Search Results (497)

In the last decades, small satellites such as CubeSats and PocketQubes have become popular platforms for scientific and applied missions in low Earth orbit (LEO). However, prolonged exposure to atomic oxygen, ultraviolet radiation, and thermal cycling in LEO leads to gradual degradation of onboard solar panels, reducing mission lifetime and performance. This study addresses the need to quantify and compare the degradation behavior of different solar cell technologies and protective coatings used in nanosatellites and pico-satellites. The aim is to evaluate the in-orbit performance of monocrystalline silicon (Si), gallium arsenide (GaAs), triple-junction (TJ) structures, and copper indium gallium selenide (CIGS) cells under varying orbital and satellite parameters. Telemetry data from recent small satellite missions launched after 2020, combined with numerical modeling in GNU Octave, were used to assess degradation trends. The models were validated using empirical mission data, and statistical goodness-of-fit metrics (RMSE, R²) were applied to evaluate linear and exponential degradation patterns. Results show that TJ cells exhibit the highest resistance to LEO-induced degradation, while Si-based panels experience more pronounced power loss, especially in orbits below 500 km. Furthermore, smaller satellites (<10 kg) display higher degradation rates due to lower thermal inertia and limited shielding. These findings provide practical guidance for the selection of solar cell technologies, anti-degradation coatings, and protective strategies for long-duration CubeSat missions in diverse LEO environments. Full article

The blocking layer is crucial for inhibiting recombination processes in photovoltaics that utilize oxide semiconductors, such as dye-sensitized solar cells (DSSCs), quantum-dot-sensitized solar cells (QDSSCs), and perovskite solar cells. However, its effectiveness strongly depends on the chosen deposition method. This study systematically evaluates the most suitable approach for obtaining a uniform, pinhole-free titanium dioxide (TiO₂) blocking layer by using three deposition methods: radio-frequency sputtering, spin-coating, and chemical bath deposition. The electrochemical, optical, and morphological properties of blocking layers were characterized using cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS), UV-VIS spectroscopy, scanning electron microscopy (SEM), atomic force microscopy (AFM), and Kelvin probe force microscopy (KPFM). KPFM analysis, together with CV and EIS, revealed that the lower R_ct values and higher CV currents observed in spin-coated (SC_11-33) and vertically deposited CBD films (CB_5, CB_6) resulted from incomplete FTO coverage. In contrast, sputtered (SP_21-24) and horizontally deposited CBD films (CB_1, CB_2) demonstrated significantly higher R_ct values and improved surface coverage. Full DSSCs fabricated with SP_23, SC_33, and CB_2 confirmed the correlation between interfacial properties and photovoltaic performance. This combined approach offers a fast, material-efficient, and environmentally conscious screening method for optimizing blocking layers in solar cell technologies. Full article

Transparent conductive aluminum-doped zinc oxide (AZO) films were investigated as potential recombination layers for perovskite/silicon tandem solar cells, comparing the results of atomic layer deposition (ALD) and magnetron sputtering (MS) on vertically aligned silicon nanowire (SiNW) scaffolds. Conformality and thickness control were examined by cross-sectional SEM/TEM and profilometry, revealing fully conformal ALD coatings with tunable thicknesses (40–120 nm) versus tip-capped, semi-uniform MS films (100–120 nm). Optical transmission measurements on glass substrates showed that both 120 nm ALD and MS layers exhibit interference maxima near 450–500 nm and 72–89% transmission across 800–1200 nm; the thinnest ALD films reached up to 86% near-IR transparency. Four-point probe analysis demonstrated that ALD reduces surface resistance from 1150 Ω/□ at 40 nm to 245 Ω/□ at 120 nm, while MS layers achieved 317 Ω/□ at 120 nm. These results delineate the balance between conformality, transparency, and conductivity, providing design guidelines for AZO recombination interfaces in next-generation tandem photovoltaics. Full article

We investigated a novel natural dye-sensitized solar cell (DSSC) utilizing gadolinium ruthenate pyrochlore oxide Gd₂Ru₂O₇ (GRO) as a photoanode and compared its performance to the TiO₂-Gd₂Ru₂O₇ (TGRO) combined-layer configuration. The films were fabricated using the spin-coating technique, resulting in spherical grains with an estimated mean diameter of 0.2 µm, as observed via scanning electron microscopy (SEM). This innovative photoactive gadolinium ruthenate pyrochlore oxide demonstrated strong absorption in the visible range and excellent dye adhesion after just one hour of exposure to natural dye. X-ray diffraction confirmed the presence of the pyrochlore phase, where Raman spectroscopy identified various vibration modes characteristic of the pyrochlore structure. Incorporating Gd₂Ru₂O₇ as the photoanode significantly enhanced the overall efficiency of the DSSCs. The device configuration FTO/compact-layer/Gd₂Ru₂O₇/Hibiscus-sabdariffa/electrolyte(I⁻/I₃⁻)/Pt achieved a high efficiency of 9.65%, an open-circuit voltage (Voc) of approximately 3.82 V, and a current density of 4.35 mA/cm² for an active surface area of 0.38 cm². A mesoporous TiO₂-based DSSC was fabricated under the same conditions for comparison. Using impedance spectroscopy and cyclic voltammetry measurements, we provided evidence of the mechanism of conductivity and the charge carrier’s contribution or defect contributions in the DSSC cells to explain the obtained Voc value. Through cyclic voltammetry measurements, we highlight the redox activities of hibiscus dye and electrolyte (I⁻/I₃⁻), which confirmed electrochemical processes in addition to a photovoltaic response. The high and unusual obtained Voc value was also attributed to the presence in the photoanode of active dipoles, the layer thickness, dye concentration, and the nature of the electrolyte. Full article

