Progress in Photovoltaics最新文献

TOPCon (tunnel oxide passivated contact) solar cell is the mainstream high-efficiency crystalline silicon solar cell structure. However, the lack of efficient passivation contact mechanisms on the front surface restricts the electrical performance ability to improve further. Selective emitter (SE) technology, considered a potential solution, needs to be more mature. This work provides a unique thermal pre-diffusion approach combined with laser treatment and post-oxidation annealing to create SE structures in TOPCon solar cells. Times for the high-temperature process are equivalent to those for a traditional homogenous emitter. The innovative thermal pre-diffusion process created a unique boron doping profile, achieving a high surface concentration of nearly 1 × 10²⁰ cm⁻³ with a shallow junction depth of approximately 0.25 μm. Laser treatment further activated boron and facilitated its diffusion, influenced by the boron silicate glass layer and surface boron atoms. Adjustments were made to improve the pre-diffusion recipe, including an additional boron deposition step, increasing non-activated boron atoms. Introducing larger pyramidal microstructures also improved the junction depth and surface concentration in the heavily doped region. Compared to homogeneous emitters, the SE structures exhibited lower surface concentration in the lightly doped region, reducing the recombination current density in the passivation region J_0,pass values. The SE structures achieved higher junction depths, limiting metal atom diffusion and reducing the current recombination density in the metal contact region J_0,metal values. The contact resistivity between metal and silicon was also decreased. Overall, introducing SE structures resulted in a batch-average efficiency improvement of 0.26%, reaching an average efficiency of 25.22% for TOPCon solar cells, and has industrial mass-producible.

All freely available plane-of-array (POA) transposition models and photovoltaic (PV) temperature and performance models in pvlib-python and pvpltools-python were examined against multiyear field data from Albuquerque, New Mexico. The data include different PV systems composed of crystalline silicon modules that vary in cell type, module construction, and materials. These systems have been characterized via IEC 61853-1 and 61853-2 testing, and the input data for each model were sourced from these system-specific test results, rather than considering any generic input data (e.g., manufacturer's specification [spec] sheets or generic Panneau Solaire [PAN] files). Six POA transposition models, 7 temperature models, and 12 performance models are included in this comparative analysis. These freely available models were proven effective across many different types of technologies. The POA transposition models exhibited average normalized mean bias errors (NMBEs) within ±3%. Most PV temperature models underestimated temperature exhibiting mean and median residuals ranging from −6.5°C to 2.7°C; all temperature models saw a reduction in root mean square error when using transient assumptions over steady state. The performance models demonstrated similar behavior with a first and third interquartile NMBEs within ±4.2% and an overall average NMBE within ±2.3%. Although differences among models were observed at different times of the day/year, this study shows that the availability of system-specific input data is more important than model selection. For example, using spec sheet or generic PAN file data with a complex PV performance model does not guarantee a better accuracy than a simpler PV performance model that uses system-specific data.

Carrier-selective contact is a fundamental issue for solar cells. For silicon heterojunction (SHJ) solar cells, it is important to improve hole transport because of the low doping efficiency of boron in amorphous silicon and the barrier stemming from valence band offset. Here, we develop a carbon dioxide (CO₂) plasma treatment (PT) process to form dipoles and defect states. We find a dipole moment caused by longitudinal distribution of H and O atoms. It improves hole transport and blocks electron transport and thus suppresses carrier recombination. In the meantime, the CO₂ PT process also results in defect states, which reduce passivation performance but improve hole hopping in the intrinsic amorphous layer. As a balance, an appropriate CO₂ PT process at the i/p interface increases fill factor and power conversion efficiency of SHJ solar cells. We emphasize, based on sufficient evidences, this work finds a distinct role of the CO₂ plasma in SHJ solar cells opposed to reported mechanisms.

Reducing the temperature of a solar cell increases its efficiency and lifetime. This can be achieved by radiative cooling, a passive and simple method relying on materials that dump heat into outer space by thermal emission within the atmosphere transparency window between 8 and $�13��\mu �m$. As most radiative coolers are expensive or possibly UV unstable, we have recently proposed cement-based solutions as a robust and cost-effective alternative. However, the assessment model used describes the cell in the radiative limit and with perfect thermal coupling to the cooler, in line with the literature. In this work, we lift these two approximations, by incorporating Auger and Shockley–Read–Hall nonradiative recombination and a finite heat transfer coefficient at the cell/cooler interface, to obtain a thermal description of the cell/cooler stack closer to reality, while preserving the universality and transparency of the detailed-balance approach. We use this model to demonstrate that the cell performance gains provided by a radiative cooler are underestimated in the radiative limit and are hence more prominent in devices with stronger nonradiative recombination. Furthermore, we quantify the relation between cell temperature and heat transfer coefficient at the cell/cooler interface and show how this can be used to define design requirements. The extended model developed, and the resulting observations provide important guidelines toward the practical realization of novel radiative coolers for solar cells, including cement-based ones.

