Progress in Photovoltaics最新文献

The use of single-layer polysilicon (poly-Si) in tunnel oxide passivated contact (TOPCon) structures has demonstrated excellent passivation and contact performance. However, commercial TOPCon solar cell fabrication requires screen-printing and cofiring techniques for electrode preparation. The single-layer structure is less efficient at preventing metal atoms in the electrode paste from penetrating the silicon bulk. Furthermore, the uniformity of doping concentration and crystallinity within this structure poses challenges as it fails to optimally meet the intricate requirements for achieving superior performance in terms of passivation, contact, and mitigating parasitic absorption. In this study, the deposition process of the amorphous silicon (a-Si) precursor layer using an in-line magnetron sputtering system incorporated an additional plasma oxidation step, resulting in a bilayer poly-Si structure with the newly introduced SiO_x acting as a partition. Detailed investigations were conducted into the passivation quality, contact resistivity, crystallinity, and the distribution of critical atoms in the bilayer structure. Subsequently, the bilayer configuration was utilized in the manufacturing process of TOPCon solar cells. These efforts resulted in a notable enhancement in open-circuit voltage (V_oc) and short-circuit current (I_sc), leading to a 0.06% efficiency improvement, based on the average performance of ~200 cells per group.

The poor crystal quality inside an absorber layer and the presence of various harmful defects are the main obstacles restricting the properties of Cu₂ZnSn (S, Se)₄ (CZTSSe) thin-film solar cells. Cation doping has attracted considerable research attention as a viable strategy to overcome this challenge. In this paper, based on Sb-substituted CZTSSe system, we prove that Ag partially substituting Cu may be a feasible strategy. After a series of characterization of the films, it was discovered that the crystal quality and crystallinity of the films were further improved by introducing Ag into Cu₂Zn(Sb, Sn) (S, Se)₄ (CZTSSSe), and the concentrations of Cu_Zn accepter defects and 2[Cu_Zn + Sn_Zn] defect clusters were effectively inhibited. At the same time, the carrier concentration is increased. The results show that when the Ag doping ratio is 15%, the photovoltaic conversion efficiency (PCE) reaches 8.34%, compared with the single-doped Sb element, the efficiency is increased by 24%. For the first time, this study investigates the collaborative effect of Sb, Ag dual-cation substitution in CZTSSe. The solar cell performance enhancement mechanism offers new potential for the advancement of CZTSSe thin-film solar cell technology in the future.

Over the past decade, silicon solar cells with carrier-selective passivating contacts based on polysilicon capping an ultra-thin silicon oxide (commonly known as TOPCon or POLO) have demonstrated promising efficiency potentials and are regarded as an evolutionary upgrade to the PERC (passivated emitter and rear contact) cells in manufacturing. The polysilicon-based passivating contacts also exhibit excellent gettering effects that relax the wafer and cleanroom requirements to some extent. In this work, we experimentally explore the impact of bulk iron contamination and polysilicon gettering on the passivation quality of the polysilicon/oxide structure and the resulting solar cells performance. Results show that both n- and p-type polysilicon/oxide passivating contacts are not affected by iron gettering, demonstrating robust and stable passivation quality. However, for a very high bulk iron contamination (1 × 10¹³ cm⁻³), the accumulated iron in the p-type lightly boron-doped emitter in crystalline silicon would degrade the emitter saturation current density. This can cause a reduction in both open-circuit voltage and short-circuit current. Meanwhile, this very high iron content (1 × 10¹³ cm⁻³) can further degrade the fill factor and temperature coefficient of the cells. On the other hand, for an initial iron content of 2 × 10¹² cm⁻³, which should be well above the iron level in the current industrial Czochralski silicon wafers, the resulting cells demonstrate similar performance as the control group with no intentional iron contamination. This work brings attention to both the benefits of polysilicon gettering effects as well as the potential degradation due to the accumulation of metal impurities in the p-type emitter region.

Consolidated tables showing an extensive listing of the highest independently confirmed efficiencies for solar cells and modules are presented. Guidelines for inclusion of results into these tables are outlined, and new entries since July 2024 are reviewed.

This paper investigates, by modeling, the potential for high-value recycling of silicon wafers recovered from end-of-life PV modules. Technology for PV module recycling is making steady progress, both at recycling companies and R&D institutes, and it is possible that as a result, soon a stream of wafers or wafer fragments recovered from waste modules will become commercially available. Recycling the silicon for manufacturing of new PV modules is an opportunity both for reduction of cost and reduction of environmental footprint of PV. In this paper, we analyze possibilities for recycling of wafer fragments as feedstock for new silicon ingot growth. This could save up to about 0.16 kWh/Wp energy for production of the new PV system. Compared with lower value applications of the recovered silicon, the potential value and energy savings when used as feedstock for ingot growth are considerably higher. This paper presents the possibilities and challenges for recycling wafer fragments from the point of view of dopant type and resistivity control, and mitigation of the impact of recombination activity from possible increased impurity levels or related to boron. Because in current PV production a rapid transition to n-type wafer doping is taking place, the paper also considers the question what can be done with p-type doped recycled wafer material. We illustrate how application for perovskite–silicon tandem cells helps to mitigate possible performance loss from metallic impurities or boron. The application in tandem cells is perhaps the only realistic approach to make economically worthwhile use of recycled B-doped silicon as feedstock for silicon ingot growth.

Lead halide perovskites have demonstrated significant potential for photovoltaic (PV) applications over the past 10 years. Perovskite solar cells (PSCs) stability, however, continues to limit their commercialization, and the inability to compare previous stability data to assess possible directions for increasing device stability is caused by a lack of effectively established unified stability testing and disseminating standards. In this article, we suggest applying machine learning (ML) to improve the thermal, chemical, and structural stability of PSCs. Data normalization and data augmentation are common preprocessing steps that are where the process starts. Then, using the Modified Grasshopper Optimisation Algorithm (MGO), feature selection techniques are used to remove unnecessary or irrelevant features. Finally, there is a novel machine learning technique that uses support vector machines (ESVM) that are based on entropy to forecast the stability classification of stable/unstable. The proposed reaches an accuracy of 0.99% far better than the proposed methods.

It is common practice in PV system simulation to use the De Soto model, which describes how to use the 1-diode equivalent circuit model for modules. De Soto's model scales the shunt with irradiance, making it disappear toward zero W/m². Also, the commercial software PVsyst uses a parameterization that reduces the shunt effect when the irradiance goes down. However, the solar cells that make up a module typically do not have an illumination-dependent shunt. We therefore investigate the origin of the intensity-dependent apparent shunt in modules. We show that this apparent shunt (derived from the slope of the quasi-linear region from I_SC onwards) is a misinterpretation for module I-V curves and has little to do with a shunt conductance, although this slope method serves well for determining the shunt conductance of individual cells. Instead, the module I-V curve slope of the quasi-linear region from I_SC onwards is strongly influenced by even small I_SC mismatches between the cells. Such mismatch can occur from small illumination inhomogeneity even for A+ solar simulators in the laboratory, or from cell production variation. Abandoning the practice of using the I-V curve slope to determine the shunt value for equivalent circuit models of modules (and the corresponding shunt scaling in the De Soto model or PVsyst) contributes to physically more meaningful I-V curve parameterizations and bears the opportunity for further improved accuracy of PV system energy yield prediction.