ABSTRACT Organic mixed ionic‐electronic conductors (OMIECs) are key components for the next‐generation bioelectronics, albeit with n ‐type materials remaining significantly underrepresented compared to their p ‐type counterparts. Furthermore, reaching low operating voltages alongside high ambient and operational stability remains challenging when employing n ‐type OMIECs in organic electrochemical transistor (OECT)‐based applications. Herein, we report two novel n ‐type polymeric OMIECs, based on an azaisatin and benzodifurandione‐based backbone, incorporating either non‐fluorinated or fluorinated bithiophene donor units. The resulting polymers, obtained via Aldol polymerization, have high electron affinities of 4.5–4.7 eV. Both polymers function in n ‐type accumulation mode OECTs with indications of tunable antiambipolar behavior. The fluorinated polymer displays a low threshold voltage of 0.14 V, while the non‐fluorinated analogue offers excellent operational stability, with the OECT retaining 96% of its initial current after 1800 s of cycling.
ABSTRACT To tackle the alarming generation of electronic waste, sustainable strategies must not be presented blindly without quantitatively assessing their environmental impacts. Here, a nature‐based flexible substrate called Triacetyl Cellulose (TAC) is analyzed as an eco‐friendly alternative to the widely‐used polyimide, not only by demonstrating functional thin‐film sensors but also through substrate recovery and reusability, and evaluation of associated environmental benefits through a life cycle assessment (LCA). Resistance temperature detectors (RTDs) and thermistors are realized on the TAC substrate using Cu, Mo, and AZO contacts, and InGaZnO. The temperature response of Cu‐ and Mo‐based RTDs show negligible hysteresis over multiple thermal cycles, while the AZO‐based RTD and the thermistors show consistent resistance drift. The sensors' mechanical performance is evaluated by bending measurements involving radii down to . We further show TAC recovery by Mo RTD dissolution in deionized water and TAC reusability by another sensor fabrication. Finally, LCA is employed to reliably compare the potential environmental implications of utilizing TAC in comparison with polyimide. Key results show that sensor fabrication on TAC demonstrates lower relative impacts than polyimide in all impact categories, including resource use and climate change, making it a more sustainable substrate choice for the fabrication of thin‐film temperature sensors.
ABSTRACT We report gate‐controlled quantum‐dot transport in a trilayer MoSe 2 device that combines a graphite back gate beneath the active region, a separate global gate for conductive access regions, and local top finger gates. In the low‐backgate regime, bias spectroscopy shows regular Coulomb‐blockade diamonds characteristic of single‐dot transport. As backgate is increased, additional low‐bias structure develops beyond a simple single‐dot pattern, indicating that the electrostatic landscape is reshaped and that a second dot becomes active in transport. In the higher‐backgate regime, plunger‐gate tuning and two‐gate measurements establish a gate‐reconfigurable double‐dot configuration with two non‐equivalent dots whose relative alignment and interdot coupling evolve with gate voltage. These results indicate that trilayer MoSe 2 supports electrically reconfigurable single‐ and double‐dot transport in the present device architecture.
ABSTRACT Despite extensive research on quantum dot light‐emitting diodes, the underlying charge transport mechanisms remain poorly understood. Previously, we have demonstrated that the hole transport in quantum dot (QD) thin films is trap‐free and space‐charge‐limited. However, the electron transport mechanism remains unexplored. In this study, we systematically investigate the electron transport in red, green, and blue (RGB) core/multi‐shell QD thin films through the analysis of the current density‐voltage ( J–V ) measurements using single‐carrier devices. Our findings reveal that the electron transport in these QD thin films is significantly impeded by the presence of electron traps, which exhibit a Gaussian energy distribution within the bandgap. Notably, the electron trap distributions observed across different QD systems exhibit a high degree of similarity. Specifically, these traps have a concentration of ∼1 × 10 23 m −3 , with the trap center energy level positioned at approximately 4.0 eV below the vacuum level. Furthermore, the width of the energy distribution of the trapping sites is comparable to that of the QD transport sites. By correlating the surface‐to‐volume ratio with the number of traps, we propose that the traps are located at the core‐shell interface and arise from uncoordinated atoms. Therefore, increasing the core size can effectively suppress the trapping effect.
