Porous hydrogels that integrate mechanical compliance with controllable molecular transport are critical for emerging soft bioelectronic and biochemical sensing platforms but the role of pore-forming strategy in governing transport behavior and interfacial stability for biosensing remains insufficiently resolved. In this work, PVA-PEGDA-SA composite hydrogels were engineered via two distinct fabrication routes-sucrose porogen leaching and electrospinning-to systematically examine how processing methodology dictates membrane architecture and transport performance. Porogen leaching produced microporous networks with characteristic pore size ranges of 10-20 & micro;m, while electrospinning generated interconnected nanofibrous membranes with sub-micrometre pores (0.2-0.4 & micro;m). These structurally distinct architectures resulted in fundamentally different transport regimes. Leached membranes exhibited enhanced swelling and high-flux diffusion pathways, whereas electrospun membranes imposed regulated molecular ingress, reduced nanoscale roughness, and improved mechanical stability. Chronoamperometric measurements of cortisol in phosphate buffer demonstrate that electrospun membranes significantly suppress baseline noise and non-specific transport, enabling stable, concentration-dependent analyte diffusion and improved antifouling behavior at low analyte concentrations. Importantly, the results reveal that fabrication route functions not merely as a structural modifier but as a transport-regime design parameter governing hydrogel-electrode interface behavior. This study provides a mechanistic framework for tailoring hydrogel membranes for soft wearable sensors, saliva-compatible diagnostics, and selective molecular monitoring applications.

The development of sustainable and efficient energy storage systems based on abundant and environmentally friendly charge carriers is paramount to achieving global net-zero goals. Ammonium (NH4+)-ion-based systems present a promising non-metallic alternative owing to their atomic structure that enhances the kinetics, assisting charge storage. However, the identification of suitable host materials for reversible NH4* storage remains a significant challenge. Herein, we report the use of manganese oxide (Mn3O4) as a novel electrode material for aqueous ammonium-ion storage. Tetragonal-shaped Mn3O4 nanoparticles were synthesised directly on carbon cloth (Mn3O4@CC) using a controlled layer-by-layer assembly method. These electrodes exhibit an excellent specific capacity of 322.8 mAh/g at a current density of 0.5 A/g, with impressive rate capability and 77.7 mAh/g capacity retention over 3000 cycles. The charge storage kinetics analysed using ex-situ characterisations confirm the reversible insertion and extraction mechanism of the NH4+-ion in the Mn3O4 structure. DFT calculations reveal the superior electronic conductivity and the interaction of the NH4+ ion with Mn3O4, by which the material could achieve a high capacity. Furthermore, an ammonium-ion supercapacitor (AISC) was constructed using the Mn3O4@CC as the positive and activated carbon (AC) as the negative electrode material. The device delivered a maximum specific energy of 47.9 Wh/kg and a specific power of 8000 W/kg, with excellent cycling stability. This investigation highlights Mn3O4 as a promising material for NH4* ion storage and paves the way for the exploration of other electrode materials synthesised using the layer-by-layer method for next-generation, environmentally friendly energy storage systems.

Achieving simultaneous enhancement of electron and hole mobility in organic semiconductors (OSCs) using a single additive remains a significant challenge. In this study, we present a unique additive strategy that enables concurrent improvement of both n- and p-type transport in an n-dominant ambipolar polymer incorporating para-azaquinodimethane and diketopyrrolopyrrole. By individually applying various additives including ionic, p-type, and n-type compounds, we achieve unprecedented enhancements of both electron (∼400%) and hole (∼100%) mobility. Such parallel improvement is unattainable via conventional electron transfer mechanism. We ascribe this effect to optimized film morphology, reduced activation energy, and lowered contact resistance. To further elucidate additive-induced variations in electronic structure and guide future molecular design, density functional theory calculations reveal that incorporating para-azaquinodimethane into the polymer backbone facilitates strong orbital coupling with additives. This coupling introduces additional charge transport pathways between polymer segments, enhancing both electron and hole transport along lamellar and π-π stacking directions. Our findings suggest promoting robust orbital coupling between host polymers and additives offers a promising strategy to concurrently boost electron and hole mobility in a single OSC, effectively circumventing traditional limitations associated with separate p- and n-type additives/dopants.

