Search Results (844)

Rapid progress on the fabrication of lead halide perovskite has led to the development of high performance optoelectronic devices, particularly in the field of solar cell technologies. This initial success has subsequently inspired investigations into layered 2D-halide perovskite structures, motivated in part by their good environmental stability, but more significantly by their intriguing fundamental photo-physics. They have recently been used to improve the photoresponsivity of monolayer transition metal dichalcogenides in hybrid heterostructures. In this paper, we report on the synthesis of the (PEA)₂(MA)_n−1Pb_nI_3n+1 series (with n = 1, 2, 3) of 2D-halide perovskites, in order to develop a platform that provides ultra-thin layers for the fabrication of hybrid heterostructures. The crystal synthesis method and its basic structural and optical characterization are shown, highlighting the differences in the crystal synthesis processes. Furthermore, we explore the preparation of 2D halide perovskite ultra-thin flakes using the mechanical exfoliation method, and few-layer-areas of n = 1 member of the series are identified using atomic force microscopy. Finally, we study the deposition of thin and ultra-thin films using the spin coating technique to provide an alternative exfoliation process. Full article

Electrolysis and biological processes, such as fermentation and microbial electrolysis cells, offer efficient hydrogen production alongside wastewater treatment. This study presents a novel microbial electrolyzer (ME) comprising a titanium dioxide (TiO₂) anode, a nickel–iron–carbon (NiFeC) cathode, and a cellulose nanocrystal proton exchange membrane (CNC-PEM) designed to generate hydrogen from palm oil mill effluent (POME). The system is powered by a 12 V electric double-layer organic supercapacitor (EDLOSC) integrated with a ZnO/PVA-based solar thin film. Power delivery to the TiO₂-NiFeC-PEM electrolyzer is optimized using an Adaptive Neuro-Fuzzy Inference System (ANFIS). Laboratory-scale pilot tests demonstrated effective degradation of POME’s organic content, achieving a hydrogen yield of approximately 60%. Additionally, the nano-structured ZnO/CuO–ZnO/PVA solar film facilitated stable power supply, enhancing in situ hydrogen production. These results highlight the potential of the EDLOSC-encased ZnO/PVA-powered electrolyzer as a sustainable solution for hydrogen generation and industrial wastewater treatment. Full article

We introduce a fully solution-processed interlayer strategy for n–p CdS/PbS thin film solar cells that combines a sol–gel ZnO compact coating with an electrospun ZnO nanofiber network. The synthesis and characterization of ZnO, CdS, and PbS thin films, complemented by electrospun ZnO nanofibers, are aimed at low-cost photovoltaic applications. Sol–gel ZnO films exhibited a hexagonal wurtzite structure with a bandgap (Eg) of approximately 3.28 eV, functioning effectively as electron transport and hole-blocking layers. CdS films prepared by chemical bath deposition (CBD) showed mixed cubic and hexagonal phases with an Eg of about 2.44 eV. PbS films deposited at low temperature displayed a cubic galena structure with a bandgap of approximately 0.40 eV. Scanning Electron Microscopy revealed uniform ZnO and CdS surface coatings and a conformal 1D ZnO network with nanofibers measuring about 50 nm in diameter (ranging from 49.9 to 53.4 nm), which enhances interfacial contact coverage. PbS films exhibited dense grains ranging from 50 to 150 nm, and EDS confirmed the expected stoichiometries. Electrical characterization indicated low carrier densities and high resistivities consistent with low-temperature processing, while mobilities remained within reported ranges. The incorporation of ZnO layers and nanofibers significantly improved device performance, particularly at the CdS/PbS heterojunction. The device achieved a V_oc of 0.26 V, an J_sc of 3.242 mA/cm², and an efficiency of 0.187%. These improvements are attributed to enhanced electron transport selectivity and reduced interfacial recombination provided by the percolated 1D ZnO network, along with effective hole blocking by the compact film and increased surface area. Fill-factor limitations are linked to series resistance losses, suggesting potential improvements through fiber densification, sintering, and control of the compact layer thickness. This work is a proof-of-concept of a fully solution-processed and low-temperature CdS/PbS architecture. Efficiencies remain modest due to low carrier concentrations typical of low-temperature CBD films and the deliberate omission of high-temperature annealing/ligand exchange. Overall, this non-vacuum, low-temperature coating method establishes electrospun ZnO as a tunable functional interlayer for CdS/PbS devices and offers a practical pathway to elevate power output in scalable productions. These findings highlight the potential of nanostructured intermediate layers to optimize charge separation and transport in low-cost PbS/CdS/ZnO solar cell architectures. Full article

