Perovskite/silicon (PS) technology includes three main configurations: two-terminal (2T), three-terminal (3T), and four-terminal (4T). Previous studies have made various comparisons between these configurations, significantly advancing our understanding of these devices. While these studies mostly focus on simulations on cell level, we perform bandgap energy ((Formula presented.)) optimization at the module level for different configurations under outdoor conditions. Using opto-electrical simulations, we predict the energy yield of each module at four geographical locations, with varying values of (Formula presented.). The optimal (Formula presented.) for the 2T, 3T, and 4T modules are 1.62, 1.80, and 1.82 eV, respectively. We also perform a loss analysis to explore the differences in power losses among the configurations. These loss differences can be attributed to the configurations having different optimal (Formula presented.) values (affecting the thermalization losses) or different module designs (affecting the interconnection losses). Among all losses, mismatch losses play the most critical role in optimizing the bandgap. Overall, all optimized configurations have similar energy yields (all differences within 1.5%) across all locations. Finally, we compare the robustness of the different configurations against different scenarios of perovskite degradation. Our results show that the 4T module is the least sensitive to degradation in the perovskite subcell.

Photovoltaic (PV) system performance is linked to climatic conditions in which the system operates. This leads to the Köppen-Geiger-Photovoltaic (KGPV) climate classification. KGPV is created by overlaying four irradiation levels with the commonly used Köppen-Geiger climate zones. Potential drawbacks of this approach are that the climate features are not considered in a combined manner in the sorting process and that the KGPV zones inherent a dependence on precipitation. We propose a machine-learning approach to address this deficiencies and improve PV climate classification. First, supervised learning is used to evaluate the correlation between climate features and a PV system's specific energy yield. We find that the inclusion of the darkest and brightest irradiation months as well as UV irradiation improves accuracy, while wind speed, relative humidity, precipitation and annual mean daily temperature difference have little impact on accuracy. Subsequently, k-means clustering combined with comprehensive qualitative analysis, identifies a PV classification based on seven climate features and 21 clusters. A mountainous climate characterized by moderate to low temperature and high irradiation is uncovered compared to KGPV. Moreover, this new PV climate classification reduces the sum of squared errors by 58 % compared to KGPV clearly signifying a more accurate PV climate classification approach.

The current industrial standard photovoltaic (PV) modules are dominated by crystalline-silicon (c-Si) PV technology, which cannot be easily recycled. This has generated worldwide concerns regarding the scarcity of critical raw materials and large waste streams of PV modules in the coming years. To overcome this problem, a lot of ongoing research focuses on upscaling the recycling process of present c-Si module designs by chemical, thermal and mechanical processes. Alternative research focuses on the development of new PV modules with enhanced circularity by design. In this work, we propose a new circular PV module design based on liquid-encapsulation technology in which silicon solar cells are encapsulated with a suitable liquid and an edge sealant instead of a polymer sheet. Our optical studies show that the selected liquids exhibit similar optical performance to ethylene vinyl acetate (EVA) due to their comparable refractive indices. We fabricate one-cell prototypes and observe comparable efficiency of liquid-encapsulated and EVA-encapsulated modules, signifying recyclable module design without an additional efficiency loss. To validate the module performance, we also simulate the optical performance of modules with different encapsulation materials. Furthermore, the new modules retained more than 95% of their efficiency after inducing accelerated ageing through damp heat, thermal cycling and humidity freeze tests, indicating the liquids as an excellent encapsulant material for PV. In the end, we disassemble the liquid-filled PV module and show the recovered components, which can directly be reused in new products. Therefore, this modular design bypasses the recycling process. Even more promising, the liquid encapsulation can improve the stability of perovskite/c-Si tandem solar cells due to the moisture barrier, which will be studied in the future. Adding further possibilities, in principle, with additional engineering, the liquid encapsulation could be used in a heat loop to turn the PV module into a photovoltaic-thermal (PV-T) module, thereby boosting the efficiency potential beyond that of traditional PV concept.

