Commercialization Of Photovoltaics Research Articles

A Comparative Study of Optimal PV Allocation in a Distribution Network Using Evolutionary Algorithms

The growing distributed energy resource (DER) penetration into distribution networks, such as through residential and commercial photovoltaics (PV), has emerged through a transition from passive to active networks, which takes the complexity of planning and operations to the next level. Optimal PV allocation (sizing and location) is challenging because it involves mixed-integer non-linear programming with three-phase non-linear unbalanced power flow equations. Meta-heuristic algorithms have proven their effectiveness in many complex engineering problems. Thus, in this study, we propose to achieve optimal PV allocation by using several basic evolutionary algorithms (EAs), particle swarm optimization (PSO), artificial bee colony (ABC), differential evolution (DE), and their variants, all of which are applied for a study of their performance levels. Two modified unbalanced IEEE test feeders (13 and 37 bus) are developed to evaluate these performance levels, with two objectives: one is to maximize PV penetration, and the other is to minimize the voltage deviation from 1.0 p.u. To handle the computational burden of the sequential power flow and unbalanced network, we adopt an efficient iterative load flow algorithm instead of the commonly used and yet highly simplified forward–backward sweep method. A comparative study of these basic EAs shows their general success in finding a near-optimal solution, except in the case of the DE, which is known for solving continuous optimization problems efficiently. From experiments run 30 times, it is observed that PSO-related algorithms are more efficient and robust in the maximum PV penetration case, while ABC-related algorithms are more efficient and robust in the minimum voltage deviation case.

An Information Extraction Method for Industrial and Commercial Rooftop Photovoltaics Based on GaoFen-7 Remote Sensing Images

With the increasing global focus on renewable energy, distributed rooftop photovoltaics (PVs) are gradually becoming an important form of energy generation. Effective monitoring of rooftop PV information can obtain their spatial distribution and installed capacity, which is the basis used by management departments to formulate regulatory policies. Due to the time-consuming and labor-intensive problems involved in manual monitoring, remote-sensing-based monitoring methods are getting more attention. Currently, remote-sensing-based distributed rooftop PV monitoring methods are mainly used as household rooftop PVs, and most of them use aerial or satellite images with a resolution higher than 0.3 m; there is no research on industrial and commercial rooftop PVs. This study focuses on the distributed industrial and commercial rooftop PV information extraction method based on the Gaofen-7 satellite with a resolution of 0.65 m. First, the distributed industrial and commercial rooftop PV dataset based on Gaofen-7 satellite and the optimized public PV datasets were constructed. Second, an advanced MANet model was proposed. Compared to MANet, the proposed model removed the downsample operation in the first stage of the encoder and added an auxiliary branch containing the Atrous Spatial Pyramid Pooling (ASPP) module in the decoder. Comparative experiments were conducted between the advanced MANet and state-of-the-art semantic segmentation models. In the Gaofen-7 satellite PV dataset, the Intersection over Union (IoU) of the advanced MANet in the test set was improved by 13.5%, 8.96%, 2.67%, 0.63%, and 0.75% over Deeplabv3+, U2net-lite, U2net-full, Unet, and MANet. In order to further verify the performance of the proposed model, experiments were conducted on optimized public PV datasets. The IoU was improved by 3.18%, 3.78%, 3.29%, 4.98%, and 0.42%, demonstrating that it outperformed the other models.

