelectronic properties and facile fabrication. The main challenge in perovskite photodetectors (PSPDs) is to achieve high responsivity and fast speed simultaneously. In this work, this challenge is overcome by employing a directly patterned nanograting methylammonium lead iodide (MAPbI3) film in metal‐semiconductor‐metal (MSM) PSPD on interdigitated indium tin oxide (ITO) electrodes. Because of the improved perovskite morphology after directly patterning by nanoimprint lithography, as well as the enhanced electric field intensity by the perovskite nanograting and interdigitated electrodes, the PSPDs have responsivity of 441 A W−1, detectivity of 8.32 × 1012 Jones, response time of 10.7 µs, all of which are among the best performances in MSM PSPDs. Moreover, the PSPDs maintain excellent photocurrent performance after 20 days of air exposure. The approach opens a path to manufacturing‐friendly, high‐performance, and reliable PSPDs and paves the way toward perovskite‐based optoelectronic circuits. [ABSTRACT FROM AUTHOR]

This article addresses the hydrolytic instability issue of surface chemistry and the repeatability issue of silicon (Si) nanowire (NW) biosensors. Si multi-NWs or nanograting (NG) field-effect transistors (FETs) were fabricated using semiconductor lithographic processing techniques. Then, the NG surfaces were coated with 3-aminopropyltriethoxysilane (APTES) via the vapor- and solution-phase methods. Their performance, including drift, stability, sensitivity, accuracy, and linearity of pH sensing, was evaluated. Sensors treated with both APTES deposition methods exhibit linear pH response with good sensitivity. Devices treated with vapor APTES show better linearity and sensitivity, and APTES-solution-coated devices are more stable with smaller drift. A hydrolysis process was developed to significantly improve the hydrolytic stability of the APTES-coated sensor surface. As a result, an accuracy of ?0.008 pH was achieved, which is comparable to or better than commercially available ion-sensitive FETs (ISFETs), whereas the sensor drift was significantly reduced for both sensors treated with vapor and solution APTES. This hydrolysis process has greatly improved the stability and repeatability of charge sensing of our Si NG bio-FETs. [ABSTRACT FROM PUBLISHER]

A numerical study on the operation of Si nanowire (NW) biosensors in charge-based sensing is presented. The simulation is built on physical models that, upon numerical convergence, coherently account for Fermi–Dirac, Poisson–Boltzman, site-binding and Gouy–Chapman–Stern theories in self-consistent manner. The method enables us to disentangle the impact of key design and experimental setup factors and assess their contribution to the sensitivity, linearity, and stability of such sensors. Our results quantitatively show SiNW sensor is significantly more stable when biased through solution gate than back gate; dense functional group at oxide surface and good SAM coverage are essential to linear and sensitive detection of uniformly distributed targets; compared to high concentration target detection, the effect of NW surface-to-volume ratio (S/V ) plays a more profound role in biomolecule detection when targets are at very low concentration, in which case, optimal S/V exists for a maximum sensitivity. Arbitrary down scaling beyond such S/V point may have reverse effect on sensor sensitivity. [ABSTRACT FROM PUBLISHER]

Nanoimprint with a large-scale nanoporous Si mold is developed to fabricate high density periodic nanopillars (∼1010/cm2) in various functional polymers. A anodic alumina membrane is first obtained using electrochemical anodization. The membrane is used as a mask for a two-step plasma etching process to obtain a Si mold of 50–80 nm wide and 100–900 nm deep pores. The mold is used in nanoimprint lithography to fabricate ordered and high density polymer nanopillars and nanopores in SU-8, hydrogen silsesquixane, polymethylmethacrylate, poly(3-hexylthiophane) (P3HT), and phenyl-C61-butyric acid methyl ester (PCBM). Then, the imprinted P3HT nanopillars were used to make bulk heterojunction solar cells by depositing PCBM on top of the pillars. Imprinting provides a way to precisely control the interdigitized heterojunction morphology, leading to improved solar cell performance. [ABSTRACT FROM AUTHOR]