Photovoltaic (PV) to virtual bus parallel differential power processing (PDPP) architecture can mitigate mismatch losses among PV strings. This article presents a comprehensive dynamic analysis by deriving a small-signal model of the PDPP architecture based on its state space model. Subsequently, the corresponding transfer functions and frequency response are obtained, offering valuable insights into the dynamic behavior of the architecture. To validate the accuracy of the derived model, the frequency response has also been achieved by observed data from both PLECS simulation and experiment through system identification. Besides, this article discusses the design considerations of the discrete controllers' parameters for both virtual and intermediate bus voltages and studies the stability of the architecture. Experimental measurements confirm the ability of the central controller to stabilize the virtual bus voltage to the desired level within 0.6 seconds, while the intermediate bus voltages settle within 15 ms, enabling proper maximum power point tracking of each PV string.

Optimizing the deposition parameters in the fabrication of passivating contacts for crystalline silicon solar cells is critical for improving efficiency. This study explored the influence of varying RF power of Plasma-Enhanced Chemical Vapor Deposition (PECVD) on the quality of hydrogenated intrinsic amorphous silicon ( a-Si:H) films. The aim is to manufacture in-situ phosphorous-doped poly-Si/SiO_x/c-Si passivating contacts with a-Si:H as buffer layer between the tunnelling oxide and the n-type poly-Si. The microstructure factor of our intrinsic layers increases from 0.176 to 0.804, that is from higher to lower film density, as the RF power increases from 5 W to 55 W. Analysis using X-ray Photoelectron Spectroscopy and Optical Microscopy indicates that the Si content in SiO_x is correlated with the formation of pinholes. Our detailed analysis showed that varying the RF power when depositing a-Si:H contacting layer is crucial in altering both the Si⁴⁺ content in SiO_x and the pinhole density, due to the interplay between the plasma etching and the buffering effects during of the a-Si:H layer growth. Notably, the sample processed with 25 W exhibited the maximum pinhole density, the lowest Si⁴⁺ content in SiO_x and the deepest phosphorus in-diffusion, potentially yielding superior results in passivation quality and contact resistivity under optimized PECVD conditions.

In this study, a modeling methodology is presented for evaluating the performance of a hybrid system integrating different types of solar collectors, namely photovoltaic (PV), glazed flat plate solar thermal (ST) and unglazed photovoltaic-thermal (PVT) collectors to harvest solar energy. Further, the system is integrated with a seasonal storage that is an aquifer thermal energy storage (ATES) system, a heat exchanger and a heat pump (HP) to provide heating, including space heating (SH), domestic hot water (DHW), as well as cooling. The investigation considers various operational modes depending on the climate conditions and building characteristics. The study focuses on comparison of solar collectors in realistic scenarios, examining heating type and insulation levels. Real energy consumption data considering five residential buildings in Amsterdam is employed for the analysis. Annual simulations for the considered buildings are conducted for SH and DHW coverage, along with cooling. The results indicate that ATES combined with glazed ST collectors demonstrates superior heat storage while HP with PV/ST combination and floor heating achieves an average coefficient of performance (COP) of 6.09 for both SH and DHW. In contrast, HP combined with PVTs shows the lowest performance, with a COP of around 5 when used with radiator heating. Additionally, majority of the demand is covered using HP storage mode with seasonal storage and HP while building insulation plays a crucial role.

