Search Results (5,749)

Defect passivation is essential for suppressing non-radiative recombination and improving the stability of perovskite solar cells. In this work, we examine how the degree of fluorination in benzylphosphonic acid additives affects film quality and device performance. Two fluorinated analogs are compared, and 2,3,4,5,6-pentafluorobenzylphosphonic acid (pFBPA) is found to adsorb preferentially at iodine vacancy sites through stable Pb-O coordination, as confirmed by binding energy analysis. This passivation effect produces better film morphology, more favorable energy level alignment, and improved charge carrier dynamics. In addition, the high electronegativity of fluorine atoms gives the film marked hydrophobicity, which enhances moisture resistance. Consequently, pFBPA-modified inverted MAPbI₃ solar cells reach a power conversion efficiency of 18.5%, compared with 16.1% for the control devices, and show improved stability. These results indicate that tuning the fluorination level of phosphonic acid additives offers a practical route to boost both efficiency and stability in inverted perovskite photovoltaics. Full article

Inverted small-area perovskite solar cells fabricated in the laboratory have achieved a power conversion efficiency of 28%. Nevertheless, stability remains the key bottleneck. This review systematically analyses external stressors moisture, heat, light, oxygen, electric field, intrinsic ion migration and interfacial defects, alongside stabilization strategies including composition, passivation, 2D/3D heterojunctions, facets engineering, and encapsulation. Synergistic stressors produce nonlinear degradation; effective strategies must tackle multiple pathways simultaneously without impairing charge transport. Full article

Interface engineering of the electron transport layer (ETL) is an effective strategy for enhancing the performance and stability of all-inorganic perovskite solar cells (PSCs). Herein, Na⁺-intercalated vermiculite nanosheets were introduced as a low-cost natural interfacial modifier for the TiO₂ ETL in CsPbI₂Br PSCs. The nanosheets were prepared via an aqueous-phase exfoliation process and deposited onto the TiO₂ surface to regulate the buried TiO₂/CsPbI₂Br interface. Morphological and spectroscopic characterizations revealed that vermiculite modification reduced the surface roughness of TiO₂, altered its surface chemical/electronic environment and was associated with improved interfacial energy-level alignment. As a result, the quality of the CsPbI₂Br film was significantly improved, leading to larger grains, enhanced crystallinity, a lower apparent trap-state density, and more efficient interfacial charge-transfer behavior. Electrical characterizations further confirmed enhanced charge extraction, reduced carrier recombination, and an increased built-in potential in the modified devices. Consequently, the vermiculite-modified devices exhibited simultaneous improvements in power conversion efficiency (PCE), open-circuit voltage, and short-circuit current density, with the best-performing device reaching a PCE of 13.94%. In addition, the modified device retained 84.51% of its initial PCE after storage in air for 35 days, significantly higher than the 71.1% retained by the control device. These findings highlight the potential of Na⁺-intercalated vermiculite nanosheets as low-cost natural modifiers for TiO₂/CsPbI₂Br buried-interface engineering in efficient and stable all-inorganic PSCs. Full article

Metal-free donor–$\pi$–acceptor (D–$\pi$–A) dyes are attractive, low-cost sensitizers for dye-sensitized solar cells (DSSC), and computational screening allows rapid exploration of this vast chemical space. However, most screening protocols characterize each candidate from a single low-energy conformer, neglecting the conformational flexibility that these dyes retain at typical operating temperatures. Here we present a thermally aware screening framework that combines CREST conformational sampling with CENSO ensemble refinement (r²SCAN-3c) and Boltzmann-weighted TD-DFT (CAM-B3LYP) descriptors to evaluate 150 D–$\pi$–A architectures built from five donors, ten $\pi$-bridges, and three acceptors. A composite Z-score ranking of five charge-transfer and photovoltaic descriptors selected the ten most promising sensitizers, which were further examined across three functionals (B3LYP, CAM-B3LYP, $\omega$B97XD), charge-transfer kinetics, and explicit anchoring onto a (${\mathrm{TiO}}_2{)}_{14}$ anatase cluster. Boltzmann-averaged and single-conformer descriptors differed most strongly for dyes in which the lowest-energy conformers had very low oscillator strengths, making the ensemble properties sensitive to higher-energy, more emissive conformers. For D4-B1-A1, for example, the difference in the idealized short-circuit photocurrent descriptor $J_{\mathrm{SC}-\max }$ approached 100%, while the average deviation across the dataset was 18%. A similarly pronounced difference was observed for the charge-transfer rate $k_{\mathrm{CT}}$ for the same sensitizer, with the trend persisting across two additional functionals. These results suggest that conformational effects can become particularly important when torsional motions involving the donor or acceptor groups substantially alter the electronic character of the D–$\pi$–A sensitizer. Thus, for architectures with appreciable donor–bridge or bridge–acceptor torsional flexibility, ensemble averaging may provide a more representative description than relying on a single low-energy conformer. Anchoring calculations further showed that dyes bearing the dicyanomethylene-rhodanine acceptor adsorb only weakly onto TiO₂, despite favorable electronic descriptors. These results establish conformational averaging as a useful component of computational DSSC screening for structurally flexible sensitizers. Full article

