Lead-free Cs2AgBiBr6 double perovskites are stable compared to other perovskites, but have a wide indirect bandgap, resulting in a low absorption coefficient and consequently a low short-circuit current density (J(sc)). In this study, we computationally designed metallic semi-hierarchical nanostructures (SHNs) and incorporated them into environmentally friendly, lead-free Cs2AgBiBr6 double perovskite solar cells to achieve ultra-high optical absorptance. The effects of SHNs on photovoltaic performance were systematically investigated through numerical simulations, considering both intrinsic material properties and structural dimensions. SHN materials were selected based on their interfacial reflectance with Cs2AgBiBr6 and subsequently categorized into two distinct groups. Group 1, represented by Ti and Al, did not exhibit total internal reflection (TIR) in the long-wavelength region; instead, a portion of the incident light was transmitted into the SHNs bulk. This spectral behavior allows these materials to absorb incident light that is otherwise unabsorbed by Cs2AgBiBr6, owing to its inherently deep absorption depth (DAD) at longer wavelengths. Conversely, Group 2, comprising materials such as Au and Ag, demonstrated TIR in the long-wavelength region, enhancing light trapping and absorption within the Cs2AgBiBr6 rather than within the SHNs. Among the investigated materials, Ti (Group 1) exhibited the highest optical absorptance, maintaining a stable value of approximately 90 % over the full solar spectrum and increasing the J(sc) from 15.02 mA/cm(2) (without SHNs) to 29.26 mA/cm(2). Overall, this study demonstrates that leveraging the structural advantages of SHNs and strategically selecting SHN materials can effectively overcome the DAD of Cs2AgBiBr6 and significantly enhance the light-harvesting performance.

Carbazole-based self-assembled monolayers (SAMs) have emerged as promising interfacial materials for inverted (p–i–n) perovskite solar cells owing to their simple synthesis, strong binding affinity toward metal oxides, and potential to enhance charge extraction at the interface. In this work, we systematically investigated the phosphonic-acid-based carbazole SAM MeO-4PACz deposited on FTO and NiO in inverted, ambient air-processed MAPbI3 perovskite solar cells. This work focuses on elucidating the interfacial role of MeO-4PACz which remains less explored in the literature, particularly under ambient air processing conditions. We elucidate the influence of this SAM on NiO and FTO surface chemistry, energy level alignment, carrier extraction dynamics at the HTL/perovskite interface and its effect on the optoelectronic properties of PSCs. Our results reveal that the incorporation of NiO beneath the MeO-4PACz layer reinforces interfacial coordination bonding, leading to improved perovskite crystallization and enlarged grain size and enhanced film quality. Furthermore, MeO-4PACz SAM anchoring induces a beneficial shift in the electrode work function improving energy level alignment, which reduces interfacial trap-assisted recombination at the interface and within the perovskite bulk. The combined NiO/SAM interfacial engineering is therefore shown to be the key factor governing both film growth and charge extraction mechanisms Consequently, the optimized FTO/NiO/MeO-4PACz device achieves a champion power conversion efficiency of 15.16% making a bond of 66.6% relative to non-treated samples (9.1%). This dramatic enhancement of power conversion efficiency results from improved open-circuit voltage, increased fill factor, and reduced hysteresis.

Junctionless (JL) thin-film transistors (TFTs) are promising candidates for low-cost, large-area electronic devices, but improvements in mobility and bias stability are still required. In this study, the effects of independent annealing of the indium oxide (InOx) channel layer and the aluminum oxide (AlOx) capping layer (CL) on the performance and reliability of InOx/AlOx heterostructure JL TFTs are examined. Devices were fabricated via solution deposition and photopatterning, and the InOx and AlOx layers were annealed at 250 °C and 400 °C. Increasing the annealing temperature from 250 °C to 400 °C, the InOx layer crystallized and densified. The AlOx layer remained amorphous at both temperatures, but its metal-hydroxyl content decreased with higher annealing. For both layers, JL TFTs annealed at 400 °C exhibited the best electrical performance (threshold voltage = 1.82 ± 0.40 V, subthreshold swing = 0.50 ± 0.07 V dec−1, saturation mobility = 1.57 ± 0.37 cm2 V−1 s−1). The threshold voltage shift under positive bias stress was 1.70 V, which demonstrates excellent bias stability. These results show that simultaneous high-temperature annealing of the channel and CL is essential to reduce trap-assisted scattering and stabilize electrostatics in JL TFTs, providing practical process guidelines for bias-stable and high-performance oxide electronics.

