Solar Energy Materials and Solar Cells最新文献

TECC-Wire (thermoplastic and electrically conductive coated wire) represents a promising interconnection technology for temperature sensitive solar cells. TECC-Wire uses round copper wires (160–300 μm) coated with a thermoplastic polymer layer (10–20 μm), filled with electrically conductive particles. This study presents a new wire coating formulation based on a polyamide-type wire enamel (Voltatex® 8609 ECO, melting temperature 180 °C), filled with 12 vol% silver resulting in a conductivity of 480 S/cm. Single half-cut M6 heterojunction (SHJ) solar cells were contacted with the manufactured wires using a laboratory scale stringing machine. Peel tests were performed to characterize the adhesion of the wires to the cell surface, module performance was evaluated using electroluminescence (EL) imaging and current-voltage (IV) measurements, damp heat (DH) tests were used to evaluate the long-term stability of the modules. The wires adhere well to the cells with a peel force of more than 1.5 N/mm, and the highly conductive coating has proven to be robust when contacted with different pressure, which might be beneficial for a reliable high throughput solar module production. The obtained fill factor FF = 81.25 ± 0,12 % is similar to those achieved for solar modules connected via standard soldering techniques IEC standard DH tests confirmed that, the modules exhibiting a power loss of less than 5 % after 1000 h of storage at +85 °C and 85 % relative humidity. These results are very encouraging for further development of the technology towards a low temperature, solder-free, low cost and robust cell interconnection technology.

To evaluate the potential of novel thermoplastic polyolefin (TPO) encapsulants as alternative for peroxide crosslinking ethylene vinyl acetate (EVA) copolymer and polyolefin elastomers (POE), compressive shear glass laminates were prepared and characterized using EVA and POE benchmark grades and TPO film adhesives (TPO-3.5, TPO-F and TPO-UV). The specimens were exposed to Xenon arc light with an UV irradiation of 40 W/m², a black panel temperature of 65 °C and relative humidity of 10 % for up to 3,000 h. Visual, optical, mechanical and chemical changes were assessed by light microscopy, UV–visible–near infrared (UVVISNIR) spectroscopy, compressive shear testing, as well as differential scanning calorimetry (DSC), Fourier transform infrared (FTIR) spectroscopy and X-ray photoelectron spectroscopy (XPS) on fractured surfaces. In contrast to EVA and POE laminates, enhanced birefringence was detected due to a higher degree of crystallinity of the TPO encapsulants. Nevertheless, the investigated TPO double-glass laminates revealed a significantly better ultimate mechanical shear performance at 60 °C, also after UV exposure for 3.000 h. TPO-3.5 was the best-performing grade after 3,000 h followed by TPO-UV, TPO-F, EVA and POE. While the aged and fractured EVA, POE, TPO-F and TPO-UV laminates exhibited carboxylic acid signatures differing in intensity, no carboxylic acid residues were detected on the fractured TPO-3.5 surface. TPO-3.5 is characterized by a lower melt flow index and hence, a higher average molar mass compared to TPO-F and TPO-UV. For the crosslinked EVA and POE, the test temperature was already within the melting range of the non-crosslinked, polyethylene rich phase of these peroxide crosslinked encapsulants.

It is known that metallization of Ag–Al pastes to boron doped emitter of N-type solar cells will reduce contact resistance, because Al will promote forming Ag–Al spikes, providing conductive channels. However, deeper Ag–Al spikes will exacerbate metal recombination and deteriorate cell performance, thus requiring regulation. It has been reported that adding Si to Ag–Al pastes could effectively limit the formation of Ag–Al spikes, but it will increase grid line resistance and reduce conductivity. Based on this, we prepared new Ag–Al pastes using Al–Si alloys, which effectively regulated Ag–Al spikes and ensured electrical properties. In addition, we comprehensively compared the contact properties of conventional Ag–Al pastes, Ag–Al pastes with added Si, and Al–Si alloy pastes. The results indicated that conventional Ag–Al pastes have lower contact potential barriers and better contact performance, but Ag–Al spikes are difficult to control. Adding Si to Ag–Al pastes effectively limited the formation of spikes, but it will significantly increase potential barriers and deteriorate electrical performance. By contrast, using Al–Si alloys can not only achieve comprehensive regulation of the size and composition of Ag–Al spikes, but also ensure good electrical performance. This study developed Al–Si alloy pastes with great potential for application, which were of great significance for regulation of Ag–Al spikes and the development of advanced Ag–Al pastes.

