Search Results (99)

The rising demand for sustainable energy solutions has spurred the development of advanced materials for photovoltaic devices. Among these, transparent conductive oxides (TCOs) play a pivotal role in enhancing device efficiency, particularly in silicon-based solar cells. However, the reliance on indium-based TCOs like ITO raises concerns over cost and material scarcity, prompting the search for more abundant and scalable alternatives. This study focuses on the fabrication and characterization of aluminum-doped zinc oxide (ZnO:Al, AZO) thin films deposited via Atomic Layer Deposition (ALD), targeting their application as transparent conductive oxides in silicon solar cells. The ZnO:Al thin films were synthesized by alternating supercycles of ZnO and Al₂O₃ depositions at 225 °C, allowing precise control of composition and thickness. Structural, optical, and electrical properties were assessed using Scanning Electron Microscopy (SEM), Energy-Dispersive X-ray Spectroscopy (EDS), Transmission Electron Microscopy (TEM), Raman spectroscopy, spectroscopic ellipsometry, and four-point probe measurements. The results confirmed the formation of uniform, crack-free ZnO:Al thin films with a spinel-type ZnAl₂O₄ crystalline structure. Optical analyses revealed high transparency (more than 80%) and tunable refractive indices (1.64 ÷ 1.74); the energy band gap was 2.6 ÷ 3.07 eV, while electrical measurements demonstrated low sheet resistance values, reaching 85 Ω/□ for thicker films. This combination of optical and electrical properties underscores the potential of ALD-grown AZO thin films to meet the stringent demands of next-generation photovoltaics. Integration of Zn:Al thin films into silicon solar cells led to an optimized photovoltaic performance, with the best cell achieving a short-circuit current density of 36.0 mA/cm² and a power conversion efficiency of 15.3%. Overall, this work highlights the technological relevance of ZnO:Al thin films as a sustainable and cost-effective alternative to conventional TCOs, offering pathways toward more accessible and efficient solar energy solutions. Full article

Metamaterials, owing to their exceptional properties such as a negative Poisson’s ratio, phonon band gap, and energy absorption, have garnered significant interest in aerospace, automotive transportation, and other domains. The increasing demand for metamaterial structures with diverse specialized attributes requires innovative design approaches. In this study, a novel bi-material triangular curved beam honeycomb metamaterial (BTBM) is designed, which exhibits a tunable Poisson’s ratio (PR), coefficient of thermal expansion (CTE), and band gap characteristics. These properties are intrinsically coupled through the geometric and material design of the bi-material triangular curved beam structure, meaning that adjustments to the unit cell configuration simultaneously influence PR, CTE, and band gap behavior. This dual-mode control offers versatile design strategies for multifunctional metamaterials. The energy band structure is calculated using finite element simulation analysis, and its accuracy is validated by computing the transmission characteristic curve. Numerical simulations were performed to systematically analyze the coupled effects of geometric parameters and material combinations on the PR and CTE. The results demonstrate significant tunability of these mechanical properties through parametric optimization. The results of this study provide valuable insights into the design and optimization of metamaterial structures with tailored properties for various applications. Full article

This research focuses on creating CuO/PANI nanocomposite films by electrodepositing copper oxide nanoparticles into a polyaniline matrix on ITO substrates. The CuO nanoparticle content was adjusted between 7% and 21%. These nanocomposites are promising for various applications, such as optoelectronic devices, gas sensors, electromagnetic interference shielding, and electrochromic devices. We utilized UV-Vis spectroscopy to examine the nanocomposites’ interaction with light, allowing us to ascertain their refractive indices and absorption coefficients. The Scherrer formula facilitated the determination of the average crystallite size, shedding light on the material’s internal structure. Tauc plots indicated a reduction in the energy-band gap from 3.36 eV to 3.12 eV as the concentration of CuO nanoparticles within the PANI matrix increased, accompanied by a rise in electrical conductivity. The incorporation of CuO nanoparticles into the polyaniline matrix appears to enhance the conjugation length of PANI chains, as evidenced by shifts in the quinoid and benzenoid ring vibrations in FTIR spectra. SEM analysis indicates that the nanocomposite films possess a relatively smooth and homogeneous surface. Additionally, FTIR and XRD analyses demonstrate an increasing degree of interaction between CuO nanoparticles and PANI chains with higher CuO concentrations. At lower concentrations, interactions were minimal. In contrast, at higher concentrations, more significant interactions were observed, which facilitated the stretching of polymer chains, improved molecular packing, and facilitated the formation of larger crystalline structures within the PANI matrix. The incorporation of CuO nanoparticles resulted in nanocomposites with electrical conductivities ranging from 1.2 to 17.0 S cm⁻¹, which are favorable for optimum performance in optoelectronic devices. These results confirm that the nanocomposite films combine pronounced crystallinity, markedly enhanced electrical conductivity, and tunable band-gap energies, positioning them as versatile candidates for next-generation optoelectronic devices. Full article

