Search Results (889)

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

This study explores the performance of an ultrathin Cu₂ZnSnSe₄ (CZTSe) absorber-based solar cell using numerical simulations carried out with SCAPS-1D software (version 3.8). Ultrathin absorber layers, generally thinner than 500 nm, are attractive because they require less material, reduce manufacturing costs, and can improve carrier collection due to the shorter distance that charge carriers must travel. However, when the absorber layer becomes very thin, it cannot absorb enough photons, which may limit the overall device performance. To overcome this challenge, the use of back surface field (BSF) layers is examined as a practical approach to improve photovoltaic efficiency. In this work, a solar cell structure composed of Carbon/BSF/CZTSe/CdS/i-ZnO/ITO was designed and simulated, with the thickness of the CZTSe absorber layer kept constant at 85 nm. Three different p⁺-type BSF materials, V₂O₅, Sb₂S₃, and CuSCN, were studied to understand how they influence device behavior. Important parameters such as electron affinity, interface defect density, acceptor defect density in the absorber layer, recombination processes, back contact properties, and operating temperature were systematically investigated. The addition of BSF layers forms a strong electric field at the p⁺–p interface, which helps push minority carriers toward the depletion region and reduces recombination losses at the back contact. The simulation results show that selecting a suitable BSF material can significantly enhance charge carrier collection and improve the efficiency of ultrathin CZTSe solar cells, offering useful guidance for designing more efficient thin-film photovoltaic devices. Full article

Bulk heterojunction (BHJ) active layers in organic photovoltaics (OPVs) are nanostructured composites in which electron-donating and electron-accepting semiconductors form interpenetrating phases for exciton dissociation and charge transport. The power conversion efficiency (PCE) of these organic-organic nanocomposites is governed by structural features spanning multiple length scales: molecular packing and energy-level alignment at donor/acceptor (D/A) interfaces, phase-separation morphology and crystallite connectivity, and thin-film optical and charge-transport characteristics. Rational design of high-performance OPV nanocomposites requires multiscale numerical modelling that bridges quantum chemistry, mesoscale morphology simulation, and device-scale optoelectronic modelling. This review surveys and critically compares recent advances in the structural design and numerical simulation of OPV BHJ nanocomposites. At the molecular scale, we examine density functional theory and non-adiabatic molecular dynamics approaches for resolving charge-separation driving forces, interfacial energy-level alignment, and exciton dynamics. At the mesoscale, we discuss molecular dynamics, kinetic Monte Carlo, and electronic coarse-graining methods for describing phase separation, crystallization kinetics, morphology evolution, and charge transport. At the device scale, we review exciton-diffusion, optical transfer-matrix, and drift-diffusion models that quantitatively link morphology to photovoltaic performance metrics. The review also evaluates how machine learning, high-throughput screening, surrogate models, and generative design accelerate donor–acceptor selection and morphology optimization, while distinguishing benchmark predictions from experimentally validated design rules. Across these scales, we compare the strengths, assumptions, and validation limits of the principal modelling approaches. Finally, we highlight emerging multiscale integration frameworks, including sequential parameter-passing pipelines and differentiable digital-twin concepts. By framing OPV BHJ layers as nanocomposites whose performance bottlenecks map onto composite-design challenges such as interface integrity, phase connectivity, multiscale charge transfer, and degradation-aware design, this review connects OPV modelling with broader structural-composites thinking for next-generation organic solar cells. Full article