Polycrystalline silicon (poly-Si) carrier-selective passivating contacts (CSPCs), featuring high photoconversion efficiency (PCE) and cost-effectiveness, have emerged as a promising approach for high-efficiency crystalline silicon (c-Si) solar cells. To minimize parasitic absorption losses induced by doped poly-Si window layers, wide bandgap oxygen-alloyed poly-Si (poly-SiO_x) layers are developed. However, challenges persist in achieving excellent surface passivation for boron-doped poly-SiO_x contact stacks, likely caused by boron diffusion during annealing and the reduced doping concentration resulting from lower crystallinity as oxygen content increases. In this study, we investigate the impact on the passivating contact structure and solar cell performance of a 10-nm thick intrinsic hydrogenated amorphous silicon buffer layer with varying oxygen content (a-Si (O_x):H) deposited by plasma-enhanced chemical vapor deposition (PECVD), and placed between the tunneling silicon oxide (SiO_x) and the poly-SiO_x (p⁺). After the hydrogenation step, we obtain both high passivation quality with implied open circuit voltage (iV_oc) of 728.3 mV and low contact resistivity (ρ_c) of 59.18 mΩ cm² on polished surface for oxygen-free a-Si:H buffer layer. These improvements can be attributed to the appropriate thickness of the tunnel oxide and confirmed by transmission electron microscopy (TEM) images, to higher crystallinity of the buffer layer, which facilitates more efficient doping in the buffer layer. This is evidenced by energy dispersive X-ray spectroscopy (EDX), and X-ray photoelectron spectroscopy (XPS) results. At the device level, a front-side textured, rear-side flat, rear junction poly-SiO_x/poly-SiO_x solar cell on n-type c-Si wafer, an efficiency improvement can be observed from 3.55 % without a PECVD buffer layer to 18.9 % with an oxygen-free a-Si:H PECVD buffer layer. The impact of the buffer layer crystallinity on cell performance is further demonstrated by deploying a 10-nm thick LPCVD buffer layer, which facilitates an efficiency of 21.15 % for the same device structure.

Photovoltaic modules are typically not optimized for conditions of partial shading. One proposed approach to improve their shade tolerance is to implement maximum power point tracking on different strings of cells within the modules. However, this approach increases the demand for sub-module power converters, which poses a challenge. To address this, researchers have suggested integrating power electronic components directly into the module laminate, or even within the solar cells themselves. Despite these advancements, limited research has focused on integrating the most bulky component: the inductor. This study investigates through simulations whether planar air-core inductors can yield the required properties to support sub-module power conversion. The simulated inductors have an area that is as large as an industrial crystalline silicon solar cell. First, it is shown how the interplay between the different design parameters, such as track spacing, track width, number of turns, and middle gap size, plays an important role in the inductor properties at high frequency. The coil geometries that are simulated yield inductance values between 0.3 μH and 3.2 μH. Subsequently, the feasibility of implementing these inductors into an exemplary DC–DC boost converter is evaluated. To adequately reduce the ripple current, a significant switching frequency of at least several hundred kHz is required. Additionally, at 500 kHz, an inductor thickness of around 0.5 mm is necessary to keep the ohmic losses in the inductor below 2% of the total generated power in standard test conditions. While demonstrating feasible combinations, these findings also present significant challenges.

Solar farm installers generally struggle with the allocation of irradiance sensors throughout the plant area, which are essential for monitoring purposes. Despite the existence of the International Electrotechnical Commission guidelines for photovoltaic (PV) plant monitoring, no specific guidance is provided when it comes to allocating sensors. This can be especially problematic for solar farms in hilly terrain. In this work, a software tool is built to allocate horizontal and in-plane irradiance sensors. Additionally, advice on the optimum number of sensors and the prevented error is provided based on the layout of the farm. The methodology consists of calculating the irradiance at every point of the solar farm area and finding the one closest to the average. This average is computed differently depending on the sensor type and monitoring purpose. A modification of the BRL irradiance decomposition model is also proposed to reduce the bias of the original model. The software has been applied to two case studies of existing solar farms in hilly areas in Greece and Germany, showing its applicability for real case scenarios in different climates and geological landscapes. The runtime of the software tool is mainly a function of solar farm size and the land morphology of its location. This methodology has been only developed for monofacial fixed-tilted PV farms.