This work proposes the construction of autonomous power supplies for specific home electronics based on reusing available materials. This would allow most standard electrical consumers, solar panels, and accumulators to connect directly and without any charging drivers. The proposed set of steps allows the creation of reproducible power supplies. The use of lead–acid accumulators enables series connection and charging directly from a high-voltage, low-current source, such as a solar panel. This will allow serial charging and discharging of accumulators without balancing, as well as support the direct connection of consumer devices and solar panels without converters. The proposed direct current (DC) operating voltage range, with a center voltage of 100 V, allows the use of eight sequentially connected 12 V accumulators for direct charging from three of the most common solar panels, with 72 cells connected in series (nine accumulators for four panels with 60 cells). At the same time, most home electronics with switched-mode power supplies (SMPSs) are designed for a voltage range of 100 V to 240 V and are capable to work from direct current starting with 15–30% less voltage. This guarantees support of the full voltage range of 8–9 lead–acid accumulators or 26s–32s lithium–ion accumulators for the reproducible construction of home power sources without extra converters. In addition, the reproducible construction of a power inverter with a true sine wave, with recommendations of how to adjust the supported input range to the required voltage for powering the fridge, is proposed. The proposed scalable circuit and assembly instructions for the power inverter based on EGS002 and widespread electrical transformers RT-1000B1 allow reproducible creation of inverters with a true sine output and a wide input voltage range, including 96 V DC. The application of the proposed method allows to reduce energy consumption up to 10% by removing converters. Full article

The decarbonization of hospitals located in remote regions with water stress requires a power source that is both reliable and cost-effective. The use of a green hydrogen energy system is proposed for use as the power source for the medical sector located in Ouarzazate, Morocco. The system utilizes photovoltaic panels to power proton exchange membrane (PEM) electrolyzers, which generate hydrogen fuel that is stored in a pipeline to the hospital site where it can be utilized in a fuel cell. A model was created in MATLAB/Simulink R2023a that considered the backward-propagation algorithm to size each of the components of the hydrogen energy system, which was optimized using the particle swarm optimization algorithm. The sizing results of the model indicated that a 924 kW electrolyzer, a 217 kW fuel cell, a 21.5 kW compressor, a 30 mm diameter pipeline, and a 7400 m² area for the photovoltaic panels are required to supply 161 kg of hydrogen per day to the hospital. The hydrogen fuel system will meet the demand of the hospital for 159 kg of hydrogen per day with a zero loss of load at the deterministic design point, in both the representative day and five-day cloudy-period stress test horizons; a full-physics Monte Carlo uncertainty analysis (N = 10,000 draws) further shows that this reliability outcome is not robust to combined ±20% uncertainty in electrolyzer efficiency and component unit costs, with zero loss of load maintained in 62.8% of draws. The installation cost of the hydrogen fuel system is approximately 8.21 M EUR. Furthermore, because the hydrogen fuel is stored upstream from the hospital, the flow rate of hydrogen fuel that passes through the pipeline is less than if it were stored downstream from the hospital. Finally, the levelized cost of hydrogen fuel of the system is approximately 13.67 EUR/kg, which shows limited sensitivity to the considered variations in solar irradiance. Thus, this hydrogen fuel system methodology can be applied to other types of critical loads, especially those critical loads within hospitals, in regions with high solar potential. Full article

