Search Results (1,452)

In this work, Cu₂CoSnS₄ (CCTS) thin films were deposited on glass substrates by thermal evaporation and investigated for photovoltaic applications. The influence of substrate temperature, varied from 25 °C to 200 °C, on the structural, morphological, and optical properties of the films was experimentally studied using X-ray diffraction (XRD), scanning electron microscopy (SEM), and photoluminescence (PL) measurements. XRD analysis confirmed the formation of crystalline CCTS with a stannite structure and a preferential orientation along the (112) plane. SEM observations revealed rough and non-uniform surfaces accompanied by an increase in grain size with increasing substrate temperature. Room-temperature PL measurements indicated a band-gap energy of approximately 1.3 eV, suitable for photovoltaic applications, and confirmed the presence of secondary phases in the p-type stannite CCTS films. Despite the promising photovoltaic properties of CCTS, numerical studies on CCTS-based solar cells remain scarce in the literature. In this context, a numerical study of the CCTS-based solar structure grown on glass was also performed using SCAPS-1D, showing good agreement with experimental photovoltaic results and validating the simulation model. Replacing the glass substrate with silicon improved the device efficiency to 5.77%. Further optimization of the series and shunt resistances significantly enhanced the photovoltaic performance, achieving a power conversion efficiency of 16.77%, with FF = 52.94%, V_oc = 0.89 V and J_sc = 35.19 mA/cm². Full article

Hybrid solar–thermal energy harvesting systems are an important advancement in renewable energy technology, enabling simultaneous production of electrical power and useful thermal energy within a single compact platform. However, their performance is often limited by poor heat transfer and inefficient mass transport of working fluids, leading to photovoltaic thermal degradation and significant exergy losses. This study aims to optimize heat and mass transport processes in a hybrid solar–thermal mechanical system to enhance energy recovery and ensure long-term operational reliability. A three-dimensional numerical model based on the finite volume method (FVM) was developed using the governing equations of continuity, momentum, and energy conservation. A Multi-Objective Genetic Algorithm (MOGA) was employed to determine optimal microchannel geometries by analyzing variable cross-section effects on flow behavior and thermal boundary layer disruption. At the Reynolds number of 2000, the optimized configuration increases the average Nusselt number by 43.5% compared to a smooth channel. Consequently, the photovoltaic operating temperature decreases by 12.6 °C, improving electrical efficiency by 9.3%. The system achieves a maximum thermal efficiency and net energy gain of 76.8%, while maintaining an acceptable 16.3% increase in pumping power. The results confirm that optimizing mass transport is essential for effective thermal regulation and improved energy conversion performance, providing a strong foundation for high-efficiency solar collector design. Full article

Grain boundaries (GBs) are important recombination-active defects in polycrystalline and multicrystalline silicon solar cells, but the effects of their electrical activity, geometry, and spatial arrangement are often difficult to separate. In this work, two-dimensional (2D) drift–diffusion simulations are used to investigate how GB trap density, carrier capture cross-section, orientation, length, number, and network geometry affect silicon solar-cell performance. A controlled comparison between rotating GBs whose length changes with angle and fixed-length GBs shows that the strong apparent orientation dependence is dominated by the accompanying variation in active GB length. When the GB length is fixed at 100 μm, the variations in short-circuit current density ($J_{\mathrm{sc}}$), open-circuit voltage ($V_{\mathrm{oc}}$), efficiency, and fill factor are comparatively small. As a second contribution, irregular polycrystalline microstructures are generated by Voronoi tessellation, producing distributions of grain sizes, shapes, boundary lengths, and junctions that are more representative than simplified structures based on isolated or regularly spaced boundaries. These networks are used to connect grain size, total electrically active GB length, recombination, local electric fields, carrier-flow redistribution, and device performance. As the characteristic grain size increases from 5 to 100 μm, $J_{\mathrm{sc}}$ rises from 15 to $34\mathrm{mA}{\mathrm{cm}}^{-2}$, $V_{\mathrm{oc}}$ from $0.54$ to above $0.61$ V, and the power conversion efficiency from $6.5\%$ to $17\%$. GB-induced photovoltaic loss is therefore governed not by GB number or nominal orientation alone, but by the combined effects of electrical activity, total active boundary length, and network geometry. Full article

