Vishal Sorathiya

This work presents a compact multilayer solar absorber based on a spiral multi‐ring resonator integrated with MXene for broadband energy harvesting. The proposed metal–dielectric–MXene–metal configuration consists of a patterned Fe resonator placed over a SiO ₂ spacer and MXene layer, backed by a metallic ground plane to suppress transmission. The structure achieves near‐perfect absorption, reaching 99.9% peak and maintaining absorption above 0.85 across 0.3 to 3.3 µm. Parametric analysis reveals that MXene enhances absorption through strong electromagnetic coupling and intrinsic losses, while SiO ₂ thickness governs spectral tuning. The design maintains stable absorption up to 60° incidence for both TE and TM modes, with superior TM performance. Broadband behavior arises from impedance matching, plasmonic resonances, and dielectric interference. Strong field confinement in the spiral resonator enhances absorption around 1.8–2.0 µm. Machine learning models predict absorption effectively, with AdaBoost achieving the highest accuracy (R ² ≈ 0.943), demonstrating scalability and application potential.

As global energy demand continues to grow along with increasing environmental challenges, the development of clean, sustainable, and eco‐friendly energy technologies has become imperative to sustain modern society. Urea‐assisted water electrolysis (UAWE) offers a sustainable hydrogen production pathway with simultaneous wastewater remediation. However, its commercialization is hindered by high cost, toxic intermediates, chemical structural complexity of catalysts, and limited long‐term stability. In recent years, transition metal phosphides (TMPs) have been identified as promising electrocatalysts for UAWE, attributed to their high conductivity, favorable catalytic activity, enhanced energy efficiency, and relatively good stability. The surface passivation, structural reconstruction during electrolysis operation, and the leaching of phosphorus at the electrode–electrolyte interface can significantly affect long‐term stability. In this review, we systematically explored diverse hybrid electrolysis with a specific focus on UAWE as the central platform for TMP electrocatalysts. The coupled HER and UOR mechanisms underlying the fundamental electrochemical principles, key synthesis and materials engineering strategies are discussed in relation to their roles in improving catalytic performance. Further, recent advances in TMPs electrocatalysts for UAWE are comprehensively reviewed with respect to catalytic activity, energy efficiency, durability, and cost‐effectiveness. Future perspectives on functional optimization, industrial scalability, and long‐term sustainability of UAWE processes are outlined.

The manuscript proposed an efficient broadband metamaterial-inspired multilayered solar absorber for efficient energy harvesting. Its structure is a periodic assembly of Fe, SiO₂, MXene, and Fe layers, thus facilitating the scalable fabrication. Finite element method (FEM) simulations are employed to evaluate and optimise the optical performance. The novel geometry and arrangement of the radiating elements result in peak absorptance exceeding 90% across 0.87–1.79 μm, 2.07–2.425 μm, and 3.045–3.295 μm. Parametric optimisation is conducted by varying resonator geometries (filled and solid), material combinations for resonator and ground layers (Au, Fe), and dielectric thicknesses to achieve optimal absorption characteristics. Angular stability is examined for both TE and TM polarisations over an incidence range of 0°–80°, demonstrating robust wide-angle performance. The TE and TM mode field are analysed at peak absorption wavelength. Furthermore, different machine learning models are implemented to analyse and predict absorption characteristics, validating the agreement between simulated and predicted results. The proposed design was compared and analysed with other similar works to identify performance improvements. The proposed design exhibits strong potential for broadband photothermal and solar-thermal energy harvesting applications.

High-performance perovskite solar cells (PSCs) have exhibited limited long-term stability, mainly driven by layer-to-layer ion diffusion in the perovskite/hole-transport layer (HTL) interface, resulting in a decrease in the HTL and component loss in the perovskite. Graphene derivatives are commonly used in PSC thanks to their high electrical conductivity and charge mobility. By using numerical simulations, reduced graphene oxide (rGO) is introduced at the formamidinium lead triiodide (FAPbI ₃ ) perovskite/HTL heterojunction to introduce interfacial engineering, allowing for improvement of the charge dynamics. The modeled rGO-based PSC devices exhibit suppressed interfacial charge accumulation and improved energy band alignment, significantly enhancing charge recombination resistance. The optimization findings demonstrate that the best-performing PSC is attained with a perovskite layer thickness of 0.8[ ] [ ]m, a trap-state density of 10[ ] [ ]cm[ ], and an effective density of states of 10[ ] [ ]cm[ ]. As a result, the simulated FTO/SnO ₂ /FAPbI ₃ /rGO/Spiro-OMeTAD/Au structure incorporating the rGO interlayer achieves a theoretical efficiency of 28.56% (a 5.65% improvement relative to the unmodified devices) with an open-circuit voltage ([ ]) of 1.273[ ]V, a short-circuit current ([ ]) of 26.495[ ]mA[ ]cm[ ], and a fill factor (FF) of 85.624%. More importantly, the simulated rGO-based PSCs exhibit tolerance to elevated trap states, parasitic resistance variations, and thermal stress. The optimized rGO-based devices maintained 82% of their original PCE after simulating at 460[ ]K. The findings of this study originate from SCAPS-1D simulation, providing a guideline for experimental realization of graphene-engineered PSCs.

This work presents a 2-port dual-band patch antenna operating in the sub-6 GHz range, suitable for various applications, including 5G, Wi-Fi, and other indoor wireless uses. It comprises two antenna elements arranged in parallel. The antenna functions effectively across two principal frequency bands: 3.50–3.68 GHz, with simulated S ₁₁ (S ₂₂ ) values of − 27.66 dB (− 27.6 dB) for 5G NR mid-band applications, and 5.20–5.46 GHz, with simulated S ₁₁ (S ₂₂ ) values of − 31.28 dB (− 29.47 dB), accommodating 5G NR, Wi-Fi 6, and more wireless standards. The antenna features a straightforward design, including a rectangular patch and a modified ground plane incorporating a semi-elliptical split-ring slot. The individual antenna element has dimensions of 20 mm × 25 mm (0.238λ × 0.298λ at 3.57 GHz), whereas the 2-port antenna measures 50 mm × 25 mm (0.239λ × 0.597λ). Two rectangular strips interconnect both ground planes, facilitating a continuous current distribution. It also aids in reducing undesirable interference among antenna elements, hence decreasing mutual coupling. The interference among antenna elements diminishes by 24 dB in the first band and 20 dB in the second band. The antenna was designed to validate the data acquired using the high-frequency structure simulator (HFSS). The constructed prototype was validated, and the obtained findings exhibit strong concordance with the simulated predictions. The reflection coefficients (S ₁₁ ) are less than − 22 dB at 3.50 GHz and − 26.10 dB at 5.35 GHz, although the observed isolation (S ₂₁ ) exceeds 22 dB at 3.50 GHz and 20 dB at 5.35 GHz. The antenna exhibits excellent performance in terms of critical performance indicators, including an envelope correlation coefficient (ECC) that does not exceed 0.002 and a diversity gain (DG) of approximately 10 dB. Additionally, the total active reflection coefficient (TARC) is less than − 10 dB, with channel capacity loss (CCL) within the limit of 0.4 bits/sec/Hz and a mean effective gain (MEG) of approximately − 3 dB, which has been evaluated to confirm the suitability of the suggested antenna for diversity and spatial multiplexing features.

The obtained results confirm that the bilayer of CsPbI ₃ and CsPbBr ₃ synergistically enhances light absorption, band alignment, and carrier dynamics in PSCs.