Graphene and graphene-derived materials have sparked a lot of interest because of their unique physico-chemical features, that have positioned graphene as a promising material for future opto-electronics, and energy-harvesting devices. Graphene possesses outstanding mechanical characteristics and chemical inertness, as well as great mobility and optical transparency. Single-layer graphene has a high optical transmissivity that allows it to pass through a wide variety of light wavelengths, making it a popular material for optically conducting windows. Graphene-based metal and metal oxide nanocomposites require substantial investigations to understand the fundamental interactions between nanostructures and the graphene surface in DSSC, for understanding the characteristic features of such nanocomposites. In the present study different donor-π-acceptor, systems were used, which are different in the type of the π –spacer units only. This D-π-A system was then decorated on a (TiO₂)₉ semiconductor leading to shifting of the absorption wavelength, the absorbed wavelength was further shifted upon interaction with tellurium–oxide@graphene, thereby exploring its application in solar energy harvesting devices. The result of such substitution was assessed in terms of various parameters such as highest occupied molecular orbital (HOMO), least unoccupied molecular orbital (LUMO), energy gap (E_gap), maximum wavelength (λ_max), the free energy of electron injection efficiency (ΔG_inject), open-circuit voltage (V_oc), reorganization energy (Δ_reorg), etc by the DFT method with Gaussian 09 set of codes. The study can prove beneficial for understanding the mechanism of high optical absorption over a broad spectrum in such multijunction systems, the feature which makes them promising materials for efficient optical, electronic, and light-harvesting devices.

Voltage-loss analysis is essential in the development of next-generation solar cells, such as perovskite, chalcopyrite, kesterite, and nano/quantum-structured solar cells. Voltage-loss analysis provides valuable insights into how the energy conversion efficiency of solar cells can be enhanced. However, a comprehensive and accurate method to evaluate the voltage loss in quantum-structured solar cells is lacking. This study establishes and demonstrates a quantitative voltage-loss analysis based on detailed balance theory. This analysis reveals the relationship between external quantum efficiency and radiative recombination voltage loss in quantum-structured solar cells. Based on the results of the analysis, we designed and fabricated a novel low-voltage loss quantum-structured solar cell. Radiative recombination in the quantum-structured solar cell was successfully suppressed by steepening the absorption edge. This voltage-loss analysis facilitates the development of next-generation solar cells.

With the exponential growth of the Internet of Things (IoT), indoor photovoltaics (IPVs) have emerged as a pivotal technology for powering low-power devices, drawing heightened interest due to their adaptability to indoor environments. The Photovoltaic Conversion Efficiency (PCE) of IPV cells is critically dependent on their ability to match the indoor spectrum with the device's response characteristics. In this realm, Antimony Trisulfide (Sb₂S₃), characterized by its wide bandgap and high absorption coefficient, emerges as a promising candidate for low-light applications. Our study focuses on the modeling and numerical analysis of Sb₂S₃ thin-film IPV cells by wxAMPS software, aiming to refine both the device structure and its photoelectric performance for effective indoor light harvesting. In a strategic shift from conventional CdS materials, we utilized SnO₂—known for its high transmissivity, non-toxicity, and wide bandgap—as the electron transport layer (ETL) in Sb₂S₃ IPV cells. This substitution notably enhanced the short-wave response, elevating the spectral response from 45 % to 80 % at 400 nm. Additionally, we introduced a bandgap-tunable ZnOS buffer layer. This innovation proved instrumental in rectifying the band alignment mismatch between SnO₂ and Sb₂S₃ layer, thereby optimizing interfacial electron transport properties. The integration of the ZnOS buffer layer effectively improved the fill factor from 40.0 % to 64.7 % of the Sb₂S₃ IPV cell by solving the band mismatch problem. The resulting optimized Sb₂S₃ IPV cell demonstrated exceptional response characteristics across the full visible spectrum (400–750 nm) and showed notable photoelectric performance under both fluorescent lamps (FLs) and light-emitting diodes (LEDs). Moreover, a detailed analysis was conducted on the performance differences of the device under indoor light sources compared to solar spectrum conditions, along with the underlying mechanisms. Finally, the Sb₂S₃ IPV cell achieved a peak theoretical efficiency of 46.25 % under cold white FL lighting, a testament to the optimal match between the device structure and this specific emission power spectrum. This modeling research not only underscores the feasibility of employing antimony-based photovoltaic technologies in indoor settings but also offers theoretical guidance for further advancements in this domain.