The increasing demand for high-efficiency photovoltaic technologies has intensified research into tandem solar cells (TSCs) as a promising strategy to surpass the performance limits of single-junction devices. In this study, a comprehensive optoelectronic simulation using a Silvaco ATLAS TCAD simulator is employed to design, optimize, and compare two tandem architectures: all-organic and hybrid organic/silicon TSCs. The all-organic configuration consists of polymer donors comprising a PBDB-T:F-M top sub-cell stacked with a PTB7-Th:CO_i8DFIC:PC₇₁BM bottom sub-cell, while the hybrid configuration integrates a PBDB-T:F-M organic top cell with a crystalline Si bottom cell. Calibrated device models, validated against experimental data of the individual sub-cells, are used to evaluate tandem performance and guide systematic optimization. The two tandem architectures employ the same PBDB-T:F-M wide-bandgap organic top absorber (E_g~1.60 eV), while the rear sub-cell consists of either the PTB7-Th:CO_i8DFIC:PC₇₁BM organic absorber (E_g~1.20 eV) or crystalline silicon (E_g~1.12 eV). The initial organic/organic tandem device accomplishes a power conversion efficiency (PCE) of 15.70% and J_SC of 10.96 mA/cm², whereas the organic/silicon tandem structure exhibits a higher initial PCE of 16.85% and J_SC of 12.26 mA/cm². Following absorber-thickness optimization, the all-organic and hybrid OSC/Si tandems achieve PCEs of 19.44% and 21.13%, respectively. Rather than constituting a simple efficiency ranking, the comparison reveals distinct optical, electrical, and technological trade-offs. The hybrid architecture benefits from the broader spectral utilization and efficient carrier collection of thin crystalline Si, whereas the all-organic configuration offers advantages associated with low-temperature solution processing, reduced material consumption, and potentially fully solution-processed photovoltaic fabrication. The calibrated comparative framework therefore provides design guidance for selecting and optimizing TSCs according to both performance and application requirements. Full article

Visible light communication (VLC) has emerged as a transformative optical wireless technology for sixth-generation (6G) networks, offering license-free spectrum access, inherent electromagnetic-interference immunity, high spatial confinement, and the unique ability to combine high-speed wireless connectivity with solid-state lighting infrastructure. However, the transition from conventional VLC links to practical 6G optical wireless systems requires far more than advanced modulation and signal processing. Future VLC performance will be strongly determined by the co-design of photonic front-ends, including high-speed transmitters, spectrally engineered emitters, reconfigurable optical interfaces, intelligent receivers, and energy-autonomous detection units. This article provides a comprehensive, device-centered review of photonic hardware and artificial intelligence (AI) enablers for next-generation 6G VLC systems. Particular attention is given to micro-LEDs, laser diodes, color-conversion materials, including perovskite quantum dots, advanced photodetectors, imaging receivers, wavelength-shifting fiber receivers, solar-cell-based receivers, optical reconfigurable intelligent surfaces (RISs), metasurfaces, beam-steering components, and optical wireless power transfer. This review discusses how AI can support inverse photonic design, transmitter and receiver calibration, nonlinear impairment mitigation, channel-aware beam control, and energy-aware resource management. Unlike broader VLC surveys that mainly emphasize network architecture, this article provides a device-centered perspective on AI-enabled photonic integration for 6G VLC, supported by a comprehensive survey of recent experimental demonstrations. Key challenges related to bandwidth, optical efficiency, receiver field of view, mobility, safety, standardization, and practical deployment are summarized, followed by a research roadmap for 2025–2032. Full article

Organic solar cells are widely recognized for their flexibility, light weight and semitransparency, all relevant for niche applications. A significant challenge in their development lies in the accurate prediction of their power conversion efficiency depending on the combination of the donor and acceptor selected in the bulk heterojunction. To address this issue, we developed a robust machine learning (ML) framework designed to establish correlations between molecular structure and device performance. A feature selection strategy, incorporating SHapley Additive exPlanations and Boruta algorithms, was employed to extract the most informative descriptors. Among the regression models that were systematically evaluated on a curated dataset comprising 1575 experimentally characterized donor–acceptor pairs, histogram-based gradient boosting demonstrated superior predictive performance, giving an R² score of 0.79, with a low root mean square error of 2.16. Subsequently, the optimized model was used to predict new donor–acceptor pairs with PCEs above 20% and identify prospective candidates for further experimental validation. Full article