Copper selenide (Cu₂Se), as a typical p-type narrow bandgap semiconductor, has garnered significant attention in the fields of thermoelectrics and optoelectronics due to its inherent low thermal conductivity, high Seebeck coefficient, low cost, and environmental friendliness. Compared with bulk materials, Cu₂Se thin films exhibit unique advantages in microdevice integration and flexible applications, holding great potential for applications in flexible thermoelectric generators, solar cells, and photodetectors. This article systematically reviews the research progress of Cu₂Se thin films, focusing on key preparation parameters such as growth temperature, annealing conditions, copper/selenium element ratio, and substrate type, and elucidates their regulation of film microstructure, crystal phase structure, and thermoelectric/optoelectronic properties. It delves into the mechanisms of doping strategies such as carrier concentration regulation, band engineering, and defect modification, clarifying the synergistic optimization effects of different doping elements on conductivity, Seebeck coefficient, and thermal conductivity. The article summarizes the current application status of Cu₂Se thin films, points out existing challenges such as poor process reproducibility and insufficient thermal stability, and anticipates future research directions such as multi-parameter synergistic optimization and heterojunction design, providing a systematic reference for the development and practical application of high-performance Cu₂Se-based functional thin films. Full article

Cadmium sulfide has been widely used as a conventional n-type window/buffer layer or heterojunction partner in several p-type thin-film solar cells, including CdTe/CdSeTe-, chalcopyrite-, kesterite-, antimony chalcogenide-, tin sulfide- and iron pyrite-based devices. Its success is related to its ability to form suitable heterojunctions, partially passivate absorber surfaces and provide favorable electronic selectivity. However, the parasitic absorption associated with the relatively narrow band gap of CdS, the toxicity and waste-management issues related to cadmium-containing auxiliary layers and the need for improved band alignment have motivated extensive research on CdS-free window and buffer layers. This review summarizes the main efforts devoted to replacing CdS in thin-film solar cells based on absorbers such as CdTe/CdSeTe, CIS, CIGS, CZTS, CZTSe, CZTSSe, Sb₂S₃, Sb₂Se₃, Sb₂(S,Se)₃, SnS and FeS₂. The most investigated alternative materials, including Zn(O,S), ZnS, In₂S₃, ZnMgO, ZnSnO, TiO₂, SnO₂ and SnS₂, are discussed with emphasis on their optical properties, band alignment, interface quality, deposition methods and impact on device performance. The analysis highlights that CdS replacement cannot be treated as a universal material substitution problem. Instead, each absorber and device architecture requires a specific front-interface design, where chemical compatibility, conduction band offset, defect passivation, optical transparency and process-induced interfacial modifications play a decisive role. CdS-free approaches are relatively mature for CdTe/CdSeTe- and CIGS-based solar cells, whereas kesterite absorbers, antimony chalcogenides and SnS still require further interface engineering. In FeS₂, by contrast, buffer-layer substitution remains secondary to the control of intrinsic surface and bulk electronic defects. This review provides a concise comparison of the most relevant CdS-free front/window materials and identifies key challenges for the future design of sustainable thin-film solar cells. Full article

One of the most promising absorber materials for solar applications is copper zinc tin sulfide/selenide (CZTS), which has good optical properties and basic elements that are readily available, affordable, and environmentally acceptable. This study examines how pulse timing and current density affect the electrodeposition of Cu₂ZnSnS₄/Cu₂ZnSn(S,Se)₄ (CZTS/CZTSSe) thin films from a diluted electrolyte, including deposition quality, film configuration, elemental composition, crystallinity, and photovoltaic performance. It evaluates the impact of these factors on device performance, film properties, layer’s compactness, surface homogeneity, microcrack-free morphology, compositional homogeneity, crystallinity, and suitability for solar device manufacturing. Using a pulsed-current technique, CZTS precursor layers were electrodeposited in a low-concentration solution with periodic changes in current density of roughly 5.3–5.9 mA/cm² and pulse-on/off durations of 50/50, 100/100, and 250/250 ms. The deposited precursors were then added to fully built CZTS-based solar cell topologies after sulphurization or selenization. Structural characteristics were analyzed using X-ray diffraction (XRD), and composition and elemental distribution were assessed using energy-dispersive X-ray spectroscopy (EDS). Measurements of transmittance and reflectance were used to evaluate optical properties relevant to photovoltaic performance. In contrast to films deposited at higher current densities and longer off-times, moderate current densities combined with short off-times yield dense, microcrack-free films with improved crystallinity and near-stoichiometric Cu/(Zn + Sn), Zn/Sn, and chalcogen/metal ratios. Additionally, absorber layers with appropriate optical band gaps and improved device performance are produced by these optimized pulse parameters. Overall, the study shows that controlling pulse parameters in diluted electrolytes is a useful tactic for improving the quality of CZTS films and developing low-cost, solution-based fabrication techniques for high-performance CZTS solar cells. Full article