ABSTRACT Programmable metasurfaces enable agile electromagnetic beam shaping, yet the inverse design of dense binary apertures is complicated by feed illumination, local coupling, finite aperture effects, and mode dependent state statistics. A physics informed generative surrogate framework is developed for real time beamforming with full wave validation. The framework integrates a conditional state matrix generator, a parametric aperture physics surrogate with hard routed residual experts, two stage NSGA‐II optimization, and CST verification. The generator achieves 96.67% binary accuracy and a 94.47% F1 score. The best predictor gives a test RMSE of 1.108 dBi, an MAE of 0.549 dBi, and a peak gain MAE of 0.114 dB. Across 137 optimized full wave validation cases, the mean peak gain bias remains close to ‐0.13 dB. For 35 paired real time/final cases, the refined search improves the full wave target region gain by 2.943 dB on average and the peak gain by 0.573 dB, indicating that the surrogate can support practical metasurface beam optimization.
ABSTRACT Memristive Pr 0.7 Ca 0.3 MnO 3 (PCMO) heterostructures exhibit area‐dependent resistive switching via a valence change mechanism, making them promising for neuromorphic architectures. A major challenge in PCMO‐based memory is higher‐dimensional lattice defects that affect oxygen‐vacancy migration and concentration. This study mitigates these defects using highly conductive amorphous PCMO fabricated via a CMOS back‐end‐of‐line‐compatible process and compares it with low‐conductive amorphous and polycrystalline PCMO. The resistance differences are attributed to changes in electronic mobility, based on the analysis of short‐ and long‐range order, Mn–O hybridization, and Mn valence state. AlO x /qa‐PCMO devices showed the highest ON/OFF ratio compared to low‐conductive amorphous and polycrystalline PCMO, because the field‐accelerated oxygen vacancy movement switches the mechanism from Poole–Frenkel emission in the LRS to trap‐assisted tunneling in the HRS. The mechanism change was identified by systematically analyzing the I–V asymmetry, device band diagrams for different PCMO types, and shape changes in the I–V curve fits. The band diagrams were calculated from the measured bandgaps and work functions of the different PCMO types. Analysis of the electric field distribution in the devices showed a clear correlation between the pre‐switching field strength in AlO x and the resulting ON/OFF ratio.
ABSTRACT Memristors exhibiting both volatile and non‐volatile resistive switching (RS) behaviors hold significant potential for their utilization as artificial neurons and synapses in neuromorphic computing systems, respectively. Inkjet printing presents an economical, low‐material‐waste, and compatible process for the fabrication of solution‐based memristors, which are essential for flexible, wearable and biocompatible applications. However, inkjet‐printed memristors typically exhibit low endurance (below 10 4 cycles) and high switching currents (above 100 µA), both of which represent critical limitations for the practical implementation and low‐power operation of neuromorphic computing systems. In this work, a hexagonal boron nitride (h‐BN) based memristor formulated via liquid phase exfoliation (LPE) and fabricated with inkjet printing demonstrates exceptional electrical performance with a remarkable endurance of 2.2 million cycles at very low currents (below 1 µA) in a volatile regime under a current‐driven approach. This result surpasses the highest endurance reported to date on inkjet‐printed‐based memristors, surpassing the threshold of one million cycles. At higher currents (above 10 µA), the same devices exhibit stable non‐volatile RS with an endurance of 70 000 cycles. This study not only demonstrates the remarkable performance of the designed memristors, but also opens new avenues for current‐driven memristive electrical characterization and neuromorphic applications.
