Search Results (289)

Organic–inorganic hybrid halide perovskites have attracted extensive attention due to their excellent optoelectronic properties and potential applications in field-effect transistors (FET), light-emitting diodes (LEDs), and photodetectors. However, conventional three-dimensional (3D) perovskites are limited by intrinsic instability and ion migration. Two-dimensional Ruddlesden-Popper (2D RP) perovskites offer improved structural stability, but many systems still suffer from modest photoluminescence efficiency and limited charge-transport performance. In this work, a novel 2D RP perovskite, (C₆H₅NH₃)₂CsPb₂Cl₇, was designed and synthesized, where the anilinium ion (C₆H₅NH₃⁺) serves as the organic spacer. Structural characterization indicates that the material possesses high crystallinity and a smooth surface morphology. Optical measurements reveal a violet emission peak at 411 nm with a single-peak feature and a full width at half maximum (FWHM) of 10 nm. The bandgap is determined to be 3.1 eV. Time-resolved photoluminescence (TRPL) measurements show an average lifetime of 4 ns, and the photoluminescence quantum yield (PLQY) is 29.8%. Based on the measured PLQY and lifetime, the radiative and non-radiative recombination rates were estimated to be K_r ≈ 7.45 × 10⁷ s⁻¹ and K_nr ≈ 1.76 × 10⁸ s⁻¹, respectively, suggesting that radiative recombination is appreciable although non-radiative pathways remain present. FET measurements demonstrate an on/off current ratio of 10⁴ and a carrier mobility of 1.1 cm² V⁻¹ s⁻¹. Without any systematic optimization, (C₆H₅NH₃)₂CsPb₂Cl₇ exhibits relatively favorable emissive behavior and measurable field-effect charge transport performance when compared with structurally similar 2D RP perovskites reported under comparable, non-optimized conditions. This study expands the family of chloride-based 2D perovskites and provides a basis for future improvements in their recombination and field-effect transport properties. Full article

The threshold voltage (Vth) of p-GaN gate enhancement-mode (E-mode) high electron mobility transistors (HEMTs) on silicon substrates grown by metal–organic chemical vapor deposition (MOCVD) is often limited to 1.0–1.5 V. Apart from the low Mg acceptor activation rate, the non-uniform vertical Mg distribution in thin p-GaN layers is also a key bottleneck limiting Vth. This work reveals that the vertical distribution (not only magnitude) of Mg doping fundamentally influences Vth by modulating the charge centroid and electric field coupling to the heterointerface. Through bis(cyclopentadienyl)magnesium (Cp₂Mg) flow modulation, surfactant-assisted growth, and growth rate adjustment, the vertical Mg doping uniformity within the 80 nm p-GaN layer was improved while effectively suppressing Mg out-diffusion. A short-cycle gate-first self-aligned process was used to fabricate the devices, and the results showed that the improved Mg vertical distribution led to a significant Vth enhancement by 0.75 V. Technology Computer-Aided Design (TCAD) simulations further demonstrated that the uniform doping profile builds a stronger negative space charge field beneath the gate, raising the energy band and increasing Vth. This work not only presents practical strategies, but also establishes a direct physical link between vertical Mg doping distribution and Vth in Si-based E-mode HEMTs. Full article

Biosensors based on electrolyte-gated organic field-effect transistors (EGOFETs) have attracted considerable attention due to their advantages, including low cost, inherent signal amplification, and low-voltage operation. A critical step influencing sensing performance is the integration of specific receptors onto the device surface. Among various strategies, the covalent immobilization of biorecognition elements onto gold surfaces via thiol chemistry is one of the most widely used approaches. In this study, we report the optimization of a mixed self-assembled monolayer (SAM) composed of 11-mercaptoundecanoic acid (11-MUA) and 3-mercaptopropionic acid (3-MPA) for label-free detection of human IgG using EGOFETs. The quality of the SAM was systematically modulated by varying the total concentration from 10 to 400 mM and characterized using X-ray Photoelectron Spectroscopy (XPS), Electrochemical Impedance Spectroscopy (EIS), Cyclic Voltammetry (CV), and Atomic Force Microscopy (AFM). The results revealed that a concentration of 50 mM yielded a densely packed and well-ordered monolayer. After covalent immobilization of anti-IgG antibodies via 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide hydrochloride/N-hydroxysuccinimide (EDC/NHS) chemistry and subsequent blocking with ethanolamine and bovine serum albumin (BSA), the functionalized gate electrodes were integrated into poly(3-hexylthiophene) (P3HT)-based EGOFETs. Electrical measurements demonstrated that EGOFET biosensors functionalized with the 50 mM SAM achieved optimal sensing performance. The devices exhibited a highly linear response (R² = 0.998) over a wide concentration range from 1 fM to 10 nM, with a LOD of 2.82 fM, and showed excellent selectivity against non-target immunoglobulins A and M (IgA and IgM). This SAM concentration optimization strategy provides a versatile approach for engineering high-performance EGOFET biosensors, with potential applicability to a broad range of disease biomarkers. Full article