Perovskite-Sensitized Upconversion under Operando Conditions

Perovskite-sensitized upconversion (UC) has resulted in near-infrared-to-visible UC at solar-relevant fluxes. However, the successful implementation of UC devices into operating solar cells will result in exposure to similar environmental stressors as for the commercial photovoltaics (PVs), mainly elevated temperatures, and continuous irradiation. In this article, we investigated the effects of these two stressors, heat and light, on the triplet generation process at the perovskite/rubrene interface. Following exposure to both stressors, local discrepancies across the upconversion device were discovered. The first region showed changes to the morphology, and no detectable upconverted emission was observed. Through the combination of optical microscopy and spectroscopy, crystallization of the organic semiconductor layer, degradation of dibenzotetraphenylperiflanthene, and concurrent degradation of the perovskite sensitizer were found. These effects culminate in a reduction in both triplet generation and triplet–triplet annihilation. In the second region, no changes to the morphology were present and visible UC emission was observed following exposure to both stressors. To probe the triplet sensitization process at elevated temperatures, transient absorption spectroscopy was performed. The presence of the excited spin-triplet state of rubrene at 60 °C highlighted successful triplet generation even at elevated temperatures. This work emphasizes the challenges and continued potential for the integration of perovskite-sensitized UC into commercial photovoltaic devices.

Cool carriers: triplet diffusion dominates upconversion yield.

Perovskites have gained popularity both as the active material in photovoltaics and as bulk triplet sensitizers for solid-state triplet-triplet annihilation upconversion (TTA-UC). Prior to widespread implementation into commercial photovoltaics, an in-depth understanding of the environmental influences on device performance is required. To this point, the temperature-dependent structure-function properties of TTA-UC within methylammonium formamidinium lead triiodide (MAFA)/rubrene UC devices are explored. A strong temperature dependence of the underlying UC dynamics is observed, where the maximum UC efficiency is achieved at 170 K, reflecting the competition between triplet diffusion length, diffusion rate, and triplet-triplet encounter events. A combination of spectroscopic and structural methods and theoretical modelling illustrates that despite the significantly increased carrier lifetime of the perovskite at low temperatures, the TTA-UC dynamics are not governed by the underlying sensitizer properties but rather limited by the underlying triplet diffusion.

Strain Control to Stabilize Perovskite Solar Cells

AbstractPerovskite solar cells (PSCs) are rivaling most commercial photovoltaics in the aspect of efficiency and cost, while their intrinsic instability remains a major concern for their practical deployment. The presence of undesirable strain in PSCs during device fabrication and operation refers to the extension/narrowing of chemical bonds and expansion/shrinkage of lattice volume, which largely affects device stability due to promoted phase transition, chemical decomposition, and mechanical fragility. Pioneering investigations and remarkable achievements have revealed that strain control is indispensable in the design of stable PSCs. Herein, the evolution of strain in perovskite thin films and its effect on device performance is elucidated, and state‐of‐the‐art strategies of strain modulation are systematically reviewed. A thorough understanding and cautious control of the strain‐related phenomenon pave the pathway to derive perovskite materials with desired properties.

Strain Control to Stabilize Perovskite Solar Cells.

Perovskite solar cells (PSCs) are rivaling most commercial photovoltaics in the aspect of efficiency and cost, while their intrinsic instability remains a major concern for their practical deployment. The presence of undesirable strain in PSCs during device fabrication and operation refers to the extension/narrowing of chemical bonds and expansion/shrinkage of lattice volume, which largely affects device stability due to promoted phase transition, chemical decomposition, and mechanical fragility. Pioneering investigations and remarkable achievements have revealed that strain control is indispensable in the design of stable PSCs. Herein, the evolution of strain in perovskite thin films and its effect on device performance is elucidated, and state-of-the-art strategies of strain modulation are systematically reviewed. A thorough understanding and cautious control of the strain-related phenomenon pave the pathway to derive perovskite materials with desired properties.