With the increased deployment of solar photovoltaic (PV), the cadmium telluride (CdTe) PV market is expected to grow substantially. CdTe PV production is crucial for the clean energy transition but problematic because of the material availability challenges. CdTe PV relies on tellurium, a scarce metal mainly produced as a byproduct of copper. Several studies investigated the availability of tellurium for CdTe PV. However, previous models are static and do not reflect the interconnection between tellurium supply, demand, and price. Despite the efforts, previous studies have inconsistent results and do not provide a clear understanding on the availability of tellurium for CdTe PV applications. This study uses system dynamics modeling to assess tellurium availability between 2023 and 2050. The model considers different scenarios for CdTe PV demand growth and PV material intensity reduction. The model also considers tellurium supply variables such as Te-rich ores, tellurium yield from anode slimes, and growth in copper mining. The historical data (2000–2020) analysis shows a negative correlation between the tellurium price and the annual tellurium surplus. All the considered demand scenarios exhibit a tellurium supply gap where annual material production falls below demand. Tellurium availability and price could delay the growth of CdTe PV production, and maintaining the current CdTe PV market share of ~4% will be challenging. The low-demand scenario, which is based on a constant CdTe PV market share, results in a supply gap starting in 2029 and a supply gap peak of 508 metric tons in 2036. Our work shows that having more manufacturing capacity is insufficient if tellurium is unavailable. More importantly, this work shows that fast growth in CdTe PV production can diminish the advantages of dematerialization. The estimated cumulative CdTe PV production by 2050 ranges between 929 and 2250 GWp. The findings also suggest that recycling retired solar panels can contribute to 17% of the total tellurium demand and 34% of the CdTe PV tellurium demand. Sensitivity analysis shows that expanding existing Te-rich ores does not alleviate tellurium scarcity. Alternatively, improving tellurium yield from copper electrorefining is a more efficient mitigation approach. The system dynamic approach outlined in this study provides a better perspective on the status of various critical metal supply chains, ultimately leading to sustainable materials management and increasing CdTe production.

The large-scale deployment of photovoltaics (PVs) along highways has the potential for the generation of clean electricity without competing for land use or burdening the power grid since energy for electric vehicles (EVs) can be generated locally on wastelands along highways near service stations. An analysis was carried out to evaluate the feasibility of integrating vertical bifacial solar modules into noise barriers. The approach involved integrating geospatial data with PV potential data using geographic information systems (GIS) technology. The results show a potential of around 200 GWh/year if all current noise barriers along highways in the Netherlands are considered suitable for PV module integration. Three case studies have been analysed regarding specific service stations for specific road orientations. It is shown that solar energy can charge more than 300 vehicles per day by combining bifacial PV noise barriers and standard mono-facial PV modules on publicly available land along the highway in all three case studies, which is sufficient to meet 80% of the expected EV charging demand along highways in 2030.

Photovoltaics (PVs) on building facades, either building-integrated or building-attached, offer a large energy yield potential especially in densely populated urban areas. Targeting this potential requires the availability of planning tools such as insolation forecasts. However, calculating the PV potential of facade surfaces in an urban environment is challenging. Complex time-dependent shadowing and light reflections must be considered. In this contribution, we present fast ray tracing calculations for insolation forecasts in large urban environments using clustering of Sun positions into typical days. We use our approach to determine time resolved PV capacity factors for rooftops and facades in a wide variety of environments, which is particularly useful for energy system analyses. The advantage of our approach is that the determined capacity factors for one geographic location can be easily extended to larger geographic regions. In this contribution, we perform calculations in three exemplary environments and extend the results globally. Especially for facade surfaces, we find that there is a pronounced intra-day and also seasonal distribution of PV potentials that strongly depends on the degree of latitude. The consideration of light reflections in our ray tracing approach causes an increase in calculated full load hours for facade surfaces between 10% and 25% for most geographical locations.

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 2023 are reviewed.

As the efficiency of perovskite silicon tandem solar cells is increasing, the upscaling for industrial production is coming into focus. Spatially resolved, quantitative, fast, and reliable contactless measurement techniques are demanded for quality assurance and to pinpoint the cause of performance losses in perovskite silicon tandem solar cells. In this publication, we present a measurement method based on spectrally integrated photoluminescence (PL) imaging to extract subcell-selective implied open-circuit ($�i�V_{\mathrm{oc}}$) images from monolithic perovskite silicon tandem solar cells. We validate the approach using spectrally resolved absolute PL measurements based on an integrating sphere for the perovskite top cell and PL-calibrated carrier lifetime images for the silicon bottom cell. Additionally, $�V_{\mathrm{oc}}$ measurements of solar cells with low contact losses are used to validate the new measurement technique. We find a good agreement of the $�i�V_{\mathrm{oc}}$ images with the validating measurements with a maximum deviation of well below 1% compared to the validation measurements.