To address the bottleneck that traditional building blinds struggle with, namely synergistically achieve shading control and energy recovery, a vertical mid-pane photovoltaic (PV) louver based on a self-powered feedback mechanism was designed. This system utilizes the voltage difference generated by differential light exposure on photovoltaic thin-film cells to drive a motor, realizing zero-energy automatic tracking of the solar azimuth and dynamic adjustment of component angles. By establishing a mathematical model for sunlight-tracking power generation and combining it with COMSOL multiphysics simulation, the coupling effects of the PV louver angle, operating conditions, and solar terms on photoelectric performance were thoroughly analyzed. The research results indicate that when the PV louver angle increases from 60° to 150°, the power generation significantly improves by 80%. Compared with the non-tracking mode, the all-day power generation efficiency gain of the vertical tracking center-mounted PV louver can reach up to 19.68%. Driven by the seasonal evolution of the solar elevation angle, the direct radiation irradiance during the tracking period across four typical solar terms exhibits a distribution pattern characterized as “higher in winter, lower in summer, and intermediate in spring and autumn.” These findings provide a technical pathway integrating dynamic shading, passive photothermal regulation, and clean power generation for south-facing facades in hot summer and cold winter zones, offering significant reference value for enhancing the energy autonomy and low-carbon level of building envelopes. Full article

Colloidal processing provides a scalable non-vacuum route for fabricating CIGS and CZTSSe thin-film absorbers, but nanoparticle-derived films should be treated as constrained particulate green bodies rather than as simple chemically deposited semiconductor layers. This review reorganizes colloidal chalcogenide photovoltaics using ceramic-processing concepts: ink dispersion, green-body packing, capillary drying stress, ligand burnout, constrained shrinkage, reactive chalcogenization, transient liquid-assisted coarsening, secondary-phase control, defect chemistry, and interface reactions. The central argument is that film densification and grain growth are necessary but insufficient for high-performance CZTSSe devices. Residual carbon, Sn loss, Cu/Zn disorder, ZnSe or Cu_2−xSe secondary phases, excessive MoSe₂, and nonideal absorber/buffer band alignment can dominate open-circuit-voltage loss, fill factor, and carrier collection even when the absorber appears dense in cross-sectional microscopy. By linking ceramic-processing variables to photovoltaic loss mechanisms, this review identifies practical routes for improving colloidal chalcogenide solar cells: controlled ligand exchange and binder burnout, high-green-density precursor design, moderated chalcogen chemical potential, transient liquid management, depth-resolved phase analysis, and integrated front/back-interface engineering. Full article

This work reports, for the first time, the use of agave bagasse from “Tequila Weber Var” as an efficient and eco-friendly template for the microwave-assisted solvothermal synthesis of C@TiO₂ photoelectrodes. The characterization of the C@TiO₂ materials was performed using composition and elemental analysis, diffuse reflectance/UV-visible spectroscopy, N₂ adsorption/desorption isotherms, scanning and transmission electron microscopy, energy-dispersive X-ray spectroscopy, X-ray diffraction patterns, cyclic voltammetry, impedance spectroscopy, and variations of the open-circuit potential in a conventional electrochemical cell. Three 1:1, 4:1, and 8:1 agave:Ti volume ratios were used to explore the influence of carbon content upon the optical and photoelectric properties of TiO₂. The composite with a 1:1 ratio showed a charge transfer kinetic capacity of 0.86 C·cm⁻²·s⁻¹ with the highest current density flow of 2.2 mA·cm⁻², and the lowest optical band gap (E_bg) value of 2.92 eV, boosting the optoelectronic behavior of TiO₂. The photoanode composed of FTO/C@TiO₂ with the hybrid material with a 1:1 ratio was preliminarily evaluated in a photovoltaic solar cell, showing a light-to-electricity conversion efficiency higher than the other two composites and up to 12.5 times higher than the photoanode only composed of neat TiO₂. The present results contribute to the state-of-the-art of eco-friendly organic–inorganic thin film photoelectrodes for the sustainable synthesis of third-generation solar cells using bagasse-derived waste as an efficient carbon source for the synthesis of hybrid photoactive semiconductors. Full article