Tunnel Oxide Passivated Contact (TOPCon) solar cells have received widespread attention in recent years, especially in improving conversion efficiency. This paper investigated the impact of hydrogenation technology using photon-injection (HPI) and electron-injection (HEI) processes on TOPCon solar cells, highlighting the higher improvement effect and broader application scope of HPI compared to HEI. In TOPCon cells, several methods are available to prepare the tunneling oxide layer, such as plasma oxidation (PO) and indirect thermal oxidation (TO). The research results indicated that significant improvement differences could be observed when utilizing the HEI treatment for TOPCon solar cells prepared by PO and TO methods, with values of 0.133%_abs. and −0.039%_abs., respectively. Meanwhile, HPI treatment induced a more significant efficiency improvement for these two types of cells, and the increase in efficiency is 0.247%_abs. and 0.244%_abs., respectively. The experimental results demonstrated that the passivation effect for TOPCon solar cells prepared by PO and TO methods remained almost the same under the HPI treatment, and the improvement effect is less dependent on the tunnel oxidation technique used. Thus, the different passivation effects between HPI and HEI were further investigated, and the reason for the difference was attributed to the charge states and concentrations of hydrogen and non-equilibrium carriers during the hydrogenation. The results provided an improved scheme for enhancing the efficiency of TOPCon solar cells, shedding light on the role of HPI and HEI in the passivation process. This work brings further insights to TOPCon solar cells.

We report a simple and effective method for producing lanthanide ion-doped lithium-fluoride-based nanocrystals (YLiF₄). We utilized those nanoparticles for up-conversion in fabricated perovskite solar cells. The obtained results shows that the up-conversion YLiF₄:Yb, Er nanoparticles improve alignment of energy levels at interface between titanium dioxide and perovskite layer. This increases power conversion efficiency of fabricated perovskite solar cells from 19.45 % to 21.32 %. To enhance comprehension of the recombination mechanism and its correlation with the conduction band offset and defects, device models are additionally integrated into the SCAPS simulator. Subsequently, the obtained J-V simulation outcomes exhibit a favorable concordance with the experimental observations.

Dielectrics are often employed for high-reflectivity mirrors in semiconductor devices, since they leverage total internal reflection to reduce optical losses at semiconductor/metal interfaces. In this work, we investigate the impact of a range of dielectrics (ZnS, Si₃N₄, Al₂O₃, SiO₂, MgF₂, air) on mirror reflectivity, photon recycling probability and open-circuit voltage ($V_{oc}$) in thin-film GaAs solar cells with Au- or Ag-based mirrors. The impact of transition metal adhesion layers is investigated, as well as the influence of the dielectric and active layer thickness. It is found that the $V_{oc}$ benefit of using a dielectric/metal mirror compared to a bare metal mirror ($\Delta V_{oc}$) is small ($\le$10 mV) when the internal luminescent efficiency ${\eta }_{int}$ is lower than 0.95 for all mirror architectures investigated. Only in very-high-quality cells, $\Delta V_{oc}$ becomes significant, reaching $\sim$30 mV at ${\eta }_{int}$ $=$ 1 when using a 250-nm air-gap to enhance the reflectivity of a lossy Au mirror. This shows that dielectric/metal rear mirrors only provide significant $V_{oc}$ benefits when ${\eta }_{int}$ is very close to unity. Furthermore, we find that for lossy mirrors, transition metal adhesion layers do not have a strong impact on $\Delta V_{oc}$, while for highly reflective mirrors like Ag, adhesion layers thicker than 1 nm are found to be detrimental to the already small $V_{oc}$ gains. Lastly, $\Delta V_{oc}$ is shown to be higher in cells with thinner active layers and in cells with planar compared to textured mirrors. In textured cells, however, the short-circuit current density and thereby the power conversion efficiency are affected more strongly by incorporating a dielectric into the rear mirror.

A switchable mirror thin film, which can switch between a transparent and a mirrored state, can play a key role in decreasing heating and cooling loads when incorporated into smart windows. In our research group, we have undertaken the development of switchable mirror sheets utilizing the gasochromic method for switching, culminating in the successful creation of a multilayer thin film structure with practical performance and the innovation of a switching system. This article presents the research and development process, emphasizing the materials obtained alongside their corresponding performance characteristics.