ABSTRACT Low‐dimensional perovskite photodetectors attract significant attention due to their tunable optoelectronic properties, quantum confinement effects and solution processability. Among them, phenethylammonium lead bromide (PEA2PbBr4) is more stable than its 3D counterparts. However, degradation under environmental stress remains an obstacle to practical applications, particularly with prolonged exposure to temperature and humidity. This study systematically evaluates the impact of these stressors on the morphology, crystallinity, and optoelectronic performance of PEA2PbBr4 photodetectors. The impact of the halogen‐bonding additive 1,4‐TFIB (1,4‐diiodotetrafluorobenzene) on the stability of the devices is also considered. Here, the devices were subjected to an increase in temperature (20°C–120°C) and humidity (40%RH–98%RH) in five steps, with each condition maintained for two days. Morphological and structural analyses are performed, as well as optoelectronic analyses under UV light and X‐ray irradiation. The results show that, while pristine films undergo significant physical degradation and material loss at elevated temperature and humidity, the incorporation of 1,4‐TFIB significantly enhances material endurance. Although the additive reduces the photocurrent signal of the device under UV and X‐ray irradiation, it mitigates physical loss of the material and maintains structural integrity in harsh conditions, thereby enhancing device longevity in optoelectronic sensing applications.
ABSTRACT X‐ray total ionization dose (TID) significantly modifies synaptic plasticity in SnO‐based volatile memristors, a device class promising for neuromorphic computing in radiation‐exposed environments. We further observe that synaptic operation becomes more stable when training is initiated after a reset, indicating a protocol‐dependent mitigation of variability. Device‐parameterized convolutional neural network simulations indicate that nonlinearity and epoch‐to‐epoch variation both decrease in irradiated devices, leading to higher training accuracy (≈80% after 200 epochs) than pristine counterparts (<50%); confusion‐matrix analysis further highlights nonlinearity as a more critical determinant of performance than raw dynamic range. To interpret this phenomenon, we propose a conduction mechanism that accounts for potentiation, relaxation, and depression dynamics under irradiation. These findings show that radiation‐induced modifications—often considered detrimental—can be harnessed to strengthen key synaptic metrics in volatile memristors. We highlight a design trade‐off in which linearity and stability may be prioritized over raw dynamic range for learning accuracy, and this positions TID‐tuned memristors as candidates for robust neuromorphic hardware operating in extreme environments.
ABSTRACT Advances in soft electronics and soft biorobotics have accelerated progress in advanced biomedical engineering. This new frontier motivates development of next‐generation healthcare technologies focused on minimally invasive robotic surgery and continuous real‐time physiological monitoring through wearable, implantable, and personalized devices. Among different physiological parameters, pressure represents a critical factor, extensively measured using diverse sensing mechanisms such as piezoresistive, capacitive, piezoelectric, optical, triboelectric and other different modalities. The integration of these sensing principles with emerging sustainable materials with advanced fabrication techniques has enabled the creation of flexible, stretchable, and conformable pressure sensors capable of adapting to unconventional surfaces. This literature review comprehensively summarizes up‐to‐date progress in pressure sensing mechanisms, materials, and structural design strategies, highlighting their potential towards developing advanced biomedical applications. Furthermore, it discusses current challenges, and future perspectives for developing high‐performance, biocompatible, and sustainable pressure sensors that will advance healthcare monitoring.
ABSTRACT Zinc oxide (ZnO) nanowires (NWs) are widely investigated for ultraviolet (UV) photodetectors (PDs) due to their wide direct bandgap, high exciton binding energy, and large surface‐to‐volume ratio enabling efficient light–matter interaction and carrier modulation. This review presents a device‐physics‐oriented analysis of recent advances in ZnO NW‐based UV photodetectors, emphasizing the interplay between nanostructure synthesis, interface engineering, and carrier transport mechanisms. Three main device architectures—photoconductive, Schottky barrier, and metal–semiconductor–metal (MSM)—are compared in terms of operating principles, performance trade‐offs, and fundamental limitations. Key enhancement strategies, including doping, surface passivation, plasmonic modification, and hybrid heterostructure integration, are discussed with respect to improvements in responsivity, response speed, and stability. Recent progress in flexible, self‐powered, and multifunctional UV photodetectors is also highlighted. Current challenges, including defect control, interface engineering, reproducibility, and scalable fabrication, are critically assessed. By establishing a unified structure–property–device physics framework, this review provides insights into the fundamental limitations of ZnO NW UV photodetectors and design guidelines for next‐generation optoelectronic devices.
