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Supercapacitor-like Na-ion batteries have attracted much attention due to the high energy density of batteries and power density of capacitors. Titanium dioxide (TiO2), is a promising anode material. Its performance is however seriously hindered by its low electrical conductivity and the sluggish diffusion of sodium ions (Na+) in the TiO2 matrix. Herein, this work combines porous TiO2 nanocubes with carbon nanotubes (CNTs) to enhance the electrical conductivity and accelerate Na+ diffusivity for Na-ion batteries (NIBs). In this composite, an interwoven scaffolded TiO2/CNTs framework is formed to provide abundant channels and shorter diffusion pathways for electrons and ions. The in-situ X-ray diffraction and cyclic voltammetry confirm the low strain and superior transport kinetics in Na+ intercalation/extraction processes. In addition, the chemically bonded TiO2/CNTs hybrid provides a more feasible channel for Na+ insertion/extraction with a much lower energy barrier. Consequently, the TiO2/CNTs composite exhibits excellent electrochemical performance with a capacity of 223.4 mAh g−1 at 1 C and a capacity of 142.8 mAh g−1 at 10 C (3.35 A g−1). The work here reveals that the combination of active materials with CNTs can largely improve the utilization efficiency and enhance their sodium storage.

Early diagnosis in exhaled breath is a key technology for next-generation personal healthcare monitoring. Current chemiresistive sensors, primarily based on metal oxide (MOx) thin films, have limited applicability in such portable systems due to their high power consumption, long recovery time, poor device-to-device consistency, and baseline drifts. To address these challenges for ammonia ($${{\rm{NH}}}_{3}$$ NH 3 ) detection in exhaled breath, a critical biomarker for a variety of kidney and liver problems, we present a formulation of a graphene–MOx functional ink-based sensing platform. We integrate our sensing layer directly onto miniaturized CMOS microhotplates (μHP) via inkjet printing, potentially enabling scalability and device-to-device performance repeatability. Using stage-by-stage temporal analysis, and a temperature-pulsed modulation (TM) strategy, we achieve ultrahigh responsivity (1500% at 10 ppm pure $${{\rm{NH}}}_{3}$$ NH 3 ), fast response and recovery time (28 and 43 s), ultralow power consumption (~6 mW), negligible baseline drift ($${{\rm{WO}}}_{3}$$ WO 3 ) device as part of the sensor array. Our dual graphene–MOx formulations and their integration with ultralow power CMOS through inkjet printing represent a significant step towards reliable and portable multi-analyte breath diagnostics.

Miniaturizing spectrometers Spectroscopy is a ubiquitous characterization tool spanning most scientific and many industrial disciplines. Most handheld spectrometers are based on tabletop optical components, which limits the scale to which these spectrometers can be shrunk. To address the desire for miniaturized spectrometers with a micrometer-scale (and smaller) footprint, Yang et al. developed such a microspectrometer based on single, compositionally engineered nanowire. This result is a practical step forward for the use of other light-sensitive nanomaterials for such ultra-miniaturized spectroscopy platforms. Science , this issue p. 1017

Metal oxides (MOx) represent one of the most investigated chemiresistive gas sensing platforms in spite of the challenges in selectivity to analytes and interference from humidity (RH). While selectivity is traditionally improved by cross-referencing sensor arrays, interferences from humidity (RH) in ambient environment, to which the majority of the MOx materials are susceptible, cannot be inherently quantified. For standalone MOx sensors, it is therefore difficult to discriminate responses from analytes and humidity. We develop a framework which employs temperature modulation (TM) algorithms and machine learning (ML) approaches using principal component analysis (PCA) and cluster analysis of transient features, to quantify NO2 concentrations under specific RH conditions. With a single inkjet-printed MOx/reduced graphene oxide (rGO) complementary metal-oxide-semiconductor (CMOS)-integrated sensor, we achieve an overall discrimination accuracy of 97.3%. Our approach may enable the development of predictive systems for humidity sensitive sensors under ambient moisture conditions, towards the realisation of low-power, miniaturised adaptive air quality monitoring.