The development of indoor photovoltaic devices for powering Internet of Things (IoT) sensors requires low-cost and sustainable components, making dye-sensitized solar cells (DSSCs) an ideal candidate for artificial light harvesting. The counter electrode plays a critical role in transferring electrons and catalyzing the reduction in the redox electrolyte. However, the traditional use of expensive and scarce platinum (Pt) limits the cost-effective, large-scale commercialization of these devices. While carbon-based materials offer a highly porous, conductive, and abundant alternative, commercial carbon pastes frequently require energy-intensive high-temperature sintering. In this study, we propose a sustainable, low-temperature, and screen-printable carbon composite counter electrode (LoT-HPC) using bio-derived hydroxypropyl cellulose (HPC) as a highly effective binder. Rheological characterizations confirm that the formulated LoT-HPC ink possesses an ideal shear-thinning profile and rapid structural recovery, ensuring excellent printability and film homogeneity. By comparing the custom LoT-HPC composite against a commercial high-temperature screen-printed graphite paste (HT-Elco) and a standard sputtered Pt-FTO electrode, we demonstrate the structural and electrocatalytic advantages of this material. When integrated into full DSSC devices and evaluated under low indoor illumination (1000 lux), the LoT-HPC cell delivers a power conversion efficiency (PCE) of 14.8% and a high short-circuit current density of 103.9 µA cm⁻². Furthermore, the custom device demonstrated exceptional operational stability, retaining 98.6% of its initial efficiency (from 14.8% to 14.6%) after 200 h of continuous light-soaking and J-V cycling under 1000 lux. Ultimately, the successful implementation of the HPC binder enables the low-temperature fabrication of sustainable carbon counter electrodes without the need for energy-intensive thermal treatments, presenting a highly scalable pathway for indoor DSSC manufacturing. Full article

Standalone DC microgrids offer a promising solution for providing reliable and sustainable electricity to remote communities in developing countries. However, the intermittent nature of solar and wind resources, combined with continuously varying load demand, presents considerable operational challenges in maintaining real-time power balance, stable DC bus voltage, and ensuring reliable continuous supply. Therefore, there is dire need for user-friendly control solutions tailored to the specific needs of isolated communities. As such, this paper presents a coordinated control and power management strategy for an isolated hybrid solar–wind–battery integrated DC microgrid for rural electrification applications. A comprehensive mathematical model of the standalone DC microgrid incorporating photovoltaic generation, wind energy conversion, battery storage, bidirectional DC-DC conversion, and common DC bus dynamics is developed at the very first stage of the proposed coordinated control framework. The framework utilizes principal local device loops and a secondary dynamic power management strategy to ensure efficient renewable power extraction, dynamic source–storage–load coordination, stable DC bus voltage, and real-time energy management within the developed standalone DC microgrid. It is worthwhile to mention that, instead of using synthesized or online available wind speed and solar irradiance data, this research utilized real-time recorded metrological data obtained from the Mehran University Jamshoro, Pakistan. The obtained results establish a stable DC bus voltage regulation within acceptable operating limits, continuous power balance, seamless bidirectional battery operation, and safe battery state-of-charge (SoC) management to prevent deep discharging or overcharging, thus ensuring reliable operation. The overall performance confirms the technical robustness, operational flexibility, and practical suitability of the proposed standalone hybrid DC microgrid architecture for its resilient operation and rural electrification applications. Full article