Crystalline silicon (c-Si) solar cells are rapidly establishing new efficiency frontiers, with front/back-contacted (FBC) designs now exceeding 26.8 % power conversion efficiency (PCE) and interdigitated back-contacted (IBC) cells surger limitepassing 27 %. This progress is driving a shift from traditional FBC PERC architectures to high-performance TOPCon, SHJ, and IBC configurations, with carrier-selective contacts (CSCs) at the core of these breakthroughs. In this work, we identify three critical factors underpinning CSC effectiveness: the work function of contact layers, energy barriers at heterointerfaces, and energy alignment across the stack of layers forming the CSC. By using advanced numerical simulations, we establish a framework for evaluating and optimizing CSC designs, including state-of-the-art poly-Si, SHJ, and dopant-free structures. We also introduce novel architectures based on TCO materials with potentially simpler manufacturing processes. Our simulations reveal that advanced FBC structures, can reach PCEs up to 28 % deploying localized CSCs architecture. In optimized IBC configurations, efficiencies as high as 28.64 % are achievable. For both, FBC and IBC configurations patterning limitations remain a barrier to theoretical efficiency peaks. Future advances in precision patterning could further close this gap, pushing c-Si solar cells closer to their intrinsic limits. This study provides a roadmap for high-efficiency CSC integration in next-generation c-Si solar cells, establishing pathways to achieve performance over 28 % and accelerating the evolution of photovoltaic technology.

In this section, we described the various device architectures in production for crystalline-silicon PV as well as the various absorber materials being used and developed for thin-film PV. We also explained why multijunction PV technology is considered the future of PV technology. We identified four major technological challenges (Fig. 1) for future mass production and deployment of PV technology in order to achieve the goal of climate neutrality and indicated how optics could help resolve these challenges. The four main challenges (Fig. 1) are: • Sustainable production of PV systems; • Higher energy conversion efficiencies; • Higher energy output and operational lifetime; • Integration of PV systems in their environment.

The authors have operated a few minor modifications in response to helpful feedback received post-publication from the readership. These updates are solely intended to clarify certain aspects of the article and enhance its overall readability. The first update concerns the caption of Fig. 7, which has been revised to improve clarity for readers through the addition of explanatory notes. The second update pertains to the Technology Readiness Level (TRL) of a technology developer in Table 3, which has been updated based on the latest provided information. As a derivative of this change, Fig. 8(a), that is a visual representation of Table 3, has also been updated to reflect the revised TRLs. Additionally, the note in the caption of Table 3 has been slightly modified for improved clarity. These modifications do not affect the outcomes, analysis, or conclusions of the article and are solely intended to improve clarity for readers and consistency with respect to most recent information.[Figure presented] Fig. 7: Proposed classification framework. FPV designs compiled and classified based on research publications and designs used by technology providers. Note: (i) each reported archetype can be technically made modular with companies deploying different (proprietary) solutions for upscaling the surface coverage of the farm; (ii) the adjective “large” in the acronym ”LRP” is related to the area of the floater as a surface that is at least bigger than one PV module. Table 3: TRLs of different FPV archetypes hosted by different organisations. Note: This table shows the TRLs based on publicly available information and represents a snapshot in time. The TRLs are subject to change over time and may not reflect the most up-to-date values.[Figure presented][Figure presented] Fig. 8: Current technology readiness landscape. (a) The trend of TRLs for inland and offshore solar deployments, (b) number of organisations working on inland and offshore solar deployment. Data derived from Table 3.

In realistic partial shading scenarios, the impact of low-intensity illumination needs to be considered. However, there is barely any research available and the published results are contradictory. Here, it is shown that the reverse bias behavior of perovskite solar cells under low-intensity illumination strongly depends on the voltage scan rate. As explanation, a hypothesis is developed and experimentally verified that is based on two antagonistic mechanisms: on one hand, illumination affects the mobile ions conductivity, decreasing the breakdown voltage. On the other hand, an electrochemical reaction caused by the reverse bias current increases the breakdown voltage. Since the two mechanisms occur on slightly different time scales, it depends on the voltage scan rate which mechanism dominates. These findings emphasize that more detailed research into the mechanism occurring in reverse bias and the factors affecting the reverse bias breakdown is still necessary. Firstly, a deeper understanding would be helpful for investigating the effect of realistic, non-ideal partial shading scenarios on perovskite modules. Secondly, knowing how cell properties and external factors influence the breakdown voltage is necessary for defining standardized measurement procedures that allow the comparison of different perovskite solar cells in regards to their reverse bias stability.

