Progress in Photovoltaics最新文献

The most common approach to directly measuring the temperature of a photovoltaic (PV) module is by attaching a sensor to its rear side. However, this is not always possible in commercial installations, as it is costly, requires routine calibrations, and is prone to detachment, which can potentially provide misleading data. To overcome this challenge, researchers have developed thermal models (as an intrinsic thermometer) to estimate the PV module's operating temperature (T_mod) under various field conditions. These self-thermometry models vary from simple empirical correlations to detailed numerical models. The model choice depends on the application, as the prediction accuracies of these models vary. For quick estimates, the empirical models suffice. However, for detailed performance analysis of the PV systems, more accurate models are required. This paper introduces the shift-factor method, an innovative, thermodynamically based approach that estimates T_mod by analyzing changes in the open-circuit voltage (V_oc) or the maximum power point voltage (V_mp). By correlating these electrical responses with irradiance and module temperature, this method not only offers a flexible and non-intrusive approach to temperature estimation but also serves to verify or rectify sensor data, effectively complementing and enhancing the reliability of traditional sensor-based measurements. Compared to other self-thermometry models, the proposed shift-factor method achieves the lowest overall root mean square error (RMSE) of 1.6 °C. While IEC 60904-5 offers slightly better precision (lower centralized RMSE), it suffers from higher bias and relies solely on V_oc. In contrast, the shift-factor model supports both V_oc and V_mp for the T_mod estimation, enhancing field applicability.

Perovskite solar cells are an emerging photovoltaic technology promising higher efficiency than monocrystalline silicon solar cells. This study assesses the environmental impacts of novel two-terminal (2T) and four-terminal (4T) perovskite/copper indium gallium selenide (CIGS) tandem solar cells at technology readiness levels (TRL) 3 (2T configuration) and 4 (4T configuration). Based on the life cycle assessment (LCA) methodology, impacts are assessed from cradle to gate, focusing on climate change impacts per 1 m² of solar cell, 1 kW_p of module capacity, and the environmental 1 kWh of produced energy. Other relevant environmental impact categories, cumulative energy demand (CED) and energy payback time (EPBT), are also considered. The impacts of critical parameters are a sensitivity analysis. The LCA results indicate global warming impacts (GWI) of 49 and 50 kg CO₂eq/m², 170 and 174 kg CO₂eq/kWp for the 2T and 4T configurations, respectively. For both configurations, the GWI ranges from 3.2 to 5.6 gCO₂eq/kWh. Prospective investigated in climate change impact assessments suggest that manufacturing impacts may increase by 4% by 2050 without climate policies because of changes in the European energy mix. Conversely, stringent climate policies could reduce climate change impacts by 77%. The sensitivity analyses identify electricity use as the most critical factor for climate change impacts. CED values are 1219 and 1266 MJ/m² for the 2T and 4T configurations, respectively. For impacts per energy output, the CED is 4231 and 4380 MJ/kWp for the 2T and 4T configurations, respectively. For both configurations, the CED ranges from 80 to 140 kJ/kWh. The average EPBT values are 0.74 and 0.76 years for the 2T and 4T configurations, respectively.

Halogen compounds are widely used in many advanced photovoltaic technologies including silicon solar cells, perovskite solar cells, and perovskite/silicon tandem cells. They not only play a key role in passivating inter-material contacts, but also act as an excellent anti-reflective layer. Here we reveal that the halogen compound serves as a double-edged sword for solar cells: on one hand, it maintains an inert surface with good anti-reflectivity and enhances short-circuit current density (J_SC) by up to 0.46 mA/cm², resulting in an enhanced power conversion efficiency (E_ff) of silicon heterojunction (SHJ) solar cells to 25.37%; on the other hand, it significantly deteriorates the optoelectronic properties in subsequent damp-heat (DH) tests. Extensive experimental analyses and first-principles simulations demonstrate that the diffusion of fluoride ions and their subsequent reaction with water under DH conditions is key to such behaviors, producing corrosive substances and creating lattice defects in the microstructure of a-Si:H/c-Si(n). Importantly, we successfully reduce E_ff degradation from >53 rel.% to 0 rel.% by incorporating a precisely engineered low-cost dielectric thin layer to impede fluoride diffusion, leading to a degradation-free high-efficiency fluoride-coated SHJ solar cell. This work provides vital insights for maintaining long-term durability of SHJ and will facilitate wide adoption of high-stability silicon solar cells and perovskite/silicon tandem devices.

Amorphous silicon thin-film photovoltaics have been widely utilized in building-integrated photovoltaics (BIPV) due to their advantages of lightweight, flexible, and easily transportable properties. However, long-term exposure to natural environmental conditions leads to the gradual degradation of their properties. To investigate the effects of aging on the mechanical performance and stress-related electrothermal reduction of these photovoltaics, this study selects naturally aged amorphous silicon thin-film photovoltaics as the research subject. Uniaxial tensile tests and microscopic morphology characterization were conducted to analyze specimen mechanical behavior throughout the full loading process and to reveal the mechanisms influencing temperature and voltage responses. Experimental results indicate that the aged photovoltaics exhibit an elastic modulus of 4108 MPa and a tensile strength of 49.86 MPa. Structural failure occurs due to the fracture of the stainless steel substrate during loading, while electrical failure and temperature decrease are observed prior to the yielding stage, with the temperature drop occurring after electrical failure. Electro–thermal–mechanical response reveals that the loss of photovoltaic capability leads to a reduction in internal current, which subsequently induces the temperature decrease. These findings can provide valuable insights for evaluating the long-term operational performance and safety of building-integrated photovoltaics.