This paper presents the design, control, and validation of a solar photovoltaic (PV)-powered DC microgrid (MG) integrated with a battery energy storage system (BESS), which was studied at laboratory scale as a step towards remote electrification in resource-constrained regions. An Adaptive Neuro-Fuzzy Inference System (ANFIS)-based maximum power point tracking (MPPT) algorithm is implemented to maximise solar energy extraction under varying irradiance. An Adaptive Power Management (APM) framework is proposed to maintain DC bus stability when the BESS is unavailable to support the bus—a condition that may arise from battery degradation, sensor or communication failures, converter malfunctions, protection trips, or physical damage. In this work, BESS unavailability is represented at the system level as the withdrawal of BESS support; the individual fault mechanisms that may cause it are not separately modelled. The APM operates across three hierarchical layers—monitoring, decision, and control—and reuses only the voltage and current measurements already present in the MG, requiring no additional sensing. The system is evaluated under three operating scenarios: (i) intermittent renewable generation; (ii) varying load demand; (iii) stochastic fluctuations in both irradiance and load. During BESS unavailability, the APM activates prioritised adaptive load shedding or PV generation curtailment as appropriate, preserving critical loads and preventing DC bus overvoltage. In the scenarios studied, the APM reduces worst-case voltage sag from 35.9% to 2.4% and worst-case swell from 53.51% to 0.14%, while maintaining BESS State of Charge (SOC) within 20%–80% during normal operation. Compared with the conventional Perturb and Observe (P&O) and Incremental Conductance (INC) methods, the ANFIS-based MPPT achieves a mean point-wise tracking and conversion efficiency of 99.46%, a 1.78% improvement and a 0.86% improvement, respectively, which were corroborated by independent energy-based assessments (1.76% and 0.92%), with voltage deviations of 2.34% and oscillations of only 0.57 V peak-to-peak. Lyapunov-based analysis establishes asymptotic stability of the DC bus voltage in the BESS-regulated operating modes under stated assumptions. The proposed control strategies are validated through MATLAB/Simulink (R2025b) simulations and laboratory-scale experimental results, with the latter demonstrating coordinated PV–BESS–converter operation and bus voltage regulation. Full article

The rise in the need for sustainable energy has facilitated the advancement of perovskite solar cells (PSCs) as potential substitutes for traditional photovoltaic technologies. Nevertheless, their performance is very sensitive to environmental factors, especially temperature, which influences the charge transport and recombination processes. This paper examines the thermal effect on the electrical characteristics and impedance response of lead-free PSCs in accordance with the FTO/ETL (C₆₀, PCBM, SnS₂, ZnSe)/CH₃NH₃SnBr₃/Cu₂O configuration. The experiments were performed with SCAPS-1D under usual illumination, using a combination of current-voltage analysis and impedance spectroscopy between 270 and 400 K. The findings indicate that there is a significant reduction in open-circuit voltage with higher temperature, whereas the short-circuit current density does not change much. The enhancement of the fill factor increases and then decreases with increased temperature, leading to a net decrease in power conversion efficiency because of the increased recombination. The impedance analysis is also an indicator of lower recombination resistance and accelerated charge carrier dynamics. These results demonstrate that thermal control and interface optimization can be important for enhancing PSC performance. Full article

Cold-climate dwellings can face coincident electricity and domestic hot-water shortfalls in winter, when solar availability is at its lowest. This study evaluates an integrated residential system for Aomori, Japan, combining photovoltaics, evacuated-tube solar water heating, and battery storage with electrolysis, compressed-hydrogen storage, and a PEM fuel cell operated in combined-heat-and-power mode. Building on a screening-level annual-balance analysis, a coupled annual TRNSYS simulation with a 0.125 h time step resolved battery dispatch, electrolyzer part-load operation, hydrogen compression and finite storage, seasonal fuel-cell operation, and heat recovery. The results show that the principal value of seasonal hydrogen lies in improving winter supply adequacy, dispatchability, and heat recovery rather than annual conversion efficiency. Fuel-cell heat recovery increased the number of days satisfying the hot-water screening indicator—a daily mean tank temperature of at least 43 °C—from 221 to 332. A reserve-aware criterion identified a 225 W electrolyzer operating-power cap as the positive-reserve case; 205 W was near-cyclic with a negligible margin, whereas the original 475 W cap was substantially oversized. The hydrogen pathway remained markedly less efficient than direct photovoltaic and solar-thermal use, and the estimated storage hardware’s lower bound substantially exceeded the break-even capital ceiling supported by the annual operating value. Seasonal hydrogen can therefore strengthen winter energy adequacy and heat recovery but is not yet cost-effective at the single-dwelling scale under the investigated conditions. Full article

Perovskite tandem solar cells (TSCs) have emerged as a transformative photovoltaic technology, offering a viable pathway to surpass the Shockley-Queisser limit of single-junction devices by enabling broader solar spectrum utilization and reduced thermalization losses. This review provides a comprehensive overview of recent progress in perovskite-based TSCs, covering four major device architectures: perovskite/silicon, perovskite/CIGS, all-perovskite, and perovskite/organic TSCs. We systematically discuss the fundamental working principles, including bandgap engineering, charge generation and separation, and current-voltage matching, followed by an in-depth analysis of strategies for perovskite layer regulation, interface engineering, and transport-layer optimization. Key advancements, such as compositional engineering, defect passivation, crystallization control, and optical management, have synergistically pushed power conversion efficiencies (PCEs) beyond 34% for perovskite/silicon TSCs and over 28% for all-perovskite and perovskite/organic configurations. Despite these achievements, critical challenges remain, including material instability, halide phase segregation, lead toxicity, scalable fabrication, and cost-effective integration. This review also outlines future perspectives, emphasizing the development of lead-free perovskites, novel charge-transport materials, advanced encapsulation techniques, and large-area manufacturing processes. With continued interdisciplinary efforts, perovskite TSCs hold great promise for driving the global transition toward sustainable and low-carbon energy systems. Full article