Self-assembled monolayers (SAMs) provide a powerful method for modifying the interfacial properties of thin-film architectures in perovskite solar cells (PSCs). This study explores the impact of amino-terminated SAMs on the structural and electronic properties of hybrid perovskite films and the overall performance of PSCs. Specifically, COOH-Sp-Y molecules were designed with carboxyl anchor groups for strong attachment to TiO2 substrates, while varying spacers (Sp = -(CH2)n-PP-(CH2)m, P = phenyl) enable precise molecular organization. The terminal NH2/NH3+ groups improve compatibility with the perovskite layer, enhancing film morphology, apparent filling levels, and photovoltaic performance. A systematic comparison is conducted to evaluate the influence of different SAM spacers on MAPbI₃ and mixed-cation perovskites. Characterization by X-ray photoelectron spectroscopy (XPS) and scanning electron microscopy (SEM-EDX) reveals significant enhancements in the quality of SAM-treated films, leading to higher power conversion efficiencies and improved device stability. This work demonstrates the potential of interface engineering using SAMs to optimize the performance and durability of perovskite solar cells.

This study investigates the optimization of (2-(3,6-dimethoxy-9H-carbazol-9-yl)ethyl)phosphonic acid (MeO-2PACz) ultrathin self-assembled monolayers (SAMs) on indium tin oxide (ITO) substrates, which serve as templates for the controlled growth of methylammonium lead iodide perovskite films. The influence of solvent composition and deposition method on the structural properties of the SAM and its effect on the perovskite morphology are investigated by using polarization modulation infrared reflection absorption spectroscopy and X-ray photoelectron spectroscopy. Our results show that the addition of 2% toluene to an ethanol solution during spin coating results in a denser, more organized SAM, with molecules exhibiting a 40 degrees tilt angle relative to the surface normal. This indicates improved molecular packing compared with SAMs deposited in pure ethanol. Our analysis indicates that the SAM chemically binds to ITO primarily through PO3 2- groups in the presence of toluene, whereas -PO2OH- contributes when ethanol is used alone. The optimized SAM was shown to significantly enhance perovskite crystal growth, producing larger, more homogeneously distributed crystals (similar to 400 nm) compared to smaller, less ordered crystals grown on less optimized layers. These results highlight the critical role of SAM structure and deposition conditions in controlling perovskite film quality and provide insights for improving the performance of hybrid perovskite devices.

As the push to enhance power conversion efficiency (PCE) in solar cells intensifies, tandem configurations that integrate photovoltaic devices with complementary bandgaps have become essential. Perovskite materials are particularly advantageous in these tandem solar cells due to their adjustable bandgaps (ranging from 1.2 to 2.2 eV), superior light absorption, remarkable structural stability, and efficient charge-carrier mobility. Lead-free perovskites offer the benefits of traditional perovskites while also being nontoxic and stable; thus, they are ideal candidates for tandem solar cells. However, the optical loss associated with light reflection from the upper surface of the cell degrades device performance, thus reducing the PCE of solar cells; therefore, continuous research efforts are needed to address this drawback. In this study, we coated a lead-free all-perovskite tandem solar cell with a parabolic zinc oxide (ZnO) moth-eye antireflection (AR) layer and assessed its efficiency in suppressing reflection using the two-dimensional finite-difference time-domain method. We analyzed the maximum short-circuit current density (Jsc,max) of the lead-free all-perovskite tandem solar cell by varying the height (H) of the ZnO moth-eye AR layer. Notably, for H = 300 nm, Jsc,max was about 30.5 mA/cm2, which indicated that 300 nm was the optimal height for performance improvement. Moreover, we generated a profile for the light-trapping phenomenon that occurs within an actual cell by simulating the electromagnetic mechanism governing the generation rate and proportion of absorbed photons. This profile enabled us to characterize the light-trapping phenomenon within the tandem solar cell induced by the ZnO moth-eye AR layer.

Biosensors have emerged as vital tools for the detection and monitoring of essential biological information. However, their efficiency is often constrained by limitations in the power supply. To address this challenge, energy harvesting systems have gained prominence. These off-grid, independent systems harness energy from the surrounding environment, providing a sustainable solution for powering biosensors autonomously. This continuous power source overcomes critical constraints, ensuring uninterrupted operation and seamless data collection. In this article, a comprehensive review of recent literature on energy harvesting-based biosensors is presented. Various techniques and technologies are critically examined, including optical, mechanical, thermal, and wireless power transfer, focusing on their applications and optimization. Furthermore, the immense potential of these energy harvesting-driven biosensors is highlighted across diverse fields, such as medicine, environmental surveillance, and biosignal analysis. By exploring the integration of energy harvesting systems, this review underscores their pivotal role in advancing biosensor technology. These innovations promise improved efficiency, reduced environmental impact, and broader applicability, marking significant progress in the field of biosensors. Energy harvesting systems represent a game-changing innovation in biosensor powering, providing long-term, off-grid options for continuous, autonomous operation. This study examines diverse harvesting techniques-optical, mechanical, thermal, and wireless-and emphasizes their vital role in improving biosensor efficiency and application. These breakthroughs have the potential to change industries such as medicine, environmental surveillance, and biosignal analysis, demonstrating considerable progress in decreasing environmental impact and increasing the reach of biosensor technology. image