Poly[bis(4-phenyl) (2,5,6-trimethylphenyl) amine (PTAA), as a hole transfer material, has been widely used in perovskite solar cells (PSCs). However, the optimal solvent for preparing the PTAA solution and coating the PTAA layer is still uncertain. In this work, we investigated three types of organic solvents (toluene, chlorobenzene and dichlorobenzene) for processing PTAA layers as the hole transport layer in PSCs. Based on the experimental verification and molecular dynamics simulation results, all the evidence indicated that toluene performs best among the three candidates. This is attributed to the significant polarity difference between toluene and PTAA, which leads to the formation of a uniform surface morphology characterized by granular protuberances after spin coating. The contact area of the hole transfer layer with the surface aggregation is increased in reference to the rough surface, and the hydrophilicity of the PTAA layer is also increased. The improvement of these two aspects are conducive to the effective interfacial charge transfer. This leads to the generation of more photocurrent. The PSCs employing toluene-processed PTAA exhibit an average power conversion efficiency (PCE) of 19.1%, which is higher than that of PSCs using chlorobenzene- and dichlorobenzene-processed PTAA (17.3–17.9%). This work provides a direct optimization strategy for researchers aiming to fabricate PSCs based on PTAA as a hole transport layer and lays a solid foundation for the development of high-efficiency inverted PSCs. Full article

This study presents a systematic approach to engineering the electron transport layer (ETL) in perovskite solar cells using a spray deposition technique to fabricate sequentially compact and mesoporous titanium dioxide (c-TiO₂, m-TiO₂) films. The spray coating method leads to the development of a distinct reticulated morphology characterized by well-defined wavy-like surface features and significantly increased roughness—at least twice that of spin-coated mesoporous films. The increased interfacial area between the mesoporous TiO₂ and the perovskite layer facilitates more efficient charge transfer, contributing to higher device performance. By optimizing the deposition parameters, particularly the number of spray cycles for the m-TiO₂ layer, we achieve a significant enhancement in device performance, with improvements in power conversion efficiency (PCE), reduced series resistance, and minimized hysteresis. Our results demonstrate that an optimal film thickness promotes better perovskite anchoring, while excessive deposition impedes light transmission and increases sheet resistance. These findings advance the practical fabrication of high-performance perovskite solar cells using simple solution-processing techniques and highlights the potential of scalable spray deposition methods for industrial-scale fabrication. Full article

Printing techniques have been instrumental in developing flexible and stretchable electronics, including organic light-emitting diode displays, organic thin film transistor arrays, electronic skins, organic electrochemical transistors for biosensors and neuromorphic computing, as well as flexible solar cells with low-cost processes such as inkjet printing, ultrasonic nozzle, roll-to-roll coating. The rise of additive manufacturing provides even more opportunities to print electronics in automated and customizable ways. In this work, we will review the current technologies of printing electronics (including printed batteries, supercapacitors, fuel cells, and sensors), especially with 3D printing. In this age of ongoing AI revolution, the application of AI algorithms is discussed in terms of combining them with 3D printing and electronics printing for a future with automated optimization, sustainable design, and customizable and scalable manufacturing. Full article

Tin oxide (SnO₂) is an attractive candidate for the electron transport layer (ETL) in perovskite-based solar cells because of its low temperature process requirement. The ability to form ETL layers at low temperatures opens up opportunities for the use of flexible and low-cost materials suitable for photovoltaic applications. The ETL is necessary for the extraction of electrons and charge separation from the perovskite active layer. Herein, we present a study of the effect of annealing temperature on SnO₂ used as an ETL. The annealing temperature of the SnO₂ has a considerable effect on the morphology, crystallinity, grain size, and surface topography of the SnO₂ layer. The surface properties of the ETL influence the structural properties of the perovskite films. In this study, the annealing temperature of the SnO₂, deposited using spin coating, was changed from 90 °C to 150 °C. The SnO₂ films annealed at 120$°$C resulted in reduced surface defects, improved electron extraction, and produced a significant increase in the grain size of the perovskite active layers. The increase in grain size led to improved efficiency of the PSCs. Devices annealed at 120 °C yielded PSCs with an average efficiency of 15% for a 0.36 cm² active area, while devices treated at 90 °C and 150 °C produced an average efficiency of 12%. The PSCs fabricated at low temperatures provide an effective technique for low-cost manufacturing, especially on flexible and polymer-based substrates. Full article