Recycling materials from end-of-use metal halide perovskite solar cells (PSCs) is essential for reducing environmental risks and improving the sustainability of this emerging photovoltaic technology, with lead iodide (PbI2) being a target due to its toxicity and material value. However, the performance of PSCs is known to be highly sensitive to the purity of precursor materials including PbI2. In this study, a simple water-based recycling and recrystallization method was developed to recover PbI2 from spent PSCs. Characterizations have shown that the recycled-PbI2 was comparable to high-purity (99.99%)PbI2. The perovskite (MAPbI3) film made from the recycled-PbI2 or lower purity (99%)PbI2 shows smaller grains, which are undesirable for their applications in solar cells. It is found that treatment of the recycled PbI2-based perovskite film with guanidinium thiocyanate (GuaSCN) can significantly enhance morphology and properties of the perovskite film with larger grains (∼700 nm), reduced trap-assisted recombination. PSCs with champion power conversion efficiency (PCE) of 17.25% were obtained, which well surpassed the performance of the PSCs made from commercial 99%PbI2 (PCE 11.68%). This work shows the potential of reclaiming PbI2 from decommissioned, decomposed perovskite materials, and even purifying the contaminated PSCs in a cost-efficient and environmentally friendly manner, generating commercial and environmental benefits.

ABSTRACT Organic electrochemical transistors (OECTs) are emerging as powerful biosensing platforms, offering high transduction efficiency, low‐voltage operation, and intrinsic compatibility with aqueous and physiological environments. Central to their recent progress is the strategic integration of biomaterials, which govern interfacial charge transfer, doping dynamics, and recognition specificity. A complete understanding of biomaterial‐enabled OECTs requires not only insights into intrinsic material chemistry but also interface engineering and device design principles that dictate signal transduction and reproducibility. In this review, we critically examine the full spectrum of biomaterials integrated into OECT biosensors (from natural macromolecules, such as proteins, nucleic acids, and polysaccharides to biocompatible polymers and synthetic engineered interfaces). Particular emphasis is placed on interfacial chemistries, including silanization and click reactions, that control receptor orientation, density, and long‐term stability. Beyond materials design, we discuss operating physics, signal transduction mechanisms, and device engineering strategies, thereby linking molecular‐scale chemistry with device‐level performance. By consolidating these interdisciplinary advances, we provide a timely roadmap for reproducible, scalable, and clinically relevant OECT biosensors. With growing demand for high‐performance and sustainable sensing platforms in precision medicine and environmental monitoring, this review highlights both key achievements and outstanding challenges that will shape the next generation of bioelectronic technologies.

ABSTRACT Lead‐free perovskite solar cells (PSCs) have emerged as sustainable alternatives to toxic lead‐based counterparts, offering environmental compatibility and tunable optoelectronic properties. However, achieving long‐term stability remains a major bottleneck hindering commercialization. Among lead‐free systems, tin‐based perovskites have received the greatest attention owing to their structural and electronic similarity to Pb‐based analogs and their potential for high efficiencies, yet they remain limited by intrinsic Sn 2 + oxidation, ion migration, and rapid degradation under ambient conditions. In contrast, antimony‐, bismuth‐, and germanium‐based perovskites exhibit superior chemical and environmental stability but suffer from wide bandgaps, localized electronic states, and low carrier mobility, resulting in modest power conversion efficiencies. This review provides a comprehensive, stability‐centered analysis of lead‐free PSCs, emphasizing intrinsic degradation mechanisms, extrinsic stress factors, and the role of fabrication, interfacial, and additive engineering in improving device stability. Advanced in‐situ and operando characterization techniques are discussed to elucidate defect dynamics and degradation pathways. While Sn‐based systems are analyzed in greater detail due to the availability and depth of mechanistic studies, equal attention is given to recent developments in Bi‐, Sb‐, and Ge‐based perovskites to present a balanced perspective. Finally, key challenges, mitigation strategies, and future research directions are outlined to guide the design of stable, efficient, and environmentally benign lead‐free perovskite photovoltaics.