This work reports the results of a study on the optical, morphological, and structural properties of cesium lead bromide iodide mixed perovskite thin films (CsPbBr_3−xI_x), synthesized by sequential evaporation of precursors (CsBr, PbBr₂, PbI₂). First, the deposition conditions were optimized to obtain thin films predominantly composed of the pure CsPbBr₃ phase. Subsequently, the influence of partial substitution of Br⁻ by I⁻ on the film properties was investigated. Particular emphasis was placed on evaluating the effect of partial Pb²⁺ substitution by Zn²⁺ on the optical, morphological, electronic, and structural properties using optical transmittance, photoluminescence, scanning electron microscopy (SEM), X-ray diffraction (XRD), Urbach energy analysis, and density functional theory (DFT) calculations. Zn²⁺-doped CsPbBr_3−xI_x films were prepared by evaporating a ZnBr₂ layer onto the pre-deposited PbBr₂/PbI₂ precursor layers. It was found that Zn²⁺-doped inorganic CsPbBr_3−xI_x perovskite films exhibit enhanced crystallinity and improved surface morphology. Additionally, photoluminescence characterization confirms that non-radiative recombination decreases significantly, apparently due to a reduction in intrinsic defect density. The effect of Zn²⁺ doping on the power conversion efficiency of carbon-based planar solar cells was also evaluated. Collectively, Urbach energy, photoluminescence, and SEM analyses revealed that the optimal Zn²⁺ doping range for CsPbBr_3−xI_x perovskite films is ≤5%. Full article

As an emerging photovoltaic technology, Cu₂ZnSn(S,Se)₄ (CZTSSe) thin-film solar cells are regarded as a viable, cost-effective alternative to satisfy future demand for green energy. This promise is attributed to their tunable bandgap (1.0~1.5 eV), high absorption coefficient (>10⁴ cm⁻¹), and environmentally friendly composition. Currently, the record power conversion efficiency (PCE) of CZTSSe devices has reached 16.6%, approaching commercial levels. However, this value remains significantly lower than its theoretical limit of 32.8% and the 23.6% achieved by the homologous CIGS technology, indicating immense potential for performance enhancement. The severe open-circuit voltage deficit (E_g/q-V_oc) remains a critical factor preventing CZTSSe solar cells from reaching their expected efficiency. This issue is primarily associated with band misalignment and deep-level defects at the interfaces. At present, interface engineering has been demonstrated to be an effective strategy to significantly improve the performance of CZTSSe thin-film solar cells. Herein, we review the development process of CZTSSe photovoltaics, systematically discuss existing interface-related issues and comprehensively summarize recent strategies in interface engineering. Finally, to further elucidate the intrinsic mechanisms and facilitate the development of high-efficiency devices, future research directions and perspectives regarding interface engineering are proposed. Full article

