Solar Energy Materials and Solar Cells最新文献

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.

Hydrogen (H) passivation is one of ideal candidates to reduce interfacial and bulk defects for providing good passivation by the light soaking process. Herein, we investigate the influence of the medium-temperature light soaking process on the passivation and electronic performance of the N-TOPCon solar cells. The medium-temperature light soaking process had the significant impact on the metallization-induced recombination of the p⁺⁺ layer and the Si substrate with a corroded silver (Ag) at a depth of >165 nm. During the light soaking process, the breaking the bending of (Si:H₂)_n bonds causes H transitions from a bound state in the Si–H bond to a free state. In this state, H captures movable Ag and boron atoms on the wafer's surface for passivation. The mechanism for enhancing the passivation on the metallization-induced recombination under the metal contact (J₀,_metal) of SiO_x/n⁺-poly-Si layer, the emitter dark saturation current density under the passivation layer (J₀) of p⁺ layer, and SiO_x/n⁺-poly-Si layer is to prevent the formation of new defects by removing excess H. An efficiency gain of 0.87 % was observed after the light soaking process, attributed to the increase in open circuit voltage (V_oc), short circuit current density (J_sc), and fill fact (FF) values by 10 mV, 0.15 mA/cm², and 1.5 %, respectively. The partial gain of FF comes from the effect of medium-temperature enhanced metal contact. This research contributes to a profound understanding of the mechanism behind improving the medium-temperature light soaking process improvement and offers a feasible strategy for enhancing the efficiency N-TOPCon solar cells. After optimizing the front surface recombination and the medium-temperature light soaking processes, we manufactured industrial-grade TOPCon cells with in-house efficiency (E_ff), V_oc, J_sc, and FF values as high as 25.8 %, 729 mV, 42.1 mA/cm², and 84 %, respectively.

Sn-doped indium oxide (ITO) film is one of the widely used transparent conductive oxide (TCO) materials. In recent years, reactive plasma deposition (RPD) technology has been used to prepare high-quality ITO film. Here, indium tin alloy is used to replace indium tin oxide as the evaporation source of RPD. By reacting with oxygen, the ITO film with a conductivity of 3.40 × 10³ S cm⁻¹ and a mobility of 121.40 cm² V⁻¹ s⁻¹ is deposited. The high mobility is mainly due to the high film crystallization rate, high doping efficiency and low Sn doping concentration. The ITO films are used as transparent conducting electrodes in silicon heterojunction (SHJ) solar cells, and a conversion efficiency of 25.38 % is achieved. Compared with conventional ITO films prepared using oxide targets, reaction-deposited ITO films using indium tin alloy have lower cost and higher quality, it is more suitable for mass production.

Understanding the elemental composition and point defect properties is crucial for improving device performance in Chalcogenide thin film solar cells. The correlation between composition and defect characteristics of CuSbS₂ thin film sulfurized from metallic precursors was systematically investigated. Interestingly, it was found that CuSbS₂ polycrystalline thin film maintains an overall Cu-rich composition with a Cu/Sb ratio greater than 1, regardless of the initial precursor compositions. Besides, no obvious difference in the performance of integrated devices is observed, due to the similar Cu/Sb atomic ratios and electronic properties (carrier concentration and mobility) in these CuSbS₂ thin films. By conducting admittance spectroscopy analysis on CuSbS₂ devices, identical defect energy was obtained at 280 meV above the valence band maximum, which can be ascribed to Cu_Sb. This could be mainly explained by the Cu-rich composition induced low formation energy of Cu_Sb. Therefore, further defects engineering focusing on Cu_Sb is required to boost the device efficiency of CuSbS₂ solar cells.

In various types of organic/inorganic solar cells, optical response enhancement is consistently observed within the external quantum efficiency spectra owing to the improvement in interface passivation and the suppression of carrier recombination. In this study, we focused on crystalline silicon solar cells and systematically investigated the impact of interface recombination on the optical response upon dual-side illumination using numerical simulations. The results shed light on the interesting phenomenon that the surface recombination velocity has a significant impact on the external quantum efficiency, and it changes as the illumination direction changes. Moreover, from a practical perspective, the spectra of external quantum efficiency under dual-side illumination conditions can act as a powerful tool for the quick diagnosis of the passivation quality at the top and bottom interfaces.

Lightweight modules are essential for next-generation vehicle-integrated photovoltaic (VIPV) applications, such as solar-powered cars, allowing integration of solar cells beyond the roof, and on the hood, boot and body panels, and thereby extending the driving range. However, the lightweight module's reliability and corresponding degradation mechanisms under various environmental stresses are less researched. In this work, we investigate interconnection and encapsulation strategies to improve reliability against damp heat and mechanical impact. We fabricated lightweight mini modules, weighing around 3.45 kg/m², and conducted hail impact and damp heat tests. These tests result in different failures, such as cracks in the solar cell, module delamination, and microcracks in the backsheet. By carrying out failure mechanism analysis and altering the fiber reinforcement in backsheet and encapsulation materials, we can increase resilience to these failure modes, thus providing guidance for the design of lightweight PV modules for next-generation VIPV.