Carbon-based materials, particularly single-walled carbon nanotubes (SWCNTs), are promising candidates for flexible thermoelectric applications due to their excellent electrical conductivity and mechanical robustness. However, severe self-aggregation of SWCNTs leads to suboptimal and degraded thermoelectric performance. Conventional dispersion strategies have proved largely ineffective in overcoming this limitation. Here, we present a pioneered radical-mediated dispersion (RMD) strategy, enabled by a rationally designed small molecule, OTN, which incorporates a donor-acceptor conjugated backbone and pendant free-radical terminals. The RMD strategy mechanism functions through dual interactions: The donor-acceptor backbone enhances π-interactions with SWCNTs, while the pendant radicals facilitate radical-radical interactions to further suppress nanotube aggregation. This synergistic molecular design enables OTN-SWCNT hybrid films to achieve a high power factor of 30.1 µW cm-1 K-2, far exceeding previous reports, while maintaining excellent free-standing mechanical flexibility. Furthermore, a nine-leg thermoelectric device assembled from these films delivers a normalized power density of 0.653 µW cm-2 K-2, representing one of the best performances for CNT-based thermoelectrics to date. This pioneering molecular design, together with the derived innovative RMD strategy overcomes the long-standing aggregation of SWCNTs and is anticipated to open new avenues for advancing carbon-based thermoelectric materials toward practical, flexible energy-harvesting applications.

ABSTRACT Electronic waste is a growing global challenge, driving the need for eco‐friendly materials and sustainable device architectures. Biodegradable and transient electronics have emerged as promising solutions by enabling controlled degradation and material recovery. Chitosan, a widely abundant biomaterial derived from chitin, has attracted significant attention due to its biocompatibility, biodegradability, and versatile chemical functionality. These properties enable its integration across multiple electronic components, supporting the development of fully or partially biodegradable systems. Chitosan has been widely employed as a dielectric layer in transistors, an ionic conductor, a transparent flexible electrode, and as a host or scaffold in electronic devices. Despite extensive research, existing reviews typically focus on specific applications or broader material classes, leaving a gap in understanding how chitosan can be systematically integrated into complete electronic architectures. This review provides a comprehensive and structured analysis of chitosan's properties and its integration into key device components, including electrodes, transistors, memory devices, optoelectronics, energy systems, and scaffolds. By adopting a component‐based framework, this work highlights the potential of chitosan as a unifying platform for the development of next‐generation sustainable and biodegradable electronic technologies.

Tsuyoshi Michinobu, Prashant Sonar and Waner He introduce the Materials Advances themed collection on Organic transistors and related devices.Tsuyoshi Michinobu, Prashant Sonar and Waner He introduce the Materials Advances themed collection on Organic transistors and related devices.

Abstract Polycyclic aromatic hydrocarbons (PAHs) are an interesting class of organic semiconducting material (OSM) due to their notable optoelectronic properties. However, their widespread use in organic electronics is often limited by their poor solubility, vacuum processes, and high cost. Herein, we report two series of PAHs integrated OSMs (DPPPy-C10-AN, DPPPy-C10-FA, and DPPPy-C10-DPB-FA; DPPPy-C-Si-AN, DPPPy-C-Si-FA, and DPPPy-C-Si-DPB-FA) in which alkyl/siloxane-appended pyridine-flanked diketopyrrolopyrrole is π-conjugated to acenaphthene (AN), fluoranthene (FA), and diphenylbenzo-fluoranthene (DPB-FA), respectively. Although both series of PAHs integrated OSMs showed sufficient solubility in common organic solvents, the siloxane derivatives exhibited superior solubility compared to the alkyl counterparts. Upon varying the PAHs (from AN to FA and further to DPB-FA) on OSMs, only marginal variations were observed in the optical properties, band gaps, and frontier energy level values. In contrast, GIWAXS results revealed substantial changes in the crystalline properties of thin films. Importantly, AN- and FA-based molecules demonstrated enhanced crystallinity compared to DPB-FA molecules. Furthermore, DPPPy-C-Si-AN:SEBS and DPPPy-C-Si-FA:SEBS stretchable blends showed ordered orientation compared to DPPPy-C10-AN:SEBS and DPPPy-C10-FA:SEBS. DPPPy-C10-DPB-FA:SEBS and DPPPy-C-Si-DPB-FA:SEBS blends exhibited poorer orientation compared to the pristine or other molecules. Organic field-effect transistors based on DPPPy-C-Si-FA displayed the highest electron mobility of 28 × 10–3 cm2 V–1 s–1 among all the molecules and their elastomeric blends.