Advances in Processing Kinetics for All‐Inorganic Halide Perovskite: Towards Efficient and Thermodynamic Stable Solar Cells

AbstractThe all‐inorganic CsPbX3 (X—Cl, Br, I) perovskite has the potential to solve the practical issues of environmental instability due to the presence of hygroscopic organic cations in the hybrid organic–inorganic perovskites. The promising CsPbX3 perovskite exists in different crystallographic phases depending upon the composition and processing conditions which potentially impact the film morphology, device efficiency, and stability. Stabilizing the black metastable phase at room temperature has substantially solved the problem of high crystallization temperature, which is the main roadblock in managing the control over morphology and also the choice of the underlying charge transporting layers. Despite this progress, most of the works have not mentioned all the signatures of the metastable lower temperature black phase. In this focused review, the difference between the processing conditions to achieve different phases of not only the CsPbI3 but also the other halogen counterparts is analyzed. Additionally, progress done for each combination of halides is presented and the best processing conditions for each combination of halides are summarized. Finally, their photophysical properties are analyzed and the current state of inorganic perovskites in solar cell applications is presented, and a roadmap is put forward for all inorganic CsPbX3 perovskite‐based commercial photovoltaics devices.

Recent advances of non‐fullerene organic solar cells: From materials and morphology to devices and applications

AbstractThe innovation of non‐fullerene acceptors (NFAs) enables the rapid progress of organic solar cells (OSCs) in power conversion efficiencies to over 19%, endowing OSCs with great potential toward real‐world application. In this critical review, we outline the recent advances of NFA‐based OSCs ‐ from ITIC‐ to Y6‐family, to exemplify the structure–performance correlations, and cover from material chemistry to nanomorphology controlling. In addition, we point out the possible degradation mechanisms behind the NFA‐based devices and strategies for mitigating the stability issues. With OSC efficiencies approaching 20% benchmark, increasing attention has been built‐up toward the technology's applications. Therefore, we describe the opportunities and challenges in the promising applications, mainly on semitransparent and flexible OSCs for commercial photovoltaics. Finally, we provide a summary and perspective to point out the primary challenges the OSC technology is facing toward commercialization.image

Boosting Synergy of Polymetal Phosphides by Core‐Shell Design of Prussian Blue Analogue Precursors as Electrocatalysts for Water Splitting

AbstractOxygen and hydrogen evolution reactions (OER and HER) are crucial for electrochemical water splitting, which is however hindered by the high cost of noble metal catalysts. Here, we present that by designing the core‐shell distribution of Prussian blue analogues, NiFe‐P@CoFe‐P nanocubes with various shell‐thickness are obtained to unlock the synergy of metal phosphides. The NiFe‐P@CoFe‐P nanocubes display a low overpotential of 248 mV at 10 mA cm−2 and great stability that outperform commercial RuO2 catalyst towards OER. We find that the OER and HER activity of NiFe‐P@CoFe‐P are dependent on the shell thickness, suggesting both the surface and sublayers determine the catalytic performance. Moreover, we demonstrate the water splitting under alkaline condition in an H‐cell powered by commercial photovoltaics using NiFe‐P@CoFe‐P catalyst, which is a promising approach for the conversion of solar energy.

Thermal Management of Photovoltaics Using Porous Nanochannels

The photoelectric conversion efficiency of a solar cell is dependent on its temperature. When the solar radiation is incident on the photovoltaics (PV) panel, a large portion of it is absorbed by the underlying material which increases its internal energy leading to the generation of heat. An overheated PV panel results in a decline in its performance which calls for an efficient cooling mechanism that can offer an optimum output of the electrical power. In the present numerical work, thermal management with a porous nanochannels device capable to dissipate high heat flux is employed to regulate the temperature of a commercial PV panel by integrating the device on the back face of the panel. The spatial and temporal variation of the PV surface temperature is obtained by solving the energy balance equation numerically. By evaluating the steady-state PV surface temperature with and without thermal management, the extent of cooling and the resulting enhancement in the electrical power output is studied in detail. The nanochannels device is found to reduce the PV surface temperature significantly with an average cooling of 31.5 oC. Additionally, the enhancement in the electrical power output by ~33% and the reduction in the response time to 1/8th highlight the potential of using porous nanochannels as a thermal management device. Furthermore, the numerical method is used to develop a universal curve which can predict the extent of PV cooling for any generic thermal management device.