The tunable bandgap of CIGSe has established bandgap engineering as a pivotal research direction for advancing the efficiency frontiers of solar cells. In particular, the proposal of the V-shaped bandgap gradient has motivated extensive efforts to achieve precise control over elemental composition and spatial distribution within the absorber layer. Against this backdrop, this review systematically classifies active control strategies—such as surface sulfurization, Ga grading, and Ag alloying—according to their doping mechanisms and the resulting bandgap profiles. It further evaluates emerging profiles, including the “hockey-stick” distribution, against the conventional V-shaped benchmark, and explores future pathways for bandgap engineering in next-generation, high-efficiency photovoltaic devices. Further improvements in photovoltaic efficiency can effectively boost power generation and lower solar power costs, providing a practical solution to future energy and environmental challenges. Full article

Barium disilicide (BaSi₂) was identified as a promising silicon-based photovoltaic absorber due to its near-optimal bandgap, strong optical absorption, and earth-abundant composition. However, the performance of BaSi₂ thin-film solar cells was severely restricted by structural defects and interfacial instabilities that introduced localized electronic states and facilitated non-radiative recombination. These imperfections degraded carrier lifetime, mobility, and open-circuit voltage. This review systematically examined the formation, energetics, and electronic roles of intrinsic and extrinsic defects in BaSi₂ thin films, and evaluated nanoscale passivation strategies developed to mitigate defect-induced losses. Chemical, dielectric, and interfacial approaches were critically analyzed with emphasis on their underlying mechanisms, limitations, and integration potential. The convergence of in situ characterization, first-principles modeling, and data-driven process optimization was expected to enable predictive defect control and rational interface design, thereby advancing BaSi₂-based photovoltaics toward practical implementation. Full article

The global temperature increase has posed urgent challenges, with buildings accountable for as much as 40% of CO₂ emissions, and their decarbonization is critical to meet the net-zero target by 2050. Solar photovoltaics present a promising trajectory, especially through building-integrated photovoltaics (BIPVs), where thin-film technologies can be used to replace traditional building materials. This article critically examined the development of thin-film solar cells for BIPVs, including their working mechanisms, material structures, and efficiency improvements in various generations. The discussion underscored that thin-film technologies, including CdTe and CIGS, had noticeably shorter energy payback times between 0.8 and 1.5 years compared to crystalline silicon modules that took 2 to 3 years, thus promising quicker recovery of energy and higher sustainability values. Whereas certain materials posed toxicity and environmental concerns, these were discovered to be surmountable through sound material selection and manufacturing innovation. The conclusions highlighted that the integration of lower material usage, high efficiency potential, and better energy payback performance placed thin-film BIPVs as an extremely viable option for mitigating lifecycle emissions. In summary, the review emphasized the critical role of thin-film solar technologies in making possible the large-scale implementation of BIPVs to drive the world toward net-zero emissions at a faster pace. Full article

The synthesis of thin films in multilayer structures on different textiles is of interest due to their potential use in flexible solar absorber coatings and thin-film solar cells. The aim of the study was to deposit bismuth(III) sulphide and copper(II) sulphide thin films on various textiles at the same time. This was achieved using the sustainable and cost-effective successive ionic layer adsorption and reaction (SILAR) method. The study examined how the elemental distribution, phase composition, crystallinity, surface morphology, and optical features of the resulting films are determined by the intrinsic structure and material makeup of structural textiles. The analysis used data from scanning electron microscopy (SEM), energy dispersive X-ray (EDX) spectroscopy and X-ray diffraction (XRD), as well as ultraviolet-visible (UV-Vis) diffuse reflectance spectroscopy. Depending on the textiles used, the formed films were polycrystalline and rich in copper. According to the findings, the normalised atomic percentages were as follows: Cu, 57.66–68.75%; Bi, 1.19–5.26%; S, 30.06–38.63%. The direct transition optical energy gap values varied from 1.3 to 2.88 eV, while the indirect varied from 0.9 to 2.25 eV, and the refractive index from 1.3 to 1.8. These properties were influenced by the composition of the textiles and the films themselves. These properties directly impact the films’ applications. Full article