Positive Energy Districts (PEDs) are integral to achieving sustainable urban development by enhancing energy self-sufficiency and reducing carbon emissions. This paper explores energy balance calculations in four diverse case study districts within different climatic conditions—Fiat Village in Settimo Torinese (Italy), Großschönau (Austria), Beursplain in Amsterdam (Netherlands), and Lunca Pomostului in Reşiţa (Romania)—as part of the SIMPLY Positive project. Each district faces unique challenges, such as outdated infrastructure or heritage protection, which we address through tailored strategies including building renovations and the integration of renewable energy systems. Additionally, we employ advanced simulation methodologies to assess energy performance. Simulation results highlight the significance of innovative technologies like photovoltaic-thermal (PVT) systems, application of demand-side actions, and flexible grid usage. Furthermore, mobility assessments and resident-driven initiatives demonstrate the critical role of community engagement in reducing carbon footprints. This study underscores the adaptability of PED frameworks across varied urban contexts and provides actionable insights for scaling similar strategies globally, supporting net-zero energy targets.

Sequential thermal evaporation is an emerging technique for obtaining perovskite (PVK) photoactive materials for solar cell applications. Advantages include solvent-free processing, accurate stoichiometry control, and scalable processing. Nevertheless, the power conversion efficiency (PCE) of PVK solar cells (PSCs) fabricated by evaporation still lags behind that of solution-processed PSCs. Here, based on multi-cycle sequential thermal evaporation, we systematically investigate the effects of the post-deposition annealing temperature on the PVK properties in terms of surface morphology, opto-electronic properties, and device performance. We find that the average grain size increases to almost 1 μm and charge carrier mobilities exceed 50 cm2 V−1 s−1 when the annealing temperature is increased to 170 °C. We introduce a trace of PbCl2 to the multi-cycle sequential deposition to improve the absorber crystallinity at a lower annealing temperature of 150 °C, as evidenced by the XRD and PL analyses. The resulting PSC in a p–i–n structure yields a PCE of 18.5% with a cell area of 0.09 cm2. With the same deposition parameters, the cell area is scaled up to 0.36 cm2, achieving champion PCEs of 17.06%. This indicates the great potential of this technology for the commercialization of PSCs in the future.

The integration of self-assembled monolayers (SAMs) in perovskite (PVK) solar cells often presents processing challenges that can hinder their industrial uptake. To address these limitations and enhance the manufacturability of the SAMs/PVK interface, a co-deposition strategy was recently developed, wherein both SAMs and PVK films are formed simultaneously in a single step. As the fundamental principles governing the SAM/PVK co-deposition process remain insufficiently explored, here we selected four commercially available SAMs molecules─MeO-4PACz, Me-4PACz, Me-2PACz, and 2PACz─and we mixed them based on their molecular size, polarity, and hydrophobicity, forming pairs. The co-deposition process of mixed-SAMs with MAPbI3precursor solutions was studied, and corresponding solar cell devices were fabricated. Among the three combinations tested, the MeO-4PACz + Me-4PACz one yields the most promising results, and a power conversion efficiency of approximately 19% was achieved without any additional passivation strategies. Our findings reveal that the co-deposition process of mixed-SAMs is primarily influenced by the interplay between molecular size and polarity. The binding strength of co-deposited mixed SAMs to the In2O3:Sn (ITO) substrate is largely dictated by their solvation behavior in the PVK precursor-DMF:DMSO solvent system. This conclusion is supported by quantum chemistry calculations and further corroborated by surface, structural, and compositional analysis.

In the quest for advancing photovoltaic efficiency, the adoption of multijunction solar cell architectures has emerged as a promising approach. Perovskite/silicon double-junction solar cells have already achieved efficiencies surpassing 33%, exceeding the theoretical efficiency limit for single-junction devices. To enhance efficiency even further, exploring perovskite/perovskite/silicon (PPS) triple-junction solar cells seems a logical next step, as they offer the potential to further reduce thermalization losses and achieve even higher efficiencies. This study delves into the potential of various configurations of PPS modules, exploring different subcell interconnections. Initially, we present an optoelectrical model to simulate the performance of these devices, incorporating both luminescence coupling and cell-to-module losses. This enables us to optimize the bandgap energy of the top and middle perovskite subcells under both standard test conditions (STC) and outdoor conditions. Our analysis reveals that the addition of a perovskite subcell can improve the STC efficiency up to 9%–13%. This gain in STC performance also translates into a similar gain in energy yield, meaning that triple-junction devices produce 8%–14% more electricity than their double-junction reference devices.