Advances in low-cost and nontoxic materials based solar cell devices

Photovoltaics (PV) have become increasingly popular and reached as the third-largest renewable energy source. Thin-film solar cells made from earth-abundant, inexpensive and environmentally friendly materials are needed to replace the current PV technologies whose large-scale applications are limited by material and/or resource constraints. Near optimum direct optical bandgap of 1.3 eV, high absorption coefficient (>104 cm−1), less toxic, and abundant raw resources along with considerable scalability have made tin sulfide (SnS) as a strategic choice for next-generation PVs. In this review, limitations of leading commercial PV technologies and the status of a few alternate low-cost PV materials are outlined. Recent literature on crucial physical properties of SnS thin-films and the present status of SnS thin-film-based solar cells are discussed. Deficiency and adequacy of some of the key properties of SnS including carrier mobility (μ), minority carrier lifetime (τ), and absorption coefficient (α) are discussed in comparison of existing commercial solar cell materials. Future research trends on SnS based solar cells to enhance their conversion efficiencies towards the theoretical maximum of 24% from present ~5% and its prospectus as next-generation solar cell is also discussed.

Identifying snow in photovoltaic monitoring data for improved snow loss modeling and snow detection

As cost reductions have made photovoltaics (PV) a favorable choice also in colder climates, the number of PV plants in regions with snowfalls is increasing rapidly. Snow coverage on the PV modules will lead to significant power losses, which must be estimated and accounted for in order to achieve accurate energy yield assessment and production forecasts. Additionally, detection and separation of snow loss from other system losses is necessary to establish robust operation and maintenance (O&M) routines and performance evaluations.Snow loss models have been suggested in the literature, but developing general models is challenging, and validation of the models are lacking. Characterization and detection of snow events in PV data has not been widely discussed.In this paper, we identify the signatures in PV data caused by different types of snow cover, evaluate and improve snow loss modeling, and develop snow detection. The analysis is based on five years of data from a commercial PV system in Norway. In an evaluation of four snow loss models, the Marion model yields the best results. We find that system design and snow depth influence the natural snow clearing, and by expanding the Marion model to take this into account, the error in the modeled absolute loss for the tested system is reduced from 23% to 3%. Based on the improved modeling and the identified data signatures we detect 97% of the snow losses in the dataset. Endogenous snow detection constitutes a cost-effective improvement to current monitoring systems.

Economically Sustainable Growth of Perovskite Photovoltaics Manufacturing

Summary The significant capital expense of photovoltaics manufacturing has made it difficult for new cell and module technologies to enter the market. We present two technoeconomic models that analyze the sustainable growth of perovskite manufacturing for an R2R single-junction technology and a perovskite-silicon tandem module, focusing on the impacts of economies of scale and average selling price on profitability. We establish a cost range of $3.30/W to $0.53/W for flexible modules manufactured in factory sizes ranging from 0.3 MW/year to 1 GW/year. In addition, we model the cost to manufacture a tandem module consisting of a single-junction perovskite cell stacked in 4-terminal configuration onto a silicon cell and show how an existing manufacturer can grow at a faster rate by co-investing in tandems. Our analyses highlight potential routes to market for perovskite photovoltaics and the possibility to sustainably grow a photovoltaics manufacturing company even in markets with higher labor rates.

Accelerating Photovoltaic Market Entry with Module Replacement

Summary Today’s approach to deploying solar photovoltaics (PV) implicitly assumes that module technology is fixed. Solar panels are installed and expected to operate for the system life of 30 years or more. However, many PV technologies are improving rapidly along several dimensions, including cost, power conversion efficiency, and reliability. Periodic module replacement or planned repowering takes advantage of this technological improvement and counteracts predictable degradation. Here, we show that a module replacement strategy allows a competitive levelized cost of electricity to be achieved with an initial module lifetime of less than 15 years, assuming backward compatibility with the original system design. We also assess the life-cycle environmental impacts of module replacement and find that all commercial PV technologies offer benefits in the majority of impact categories, regardless of the replacement strategy, compared to today’s electric generation mix. Module replacement can thus accelerate the market introduction and decarbonization impact of emerging PV technologies that have achieved a competitive module efficiency (≥20%), cost (≤$0.30/W), and lifetime (≥10 years) and have the potential to improve further on all three metrics but lack decades-long field deployment experience.