Perovskite solar cells (PSCs) have emerged as one of the most rapidly advancing photovoltaic technologies of the past decade, progressing from the initial demonstration of 3.8% power conversion efficiency (PCE) in 2009 to certified single-junction efficiencies exceeding 26% and perovskite–silicon tandem efficiencies exceeding 33.9% as of 2024. Their appeal resides in the combination of a broadly tunable bandgap achieved through compositional engineering of the ABX₃ perovskite crystal structure, compatibility with low-temperature solution processing, and the potential for manufacturing costs substantially below those of silicon photovoltaics. However, the translation of laboratory-scale performance to commercially viable modules at industrial throughput remains the central challenge in the field. This review provides a comprehensive and critically organized account of PSC manufacturing, spanning device architectures and material requirements, scalable deposition and coating technologies, charge transport layer integration and interface engineering, process control and crystallization strategies, post-treatment methods, artificial intelligence and machine learning-assisted manufacturing, module fabrication and encapsulation, advanced tandem and flexible device configurations, green chemistry and circular lifecycle strategies, and the critical barriers to commercialization. The review concludes with a strategic assessment of the technological, regulatory, and economic requirements for PSC technology to transition from pilot-scale demonstration to utility-scale deployment. Full article

Molybdenum carbide (MoC) thin films were deposited by dual-target magnetron co-sputtering and investigated as platinum-free counter electrodes (CEs) for dye-sensitized solar cells (DSSCs). The effects of Mo target power and film thickness on structural evolution, electrical transport properties, and photovoltaic performance were systematically examined. Raman analysis revealed progressive modifications in the carbon bonding structure, accompanied by variations in the G-band position and an overall reduction in the I_D/I_G ratio. These structural changes were correlated with increased hardness, reduced electrical resistivity, and decreased surface wettability, indicating improved structural integrity and electrical transport characteristics of the MoC films. The optimized films exhibited a resistivity as low as 2.04 mΩ·cm and improved charge-transport behavior. DSSCs employing the optimized MoC CEs achieved a maximum power conversion efficiency of 4.13%. The photovoltaic performance trends were consistent with the evolution of the electrical transport properties of the MoC thin films, suggesting a close relationship between electrode structure, charge transport, and device operation. The results demonstrate that sputtered MoC thin films are promising functional materials for Pt-free DSSC CEs and provide insight into structure–transport–performance correlations relevant to sustainable photovoltaic energy-conversion systems. Full article

As the most critical component of organic solar cells (OSCs), the morphology of the active layer directly dictates the photovoltaic performance of the devices. Recent studies have demonstrated that tailoring the active layer morphology using solid additives is a facile and effective strategy to boost the performance of OSCs. Herein, we design and synthesize a novel solid additive, 5-bromobenzo[b]thiophene (5-BrBT), by introducing a bromine substituent onto the common benzothiophene unit. It is found that 5-BrBT optimizes the active layer formation process by effectively prolonging the nucleation time, which facilitates more controllable molecular nucleation and subsequent crystal growth during the pre-aggregation stage, leading to a more ideal donor-acceptor phase distribution. Furthermore, the binary PM6:L8-BO organic solar cells, fabricated with the incorporation of 5-BrBT, exhibit superior charge transport properties and exciton-generation efficiency, along with significantly suppressed charge recombination behaviors. Consequently, the 5-BrBT-treated binary PM6:L8-BO-based OSCs achieve an outstanding power conversion efficiency (PCE) of up to 19.44%, accompanied by simultaneous enhancements in short-circuit current density (J_SC) and fill factor (FF). This work provides a promising optimization strategy for achieving ideal nucleation behaviors during the bulk-heterojunction (BHJ) film processing via solid additives, which is expected to promote the development of more efficient OSCs. Full article