The efficiency of perovskite solar cells has increased to a certified value of 27% over the past decade, benefiting from the superior properties of metal halide perovskite materials. However, their long-term operational stability is still far inferior to that of commercial crystalline silicon solar cells. A key source of this instability is field-driven ion migration in vertical architectures, along with the consequent degradation at the absorber–electrode interfaces. Compared with the widely investigated vertical structures, back-contacted (BC) perovskite solar cells—wherein both electrodes are positioned on the same side of the absorber—offer a unique route to suppress interfacial ion migration and thereby enhance long-term device stability. These advantages are especially pronounced when combined with single-crystal perovskites, which possess low charge trap densities, long carrier diffusion lengths, and high bulk ion migration barriers. Unfortunately, only a handful of research groups have participated in the development of single-crystal BC perovskite solar cells; thus, the advancement of this area lags far behind that of its vertical counterpart. Therefore, a review that discusses the recent developments and challenges of single-crystal BC perovskite solar cells is urgently required to provide guidelines for this emerging field. In this progress report, we first introduce the main growth methods of single-crystal wafers compatible with BC architectures, followed by an outline of the developmental history of BC perovskite solar cells. Finally, the core bottlenecks facing single-crystal BC devices and corresponding optimization strategies are discussed in detail. Full article

Thin-film solar cells (TFSCs) remain a cornerstone of the global transition toward renewable energy, characterized by consistent reductions in manufacturing costs and steady gains in power conversion efficiency. In addition to electricity generation, TFSCs play an important role in advanced solar thermal cooling, heating, and energy storage systems, where their tunable optical absorption, low thermal mass, and flexibility enable integration with photovoltaic–thermal (PV/T) collectors, thermally driven cooling cycles, and hybrid thermal–electrical storage architectures. This paper provides a comprehensive review of prominent TFSC technologies, including copper indium gallium selenide (CIGS), cadmium telluride (CdTe/CdS), amorphous silicon (a-Si), copper zinc tin sulfide (CZTS), organic photovoltaics (OPVs), and metal halide perovskite solar cells (PSCs), with a focus on their material structures, performance specifications, and current efficiency benchmarks. Compared to state-of-the-art reviews, this article distinguishes itself by addressing next-generation innovations, cross-domain solar thermal–photovoltaic applications, and economic analysis. Specifically, the integration of machine learning and simulation-based material dynamics is examined to accelerate material discovery, process optimization, and the characterization of novel TFPV components relevant to coupled thermal–electrical energy systems. Furthermore, the study explores how additive manufacturing is transforming the industry through the development of high-efficiency electrodes, electrohydrodynamic atomization for thin-film deposition, and the fabrication of flexible solar arrays suitable for thermally integrated and building-scale energy systems, including space applications. By integrating advancements in module efficiency, scalable manufacturing approaches, and techno-economic analysis, this paper positions TFSCs as sustainable, resource-abundant technologies essential for next-generation solar thermal cooling, heating, and energy storage infrastructures. Full article

The substrate plays a critical yet often underappreciated role in determining the performance, stability and manufacturability of photovoltaic devices. While conventional glass and polymer films have enabled the rapid development of solar technologies, emerging applications such as building-integrated photovoltaics, wearable systems and large-area conformal devices demand the use of non-conventional substrates, including ceramics, metals, paper, textiles and elastomeric materials. This review provides a comprehensive analysis of the current state of the art of non-conventional substrates for photovoltaic technologies, with particular emphasis on the interplay between material properties, surface chemistry and deposition processes. These substrates introduce distinct mechanical, thermal and interfacial constraints that fundamentally alter thin-film growth, defect formation and device reliability. Key challenges such as porosity, roughness, thermal transport limitations and outgassing are discussed in relation to nucleation, film continuity and interfacial stability. The role of substrate-dependent effects in both chemical and physical deposition techniques is critically examined, highlighting cases where conventional processing approaches are insufficient. Representative device demonstrations are analyzed to illustrate how substrate selection influences performance and integration strategies across different photovoltaic platforms. Finally, common limitations and emerging opportunities are identified, emphasizing the need for the co-design of substrates, materials and processing routes. This work establishes a unified framework to guide the development of next-generation photovoltaic devices on unconventional substrates. Full article