Design and fabrication of high-performance organic semiconductors are still challenging. Here, we designed new D-(A)n type zinc porphyrin end-capped ethynylene-7-(4-hexyl-thiophen-2-yl)-2,1,3-benzothiadiazole (EBTT) oligomers by linking 5,10,15-trisphenyl porphyrin zinc (ZnTPP) with length-variable EBTT oligomers (at the 20-position of porphyrin) [ZnTPP(EBTT)_n (n = 1–6)]. The influence of oligomer length on molecular structures, orbital energies, electronic absorption spectra, ionization energies, electronic affinities, and reorganization energies was systematically studied through density functional theory. The charge-carrier mobility of the simulated crystals and the power conversion efficiencies (PCE) using PCBM as the accepter were also predicted. ZnTPP(EBTT)₆ show excellent hole/electron mobility of 76.161/9.395 cm²V⁻¹s⁻¹ and extremely high PCE of 25.45%. This work would have significance for the design and synthesis of organic semiconductor materials with large charge-carrier mobility and high PCE performance. Full article

In this study, enhancement- and depletion-mode (E- and D-mode) GaN-based 120 nm-wide fin-gated multiple nanochannel metal–oxide–semiconductor high-electron-mobility transistors (MOS-HEMTs) were manufactured on the epitaxial Al_0.83In_0.17N/GaN/Al_0.18Ga_0.82N/GaN two-dimensional electron gas (2DEG) channel layers grown on Si substrates using a metal-organic chemical vapor deposition system. The oxide layer grown directly by the photoelectrochemical oxidation method was used as the gate oxide layer in D-mode MOS-HEMTs. Furthermore, E-mode MOS-HEMTs used ferroelectric stacked LiNbO₃/HfO₂/Al₂O₃ layers as the gate oxide layers. The 120 nm-wide multiple nanochannels and various-length source field plates (SFPs) were fabricated and incorporated into monolithic complementary MOS-HEMTs (CMOS-HEMTs) consisting of D- and E-mode MOS-HEMTs. The resulting monolithic unskewed inverter was achieved by modulating the drain-source current of the D-mode MOS-HEMTs. The noise low margin of 2.03 V and noise high margin of 2.10 V of the unskewed monolithic inverter were obtained. From the dynamic experimental results, the rising time and falling time of the unskewed monolithic inverter were 4.9 μs and 3.2 μs, respectively. The breakdown voltage could be improved by incorporating an SFP. When the SFP edge was located at the center between the gate electrode and the drain electrode, the maximum breakdown voltage of 855 V was obtained. Full article

Developing reliable processing routes for semiconductor thin films is essential for advancing photodetection technologies. The amine-thiol solvent system, in comparison with other liquid-phase synthesis methods, does not necessitate stepwise ion-exchange reactions. It is capable of obtaining the target semiconductor thin film by directly dissolving bulk powder followed by subsequent annealing. Although PbO can be dissolved in this solvent as a raw material to obtain PbS thin films, the structural evolution, optical properties, and photodetection performance of the films obtained via this solvent system still require further exploration. This solvent system was employed to prepare PbS thin films, and a comprehensive investigation was carried out on the evolution of their structure, morphology, and optical properties during preheating and annealing treatments. During preheating, the films exhibit directional ordering within the organic matrix, which converts into phase-pure PbS upon annealing. Based on the optimized films, interdigitated photodetectors and hybrid devices integrated with graphene transistors are fabricated. The resulting devices exhibit strong photoresponse and operational stability, demonstrating the viability of amine-thiol-processed PbS films for photodetection applications. Full article

While sustainability is set as a goal by a broad range of international organizations, its definition varies, and there is still a lack of practical criteria for product designers to evaluate the degree of (un)sustainability in the design phase. Life cycle assessment (LCA) can allow quantification of the environmental impacts of a product but is often carried out post-design, when the manufacturing process is already settled. Finally, while significant advances have been made towards standardizing LCA calculations by providing product category rules, large uncertainties remain in the calculation results due to a lack of transparency regarding the choices of databases, system boundaries, allocation, cut-off rules, and level of data granularity. A practical way to improve in those areas is to share with the semiconductor community a parametrizable life cycle inventory (LCI) model based on a target device to (1) identify knowledge gaps in LCA methods for such products, (2) identify the main process variables, and (3) provide a starting point for LCA calculations by the designers themselves. With this aim, a parametrizable cradle-to-gate manufacturing LCI model was developed based on the peer-reviewed process flow of a trench field-stop silicon insulated gate bipolar transistor (IGBT) semiconductor power device. The model allows computation of the environmental impacts of the IGBT manufacturing process based on different tunable parameters such as die size, wafer diameter, manufacturing yield, abatement efficiency, wafer fab throughput, wafer fab location, and associated electricity mix. Embedding a high level of data granularity, it helps identify, at elementary process levels, key environmental hotspots and associated technical levers for their reduction. Analysis of the IGBT manufacturing process tends to demonstrate the importance of an impact assessment approach considering multiple environmental categories, going beyond the sole focus on greenhouse gas emissions and accounting for potential transfers of impact. With an open-source mindset and in a continuous improvement prospective, the manufacturing inventory model and its associated tools are freely available from a public GitHub repository and open for comments and consolidation from users. Full article