Perovskite/organic tandem solar cells, as a next-generation high-efficiency photovoltaic technology, integrate the tunable bandgap characteristics of perovskite materials with the broad spectral absorption advantages of organic semiconductors, demonstrating remarkable potential to surpass the theoretical efficiency limits of single-junction cells, enhance device stability, and expand application scenarios. This architecture supports low-temperature solution processing and offers tunable bandgaps, lightweight flexibility, and ecofriendly advantages. This review systematically summarizes research progress in this field, with a primary focus on analyzing the working principles, performance optimization strategies, and key challenges of the technology. Firstly, the article discusses strategies such as defect passivation, crystallization control, and suppression of phase separation in wide-bandgap perovskite sub-cells, offering insights into mitigating open-circuit voltage losses. Secondly, for the narrow-bandgap organic sub-cells, this paper highlights the optimization strategies for both the active layer and interfacial layers, aiming to improve spectral utilization and enhance power conversion efficiency. Additionally, this paper emphasizes the optimization of optical transparency, electrical conductivity, and energy level alignment in the recombination layer, providing theoretical guidance for efficient current matching and carrier transport. Full article

Two-dimensional materials have emerged as core components for next-generation optoelectronic devices due to their quantum confinement effects and tunable electronic properties. Indium selenide (InSe) demonstrates breakthrough photoelectric performance, with its remarkable light-responsive characteristics spanning from visible to near-infrared regions, offering application potential in high-speed imaging, optical communication, and biosensing. This study investigates the doping characteristics of InSe using first-principles calculations, focusing on the doping and adsorption behaviors of Argentum (Ag) and Bismuth (Bi) atoms in InSe and their effects on its electronic structure. The research reveals that Ag atoms preferentially adsorb at interlayer vacancies with a binding energy of −2.19 eV, forming polar covalent bonds. This reduces the band gap from the intrinsic 1.51 eV to 0.29–1.16 eV and induces an indirect-to-direct band gap transition. Bi atoms doped at the center of three Se atoms exhibit a binding energy of −2.06 eV, narrowing the band gap to 0.19 eV through strong ionic bonding, while inducing metallic transition at inter-In sites. The introduced intermediate energy levels significantly reduce electron transition barriers (by up to 60%) and enhance carrier separation efficiency. This study links doping sites, electronic structures, and photoelectric properties through computational simulations, offering a theoretical framework for designing high-performance InSe-based photodetectors. It opens new avenues for narrow-bandgap near-infrared detection and carrier transport optimization. Full article

Rare-earth (RE) doping has been found to be a potent method to improve the structural, optical, electronic, and magnetic properties of ZnO, positioning it as a versatile material for future optoelectronic devices. This review herein thoroughly discusses the latest developments in RE-doped ZnO based on the role of the dopant type, concentration, synthesis method, and consequences of property modifications. The 4f electronic states of rare-earth elements create strong visible emissions, control charge carriers, and design defects. These structural changes lead to tunable bandgap energies and increased light absorption. Also, RE doping considerably enhances ZnO’s performance in electronic devices, like UV photodetectors, LEDs, TCOs, and gas sensors. Though, challenges like solubility constraints and lattice distortions at higher doping concentrations are still key challenges. Co-doping methodologies and new synthesis techniques to further optimize the incorporation of RE into ZnO matrices are also reviewed in this article. By showing a systematic comparison of different RE-doped ZnO systems, this paper sheds light on their future optoelectronic applications. The results are useful for the design of advanced ZnO-based materials with customized functionalities, which will lead to enhanced device efficiency and new photonic applications. Full article

Previous studies have demonstrated that underwater low-temperature plasma is effective for synthesizing nanomaterials by generating plasma discharges between metal electrodes submerged in water. This study extends this approach to the one-step synthesis of MXenes containing titanium, molybdenum, and titanium–molybdenum composites through pulsed discharges in carbon tetrachloride, an oxygen-free, non-flammable solvent characterized by a high boiling point and low permittivity. By employing titanium and molybdenum electrodes in various configurations, three MXene samples were synthesized: Ti₂CT_X, Mo₂CT_X, and Mo₂TiC₂T_X. Characterization techniques, including UV-Vis spectroscopy, X-ray diffraction, Raman spectroscopy, scanning electron microscopy, and energy-dispersive X-ray spectroscopy, confirmed the successful synthesis of high-purity MXenes with distinct structural and optical properties. Notably, the bandgap values of the synthesized MXenes were determined as 1.71 eV for Ti₂CT_X, 1.42 eV for Mo₂TiC₂T_X, and 1.07 eV for Mo₂CT_X. The photocatalytic performance of the synthesized MXenes was evaluated, showing a removal efficiency of 65% to 98% for dye mixtures, with methylene blue showing the highest degradation rate. This plasma-assisted method offers a scalable, precursor-free route for the synthesis of MXenes with potential applications in energy storage, environmental remediation, and optoelectronics due to their tunable bandgaps and high catalytic activity. Full article

