Journal of Materials Science: Materials in Electronics最新文献

The inherent vulnerability of ambient-processed CsFAMAPbX₃ perovskite solar cells to humidity has long presented a significant challenge. Incorporating lithium bis(trifluoromethanesulfonyl)imide (Li-TFSI) into the CsFAMAPbX₃ perovskite lattice markedly improves its processability under ambient conditions with up to 60% relative humidity. Investigation reveals that Li-TFSI facilitates improved bulk structure, morphology, and optoelectronic properties in the resulting perovskite film. Specifically, Li-TFSI dissociation into Li⁺ and TFSI⁻ ions enhances crystallinity and grain size, leading to faceted grains with a smoother surface topology conducive to interfacial coupling and charge transfer. This passivation effect enables perovskite solar cell fabrication under ambient conditions. Furthermore, Li-TFSI doping reduces the optical band edge, expanding spectral response, and mitigates defect density, all critical factors for ambient processing. Resulting Li-TFSI-doped CsFAMAPbX₃ perovskite solar cells (0.1 cm² active area) exhibit power conversion efficiencies reaching 21.24%, with a short-circuit current density of 25.2 mA/cm², an open-circuit voltage of 1.11 V, and a fill factor of 75.68%. This represents a 22.3% improvement over pristine devices, which attain maximum efficiencies of approximately 17.37% with corresponding parameters of 23.1 mA/cm², 1.09 V, and 69.09%, respectively. The champion device maintained 91.8% of its original efficiency following 27 days of storage in an N₂ atmosphere. The integration of Li-TFSI demonstrates substantial promise for ambient-processed CsFAMAPbX₃ perovskite solar cells.

Facile, fast and high yield synthesis of silver nanowires (Ag NWs) have always been difficult due to lack of optimized control over affecting parameters. Solution-based polyol synthetic routes have enabled Ag NWs with unique and novel properties to provide a base for a wide range of applications. Ag NWs are indispensable for flexible electronics but achieving fast high yield synthesis with single crystalline and high purity remains a challenge. Here, we report a novel, scalable solution-phase method that produces Ag NWs with (>) 90% yield, single-crystalline structure, and ultrahigh purity (no detectable oxides or impurities) with fast synthetic process. By optimizing a dual-reductant system (ascorbic acid/citric acid) ratio in a mixed solvent (ethylene glycol/water) with precise control of silver nitrate (AgNO₃) concentration (0.03 M) and PVP (0.09 M, MW: 360 k), we achieve high yield uniform NWs with mean diameter (μ) = 64.4 ± 16.2 nm (nm) with single crystalline nature. Finally, the potential applications of as-synthesized Ag NWs are demonstrated by successfully preparing Ag-based conductive ink. The conductive material exhibits resistivity of 11.7 µΩ cm equals 7.4 times the resistivity of bulk Ag. Flexibility and stability of the prepared Ag conductive material were determined by tensile-bending testing system and placing the Ag conductive material in air, respectively. It indicates that the prepared Ag conductive material has the potential to be used in flexible electronics and wearable equipment.

This study illustrates the pivotal importance of substrate selection in enhancing the structural, and optical characteristics of photodetector devices. V₂O₅/PANI composites were synthesized by a 6-h hydrothermal process at 180°C and subsequently coated onto two distinct substrates, silicon and FTO, utilizing a sputter coating approach. X-ray diffraction (XRD) studies revealed that the active layer placed on silicon exhibited distinct peaks of the orthorhombic V₂O₅ phase, but crystallinity was less evident on FTO, with the predominant PANI phase. FESEM and AFM investigations demonstrated a more homogenous and uniform surface on silicon, exhibiting reduced surface imperfections. Photoluminescence experiments indicated enhanced and more uniform emission within the silicon samples’ 450–650 nm spectrum, signifying superior charge transfer efficiency. At the photodetector performance level, I–V tests indicated that the films formed on silicon had markedly enhanced performance, with a photocurrent of (I_{F (+5)} Light = 3113µA) versus a dark current (I_{F (-5)} dark = 1689 µA), with a better on/off ratio (0.26 /0.19 s). They documented a photoresponsivity of 0.27 A/W, a photodetectivity of 1.26 × 10²⁰ Jones, and an external quantum efficiency (EQE) of 109%. The results demonstrate that employing a silicon substrate boosts the quality of the composite nanofilm and optimizes the separation and transport dynamics of photocarriers, hence benefiting the performance of the V₂O₅/PANI hybrid photodetector. The research underscores the significance of substrate selection as a pivotal factor in enhancing the structural, optical, and electrical characteristics of performance photodetector devices.