Hybrid solar cells, which combine inorganic and organic materials, offer a promising pathway to achieve low cost, flexible, high-performance photovoltaic devices. This work explores the application of oxidative chemical vapor deposition (oCVD) to deposit poly(3,4-ethylenedioxythiophene) (PEDOT) as a transparent hole transfer layer in hybrid solar cells. Unlike solution-processed PEDOT with polystyrene sulfonate solubilizer (PEDOT:PSS), oCVD allows for growing high-purity PEDOT that provides conformal coverage on textured substrates, enabling enhanced antireflective effects and improved charge extraction. We discuss the advantages of oCVD PEDOT in hybrid architecture, its compatibility with textured substrates, and its potential to achieve higher efficiency. Full article

The earth-abundant, ecologically friendly structure of kesterite Cu₂ZnSn(S,Se)₄ (CZTSe) solar cells, with their advantageous optoelectronic characteristics, including a direct bandgap (1.0–1.5 eV) and a high optical absorption coefficient (>10⁴ cm⁻¹), have made them a very promising member of thin-film photovoltaics. However, the path toward commercialization has been slowed down by restraint such as high open-circuit voltage deficits, deep-level defect states, and compositional inhomogeneities that lead to charge recombination and efficiency loss. Despite these obstacles, very recent advances in material processing and device engineering have revitalized this technology. Incorporating elements like Ge, Ag, and Li; optimizing interface properties; and introducing methods like hydrogen-assisted selenization have all contributed to raising device efficiencies by around 15%. This review discusses recent progress and evaluates how far CZTSSe has come and what remains to be done to realize its commercial promise. Full article

A solvent-free, solid-state mechanochemical method was developed to synthesize the chalcohalide compound SbSI at room temperature. Dry high-energy planetary ball milling of elemental antimony, sulfur, and iodine produced a pure, stoichiometric polycrystalline SbSI powder with an orthorhombic structure. This powder was then sintered under mild thermal conditions to create dense targets. Amorphous SbSI thin films were subsequently deposited from these targets at room temperature using Pulsed Electron Deposition. The films maintained the correct stoichiometry and exhibited an optical bandgap of 1.89 eV. Post-deposition annealing at 90 °C in air successfully induced crystallization, demonstrating a viable, low-temperature, and eco-friendly route to produce polycrystalline SbSI thin films. This scalable approach has promising potential for optoelectronic and energy-harvesting applications. Full article

Copper nitride (Cu₃N) is gaining attention as an eco-friendly thin-film semiconductor in a myriad of applications, including storage devices, microelectronic components, photodetectors, and photovoltaic cells. This work presents a detailed optoelectronic study of Cu₃N thin films grown by reactive RF-magnetron sputtering under pure N₂. An overview of the state-of-the-art literature on this material and its potential applications is also provided. The studied films consist of Cu₃N polycrystals with a cubic anti-ReO₃ type structure exhibiting a preferential (100) orientation. Their optical properties across the UV-Vis-NIR spectral range were investigated using a combination of multi-angle spectroscopic ellipsometry, broadband transmission, and reflection measurements. Our model employs a stratified geometrical approach, primarily to capture the depth-dependent compositional variations of the Cu₃N film while also accounting for surface roughness and the underlying glass substrate. The complex dielectric function of the film material is precisely determined through an advanced dispersion model that combines multiple oscillators. By integrating the Tauc–Lorentz, Gaussian, and Drude models, this approach captures the distinct electronic transitions of this polycrystal. This customized optical model allowed us to accurate extract both the indirect (1.83–1.85 eV) and direct (2.38–2.39 eV) bandgaps. Our multifaceted characterization provides one of the most extensive studies of Cu₃N thin films to date, paving the way for optimized device applications and broader utilization of this promising binary semiconductor, and showing its particular potential for photovoltaic given its adequate bandgap energies for solar applications. Full article

In this study, first-principles calculations were employed to systematically investigate the interaction mechanisms between (18-crown-6) potassium (18C6-K⁺) and six typical defect sites on the SnO₂ (110) surface, including Sn_i + Sn_O, O_i + O_Sn, V_O + Sn_i, V_Sn + Sn_O, V_Sn + Sn_i, and Sn_i. Six intrinsic or complex defects universally coexist on the SnO₂ surface, and the defect states they introduced allow for precise tuning of material performance. The results demonstrated that the 18C6-K⁺ molecule can stably adsorb on all six defect sites and significantly increase defect formation energies, indicating its thermodynamic capability to suppress defect generation. A subsequent density of states (DOS) analysis revealed that the 18C6-K⁺ molecule exhibits strong defect passivation effects at Sn_i + Sn_O, V_O + Sn_i, V_Sn + Sn_i, and Sn_i sites, and partially mitigated the electronic disturbances induced by O_i + O_Sn and V_Sn + Sn_O defects. Furthermore, the incorporation of 18C6-K⁺ has been shown to reduce the electronic effective mass of defective systems, thereby enhancing surface carrier transport. A subsequent charge density difference (CDD) analysis revealed that the 18C6-K⁺ molecule forms Sn-ether and O-ether interactions through its ether bonds (C-O-C) with surface Sn and O atoms, inducing interfacial electronic reconstruction and charge transfer. The Bader charge analysis revealed that the H, C, and O atoms in 18C6-K⁺ lose electrons, whereas the Sn or O atoms at the surface defect sites gain electrons. This outcome is consistent with the CDD analysis and quantitatively confirms the extent of electron transfer from 18C6-K⁺ to the SnO₂ defect regions. These interactions effectively passivate defect states, thereby enhancing interfacial stability. The present study offers theoretical guidance and design insights for the development of molecular passivation strategies in SnO₂-based optoelectronic devices. Full article