Solution‐processable thin‐film dielectrics represent an important material family for large‐area, fully‐printed electronics. Yet, in recent years, it has seen only limited development, and has mostly remained confined to pure polymers. Although it is possible to achieve excellent printability, these polymers have low (≈2–5) dielectric constants (εr). There have been recent attempts to use solution‐processed 2D hexagonal boron nitride (h‐BN) as an alternative. However, the deposited h‐BN flakes create porous thin‐films, compromising their mechanical integrity, substrate adhesion, and susceptibility to moisture. These challenges are addressed by developing a “one‐pot” formulation of polyurethane (PU)‐based inks with h‐BN nano‐fillers. The approach enables coating of pinhole‐free, flexible PU+h‐BN dielectric thin‐films. The h‐BN dispersion concentration is optimized with respect to exfoliation yield, optical transparency, and thin‐film uniformity. A maximum εr ≈ 7.57 is achieved, a two‐fold increase over pure PU, with only 0.7 vol% h‐BN in the dielectric thin‐film. A high optical transparency of ≈78.0% (≈0.65% variation) is measured across a 25 cm2 area for a 10 μm thick dielectric. The dielectric property of the composite is also consistent, with a measured areal capacitance variation of, A hexagonal boron nitride‐enhanced, flexible, and optically transparent thin‐film dielectric is reported. The pin‐hole‐free composite is fabricated by K‐bar coating and shows up to a two‐fold increase in dielectric constant. The optical transparency is consistent, with 0.65% variation. The formulation is suitable for large‐area applications such as printed capacitors and transparent capacitive touch surfaces.

Printing has drawn a lot of attention as a means of low per-unit cost and high throughput patterning of graphene inks for scaled-up thin-form factor device manufacturing. However, traditional printing processes require a flat surface and are incapable of achieving patterning on to 3D objects. Here, we present a conformal printing method to achieve functional graphene-based patterns on to arbitrarily-shaped surfaces. Using experimental design, we formulate a water-insoluble graphene ink with optimum conductivity. We then print single and multi-layered electrically functional structures on to a sacrificial layer using conventional screen printing. The print is then floated on water, allowing the dissolution of the sacrificial layer, while retaining the functional patterns. The single and multilayer patterns can then be directly transferred on to arbitrarily-shaped 3D objects without requiring any post deposition processing. Using this technique, we demonstrate conformal printing of single and multilayer functional devices that include joule heaters, resistive strain sensors and proximity sensors on hard, flexible and soft substrates, such as glass, latex, thermoplastics, textiles, and even candies and marshmallows. Our simple strategy offers great promises to add new device and sensing functionalities to previously inert 3D surfaces., 12 pages, 5 Figures

We demonstrate a long-term stable, all-fiber, erbium-doped femtosecond laser mode-locked by a black phosphorus saturable absorber. The saturable absorber, fabricated by scalable and highly controllable inkjet printing technology, exhibits strong nonlinear optical response and is stable for long-term operation against intense irradiation, overcoming a key drawback of this material. The oscillator delivers self-starting, 102 fs stable pulses centered at 1555 nm with 40 nm spectral bandwidth. This represents the shortest pulse duration achieved from black phosphorus in a fiber laser to date. Our results demonstrate the great potential for black phosphorus as an excellent candidate for long-term stable ultrashort pulse generation.

We report self-starting mode-locking in all-fiber erbium-doped lasers utilizing inkjet-printed transition metal dichalcogenide saturable absorbers, exhibiting highly optical uniformity, with

We demonstrate an inkjet-printed temperature- and humidity-resistant black phosphorus saturable absorber, enabling stable continuous mode-locking over 210 hours. Our work highlights the potential of BP-based devices for photonic applications operating under challenging environmental conditions.

We demonstrate a wavelength tunable dual-wavelength fiber laser using black phosphorus (BP) saturable absorber. By controlling the tunable filter together with a polarization controller to adjust intra-cavity birefringence, dual-wavelength pulses tunable from 1532 nm to 1545 nm are observed.

We demonstrate a long-term stable fiber laser mode-locked by a solution deposited and encapsulated black phosphorus (BP) saturable absorber. Our work highlights the potential of BP-based devices for photonic applications when operating under ambient conditions.

We demonstrate an all-fiber erbium-doped laser mode-locked by an inkjet-printed black phosphorus saturable absorber, delivering 102 fs pulses with 40 nm spectral width. Our work highlights the potential of BP-based devices for future photonic technologies.

A binary solvent ink exploiting solutal Marangoni flows to suppress the coffee-ring effect for uniform printing of 2D crystals., Recent advances in inkjet printing of two-dimensional (2D) crystals show great promise for next-generation printed electronics development. Printing nonuniformity, however, results in poor reproducibility in device performance and remains a major impediment to their large-scale manufacturing. At the heart of this challenge lies the coffee-ring effect (CRE), ring-shaped nonuniform deposits formed during postdeposition drying. We present an experimental study of the drying mechanism of a binary solvent ink formulation. We show that Marangoni-enhanced spreading in this formulation inhibits contact line pinning and deforms the droplet shape to naturally suppress the capillary flows that give rise to the CRE. This general formulation supports uniform deposition of 2D crystals and their derivatives, enabling scalable and even wafer-scale device fabrication, moving them closer to industrial-level additive manufacturing.