Zinc oxide (ZnO), a cheap, abundant, biocompatible, and wide band gap semiconductor material with easy tunable morphologies and properties, makes it one of the mostly studied metal oxides in the area of materials science, physics, chemistry, biochemistry, and solid-state electronics. Its versatility, easy bandgap engineering with transitional and rare earth metals, as well as the diverse nanomorphology empower ZnO as a promising photocatalyst. The use of ZnO as a functional material is attracting increased attention both for academia and industry, especially under the current energy paradigm shift toward clean and renewable sources. Extensive work has been performed in recent years using ZnO as an active component for different photocatalytic applications. Therefore, a thorough and timely review of the process is necessary. The aim of this review is to provide a general summary of the current state of ZnO nanostructures, synthesis strategies, and modification approaches, with the main application focus on varied photocatalysis applications, serving as an introduction, a reference, and an inspiration for future research. Full article

Boron phosphide (BP), an emerging III–V semiconductor, has garnered significant interest because of its exceptional structural stability, wide bandgap, high thermal conductivity, and tunable electronic properties. This review provides a comprehensive analysis of BP, commencing with its distinctive structural characteristics and proceeding with a detailed examination of its exceptional physicochemical properties. Recent progress in BP synthesis is critically examined, with a focus on key fabrication strategies such as chemical vapor deposition, high-pressure co-crystal melting, and molten salt methods. These approaches have enabled the controlled growth of high-quality BP nanostructures, including bulk crystals, nanoparticles, nanowires, and thin films. Furthermore, the review highlights the broad application spectrum of BP, spanning photodetectors, sensors, thermal management, energy conversion, and storage. Despite these advances, precise control over the growth, morphology, and phase purity of BP’s low-dimensional structures remains a critical challenge. Addressing these limitations requires innovative strategies in defect engineering, heterostructure design, and scalable manufacturing techniques. This review concludes by outlining future research directions that are essential for unlocking BP’s potential in next-generation electronics, sustainable energy technologies, and multifunctional materials. Full article

The avalanche multiplication effect, capable of significantly amplifying weak optical or electrical signals, plays a pivotal role in enhancing the performance of electronic and optoelectronic devices. This effect has been widely employed in devices such as avalanche photodiodes, impact ionization avalanche transit time diode, and impact ionization field-effect transistors, enabling diverse applications in biomedical imaging, 3D LIDAR, high-frequency microwave circuits, and optical fiber communications. However, the evolving demands in these fields require avalanche devices with superior performance, including lower power consumption, reduced avalanche threshold energy, higher efficiency, and improved sensitivity. Over the years, significant efforts have been directed towards exploring novel device architectures and multiplication mechanisms. The emergence of two-dimensional (2D) materials, characterized by their exceptional light-matter interaction, tunable bandgaps, and ease of forming junctions, has opened up new avenues for developing high-performance avalanche devices. This review provides an overview of carrier multiplication mechanisms and key performance metrics for avalanche devices. We discuss several device structures leveraging the avalanche multiplication effect, along with their electrical and optoelectronic properties. Furthermore, we highlight representative applications of avalanche devices in logic circuits, optoelectronic components, and neuromorphic computing systems. By synthesizing the principles and applications of the avalanche multiplication effect, this review aims to offer insightful perspectives on future research directions for 2D material-based avalanche devices. Full article

Metal halide perovskites have emerged as a groundbreaking material class for photovoltaic applications, owing to their exceptional optoelectronic properties, tunable bandgap, and cost-effective fabrication processes. This review offers a comprehensive analysis of recent advancements in synthesis, structural engineering, and characterization of metal halide perovskites for efficient solar energy conversion. We explore a range of fabrication techniques, including solution processing, vapor deposition, and nanostructuring, emphasizing their impact on material stability, efficiency, and scalability. Additionally, we discuss key characterization methods, such as X-ray diffraction, electron microscopy, impedance spectroscopy, and optical analysis, that provide insights into the structural, electrical, and optical properties of these materials. Despite significant progress, challenges related to long-term stability, degradation mechanisms, and environmental sustainability persist. This review delves into current strategies for enhancing the durability and performance of perovskite-based photovoltaics and highlights emerging trends in device integration and commercialization. Finally, we provide future perspectives on optimizing material design and overcoming existing limitations to guide continued research in this rapidly advancing field. Full article