Perovskite, as a promising candidate for the next generation of photovoltaic materials, has attracted extensive attention. To date, the power conversion efficiency (PCE) of perovskite solar cells (PSCs) has reached 26.7%, which is competitive with that of commercial silicon cells. However, high PCE is usually achieved in devices with a small surface area fabricated by the spin-coating method. Perovskite thin films, as the most important layer, suffer from poor uniformity and crystallization caused by the large-area fabrication process, which leads to a dramatic drop in efficiency and exhibits poor reproducibility. Here, we summarize common architectures of PSC and perovskite solar modules (PSMs), as well as analyzing the reasons for efficiency loss on the modules. Subsequently, the review describes the mechanism of perovskite growth in detail, and then sums up recent research on small-to-large-area perovskite devices. Large-area fabrication methods mainly include blade coating, slot-die coating, spray-coating, inkjet printing, and screen printing. Moreover, we compare the advantages and disadvantages of each method and their corresponding mechanisms and research progress. The review aims to provide potential logical conclusions and directions for the commercial large-area perovskite fabrication process. Full article

Conductive polymers play a crucial role in the advancement of modern technologies, particularly in the field of organic photovoltaics (OPVs). Due to advantages such as flexibility, low specific weight, ease of processing, and low production costs, polymeric materials present an attractive alternative to traditional photovoltaic materials. This study investigates the properties of a polymer blend composed of PCPDTBT (donor) and PNDI(2HD)2T (acceptor), used as the active layer in bulk heterojunction (BHJ) solar cells. The motivation behind this research was the search for a novel n-type polymer material with potentially better properties than the commonly used P(NDI2OD-T2). Comprehensive characterization of thin films made from the individual polymers and their blend was conducted using Fourier Transform Infrared Spectroscopy (FTIR), Atomic Force Microscopy (AFM), Scanning Electron Microscopy (SEM), Ultraviolet-Visible Spectroscopy (UV-Vis), four-point probe conductivity measurements, and photovoltaic testing. The prepared films were continuous, uniform, and exhibited low surface roughness (R_a < 2.5 nm). Spectroscopic analysis showed that the blend absorbs light in a broad range of the spectrum, with slight bathochromic shifts compared to individual polymers. Electrical measurements indicated that the blend’s conductivity (9.1 µS/cm) was lower than that of pure PCPDTBT but higher than that of PNDI(2HD)2T, with an optical band gap of 1.34 eV. Photovoltaic devices fabricated using the blend demonstrated an average power conversion efficiency (PCE) of 6.45%, with a short-circuit current of 14.37 mA/cm² and an open-circuit voltage of 0.89 V. These results confirm the feasibility of using PCPDTBT:PNDI(2HD)2T blends as active layers in BHJ solar cells and provide a promising direction for further optimization in terms of polymer ratio and processing conditions. Full article

This study presents an effective strategy to enhance the efficiency and stability of perovskite solar cells (PSCs) by integrating neodymium-doped upconversion nanoparticles (UCNPs) coated with a TiO₂ shell into the mesoporous electron transport layer. The incorporation of neodymium (Nd³⁺) as a novel sensitizer shifts the near-infrared (NIR) absorption band away from the water vapor absorption region in the solar spectrum. This modification enables UCNPs to efficiently convert NIR light into ultraviolet (UV) and blue wavelengths, which are readily absorbed by TiO₂, generating additional charge carriers and improving photovoltaic performance. The optimized PSCs, fabricated by blending 30% UCNPs@TiO₂ with commercial TiO₂ paste, achieved a peak power conversion efficiency (PCE) of 21.71%, representing a 20.4% improvement over the control (18.04%). This enhancement included a 0.9% increase in the open-circuit voltage (V_oc), a 6.6% rise in the short-circuit current density (J_sc), and an 11.9% boost in the fill factor (FF). Additionally, the optimized PSCs exhibited remarkable stability, retaining over 90% of their initial PCE after 900 h in humid conditions, compared to only 70% for the control. These improvements result from enhanced light absorption, reduced moisture infiltration, and lower defect-related recombination. This approach provides a promising pathway for developing highly efficient and durable PSCs. Full article