In this work, we present the introductory methodology for a graphene field-effect transistor (GFET)-based platform for probing the electrochemical fingerprints of amino acids, designed to enable stable and controlled surface chemistry and electrochemical measurements toward peptide and protein sequencing. We begin with a focused conceptual review that motivates electrochemical fingerprinting as a strategy for amino acid and peptide identification and contextualizes this approach within recent advances in protein manipulation relevant to sequencing. We then describe a graphene functionalization protocol that facilitates the directional attachment of amino acids onto the graphene surface. This surface chemistry is quantitatively characterized through surface plasmon resonance (SPR), yielding surface densities in the order of 10¹² molecules/cm². The same functionalization protocol enables in situ peptide synthesis directly on graphene, as demonstrated by the successful synthesis of a model tripeptide. To support electrochemical interrogation, we developed three complementary platforms for sensor preconditioning, surface functionalization, and titration-based electrochemical measurements, compatible with both aqueous and organic solutions. Preliminary stability measurements indicate a Dirac point drift below 10 mV over 45 min. Altogether, this work establishes the experimental foundations for electrochemical amino acid and peptide fingerprinting using GFET sensors and provides a framework for the future development of electrochemically enabled protein sequencing technologies. Full article

An efficient synthetic method for the preparation of self-assembling conjugated organic materials with a silazane anchor group based on direct hydrosilylation reaction is reported. A novel organic semiconductor molecule, NH(Si-Und-BTBT-Hex)₂, consisting of a polar silazane anchor group linked through undecylenic (Und) aliphatic spacers to conjugated blocks based on benzothieno[3,2-b][1]benzothiophene (BTBT) and solubilizing hexyl (Hex) end groups, was synthesized. Its self-organization on the air-water interface and solid substrates into ultrathin layers obtained by the Langmuir–Schaefer or Langmuir–Blodgett methods was investigated. Monolayer organic field-effect transistors manufactured from NH(Si-Und-BTBT-Hex)₂ showed operation in the p-type mode. Full article

We present a methodology that enhances the analytical performance of organic electrochemical transistors (OECTs) by continuously cycling the devices through gate potential sweeps during sensing experiments. This continuous cycling methodology (CCM) enables real-time acquisition of full transfer curves, allowing simultaneous monitoring of multiple characteristic parameters. We show that the simultaneous temporal evolution of several OECT response parameters (threshold voltage (V_TH), maximum transconductance (g_max), and maximum transconductance potential (V_G,gmax)) provides highly sensitive descriptors for detecting pH changes and macromolecule adsorption on OECTs based on polyaniline (PANI) and poly(3,4-ethylenedioxythiophene) (PEDOT) channels. Moreover, the method allows reconstruction of I_DS–t (drain–source current vs. time) profiles at any selected gate potential, enabling the identification of optimal gate voltage (V_G) values for maximizing sensitivity. This represents a substantial improvement over traditional measurements at fixed V_G, which may suffer from reduced sensitivity and parasitic reactions associated with gate polarization. Moreover, the expanded set of parameters obtained with the CCM provides deeper insight into the physicochemical processes occurring at both gate and channel electrodes. We demonstrate its applicability in monitoring polyelectrolyte and enzyme adsorption, and detecting urea and glucose through enzyme-mediated reactions. Owing to its versatility and the richness of the information it provides, the CCM constitutes a significant advance for the development and optimization of OECT-based sensing platforms. Full article