Quasi-two-dimensional (quasi-2D) perovskites have emerged as a transformative platform for high-efficiency perovskite light-emitting diodes (PeLEDs), benefiting from their tunable quantum confinement, high photoluminescence quantum yields (PLQYs), and self-assembled energy funneling mechanisms. This review systematically explores interfacial energy transfer engineering strategies that underpin advancements in device performance. By tailoring phase composition distributions, passivating defects via additive engineering, and optimizing charge transport layers, researchers have achieved external quantum efficiencies (EQEs) exceeding 20% in green and red PeLEDs. However, challenges persist in blue emission stability, efficiency roll-off at high currents, and long-term operational durability driven by spectral redshift, Auger recombination, and interfacial ion migration. Emerging solutions include dual-cation/halogen alloying for bandgap control, microcavity photon management, and insulator–perovskite–insulator (IPI) architectures to suppress leakage currents. Future progress hinges on interdisciplinary efforts in multifunctional material design, scalable fabrication, and mechanistic studies of carrier–photon interactions. Through these innovations, quasi-2D PeLEDs hold promise for next-generation displays and solid-state lighting, offering a cost-effective and efficient alternative to conventional technologies. Full article

Hybrid organic–inorganic perovskites have emerged as promising materials for next-generation optoelectronic devices owing to their tunable properties and low-cost fabrication. We report the synthesis of 3D hybrid perovskites with monoethanolammonium cations. Specifically, we investigated the optoelectronic properties and morphological characteristics of polycrystalline films of hybrid perovskites MA_xMEA_1−xPbI₃, which contain methylammonium (MA) and monoethanolammonium (MEA) cations. MA_xMEA_1−xPbI₃ crystallizes in a tetragonal perovskite structure. The substitution of methylammonium cations with monoethanolammonium ions led to an increase in the lattice parameters and the bandgap energy. Energy level diagrams of the synthesized samples were also constructed. The bandgap of MA_0.5MEA_0.5PbI₃ makes it a promising material for use in tandem solar cells. These polycrystalline films, namely MA_0.5MEA_0.5PbI₃ and MA_0.25MEA_0.75PbI₃ were fabricated using a one-step spin-coating method without an antisolvent. These films exhibit a uniform surface morphology under the specified deposition parameters. Within the scope of this study, no evidence of dendritic structures or pinhole-type defects were observed. All synthesized samples demonstrated photocurrent generation under visible light illumination. Moreover, using monoethanolammonium cations reduced the hysteresis of the I–V characteristics, indicating improved device stability. Full article

Rare-earth high-entropy oxides are a new promising class of multifunctional materials characterized by their ability to stabilize complex, multi-cationic compositions into single-phase structures through configurational entropy. This feature enables fine-tuning structural properties such as oxygen vacancies, lattice distortions, and defect chemistry, making them promising for advanced technological applications. While initial research primarily focused on their catalytic performance in energy and environmental applications, recent research demonstrated their potential in optoelectronics, photoluminescent materials, and aerospace technologies. Progress in synthesis techniques has provided control over particle morphology, composition, and defect engineering, enhancing their electronic, thermal, and mechanical properties. Rare-earth high-entropy oxides exhibit tunable bandgaps, exceptional thermal stability, and superior resistance to phase degradation, which positions them as next-generation materials. Despite these advances, challenges remain in scaling up production, optimizing compositions for specific applications, and understanding the fundamental mechanisms governing their multifunctionality. This review provides a comprehensive analysis of the recent developments in rare-earth high-entropy oxides as relatively new and still underrated material of the future. Full article

This paper details the enhancement of the optoelectronic properties of Cu-(In, Ga)-Se₂ (CIGSe) solar cells through a two-segment process in the ultraviolet (UV)–visible spectral range. These include fine-tuning the DC sputtering power of the absorber layer (ranging from 20 to 40 W at segment I) and thoroughly checking the trace micro-chemistry composition of the absorber layer (CdS, ZnO/CdS, ZnMgO/CdS, and ZnMgO at segment II). After segment I of treatment, the optimal 30 W CIGSe absorber layer (i.e., with a 0.95 CGI ratio) can be obtained, it can be seen that the Cu-rich film exhibits the ability to significantly promote grain growth and can effectively reduce its trap state density. After the segment II process aimed at replacing toxic CdS, the optimal metal alloy (Zn_0.9Mg_0.1O) composition (buffer layer) achieved the highest conversion efficiency (η) of 8.70%, also emphasizing its role in environmental protection. Especially within the tunable bandgap range (2.48–3.62 eV), the developed overall internal and external quantum efficiency (IQE/EQE) is significantly improved by 13.15% at shorter wavelengths. A photovoltaic (PV) module designed with nine optimal CIGSe cells demonstrated commendable stability. Variation remained within ±5% throughout the 60-day experiment. The PV modules in this study represent a breakthrough benchmark toward a significant advance in the scientific understanding of renewable energy. Furthermore, this research clearly promotes the practical application of PV modules, harmonizes with sustainable goals, and actively contributes to the creation of eco-friendly communities. Full article