ABSTRACT Memristive devices integrating non‐volatile memory and artificial synaptic functionalities are promising candidates for neuromorphic in‐memory computing. However, stochastic and non‐linear evolution of conductive filaments often hinders stable and gradual synaptic weight updates. Here, we investigate pulse‐protocol optimization in an Au/MoO3/TiO2/FTO bilayer‐oxide memristor to achieve both digital memory operation and analog conductance modulation. The switching characteristics evolve from interface‐driven self‐rectifying behavior prior to electroforming, to filament‐governed non‐volatile bipolar resistive switching. The device exhibits good endurance (25,000 cycles) and retention (1000 s), fast switching, low variability, operational stability up to 60°C, and reliable performance over a testing duration of 70 weeks. Furthermore, the RESET process exhibits quantized conductance features, indicating atomic‐scale constricted conduction pathways across the switching layers. Importantly, the optimized combinational voltage pulse scheme enables gradual and controlled conductance evolution, resulting in highly linear and stable potentiation– depression characteristics. The pulse‐engineered synaptic linearity further enables a significant ∼20% enhancement in artificial neural network inference accuracy for handwritten digit recognition. This work highlights pulse‐protocol control combined with oxide‐bilayer architecture as an effective strategy for developing multifunctional memristors for neuromorphic computing applications.
ABSTRACT To enable compact quantum computing systems, cryogenically compatible CMOS‐based non‐volatile memories are required. In this work, we investigate 1‐transistor–1‐resistor (1T1R) resistive random‐access memory (RRAM) devices over an extended temperature range, including previously unexplored cryogenic regimes. To enhance storage density, we explore a multilevel‐cell approach via multilevel programming. As temperature decreases, the low‐resistance state (LRS) effective conductance increases, improving state separation but also leading to higher LRS currents and increased reset voltages required for reliable switching to the high‐resistance state (HRS), resulting in incomplete filament rupture and a broader HRS distribution. Through independent characterization of the access nMOS transistor, we identify transistor temperature dependence as the dominant factor governing LRS evolution, while extraction of the intrinsic metal–insulator–metal (MIM) behavior reveals an opposite trend, with decreasing conductivity at lower temperatures. Based on these insights, we implement an optimized programming strategy for cryogenic operation by tuning the nMOS gate bias during set, reducing LRS currents, particularly in intermediate and high conductance states, while preserving state separation, narrowing the HRS distribution, and lowering reset voltages. Overall, this work establishes a robust and scalable approach for reliable 1T1R operation at cryogenic temperatures and provides a key step toward nonvolatile memory integration in quantum computing architectures.
ABSTRACT Organic electrochemical transistors (OECTs) require antifouling channel materials to operate stably in biological environments. Here, we demonstrate a simple strategy to introduce antifouling functionality into PEDOT:PSS‐based OECTs using zwitterionic polymers. Homo‐, random‐, and block‐type zwitterionic polymers are synthesized and mixed with PEDOT:PSS via solution processing, enabling the fabrication of blend films without additional steps. Structural and spectroscopic analyses show that the zwitterionic polymers are retained within the films, maintaining the doping state and crystalline structure of PEDOT:PSS. Instead, differences in polymer architecture produce distinct structural features within the preserved core–shell PEDOT:PSS framework, including variations in the apparent shell thickness and, for zwitterionic (co)monomer components, the formation of an outer polymer‐rich region. These structural differences directly influence charge transport. Electrochemical and OECT measurements reveal reductions in volumetric capacitance and transconductance, mainly due to decreased apparent mobility. Protein adsorption studies further show reduced device degradation upon exposure to two proteins: bovine serum albumin and fibronectin. This blending strategy provides a practical route to antifouling, solution‐processable OECT materials for bioelectronic interfaces.