Organic field-effect transistors (OFETs) require reliable micro- and nanoscale patterning of semiconducting layers, yet conjugated polymers have long been considered incompatible with photolithography due to dissolution and chemical damage from photoresist solvents. Here, we present a photolithography-compatible strategy based on doping-induced solubility conversion (DISC), demonstrated using poly[2,5-bis(3-tetradecylthiophen-2-yl)thieno[3,2-b]thiophene] (PBTTT). AuCl₃ doping reversibly modulates the benzoid/quinoid resonance balance, lamellar stacking, and π–π interactions, suppressing solubility during lithographic exposure, while dedoping restores the intrinsic electronic properties. Using this approach, micropatterns with linewidths as small as 2 µm were fabricated in diverse geometries—including line arrays, concentric rings, dot arrays, and curved channels—with high fidelity; quantitative analysis of dot arrays yielded mean absolute errors of 48–66 nm and coefficients of variation of 2.0–3.9%, confirming resolution and reproducibility across large areas. Importantly, OFETs based on patterned PBTTT exhibited charge-carrier mobility, threshold voltage, and on/off ratios comparable to spin-coated devices, despite undergoing multiple photolithography steps, indicating preservation of transport characteristics. Furthermore, the same DISC-assisted lithography was successfully applied to other representative p-type conjugated polymers, including P3HT and PDPP-4T, confirming the universality of the method. This scalable strategy thus combines the precision of established lithography with the functional advantages of organic semiconductors, providing a robust platform for high-density organic electronic integration in flexible circuits, biointerfaces, and active-matrix systems. Full article

Organic field-effect transistor (OFET) biosensors have emerged as a transformative technology for clinical biomarker detection, offering unprecedented sensitivity, selectivity, and versatility in point-of-care (POC) diagnostics. This review examines the fundamental principles, materials innovations, device architectures, and clinical applications of OFET-based biosensing platforms. The unique properties of organic semiconductors, combined with advanced biorecognition strategies, enable the detection of clinically relevant biomarkers at low concentrations. Recent developments in organic semiconductor materials have significantly enhanced device performance and stability. The integration of novel device architectures such as electrolyte-gated OFETs (EGOFETs) and extended-gate configurations has expanded the operational capabilities of these sensors in aqueous environments. Clinical applications span a broad spectrum of biomarkers, demonstrating the versatility of OFET biosensors in disease diagnosis and monitoring. Despite remarkable progress, challenges remain in terms of long-term stability, standardization, and translation to clinical practice. The convergence of organic electronics, biotechnology, and clinical medicine positions OFET biosensors as a promising platform for next-generation personalized healthcare and precision medicine applications. Full article

Gate driver-on-array (GOA) circuits employing amorphous indium–gallium–zinc oxide (IGZO)-based thin-film transistors (TFTs) have been successfully utilized to generate the driving signals for the commercialization of active-matrix organic light-emitting diode (AMOLED) displays. The depletion-mode TFTs in GOA circuits can be completely turned off by the introduction of series-connected, two-transistor, dual low-voltage-level power signals. Simulation results demonstrate that a GOA exhibits high process stability with a threshold voltage margin from −5 V to +5 V. Furthermore, the GOA output characterization and mobility compensation effect are evaluated by the integration of the GOA and pixel in a 31-inch 4K AMOLED display. Experimental results demonstrate that full-swing driving pulses can be obtained with the GOA. Finally, the stripe mura in the display caused by mobility variation can be successfully eliminated by the introduction of GOA circuits. Full article

This study investigates the interfacial interactions between two organic semiconductors (tetrathiafulvalene (TTF) and hexaazatriphenylene-hexacarbonitrile (HAT-CN)) and graphene-based materials (nanocrystalline graphite and vertically aligned graphene) used in Field-Effect Transistors (FETs). The interaction mechanisms, including π–π stacking, charge transfer, and dipole–dipole interactions, were explored through SEM imaging, Raman and FTIR spectroscopy, and FET transfer characteristics. Spectroscopic data confirmed strong π–π and charge-transfer interactions, with distinct modifications in graphene structural and electronic features. Electrical measurements revealed significant modulation of channel conductivity, confirming effective surface functionalization. These findings provide a framework for engineering high-performance organic/graphene hybrid interfaces in electronic devices and biosensors. Importantly, the results demonstrate that molecular design and interfacial control at the nanoscale can be strategically used to modulate charge transport in graphene-based FETs. This approach opens new pathways for developing tunable, molecule-specific biosensors and nanoelectronic platforms with enhanced sensitivity and selectivity. Full article

We report here on the synthesis and characterization of three novel isoindigo (II)-based organic semiconductors. The three dyes are based on an electron acceptor II core, symmetrically linked to two 3-octylthiophene donor rings; this common fragment, easily synthesizable, is end-capped with three different auxiliary electron acceptor groups, 1,1-Dicyanomethylene-3-Indanone (IDM) and two derivatives of it, bearing a bromine atom in position 5 or 6 of the IDM ring. The effect of the bromination and of the position of the bromine atom on the chemical–physical and electrical properties of the compounds were examined by means of thermal, optical, and electrochemical analysis; the electronic properties were investigated in more details at the DFT level. The novel compounds were used as active layers in organic field effect transistors: all the II derivatives were n-type unipolar semiconductors with electron mobilities ranging between 10⁻³ and 10⁻⁴ cm²/V∙s. Full article