Wearable supercapacitors (SCs), commonly known as smart SCs, have garnered much attention for wearable and Internet of Things (IoT) devices, including smartwatches, sensors, and health monitoring patches. In this direction, the developments of low-cost, flexible, and lightweight electrodes for SCs are highly demanded. Here, an efficient wearable supercapacitor based on copper oxide nanostructures on carbon cloth (CuO Ns/CC) was fabricated by a cost-effective, binder-free, additive-free and simple method of electrodepostion. The CuO Ns/CC electrode exhibits a high specific capacity of 326.6 C/g at 2 A/g and excellent cyclic stability (capacitance retention ~ 97.8%) after 10,000 charge–discharge cycles. Kinetic processes involved in the energy storage mechanism are well discussed. In addition, a solid-state symmetric SC with CuO Ns/CC electrodes has been fabricated, which shows a high energy density of 142.9 Wh/kg at a power density of 18,999.3 W/kg and good cyclic stability. The device performance is retained even after bending the device by 180°, showing the superior flexibility of the SC. The present study is promising for the fabrication of inexpensive, binder-free, and efficient electrodes for smart SCs.

Position-sensitive photodetectors (PSDs) are crucial in applications such as target tracking, machine vision, and other fields that require precise spatial measurement. Conventional PSDs often face challenges in balancing long operating distances with high sensitivity. In this study, a self-powered, high-performance PSD with an extended operational range is developed. This enhancement was achieved by growing a PbZr_0.3Ti_0.7O₃ (PZT) film with strong polarization properties on a p-GaN substrate, utilizing the residual polarization field to modulate the Lateral Photovoltaic Effect (LPE) at the TiO₂/PZT/p-GaN heterojunction. The PSD demonstrates excellent photoresponse and sensitivity under ultraviolet (UV) illumination (365 nm). In the absence of an external electric field, a position sensitivity of 204 mV/mm is achieved when the PZT layer is transversely polarized at − 100 V. This represents a 128% increase compared to the device with the unpolarized PZT layer. This study presents an effective and straightforward approach for developing highly sensitive PSDs with extended working distances.

Memristors have attracted a great deal of attention due to their potential for storage and computation. In this paper, we designed an Au/Al:HfO₂/ZnO/Al:HfO₂/FTO three-layer structure of the memristor. We doped the HfO₂ film was doped with different concentrations of Al elements to explore its resistive switching (RS) performance and photocatalytic synaptic properties. The experimental results showed that the device displayed a reliable switching ratio (~ 10²) under 100 consecutive cycles when the Al doping concentration is 10%. We further analyzed the conduction mechanism governing the device’s high-resistance state (HRS) and low-resistance states (LRS) under varying voltages. The device demonstrated similar resistive switching behavior across the scanning voltages, suggesting its ability to mimic the enhancing and inhibiting behaviors of biological synapses. Additionally, we explored the optoelectronic synaptic properties of the 10% Al:HfO₂/ZnO/10% Al:HfO₂ triple-structured memristor, successfully simulating the plasticity of biological neuronal synapses. Finally, we trained a convolutional neural network on the MNIST and Fashion_MNIST datasets, achieving recognition rates of 95.4% and 84.5%, respectively. These findings provide a unique opportunity for future advances in non-transitory memory and in neuromorphic computing.

Fuel and energy sources are crucial for the advancement of humanity and switching to renewable energy sources from non-renewable sources has become an urgent necessity. Among the various known sustainable resources such as wind, small-hydro and geothermal solar energy has emerged as the most promising energy resource, with its efficiency largely determined by the choice of materials. In recent years, lead-free double perovskite (DPs) materials, A₂BB′X₆ where ‘A’ is alkali metal, ‘B’ and ‘B′’ are transition or post-transition metals, and ‘X’ are oxides or halides, have gained significant attention as these perovskites demonstrate good environmental stability, eco-friendly nature, and are non-toxic nature and potential for diverse applications in energy storage, optoelectronic, and thermoelectric. In this review, we have systematically explored the structural, optoelectronic and thermoelectric properties of oxide and halide DPs with particular emphasis on their potential in photovoltaic applications. We have examined the role of these DPs in improving the stability of perovskite solar cells (PSCs), the design of single-junction structures and the cohesive strategies to broaden solar spectrum utilization. We have also highlighted the recent progress in computational and experimental approaches, and provides future directions for designing high-performance lead-free double perovskites. This review also provide a critical analysis on the challenges and limitations of perovskite materials, including bandgap tunability, stability–efficiency trade-offs, and intrinsic material constraints. The article identifies emerging strategies and knowledge gaps that could accelerate the advancement of lead-free double perovskites for eco-friendly energy conversion technologies.