ABSTRACT Indium gallium zinc oxide (IGZO) is a well‐established channel material for thin‐film transistors and has also emerged as a promising active layer for memristor applications. Further, IGZO memristors can exhibit both abrupt and gradual switching behaviors, which offer enhanced adaptability for future memory and neuromorphic computing systems. In this study, we have systematically modulated the surface defect states in IGZO thin films through Ar‐plasma and ultraviolet ozone (UV‐O 3 ) treatments, and investigated their influence on the memristive switching characteristics in a W/IGZO/Pt device architecture. Notably, Ar‐plasma enabled forming‐free abrupt switching behavior, while UV‐O 3 led to a transition to gradual switching. The devices were subjected to 10 3 direct‐current sweep cycles and 10 4 s of retention testing. Especially the Ar‐plasma and untreated reference devices showed stable behavior, while the UV‐O 3 showed initial drifts in both measurements. Additionally, the absolute switching voltages of all samples are ≤1 V. These results demonstrate that the switching behavior of IGZO‐based memristors can be effectively tuned through simple surface treatments while maintaining reliable device performance, underscoring the strong potential of IGZO as a versatile material for next‐generation memristor technologies.
ABSTRACT Achieving stable, ultrafast current‐induced domain wall motion (CIDWM) is essential for practical racetrack memory devices. Here, anisotropy‐engineering at the edges of Pt/GdFe ferrimagnetic nanowires with composition near magnetic compensation is investigated through experimental laser‐annealing (LA) treatments and Landau–Lifshitz–Gilbert (LLG)‐based micromagnetic simulations. CIDWM measurements show that LA enhances DW velocity and stabilizes propagation over a wide current‐density range. The velocity reaches approximately 3200 m s −1 and remains relatively stable at high current densities, indicating a stable high‐speed propagation regime. Kerr microscopy further reveals that LA transforms curved and distorted DW profiles into straighter, more uniform configurations. Simulations varying the local perpendicular magnetic anisotropy (K u ) and annealed‐edge width clarify the underlying mechanism. Moderate edge‐anisotropy reduction suppresses pinning, stabilizes the DW configuration, and enables coherent spin–orbit‐torque‐driven propagation. In contrast, excessive anisotropy reduction or excessively wide annealed regions induce multidomain instability and deteriorate DW motion. The simulated dynamics reproduce the experimentally observed velocity saturation and stable propagation behavior. LA‐defined channels further suggest a scalable multi‐lane architecture in which N laser traces can define up to N+1 DW transport paths within a single wire. These findings establish LA as an effective anisotropy‐engineering technique and provide a quantitative design framework for racetrack memory and reconfigurable spintronic devices.
ABSTRACT Self‐powered perovskite photodiodes are promising candidates for low‐power optical sensing, yet their stability under particle irradiation remains insufficiently understood. In this work, we investigate the influence of 0.5 MeV proton irradiation on fully printed carbon‐electrode perovskite photodetectors. The devices were exposed to irradiation fluences of 10 13 , 10 14 , and 10 15 protons cm −2 and systematically characterized through structural, optical, chemical, and electrical measurements. Structural characterization shows that the main perovskite phase is preserved after irradiation, while weak additional diffraction features and XPS binding‐energy shifts indicate defect formation and modifications in the local Pb–halide coordination environment. Optical measurements reveal photoluminescence quenching and shorter carrier lifetimes, confirming enhanced non‐radiative recombination. Under self‐powered (0 V) operation, a reference device exhibits a photocurrent of 7.8 mA cm −2 under 100 mW cm −2 illumination with a maximum responsivity of 0.31 A W −1 and detectivity on the order of 10 10 Jones. After irradiation at 10 15 protons cm −2 , the photocurrent and responsivity decrease to 3.3 mA cm −2 and 0.19 A W −1 , respectively. Although proton irradiation significantly reduces the photovoltaic and photodetection performance, the photodiodes remain functional and maintain a stable photoresponse, indicating that irradiation primarily increases non‐radiative recombination rather than causing complete loss of device operation.