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This review elucidates the potential of Organic Thin Film Transistors (OTFTs) for biocompatible synaptic devices in in-vivo medical applications. Emphasizing attributes like flexibility and reduced environmental footprint, OTFTs are distinguished from traditional silicon counterparts. The synthesis of electronic capabilities and biological emulation in synaptic transistors is dissected, spotlighting their role in neuromorphic computing. This exploration centers on biocompatibility, detailing criteria, challenges, and the integration of organic electronics with living systems. Furthermore, potential applications, innovations, and future prospects of OTFT-driven synaptic devices are addressed. Critical technical, ethical, and societal challenges within this interdisciplinary nexus are outlined. The confluence of OTFTs, synaptic transistors, and biocompatibility heralds a paradigm shift in techno-biological convergence.

We investigate the combination of nitrogen doping and vacancies in highly ordered pyrolytic graphite (HOPG), to engineer defect sites with adjustable electronic properties. We combine scanning tunneling microscopy and spectroscopy and density functional theory calculations to reveal the synergistic effects of nitrogen and vacancies in HOPG. Our findings reveal a remarkable shift of the vacancy-induced resonance peak from an unoccupied state in pristine HOPG to an occupied state in nitrogen-doped HOPG. This shift directly correlates with the shift of the charge neutrality point resulting from the n-doping induced by substitutional nitrogen. These results open new avenues for defect engineering in graphite or graphene and achieving novel functionalities for chemical activity or electronic properties.

The treatment of water-soluble PEDOT:PSS copolymer film by DMSO or DMF considerably enhances its electrical conductivity. The mechanism leading to a new molecular conformation in the PEDOT:PSS layer was investigated by in situ ATR, PM-IRRAS and XPS spectroscopies. The release of PSS chains containing excess [Na+, (-phi-SO3-)-] and (-phi-SO3H)-] moieties by the solvent treatment and the implications of this process are discussed. By comparison with a NaPSS/HPSS adduct, the essential role of the conformational reorganization of the poly(styrene sulfonic/sulfonate) chains via hydrogen bonds between -SO3H functions is demonstrated. Residual water molecules play a fundamental role both in the removal of excess sulfonates or sulfonic groups, the separation of the (Na, H, PSS) chains, which can then be extracted, and the establishment of the suitable PEDOT conformation.

Self-assembled monolayers (SAMs) have been grafted via a carboxylic acid group onto a ZnO electron transport layer to control the growth and structure of a hybrid perovskite CH3NH3PbI3 (MAPI) used as an active layer in a solar cell. In addition to the basic molecule, HO2C-PP-NH2 (PP = biphenyl), two bipolar molecules, HO2C-(CH2)(n)-PP-CH2-NH3Cl (A: n = 0), 4'-(carboxy)-(1,1'-biphenyl)-4-aminomethyl hydrochloride and B: (n = 1), 4'-(carboxymethyl)-(1,1'-biphenyl)-4-aminomethyl hydrochloride, are used in this work. They have been tailored to ensure (i) rigidity/self-assembly and conductivity via biphenyl and (ii) some flexibility via the methylene groups to ensure bonding to both the solid ZnO layer and the methylammonium lead iodide (MAPI) layer. The protonated amino group was chosen to create an efficient 2D sublayer for the growth of the methylammonium-3asa. perovskite. The deposition of SAMs on the metal oxide layers improves device stability and the efficiency of perovskite solar cells (PCSs). The long-term stability of PSCs in ambient air is enhanced by the SAMs.

WO3 nanostructures have been synthesized on Au(111) through the solution-processing method. Three types of structures have been obtained: reticulated polymeric structures, two dimensional WO3 (111), and three-dimensional islands. Their electronic properties have been probed by scanning tunneling spectroscopy. The reticulated structure has a featureless spectrum. WO3 (111) shows n-type semiconducting properties with resonances corresponding to surface states arising from W 5d states. These oxide nanostructures efficiently decouple the electronic states of molecular adsorbates from the metal substrate.