Concentrating solar power (CSP) can simultaneously provide high-temperature steam and renewable electricity for solid oxide electrolysis cells (SOECs), offering an efficient pathway for solar hydrogen production. This study proposes and compares two CSP-SOEC integrated hydrogen production configurations based on different steam extraction strategies: main steam extraction before turbine expansion (Scheme 1) and reheated steam extraction after the reheating process (Scheme 2). The effects of steam extraction rate and SOEC operating temperature on the thermodynamic performance of the integrated system are systematically investigated. At an SOEC operating temperature of 600 °C, Scheme 1 achieves a maximum hydrogen production rate of 296.33 g s⁻¹ with an SOEC power consumption of 36.59 MW, while the CSP net output decreases to 1.15 MW. Under the same conditions, Scheme 2 reaches a hydrogen production rate of 240.67 g s⁻¹ and an SOEC power consumption of 29.74 MW, with the CSP net output reduced to 9.37 MW. Increasing the SOEC operating temperature to 1000 °C improves the hydrogen production rates to 271.61 g s⁻¹ and 225.31 g s⁻¹ for Scheme 1 and Scheme 2, respectively. The maximum solar-to-hydrogen energy conversion efficiency reaches 19.5%. For a 50 MW CSP plant, the maximum peak-shaving revenues are 21,002 CNY day⁻¹ for Scheme 1 and 21,350 CNY day⁻¹ for Scheme 2, respectively. The corresponding minimum LCOHs are 40.91 CNY kgH₂⁻¹ and 42.36 CNY kgH₂⁻¹, respectively. Full article

Impedance spectroscopy (IS) is a powerful tool for analyzing the physical mechanisms occurring in single-junction solar cells. However, identifying the impedance responses of the top and bottom sub-cells within a tandem solar cell remains challenging. This is because the series connection of the two sub-cells results in an overall tandem impedance in which the contributions of the individual sub-cells are combined and may even overlap, making their individual impedance contributions difficult to distinguish and investigate. This work proposes a diagnostic approach for monolithic perovskite/silicon tandem solar cells. The proposed approach requires a preliminary numerical or experimental characterization of the individual sub-cells before analyzing the monolithic tandem device. In particular, static and dynamic characterization techniques, including J-V curve tracing, C-V and C-f analyses, relaxation-time measurements, and IS, can be performed on each sub-cell as a standalone device to identify the frequency ranges in which its contribution to the overall tandem impedance is expected to be dominant. Subsequently, J-V curve tracing and IS are performed on the monolithic tandem device. The regions of the Nyquist plot in which the contribution of each sub-cell is expected to be dominant are then analyzed to extract information on the actual operating conditions of the individual sub-cells. The proposed methodology is demonstrated through TCAD numerical simulations and applied to case studies involving a tandem cell operating under near-current-matched and current-mismatched conditions. Full article

Nitrogen-doped carbon dots (N-CDs) have attracted considerable attention owing to their unique physicochemical and optoelectronic properties, as well as their promising potential for energy-related applications. However, only a limited number of studies have systematically investigated the influence of microwave-assisted synthesis conditions on the formation of these nanomaterials. In this work, five different N-CDs samples were synthesized from the same precursor system, consisting of citric acid and urea, by varying the microwave irradiation power and exposure time. The effects of these synthesis parameters on the formation and physicochemical characteristics of the carbon dots were systematically investigated. The synthesized materials were comprehensively characterized by ATR-FTIR, SEM, XPS, TG-DTA, UV-Vis absorption spectroscopy, photoluminescence spectroscopy, and electrochemical analyses. All samples exhibited similar chemical compositions and surface functional groups, while variations in the synthesis conditions led to noticeable differences in their thermal behavior, optical properties, and electrochemical responses. These findings highlight the important role of microwave synthesis parameters in fine-tuning the physicochemical properties of N-CDs and contribute to a deeper understanding of the relationship between synthesis conditions and the resulting material characteristics. The materials obtained were preliminarily tested as additives in the photoactive layer of perovskite solar cells. Overall, this study provides useful insights for the design and optimization of carbon dots with properties tailored for specific applications. Full article