Reliable power generation from solar cells is critical for spacecraft operation. High-energy laser irradiation poses a significant threat, as it can potentially cause irreversible damage to solar cells, which is difficult to detect remotely using conventional techniques such as radar or optical imaging. Spectral detection offers a potential approach through unique “spectral fingerprints,” but the spectral characteristics of laser-damaged solar cells remain insufficiently documented. This study investigates the scattering spectral characteristics of triple-junction GaAs (Gallium Arsenide) solar cells subjected to nanosecond pulsed laser irradiation to establish spectral signatures for damage assessment. GaAs solar cells were irradiated at varying energy densities. Bidirectional Reflectance Distribution Function (BRDF) spectra (400–1200 nm) were measured. A thin-film interference model was used to simulate damage effects by varying layer thicknesses, thereby interpreting experimental results. The results demonstrate that as the laser energy density increases from 0.12 to 2.96 J/cm², the number of absorption peaks in the visible range (400–750 nm) decreases from three to zero, and the oscillation in the near-infrared range vanishes completely, indicating progressive damage to the GaInP (Gallium Indium Phosphide) and GaAs layers. This study provides a spectral-based approach for remote assessment of laser-induced damage to solar cells, which is crucial for satellite health monitoring. Full article

Perovskite materials have garnered significant attention in both fundamental research and practical applications owing to their exceptional light absorption coefficients, low fabrication costs, and inherent advantages for thin-film and flexible device fabrication. Nevertheless, interface defects within perovskite films induce detrimental non-radiative carrier recombination and pronounced hysteresis effects, which collectively impose substantial limitations on the photovoltaic performance and long-term operational stability of perovskite solar cells (PSCs). Conventional passivation strategies, despite their demonstrated efficacy in mitigating interface defects, often inadvertently introduce secondary defects in originally defect-free regions, thereby restricting the extent of device performance improvement. To overcome this critical limitation, we have developed a precision defect passivation methodology that employs a targeted two-step immersion–cleaning process, achieving selective defect passivation while concomitantly eliminating residual passivating agents. This approach effectively prevents the formation of new defects in unaffected regions of the perovskite films, and the resultant PSC possesses a power conversion efficiency (PCE) of 21.08%, accompanied by a substantial mitigation of hysteresis behavior. Furthermore, unencapsulated devices demonstrate remarkable stability, retaining over 81% of their initial efficiency after 20 days of atmospheric storage under 50% relative humidity, which underscores the effectiveness of our passivation strategy in simultaneously enhancing both device performance and operational stability. Full article

Cobalt-doped iron disulfide (FeS₂) thin films were synthesized via chemical bath deposition (CBD) followed by annealing at 450 °C, yielding phase-pure pyrite structures with multifunctional properties. A deposition temperature of 95 °C is critical for promoting Co incorporation, suppressing sulphur vacancies, and achieving structural stabilization of the film. After annealing, the dendritic morphologies transformed into compact quasi-spherical nanoparticles (~100 nm), which enhanced the crystallinity and optoelectronic performance of the films. The films exhibited strong absorption (>50%) in the visible and near-infrared regions and tunable direct bandgaps (1.14 to 0.96 eV, within the optimal range for single-junction solar cells. Electrical characterization revealed a fourth-order increase in conductivity after annealing (up to 4.78 Ω⁻¹ cm⁻¹) and confirmed stable p-type behavior associated with Co²⁺-induced acceptor states and defect passivation. These results demonstrate that CBD enabled the fabrication of Co-doped FeS₂ thin films with synergistic structural, electrical, and optical properties. The integration of earth-abundant elements and tunable electronic properties makes these films promising absorber materials for the next-generation photovoltaic devices. Full article