Electrochemical CO 2 reduction into value-added chemicals represents an attractive and promising approach to capitalize on the abundant CO 2 present in the atmosphere. This reaction, however, is hampered by low energy efficiency and selectivity owing to competition from hydrogen evolution reaction and multiple-electron transfer processes. Therefore, there is a pressing need to develop efficient yet cost-effective electrocatalysts to facilitate practical applications. Sn-based electrocatalysts have gained increasing attention in this active field due to their outstanding merits such as abundance, non-toxicity, and environmental friendliness. This review provides a comprehensive overview of recent advances in Sn-based catalysts for the CO 2 reduction reaction (CO 2 RR), beginning with a brief introduction to the CO 2 RR mechanism. Subsequently, the CO 2 RR performance of various Sn-based catalysts with different structures is discussed. The article concludes by addressing the existing challenges and offering personal perspectives on the future prospects in this exciting research area.

Chemical functionalization of silicon oxide (SiO(2)) surfaces with silane molecules is an important technique for a variety of device and sensor applications. Quality control of self-assembled monolayers (SAMs) is difficult to achieve because of the lack of a direct measure for newly formed interfacial Si-O bonds. Herein we report a sensitive measure of the bonding interface between the SAM and SiO(2), whereby the longitudinal optical (LO) phonon mode of SiO(2) provides a high level of selectivity for the characterization of newly formed interfacial bonds. The intensity and spectral position of the LO peak, observed upon silanization of a variety of silane molecules, are shown to be reliable fingerprints of formation of interfacial bonds that effectively extend the Si-O network after SAM formation. While the IR absorption intensities of functional groups (e.g., >C=O, CH(2)/CH(3)) depend on the nature of the films, the blue-shift and intensity increase of the LO phonon mode are common to all silane molecules investigated and their magnitude is associated with the creation of interfacial bonds only. Moreover, results from this study demonstrate the ability of the LO phonon mode to analyze the silanization kinetics of SiO(2) surfaces, which provides mechanistic insights on the self-assembly process to help achieve a stable and high quality SAM.

Control of polymer morphology and chain orientation is of great importance in organic solar cells and field effect transistors (OFETs). Here we report the use of nanoimprint lithography to fabricate large-area, high-density, and ordered nanostructures in conjugated polymer poly(3-hexylthiophene) or P3HT, and also to simultaneously control 3D chain alignment within these P3HT nanostructures. Out-of-plane and in-plane grazing incident X-ray diffraction were used to determine the chain orientation in the imprinted P3HT nanostructures, which shows a strong dependence on their geometry (gratings or pillars). Vertical chain alignment was observed in both nanogratings and nanopillars, indicating strong potential to improve charge transport and optical properties for solar cells in comparison to bulk heterojunction structure. For P3HT nanogratings, pi-pi stacking along the grating direction with an angular distribution of +/-20 degrees was found, which is favorable for OFETs. We propose the chain alignment is induced by the nanoconfinement during nanoimprinting via pi-pi interaction and hydrophobic interaction between polymer chain and mold surfaces.

We demonstrate a guided self-assembly approach to the fabrication of DNA nanostructures on silicon substrates. DNA oligonucleotides self-assemble into "rafts" 8 x 37 x 2 nm in size. The rafts bind to cationic SAMs on silicon wafers. Electron-beam lithography of a thin poly(methyl methacrylate) (PMMA) resist layer was used to define trenches, and (3-aminopropyl)triethoxysilane (APTES), a cationic SAM precursor, was deposited from aqueous solution onto the exposed silicon dioxide at the trench bottoms. The remaining PMMA can be cleanly stripped off with dichloromethane, leaving APTES layers 0.7-1.2 nm in thickness and 110 nm in width. DNA rafts bind selectively to the resulting APTES stripes. The coverage of DNA rafts on adjacent areas of silicon dioxide is 20 times lower than on the APTES stripes. The topographic features of the rafts, measured by AFM, are identical to those of rafts deposited on wide-area SAMs. Binding to the APTES stripes appears to be very strong as indicated by "jamming" of the rafts at a saturation coverage of 42% and the stability to repeated AFM scanning in air.