Lead-free perovskite solar cells are promising as sustainable photovoltaics, but most of the copper-based alternatives are inefficient and unstable. The copper(I) perovskite chlorides (CuMCl₃, M = Fe, Cr, Zn) are optimized by tuning the thickness and doping of the TiO₂ electron transport layer, CuMCl₃ absorber, and Spiro-OMeTAD hole transport layer, respectively, using SCAPS-1D simulations. The notable performance of CuZnCl₃ (Voc = 0.79 V, Jsc = 38.2 mA·cm⁻², FF = 80.2%) is observed due to the comparatively small bandgap (~1.10 eV) and appropriate thickness of the absorber (700 nm), achieving a balance between the generation of photocurrent and bulk recombination. The optimized n-i-p configuration yields power conversion efficiencies of 9.7% (CuFeCl₃), 21.4% (CuCrCl₃), and a relatively high 24.2% (CuZnCl₃). CuCrCl₃ works effectively (Voc = 0.99 V, Jsc = 25.1 mA·cm⁻², FF = 86.15%) because it has a high dielectric constant and enables long diffusion. CuZnCl₃ has a relatively good initial efficiency but considerable thermal sensitivity at 300–345 K, whereas CuFeCl₃ has negligible thermal sensitivity. A rise in trap density leads to cation-dependent performance loss in all devices. This study proposes CuMCl₃ as a promising lead-free perovskite platform for future photovoltaics. Full article

Since their breakthrough development, dye-sensitized solar cells (DSSCs) have emerged as highly promising third-generation photovoltaics; however, interfacial charge carrier recombination remains a persistent bottleneck. This study investigates the application of a wide bandgap ZrO₂ electron blocking layer (EBL) to mitigate this recombination. A 48 nm ZrO₂ EBL was deposited on fluorine-doped tin oxide (FTO) via hydrothermal treatment. Empirical results demonstrate a remarkable 43.9% enhancement in overall power conversion efficiency (6.77%) and a 69% improvement in total Incident Photon-to-Current Efficiency (IPCE) compared to bare FTO architectures. To theoretically validate the role of an insulating material as an EBL, the empirical data is supported by mathematical modeling, specifically utilizing Wentzel–Kramers–Brillouin (WKB) quantum tunneling probabilities and 1D diffusion–recombination kinetics. The models confirm that at nanoscale thicknesses, ZrO₂ acts as a selective physical barrier that shifts the surface Fermi level and extends the electron lifetime to 0.0146 s. Furthermore, potential optimization pathways utilizing machine learning algorithms for ideal thickness prediction and IPCE clustering are discussed, paving the way for next-generation predictive device engineering. Ultimately, this dual empirical–theoretical approach provides a comprehensive understanding of the interfacial charge transport mechanisms, establishing a robust framework for designing highly efficient, leak-free photoanode architectures in next-generation photovoltaics. Full article

Phenethylammonium iodide (PEAI) is widely used to passivate undercoordinated ionic defects and regulate the near-surface structure of inverted perovskite solar cells; however, the solvent used for PEAI deposition can also interact with the underlying perovskite and therefore determine the treatment outcome. Here, ethanol (EtOH), isopropanol (IPA), and n-butanol (n-BuOH) were compared as aliphatic alcohol solvents for the PEAI post-treatment of inverted p–i–n solar cells based on a mixed-cation, mixed-halide Cs_0.05(FA_0.95MA_0.05)_0.95Pb(I_0.95Br_0.05)₃ absorber. EtOH caused pronounced surface disturbance and substantially reduced device performance. IPA afforded the highest initial power conversion efficiency (PCE) of 21.92% but was accompanied by a stronger PbI₂ diffraction signal. In contrast, n-BuOH provided a milder treatment, producing a comparable PCE of 21.83%, a weaker PbI₂ signal, and the highest water contact angle. After dark storage in air at 25 °C and 25% relative humidity for 168 h, the unencapsulated n-BuOH-treated devices retained 82% of their initial PCE, compared with 77% for the Control. These results demonstrate that the PEAI processing solvent is an active component that governs the balance among defect passivation, surface reconstruction, initial efficiency, and short-term storage stability. Full article

Physics-based models are useful for the analysis and optimization of crystalline-silicon solar cells when many device designs must be evaluated. This paper presents a compact transfer-matrix framework for one-dimensional carrier transport and physics-constrained optimization in bifacial $p^{+}$–n–$n^{+}$ crystalline-silicon solar cells under front-side illumination. The model includes a distributed optical generation profile, explicit emitter, base, and rear-field regions, surface recombination, doping-dependent mobility, Auger recombination, band-gap narrowing, sheet and contact resistances, and external series and shunt losses. The front and rear dopant distributions are described by complementary-error-function profiles, so their junction depths follow from the diffusion parameters and base concentration instead of being independent optimization variables. The solver is verified in limiting transport conditions and with tabulated generation data. The complete model is then calibrated against the reported photovoltaic figures of merit of an experimental bifacial n-type passivated-emitter and rear-totally-diffused (n-PERT) solar cell, which serves as the reference device and is subsequently applied to global optimization. The calibration reproduces a short-circuit current density of $J_{sc}=39.20\mathrm{mA}/{\mathrm{cm}}^2$, an open-circuit voltage of $V_{oc}=653.1\mathrm{mV}$, a fill factor of 0.783, and an efficiency of 20.05%. For the 180 µm reference geometry, the optimized design reaches an efficiency of 20.63%. Independent optimizations for wafer thicknesses of 160, 180, and 200 µm produce a consistent family of solutions with efficiency gains of approximately 0.56–0.60 percentage points. These gains result from the higher open-circuit voltage and fill factor despite a moderate reduction in short-circuit current density, while the optimized total series resistance remains nearly constant. The framework provides a physically interpretable method for combining carrier-transport modeling, experimental calibration, inverse design, and repeated global optimization. Full article