This article introduces an innovative parallel differential power processing (PDPP) architecture designed to mitigate the effect of mismatch among photovoltaic (PV) strings. The proposed PV to virtual bus PDPP architecture leverages a virtual bus as the input for all string-level converters. Notably, this approach allows for a reduction in the voltage rating of components since the virtual bus voltage can be set lower than the main bus or PV strings voltage. In this architecture, crucial requirements for the string-level converters (SLCs) include the capability to generate positive and negative output voltages and to provide isolation. To fulfill these requirements, a dual active bridge converter connected to a bridgeless converter as the PDPP SLCs is considered. In this architecture, while SLCs ensure maximum power point tracking (MPPT) for each PV string using conventional MPPT algorithms, the central converter controls the virtual bus voltage. Experimental results validate the performance of the proposed PV to virtual bus PDPP architecture with a system efficiency ranging from 96.4% to 99%.

Increasing the operating lifetime of photovoltaic (PV) modules is a key factor in further reducing their levelized cost of electricity. Analytical degradation models typically use the external relative humidity (RH) as a stress factor, rather than the moisture concentration inside the module. This study presents a Finite Element Method (FEM) model, built in COMSOL Multiphysics, to simulate the moisture ingress inside a PV module. We explore the effects of different encapsulant and backsheet materials, as well as various climatic conditions, on moisture penetration. Overall, the impact of the climate has a larger impact on the moisture ingress than the choice of material, implying that the PV module design should be adjusted for different climates. As FEM simulations are computationally intensive, we also present an analytical model, based on empirically determined characteristics, to simulate the moisture ingress. This reconstruction can be done with a deviation lower than 0.05 for all conditions. Finally, our findings indicate that the relative moisture content (RMC) within the module serves as a more accurate stress factor than outdoor RH. Degradation rates over time found in literature are captured more accurately when deploying RMC.

Interdigitated-back-contacted silicon heterojunction (IBC-SHJ) solar cells with molybdenum oxide (MoOx) as a hole transport layer and a novel (n)-type hydrogenated nanocrystalline silicon (nc-Si:H)/MoOx electron transport stack use ultra-thin MoOx as a full-area blanket layer. This solar cell architecture is realized with a simplified fabrication process and ensures high shunt resistances, attributed to the low lateral conductivity of the MoOx layer. Here we investigate the electron transport mechanisms through the electron collection contact to improve the understanding and performance of the IBC-SHJ solar cells. For this evaluation, we first introduce plasma treatments between (n)nc-Si:H and MoOx and assess their role in passivation, charge carrier transport and MoOx growth. Temperature-dependent current–voltage (I–V) measurements of front/back-contacted (FBC) solar cells with (n)nc-Si:H/MoOx stack, supported by high-resolution transmission electron microscopy (HR-TEM) and energy dispersive X-ray spectroscopy (EDX) imaging and numerical simulations, reveal that plasma treatment (PT) and plasma treatment with boron (PTB) enable electron transport based on direct energy transitions. Next, we perform thickness sensitivity analysis to find the optimal layer thicknesses of (n)nc-Si:H and MoOx. While FBC-SHJ devices exhibit stable performance across a broad range of (n)nc-Si:H thicknesses (10–50 nm), IBC-SHJ devices are more sensitive to such a thickness variation, with thinner (n)-layers limiting final device efficiency. The combination of 50-nm thick (n)nc-Si:H, PTB, and 1.7-nm thick MoOx enables the best performance of IBC-SHJ solar cells. When metallized with electroplated Cu, our champion IBC-SHJ solar cell with MoOx blanket layer reaches an efficiency of 23.59%. Further advancements in (n)nc-Si:H properties, passivation, transparent conductive oxide selection, and front-side light management are expected to drive efficiencies well above 24%.