Diketopyrrolopyrrole (DPP)-based conjugated polymers show strong promise for electronic applications, including bioelectronic gas sensors, yet their use in aqueous environments remains largely unexplored, especially for minimally invasive point-of-care testing (POCT) biosensors. We present the first systematic study of DPP-based organic field-effect transistors (OFETs) that deliver highly stable signal responses under both ambient and aqueous conditions. A scalable lab-on-a-chip fabrication strategy is demonstrated, highlighting the critical roles of polymer deposition, dielectric selection, and device engineering in achieving uniform and reproducible electronic performance. The resulting OFETs exhibit excellent operational stability in water and phosphate-buffered saline (PBS), supporting their suitability for sensing biological fluids. Devices display high output current, low transfer hysteresis, and strong batch-to-batch consistency, and are fabricated entirely under ambient conditions without oxygen or humidity control, underscoring compatibility with large-scale manufacturing. OFET operation is sustained with minimal signal drift for up to 1 h in water and PBS. Comprehensive characterization of water-immersed DPP films using PESA, UV-vis spectroscopy, XRD, and ToF-SIMS confirms material robustness. A pilot real-time dopamine sensing study achieves a detection limit of 1 pm, demonstrating feasibility for biosensing. Overall, DPP-based organic semiconductors represent strong candidates for robust aqueous OFET-based POCT technologies.

The rise of electronic societies is driving a surge in the demand for energy storage solutions, particularly in the realm of renewable energy technologies like batteries, which rely heavily on efficient electrode materials and separators. As an answer to this necessity, Covalent Organic Frameworks (COFs) are emerging and a highly intriguing class of materials, garnering increased attention in recent years for their extensive properties and possible applications. This review addresses the remarkable versatility and boundless potential of COFs in scientific fields, mainly focusing on multivalent metal ion batteries (MMIBs), which include AIB (Aluminium-ion batteries), MIB (Magnesium-ion battery), CIB (Calcium-ion battery), and ZIB (Zinc-ion battery), as both electrode materials and separators across a spectrum of battery technology. Inclusive of their approaches, merits, and reaction mechanisms, this review offers an extensive summary of COFs concerning multivalent ion batteries. By providing a rigorous analysis of COF attributes, electrochemical behaviour, and methodologies, our explanation contributes to a deeper understanding of their potential in advancing battery technology.

This study presents the development of PEDOT:Tosylate‐based organic electrochemical transistor (OECT) wearable devices with a biocompatible substrate and investigates its transfer and output characteristics under bending conditions. Initial studies focused on casting chitosan film and evaluating their biocompatibility via viability assays of cultured human cells, followed by vapor phase polymerization of highly conductive PEDOT:Tosylate layers on top of chitosan films. Subsequently, the modified chitosan substrate is employed in the fabrication of OECT devices with the top‐gate bottom‐contact configuration, enabling a comprehensive characterization of its transistor performance. Accordingly, the OECT operation showed good performance metrics, with a product of volumetric capacitance and mobility (the μC* product) of the conjugated polymer layer reaching 245.75 ± 48.57 F cm−1 V−1 s−1, a normalized transconductance of 153.59 ± 24.01 S cm−1, and a current output retention of up to 85% after 500 cycles of ON‐OFF testing. Nanoscratch testing revealed a high critical stress of nanoscratch (σc) of 497 ± 40 MPa and an adhesive energy (Gc) of 1.91 ± 0.34 J m−2, indicating strong resistance to delamination and peeling. Under bending conditions, the devices retained up to 81% of their initial current signal and remained as high as 97% after returning unbended.

The contemporary research on developing n-type organic semiconducting materials (OSMs) has great significance for stretchable organic field-effect transistors (OFETs). Two n-type OSMs (DPPPy-C10-TN and DPPPy-C-Si-TN) based on alkyl/siloxane-substituted pyridine flanked diketopyrrolopyrrole (DPPPy) end capped with thienyl naphthalimide (TN) are reported. Although DPPPy-C10-TN and DPPPy-C-Si-TN show similar optical and electrochemical properties, they show a significant variation in their morphological and crystalline properties in pristine form or within an elastic polymer (polystyrene-block-poly(ethylene-ran-butylene)-block-polystyrene; SEBS) matrix, which further reflects on their electrical properties. Interestingly, bottom-gate top-contact OFETs of as-cast pristine DPPPy-C10-TN show a higher electron mobility (mu e = 0.103 cm2 V-1 s-1) than DPPPy-C-Si-TN (mu e = 0.0145 cm2 V-1 s-1), underscoring the influence of alkyl substitution on charge transport efficiency. By contrast, stretchable DPPPy-C-Si-TN:SEBS blend shows a significantly higher electron mobility (mu e = 0.322 cm2 V-1 s-1) in comparison to the DPPPy-C10-TN:SEBS blend (mu e = 0.00196 cm2 V-1 s-1). To the best of the authors' knowledge, this is the first successful report about a high mu e value reported for a DPPPy-based n-type small molecule stretchable OSM blend in OFETs and provides new insights into the design and processing principles of small molecule based OSMs for flexible electronics.