Top-gate amorphous indium gallium zinc oxide (IGZO) thin-film transistors (TFTs) are designed with numerical analysis to control their electron potential energy. Design simulations show the effects of structural design on the electrical characteristics of these TFTs. In particular, the thicknesses of the channel (tch) and conducting (tc) layers, which play vital roles in TFT electrical performance, are varied from 1 to 50 nm to investigate the effect of thicknesses on the electron potential energies of the channel region and the electrode-semiconductor interfaces. The potential energies are precisely optimized for efficient charge transport, injection, and extraction, thus enhancing the electrical performance of these devices. It is also demonstrated that tch mainly affects mobility and threshold voltage, while tc mainly affects on-current. An acceptable threshold voltage of 0.55 V and high mobility of 14.7 cm²V-1s-1 are obtained with a tch of 30 nm and tc of 10 nm. Controllability of the electron potential energies and electrical performance of IGZO TFTs by means of structural design will contribute to realization of next-generation displays that have large areas and high resolutions.

The surface of a copper (Cu) electrode is modified by the combination of preliminary oxidative treatment and grafting of a bifunctional self-assembled monolayer based on fluorobiphenylthiol (FBPS) or biphenylthiol (BPS). In these conditions, a dinaphtho [2, 3-b: 2 ',3 '-f] thieno [3,2-b] thiophene (DNTT)-based diode exhibits high mobility (0.35 cm2.V- 1.s 1) due to the formation of organized assembly of FBPS on the oxide Cu that has been partially reduced in Cu2O; this organization controls that of the semiconductor film. On the other hand, the same treatment of Cu electrode with BPS molecules does not function, due to the disorganization of both the BPS SAM and the DNTT film. These results suggest that a monolayer of dipolar-oriented molecules lowers the injection barrier; steers the semiconductor organization and thereby enhances the performance of the derived electronic component.

Control of film's properties is the most important for providing of customized electronic devices. In particular, when the nanocomposite networks are applied to the films for needs of various applications, the quality of film is considered as one of the most potent factors. Here, we propose a viable and facile method of controlling the silver nanowire (Ag NW)-elastomer nanocomposite networks through elaborate direct printing for implementing sandwich-structured ultrathin and stretchable strain sensors. According to the different Ag NW network densities controlled by various blade coating parameters, surface morphological characteristics, optical transmittance, and current-voltage performance were investigated. In order to exhibit the importance of network density control to electronic devices, we fabricated two stretchable strain sensors with different sensitivities (Delta R/R-0: 6.31, 0.70 at 10% strain) using low density (LD) and high density (HD) Ag NWs networks for detecting small and large movements, respectively. Under repeated stretching fatigue tests (1000 cycles), LD and HD Ag NW sensors show stable sensing operation with electromechanical durability and frequency-responsive features. A simple application for wrist motion detection with a fast response speed and stable operation is demonstrated. These results provide a new route towards next-generation skin electronics.

We describe how the off-state current (I-off) property of amorphous InGaZnO (a-IGZO) thin-film transistors is caused by trap-assisted tunneling (TAT) by using a two-dimensional device simulation software application (Atlas 2 D, Silvaco). We found thatI(off)can be increased by controlling the bandgap energy (E-G) and the effective mass of electron (m(e)) of a-IGZO transistors. Whenm(e)was increased from 0.32 to 0.38 m(o)(mass of a free electron), the point at whichI(off)started to increase in the region of negative gate voltage (V-GS) shifted from -4.7 to -7.4 V. In addition, whenE(G)was changed from 3.05 to 3.2 eV, the average value ofI(off)changed from 3.13 x 10(-13)to 2.4 x 10(-14)A. This implies thatE(G)andm(e)influence the increase inI(off)in a-IGZO TFTs because of the difficulty associated with TAT.

We fabricate high-performance solution-processed SnO2 thin-film transistors (TFTs) exhibiting improved carrier transport features by exposing the ultraviolet/ozone (UV/O3) on the SnO2 film during the pre-annealing stage. The SnO2 layer is treated with different UV/O3-exposure times from 0 to 60 minutes before the post-annealing step. As UV/O3-exposure time increases from 0 to 30 minutes, the M-O-M (M, metal; and O, oxygen) network, mass density, and oxygen vacancies of films are enhanced. In contrast, the M-O-M network and mass density decrease, while the oxygen vacancies rather increase when the UV/O3-exposure time reaches 60 minutes beyond 30 minutes. The SnO2 (Sn4+) phase, thickness, and surface morphology of SnO2 films are not considerably changed regardless of UV/O3-exposure time. When the UV/O3-exposure time is 30 minutes, devices demonstrate superior field-effect mobility (10.1 cm2 V−1 s−1) at approximately two times higher than the TFT without UV/O3-exposure. Furthermore, the SnO2 TFT with UV/O3-exposure time for 30 minutes shows improved subthreshold-swing characteristics and a high on/off current ratio. These devices are adequate for use in high-resolution active-matrix LCDs or OLED displays that demand a high field-effect mobility (>10 cm2 V−1 s−1) and on/off ratio (>106).