Titanium oxynitride (TiNO) thin films represent a multifaceted material system applicable in diverse fields, including energy storage, solar cells, sensors, protective coatings, and electrocatalysis. This study reports the synthesis of TiNO thin films grown at different substrate temperatures using pulsed laser deposition. A comprehensive structural investigation was conducted by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), Non-Rutherford backscattering spectrometry (N-RBS), and X-ray absorption spectroscopy (XAS), which facilitated a detailed analysis that determined the phase, composition, and crystallinity of the films. Structural control was achieved via temperature-dependent oxygen in-diffusion, nitrogen out-diffusion, and the nucleation growth process related to adatom mobility. The XPS analysis indicates that the TiNO films consist of heterogeneous mixtures of TiN, TiNO, and TiO₂ phases with temperature-dependent relative abundances. The correlation between the structure and electrochemical behavior of the thin films was examined. The TiNO films with relatively higher N/O ratio, meaning less oxidized, were more electrochemically active than the films with lower N/O ratio, i.e., more oxidized films. Films with higher oxidation levels demonstrated enhanced crystallinity and greater stability under electrochemical polarization. These findings demonstrate the importance of substrate temperature control in tailoring the properties of TiNO film, which is a fundamental part of designing and optimizing an efficient electrode material. Full article

In the context of the global energy transition, enhancing the efficiency of polycrystalline silicon-based solar cells remains a critical research priority. This study investigates the integration of ZnO-based nanostructured layers. ZnO and Al-doped ZnO nanoparticles, synthesized via hydrothermal methods and concentrated solar power (CSP) vapor condensation, exhibiting diverse morphologies—nanorods, spheres, and whisker structures—were deposited onto commercial solar cells using the spin coating technique. Structural, morphological, and spectroscopic analyses confirmed the formation of crystalline layers with high active surface areas and controlled morphology. Photovoltaic performance was assessed using a dedicated hardware–software system under real sunlight conditions. The results demonstrate a significant increase in energy efficiency, reaching up to 10.97%, compared with 1.51% for polycrystalline silicon cells without any supplementary layers. This improvement is attributed to enhanced light absorption, reduced carrier recombination, and more efficient charge transport, driven by nanoscale design and doping. This study underscores the importance of sustainable synthesis and morphological control in the development of high-performance and cost-effective solar technologies. Full article

Among hole transport materials (HTMs), 2,2′,7,7′-Tetrakis(N,N-di-p-methoxyphenylamino)-9,9′-spirobifluorene (spiro-OMeTAD) is the most frequently adopted, due to its suitable energy band level in conventional-type perovskite solar cells (PSCs). However, the high price of spiro-OMeTAD is an obstacle faced in its research and commercialization. In our previous work, we introduced a low-cost HTM, (E,E,E,E)-4,4′,4″,4‴-[Benzene-1,2,4,5-tetrayltetrakis(ethene-2,1-diyl)]tetrakis[N,N-bis(4-methoxyphenyl)aniline] (α2); however, it was immiscible in the conventional solvent chlorobenzene, leading to the adoption of dichloromethane (DCM) as an alternative. Nevertheless, its high vapor pressure led to poor reproducibility, limiting its practical applicability. To address this issue, we investigated alternative solvents to DCM to facilitate the application of α2 to dichloride alkane materials, from 1,2-dichloroethane (DCE) to 1,4-dichlorobutane. In these materials, DCE exhibits the most superior properties in terms of layer formation control, due to its vapor pressure in spin-coating. Accordingly, a PSC containing α2-DCE HTL showed high performance, with 1.15V of open-circuit voltage and a 22.7% power conversion efficiency. Full article

With the increasing demand for alternatives to traditional indium tin oxide (ITO), copper nanowires (Cu NWs) have gained significant attention due to their excellent conductivity, cost-effectiveness, and ease of synthesis. However, challenges such as wire–wire contact resistance and oxidation susceptibility hinder their practical applications. This review discusses the development and challenges associated with Cu NW-based flexible transparent conductors (FTCs). Cu NWs are considered a promising alternative to traditional materials like ITO, thanks to their high electrical conductivity and low cost. This paper explores various synthesis methods for Cu NWs, including template-assisted synthesis, hydrazine reduction, and hydrothermal processes, while highlighting the advantages and limitations of each approach. The key challenges, such as contact resistance, oxidation, and the need for protective coatings, are also addressed. Several strategies to enhance the conductivity and stability of Cu NW-based FTCs are proposed, including thermal sintering, laser sintering, acid treatment, and photonic sintering. Additionally, protective coatings like noble metal core–shell layers, electroplated layers, and conductive polymers like PEDOT:PSS are discussed as effective solutions. The integration of graphene with Cu NWs is explored as a promising method to improve oxidation resistance and overall performance. The review concludes with an outlook on the future of Cu NWs in flexible electronics, emphasizing the need for scalable, cost-effective solutions to overcome current challenges and improve the practical application of Cu NW-based FTCs in advanced technologies such as displays, solar cells, and flexible electronics. Full article