The smoking of nicotine and passive exposure to environmental tobacco smoke can lead to many chronic medical conditions such as respiratory, cardiovascular, and cancer diseases. Nicotine smoking can also cause complications for patients undergoing medical procedures. The prevalence of vaping among young people has added a significant challenge to the health care systems as many commercial vaping oils contain undeclared nicotine content, thus leading to nicotine addiction. Governments around the world criminalised the undeclared presence of nicotine in vaping oils. Therefore, there a is strong demand for new materials and sensors that can rapidly detect nicotine/tobacco smoke in vaping products and the environment. Similarly, there is an ongoing need for rapid methods to determine the concentration of the nicotine metabolite, cotinine, in patients prior to medical procedures. To address these needs, we have synthesised and utilised a cost-effective paper sensor for the rapid screening of nicotine and cotinine in vaping the oil, the gas phase, and the human saliva by surface-enhanced Raman spectroscopy (SERS). The new sensor can detect ultra traces of nicotine and cotinine down to 1 pg/mL and 1 ng/mL respectively, within 20 min. The new sensor can be recycled for repeated screening of nicotine and its metabolite, thus maximizing its economic viability. The was successfully utilised for the detection of nicotine in tobacco smoke and in spiked human saliva by a handheld Raman spectrometer, thus indicating its potential for real-life applications.

This review provides an insightful and comprehensive exploration of the emerging 2D material borophene,both pristine and modified,emphasizing its unique attributes and potential for sustainable applications.Borophene's distinctive properties include its anisotropic crystal structures that contribute to its exceptional mechanical and electronic properties.The material exhibits superior electrical and thermal conductivity,surpassing many other 2D materials.Borophene's unique atomic spin arrangements further diversify its potential application for magnetism.Surface and interface engineering,through doping,functionalization,and synthesis of hybridized and nanocomposite borophene-based systems,is crucial for tailoring borophene's properties to specific applications.This review aims to address this knowledge gap through a comprehensive and critical analysis of different synthetic and functionalisation methods,to enhance surface reactivity by increasing active sites through doping and surface modifications.These approaches optimize diffusion pathways improving accessibility for catalytic reactions,and tailor the electronic density to tune the optical and electronic behavior.Key applications explored include energy systems(batteries,supercapacitors,and hydrogen storage),catalysis for hydrogen and oxygen evolution reactions,sensors,and optoelectronics for advanced photonic devices.The key to all these applications relies on strategies to introduce heteroatoms for tuning electronic and catalytic properties,employ chemical modifications to enhance stability and leverage borophene's conductivity and reactivity for advanced photonics.Finally,the review addresses challenges and proposes solutions such as encapsulation,functionalization,and integration with composites to mitigate oxidation sensitivity and overcome scalability barriers,enabling sustainable,commercial-scale applications.

Numerous flexible and wearable devices are in dire need of stretchable power sources for future smart innovations and applications. These devices must endure large deformations and harvest energy from mechanical stress–strain changes to enable truly self‐powered wearables. In this work, a stretchable thermoplastic elastomer, styrene‐ethylene‐butylene‐styrene (SEBS), is effectively used to fabricate triboelectric nanogenerators (TENG) for harvesting energy from mechanical motion, wind, and skin‐attachable gesture sensing. The SEBS‐based TENG delivers an output of 0.228 W m⁻² under 10 N of force, while exhibiting linear dependence on force. The excellent processability of SEBS enables scalable, low‐cost, and straightforward fabrications suitable for commercial productions. Furthermore, leveraging SEBS’s flexibility, a flapping‐style wind energy harvester is developed, capable of working under very low to high wind velocities. This device addresses challenges faced by conventional wind harvesters, including material degradation and poor low‐wind performance, through innovative material engineering and structural design choices. Additionally, for gesture sensing, SEBS enables the development of a stretchable sensor responsive to flexing during human or robotic movements. This sensor seamlessly integrated with current cost‐effective systems, push real‐time smartphone notifications, showcasing its practical applicability. Overall, this multifunctional SEBS‐based TENG devices advances sustainable energy generation and self‐powered sensing for next‐generation wearable technologies.