Although CoFe alloy microstructures have been widely studied for their tunable magnetic properties in applications ranging from microwave devices to biomedicine and environmental remediation, their precise magnetic behavior has not been fully elucidated so far. Here, a chemical reduction method is utilized to synthesize CoFe alloy microparticles (MPs) with variable compositions (Co_10-xFe_x, 0 ≤ x ≤ 7), followed by characterizing them using different techniques. Magnetic measurements are performed in detail by hysteresis curve and first-order reversal curve (FORC) methods. Hysteresis curves show a continuous increasing trend of saturation magnetization of Co_10-xFe_x MPs from about 72 to 173 emu/g with increasing x from 0 to 7, and a non-monotonic variation of coercivity with maximum and minimum values of 202 and 92 Oe for x = 1 and 7, respectively. Meanwhile, FORC diagrams manifest multidomain behavior of the MPs with a narrow distribution of coercive fields, which is accompanied with enhanced magnetostatic interactions for high Fe contents (x ≥ 3). Microwave absorption properties of Co₃Fe₇ alloy MPs are optimized by varying their thickness in the range of 1.4–3.0 mm, resulting in a minimum reflection loss of about –50 dB at 11.7 GHz.

This study investigated the structural and optical characteristics of tin dioxide/tin sulfide (SnO₂/SnS) nano-heterojunction thin films fabricated by spray pyrolysis at 400 °C. X-ray diffraction (XRD) confirmed the coexistence of tetragonal SnO₂ and orthorhombic SnS phases, with the crystallite size decreasing from 23.6 nm (SnS) to 16.1 nm for the heterojunction film. Field emission scanning electron microscopy (FESEM) images revealed a morphological transition from compact nano-grains in pure SnS to vertically aligned rod-like structures in the SnO₂/SnS films, with feature sizes ranging from 30 to 270 nm. In terms of optical properties, measurements show an increase in absorbance across the UV–Vis range for the heterojunction film, as well as an increase in the optical energy bandgap from 2.1 eV (SnS) to 2.2 eV (SnO₂/SnS), attributed to the contribution of the wide-bandgap SnO₂ layer. The formation of the p–n heterojunction enhanced charge separation across the junction, representing an advanced strategy for enhancing gas-sensing performance. As a result, the SnO₂/SnS sensor demonstrated a notable improvement in gas response of 2.2 to 20 ppm H₂S at 150 °C, about 62% higher than pure SnS (1.36), with faster response (20 s) and recovery (26 s) times. The gas response further increased sharply with gas concentration, reaching 2.9 at 40 ppm of H₂S for the SnO₂/SnS sample. These results demonstrate the effectiveness of SnO₂/SnS heterostructures in developing the performance of low-cost gas sensors for environmental monitoring applications.

In this work, SnO₂ thin film was deposited on p-Si wafer substrates using the Hot Wall-Nebulizer Spray Pyrolysis technique with various precursor concentrations (PCs) of 0.015 M, 0.02 M, 0.025 M, and 0.05 M to form SnO₂/p-Si heterojunctions. The deposited SnO₂ matrix was characterized by XRD, FESEM and the Hall effect measurements to analyse their structural, morphological, and electrical properties, respectively. Different PCs resulted in modifications to the surface morphology and electrical characteristics of the films. The photoelectrical properties were investigated based on two distinct sections; various PCs and different electrode geometries (EGs), designated as ET-I, ET-II, and ET-III to fabricate Photodetectors (PDs). Silver contacts were placed in the configuration of Ag/SnO₂/p-Si/Ag. The study was conducted under 365 nm UV LED illumination at a power density of 0.2 mW/cm². Among all the EGs, the PD device of ET-III exhibited the excellent sensing capability. The fabricate PDs were analyzed through current–voltage (I-V) characteristics, light intensity versus photocurrent, and time-dependent transient photoresponse measurement. The ET-III device, fabricated using 0.05 M PC, demonstrated excellent performance: a sensitivity (R_λ) of 1750.1 mA/W, external quantum efficiency (EQE) of 598%, detectivity (D) of 4.0437 × 10¹¹ Jones, and sensitivity (k) of 2263. Furthermore, all devices operated without an external power source (self-powered mode), making them ideal candidates for the development of efficient, low-power optoelectronic devices.