Cu²⁺, VO₂²⁺, and Fe³⁺ mononuclear complexes of the oxime-based ligand, 2-hydroxy-5-(p-tolyldiazenyl)benzaldehyde oxime (H₂L, 1), have been synthesized and structurally characterized by analytical, thermal, and spectral tools. They have been characterized by microanalyses (C, H, and N), ¹H and ¹³C-NMR, FT-IR, UV-Vis, and/or ESR spectral measurements. The various analytics data indicate that the oxime-based ligand behaved as a neutral bidentate chelator binding Cu²⁺, VO²⁺, and Fe³⁺ cations via the nitrogen atom of the protonated oximatic group and protonated phenolic hydroxyl oxygen atom, adopting a distorted octahedral geometry. Furthermore, computational studies utilizing DFT/B3LYP/6-311(pd) include assessment of dipole moment, global reactivity descriptors, optimized geometry, LUMO-HOMO energy gaps, and molecular electrostatic potential image (MEP), which were estimated to support the geometrical structure of Cu²⁺, VO²⁺, and Fe³⁺ complexes. Furthermore, the optical parameters, viz. the refractive index (n) and extinction coefficient of azo-oxime ligand and its complexes, have been precisely estimated within a 300–1100 nm wavelength. The values of optical gap (E_gap) for the azo-oxime ligand and its complex films diminished from 2.96 eV for H₂L to 1.83 eV for the Fe³⁺ film; however; the n values follow an opposite behavior. The obtained n and E_g values are comparable to those reported for various semiconducting materials, suggesting the potential suitability of the investigated films for future semiconductor and optoelectronic applications. Although practical device performance remains to be evaluated, these low-cost and easily prepared materials could serve as promising candidates in these fields. Furthermore, the dielectric and nonlinear optical parameters have been thoroughly evaluated and comprehensively discussed. Full article

The use of algae-based bioenergy platforms in establishing circular bioeconomy systems is due to their capacity to generate biomass of renewable origin, using solar energy and carbon dioxide (CO₂), while the process also involves remediation and recovery of resources. The introduction of algae to bioenergy systems is still limited by obstacles related to biomass productivity, efficiency of harvesting, and energy demands of further utilization of biomass, not to mention lack of system integration. The present paper provides a review of the new developments in the area of algal bioenergy platforms, focusing on the use of algae-assisted microbial fuel cells (MFCs) and biotech solutions based on nanotechnology. The combination of algae with MFC technology allows for the generation of bioelectricity and the use of algal systems for carbon fixation, nutrient removal, bioconversion of biomass, etc. Meanwhile, nanotechnology has become an important approach to enhance the development of algal bioenergy technologies by providing better cultivation activity, light absorption, nutrient transport, biomass extraction, catalysis, and electrodes. Advanced nanomaterials, such as magnetic nanoparticles, metal oxides, carbon-containing nanostructures, and combined nanomaterials, have allowed the industry to overcome the most important problems in algal biomass processing and bioelectrochemical energy production. At the same time, integrated algal biorefineries make it possible to transform a variety of biomass forms into biofuels or something even more valuable. Nevertheless, despite achieving significant resolution of many concerns, the scalability of technologies and the safety of the nanoparticles are still among major challenges to industrial implementation. The further development of algae-based technologies should allow sufficient integration of advanced nanomaterials, genetically engineered microbes, and scaling of reactor technologies. This review provides a unique integrated framework connecting algae cultivation, microbial fuel cell technologies, and nanotechnology-enabled biorefineries toward scalable circular bioenergy systems. Full article