ABSTRACT The growing demand for flexible electronics has paralleled increasing attention to sustainability and eco‐friendly device fabrication. Laser‐induced graphene (LIG), which can be directly generated from natural carbon sources, offers a cost‐effective and environmentally responsible approach to next‐generation electronics. In this work, we demonstrate the direct laser writing of LIG on cellulose filter paper under ambient conditions, producing a flexible and patterned sensing substrate. To enhance optoelectronic performance, LIG was further integrated with the highly light‐absorbing MAPbI 3 perovskite via a simple solution deposition method. Photodetectors based on pure LIG and hybrid LIG/MAPbI 3 structures were fabricated and systematically compared. The hybrid devices exhibited a nearly tenfold improvement in responsivity (13.9 to 136.9 mA/W) and a sevenfold increase in detectivity (7.67 × 10 7 to 5.33 × 10 8 Jones) over pure LIG devices, while retaining excellent stability after 1000 bending cycles. These results highlight paper‐based LIG/perovskite photodetectors as promising candidates for sustainable optoelectronic applications.
ABSTRACT III‐V materials exhibit superior optoelectronic properties compared to conventional semiconductors, making them ideal for short‐wavelength infrared (SWIR) photodetectors. These devices are in demand for applications such as telecommunications, LiDAR, and biomedical engineering around 1100 nm wavelength, which is safer for humane eyes, minimally absorbed by the atmosphere, and resistant to ambient light interference. Despite this, semiconductor‐based solutions in this range remain limited. Here, we present a strain‐compensated InGaAs/GaAsP superlattice grown by metal‐organic vapor phase epitaxy on a 100 mm GaAs substrate. High‐quality epitaxy is confirmed by Transmission Electron Microscopy, surface morphology is analyzed by Atomic Force Microscopy, structural properties are characterized using X‐Ray Diffraction, and optical characteristics are assessed via photoluminescence and absorbance. At −1 V bias, the device exhibits a low dark current density of 2.3 × 10 −7 A/cm 2 at room temperature and a high detectivity of 1.9 × 10 11 Jones under 1100 nm excitation, with an external quantum efficiency (EQE) close to expectations. The structural and optoelectronic results demonstrate the potential for producing very thin photodetectors compared to those currently on the market with performances that can be further improved by integrating these photodetectors into resonant cavities.
ABSTRACT Organic phototransistors (OPTs) are promising as low‐cost detectors compatible with plastic‐substrate electronics for visible light communication (VLC) systems. However, enhancing their sensitivity without sacrificing speed remains challenging. In this work, we report on an OPT based on dinaphtho[2,3‐b:2′,3′‐f]thieno[3,2‐b]thiophene (DNTT) optimized for detecting blue light. The device employs an Al/Al 2 O 3 /DNTT/Au layered structure fabricated at ≤100°C on a PEN substrate by shadow‐mask patterning. Key performance metrics include stable low‐voltage transistor operation, a field‐effect mobility in the range 0.16–0.24 cm 2 V −1 s −1 , and a low contact resistance (≈12 kΩ·cm). Under low‐intensity illumination (≈10 − 8 W cm −2 ) the phototransistor achieves an exceptional responsivity of ≈ 250 A/W and a specific detectivity on the order of 10 1 2 Jones, indicating competitive weak‐light sensing capability. Even at higher light levels (≈10 − 3 W cm −2 ), it maintains a large photosensitivity up to ≈120. High‐frequency tests demonstrate fast and detectable response up to 150 kHz. The device thus offers a rare combination of high sensitivity and fast response. These results represent a substantial advancement for organic optoelectronics, suggesting that the proposed OPT design is a promising candidate for future high‐speed VLC and other applications requiring lightweight, high‐performance photodetectors in the visible range.
