Solar Energy Materials and Solar Cells最新文献

To cope with rapid increase in energy demand and the related sustainability issues, it is of paramount importance to improve existing energy conversion machines. In this paper, a 3D model of roll bond photovoltaic thermal (RB-PVT) unit incorporating a novel channel of hexagon-grid coupled with serpentine arrangement, was considered. In ANSYS Fluent 18, the model was solved both as an evaporator and a condenser to investigate its operation in perspective of performance and environment. The difference in temperature between two areas (refrigerant and ambient) and pressure drop in micro-channels were found the main two causes to change the performance of RB-PVT evaporator/condenser. In this view, the maximum average values of 9.25 and 17.56 % were respectively achieved for COP_h and electrical efficiency of RB-PVT evaporator. In addition, the maximum COP_refr of 4.64 was obtained from the RB-PVT condenser. Considering the compressor to be powered by non-renewable energy for a period of 15years, 6946USD would be spent in buying power equivalent to 144442.35 kWh. Moreover, 797USD would be spent to sequestrate 26.5tons of CO₂ emissions. RB-PVT evaporator/condenser integrating hexagon-grid coupled with fluid channel of serpentine arrangement not only can improve the performance characteristics but can also be a best alternative to achieve net zero emissions.

The primary challenge in recycling crystalline silicon (c-Si) photovoltaic (PV) modules is separating the polymeric fractions, including back sheets, from the module structure. Thermal treatment, commonly used for this purpose, adversely affects the environment by releasing harmful gases and degrading polymers. With this in mind, this study introduces a novel hot knife method to efficiently separate and recover the back sheet layer from c-Si PV modules, a primary source of toxic gases during thermal treatment. A thin and highly conductive knife was selected for the hot knife-cutting process. The heating of the knife was accomplished by connecting it to a hot air gun, which offers complete parameter control, enabling precise adjustments to maintain the knife at the required temperature. Experimental tests were conducted to determine the best conditions for separating the back sheet from solar cells. The effectiveness of this method was evaluated using FTIR, TGA, and SEM-EDS. The findings reveal that the proposed hot knife technique effectively separate the back sheet layers from c-Si PV panels without breaking their integrity. The recovered back sheet can significantly reduce environmental pollution risks by preventing polymer material depletion. As a result, the production gases that arise from the degradation of back polymers can be eliminated.

Tunnel Oxide Passivated Contact (TOPCon) technology is one of the most influential and industrially viable solar cell technologies available today. Improving the quality of passivation contact has become a central focus of current research. Although the conventional monolayer polycrystalline silicon method is highly effective in TOPCon solar cells, it is limited by doping inhomogeneity, which impairs the passivation and electrical properties, and the cell's photovoltaic conversion efficiency remains suboptimal. To address this issue, this study investigates the deposition of two layers of silicon oxide and two layers of in-situ doped phosphorus amorphous silicon, termed double poly-Si/SiO_x structures, on n-type silicon wafers using plasma-enhanced chemical vapor deposition (PECVD). The effectiveness of the structure was confirmed through various characterization techniques such as scanning electron microscopy (SEM), X-ray diffraction (XRD), and X-ray photoelectron spectroscopy (XPS). Key findings indicate that the double-polysilicon structure significantly enhances the uniformity of phosphorus doping, improving the carrier lifetime of the cell and reducing the contact resistance. As a result, the average efficiency in the final production stage has a conversion efficiency gain of 0.23 % over the baseline group. This study underscores the potential of this PECVD methodology to advance the fabrication of high-efficiency solar cells by providing significant improvements in passivation, doping uniformity, and overall cell performance.

Background

Energy is an indispensable part of human life. To meet the ever-increasing energy demands and mitigation of its adverse production effects, the new technological advancements and shifting towards the renewable energy resources (RERs) has become imminent. Solar energy is the most prominent among RERs, where solar thermal collectors utilizes more effective working wavelength range compared to photovoltaic cells. Nanofluids are engineered working fluids for enhancing collector performance. Synthesized carbon nanofluids usually have higher thermal conductivities than metals and metal oxides, leading to higher collector performance.

Methods

This review presents the outcomes of experimental investigations conducted with carbon based nanofluids in non-concentrating collectors and discusses its effects on thermophysical properties.

Findings

From review, it can be inferred that the carbonaceous nanofluids improved the performance of solar collector systems. It was noted that the thermal performance and stability of nanofluid was affected by several factors such as preparation method, working temperature, concentration and dimension of nanoparticles etc. Likewise, the performance enhancements of collectors reported were mutually inconsistent and repeatability of the data was difficult to produce. There are also lack of studies on stability of nanofluids after utilization, carbon allotropes except nanotubes and graphene, and base fluids except water and glycols.

VIPV surfaces operate predominantly under non-normal irradiance conditions, underscoring the importance of understanding their angular performance for energy modeling in this technology. However, vehicle surfaces require double curvature for aesthetic and aerodynamic reasons, causing their angular response to deviate from conventional flat plates. This paper addresses the study and characterization of the angular performance of curved VIPV surfaces. A quasi-commercial VIPV module was measured indoors using a collimated beam solar simulator and a two-axis rotating structure. Furthermore, outdoor characterization under real sunlight was also performed by installing the VIPV module on a two-axis tracker. The solar tracker control has been programmed to introduce fixed misalignments between the aperture plane of the assembly and the solar disk. This feature allows measuring the IV curve of the modules under various angles of incidence, limited only by the angular range of the tracker (±60°). The two-dimensional angular responses measured both indoors and outdoors are compared and discussed. In addition, simulations based on optical ray-tracing to determine the irradiance distribution on the module surface and a SPICE electrical model to calculate the IV curves were conducted and validated with the experimental results. The opto-electrical models were then used to explore several cell interconnections and analyze the impact on the angular response.

The optimization of semi-transparent organic solar cells involves balancing average visible transparency (AVT) and power conversion efficiency (PCE). We propose enhancing ST-OSC performance by replacing the conventional opaque Ag electrode with a MoO₃/Ag/MoO₃ as a dielectric/metal/dielectric (DMD) layer structure, explored theoretically and experimentally. A prototype ST-OSC configuration, comprising ITO/ZnO/P3HT: PCBM/MoO3/Ag/MoO3, was fabricated with varying thicknesses of the MoO₃/Ag/MoO₃ layer, determined through theoretical calculations utilizing MATLAB software. This study investigates the impact of metal layer thickness on two active layer densities (10 and 18 mg/mL) and evaluates AVT, color rendering index, Correlated Color Temperature, and CIELAB color coordinates (a*, b*). Both theoretical calculations and experimental results confirm that the optimized configuration of the DMD structure with specific layer thicknesses for each component (MoO₃ = 10nm/Ag = 6nm/MoO₃ = 30 nm) achieves an AVT of over 59.60 %. This high level of transparency makes this configuration suitable for applications requiring both high transparency and efficient light transmission. The optimized device delivered high-quality light transmission, approaching white perception to the human eye. This combined approach validates empirical results and provides a deeper understanding of transparent OSC mechanisms.

Metal contacts are an extremely important part of photovoltaic devices, since they might decrease device stability, or underperform in their function of current extraction. In the case of perovskite solar cells, the metallic component has been less investigated than other cell components, either in the back (rear) contact, or in the form of grid collectors in the front contact. The interaction between the perovskite layer and the metal contact is of utmost importance, since it has been demonstrated for gold and silver (most used metals in perovskite cells) that degradation processes might derive from unwanted contacts between the metal and the perovskite components. Herein, we present a systematic investigation of a series of metals typically used in the electronic or photovoltaic industries (Ag, Al, Au, Cu, Mo, Ni, Pd, Pt, and Ta) in order to assess their stability towards the processing steps of a typical perovskite cell assembly, and also when direct contact between the perovskite and the metal layer takes place. By assessing the morphological and electrical properties of the metal layer after performing a variety of tests, we observed that only four of those metals maintained their integrity. Based on the results, we point out which metal is expected to be most suitable one, from an industrial point of view, and to enable long-term device operation.

Silica aerogel, renowned for its low thermal conductivity and high optical transparency, is widely used as a transparent insulating material. However, its inherent fragility significantly hinders its practical performance. In this study, a type of nanofibrous silica aerogel is investigated to strengthen the mechanical properties and achieve improved optical transparency. The fibrous microstructure of aerogel is numerically reproduced by the Voronoi Tessellation algorithm. Its radiative properties are analyzed through a combination of the discrete dipoles approximation (DDA) and the Monte Carlo (MC) method, examining the influence of frame structure, fiber radius, porosity, and thickness. Findings indicate that aerogels with fiber radius under 1 nm, over 95% porosity, and thickness below 1 cm fulfill the criteria for light transmission and haze necessary for energy-efficient windows. Energy simulations of fibrous aerogel windows across various Chinese climates suggested up to 45% of energy savings compared to traditional single-pane windows. Furthermore, the study assessed the economic and environmental advantages of aerogel windows throughout their life cycle, offering valuable insights for sustainable building design.

To enhance the efficiency of Tunnel Oxide Passivated contacts (TOPCon) solar cells, optimizing the electrode material components is essential. Glass frit, as one of the important components of silver-aluminum (Ag–Al) paste, plays a key role in the formation of good ohmic contacts, however, its specific impact on cell performance remains unclear. The effectiveness of glass frit is mainly reflected in its effect on the emitter surface. In this study, we aim to optimize the glass frit used for the frontal sub-grid of industrial n-TOPCon solar cells using inverse analysis based on known cell performance parameters. The overall morphology and internal structure at the Ag–Si interface of intact cells were analyzed by etching experiments. In combination with the composition of the glass frit, to probe the wettability difference between glass frit and c-Si, along with the reactions between the components of the Ag–Al paste after sintering, explaining the main reasons for the difference in the performance of the solar cell. It provides research ideas for characterizing the performance of the glass layer at the Ag–Si interface, which is conducive to the researchers in-depth understanding of the important role of glass frit in the metallization of solar cells, facilitating more targeted optimization of electrode pastes for solar cells.

Advanced passivation contact in high-efficiency silicon solar cells plays an important role for the sake of minimizing recombination losses. A stack of heavily doped polycrystalline silicon (poly-Si) and tunnel SiO_x contact has attracted much attention, benefitting from its excellent characteristics of carrier selectivity and passivation, and which has been successfully applied in double-side poly-Si/SiO_x passivating contact solar cells. Note that characteristics analysis of defects at tunnel SiO_x/c-Si (crystalline silicon) interface remains an issue of concern. Herein, we observe capacitance transient spectroscopy arise from both electron and hole traps in the passivating contact structure of poly-Si(p⁺)/tunnel SiO_x/c-Si(n). Subsequently, we propose a skillful procedure of deep-level transient spectroscopy (DLTS) measurement to confirm that the observed electron and hole traps are located at the tunnel SiO_x/c-Si interface but not in the bulk of the c-Si substrate. Finally, we show a clear physical picture of continuous energy distribution for interface states.