The role of the third component in ternary organic solar cells

Ternary organic solar cells (TSCs) contain a single three-component photoactive layer with a wide absorption window, which is obtained without the need for multiple stacks. Subsequently, TSCs have attracted great interest in the photovoltaics field. Through careful selection of the three (or more) active components that form the photoactive layer, all photovoltaic parameters can be simultaneously enhanced within a TSC — a strategy that has resulted in record efficiencies for single-junction solar cells. In this Review, we outline key developments in TSCs, with a focus on the central role of the third component in achieving record efficiencies. We analyse the effects of the third component on the nanomorphology of the bulk heterojunction and the photovoltaic parameters of TSCs. Moreover, we discuss the charge-transfer and/or energy-transfer mechanisms and nanomorphology models that govern the operation of TSCs. We consider both polymer and small-molecule donors as well as fullerenes and recently developed non-fullerene acceptors. In addition, we summarize the recent success of TSCs in mitigating the stability issues of binary solar cells. Finally, we provide a perspective on the advantages of ternary blends and suggest design strategies for highly efficient and stable devices for commercial photovoltaics. Adding a third component into a binary blend is a promising strategy for simultaneously improving all photovoltaic parameters in organic solar cells. In this Review, we discuss the role of the third component in influencing the energetics, charge-carrier recombination and stability in ternary solar cells.

Extraordinary Carrier Diffusion on CdTe Surfaces Uncovered by 4D Electron Microscopy

Summary Herein, we describe the selective mapping of surface charge carriers, achieved using scanning ultrafast electron microscopy, for visualization of light-triggered carrier dynamics on the nanometer scale, diffusing on the surface of CdTe, a leading semiconductor in commercial photovoltaics. We reveal a novel diffusion model of charge carriers on surfaces. The nature of charge diffusion varies significantly, from superior diffusion to virtually trapped, depending on the crystal orientation. For instance, carriers on the (110) crystal orientation displayed a diffusion coefficient of ∼40,000 cm2·s−1 (i.e., ∼104 times larger than measured in the bulk). In contrast, the (211) polar facets formed oxidative layers that, in turn, formed mid-surface-trap states that nearly arrested the charge diffusion completely. Complementary techniques and theoretical modeling explain the acute sensitivity of charge carriers to surface orientation and termination. Our findings reveal the enormous untapped potential for improved CdTe-based devices and optoelectronic materials in general through facet management.

Nanostructure-induced fast texturization of mono-crystalline silicon in low-concentration alkaline solution

Silicon solar cells have been center of focus over the decades while the price challenge still hinders its large-scale application. Cost reduction is the urgent pursuit and our work focuses on the texturization process for mono-crystalline silicon. In this report, nanostructures made by metal-assisted chemical etching (MACE) method were introduced before texturization in low-concentration alkaline solution, which shows the advantage in controlling uniformity and thickness losses compared with standard-concentration alkaline solution. By varying MACE etching time, black silicon layers with different morphologies and depths were obtained. Consequently, pyramid structures of different sizes were observed after texturizaiton. Minimum reflectance value of 10.3% and mean pyramid size of 2.95 µm were achieved in low-concentration alkaline solution with optimized MACE etching time. By using SEM, PL and analytical balance to analyze the morphologies of black silicon samples and corresponding thickness losses, we speculated that the nanostructures of black silicon layers acted as the preferential sites for etching, thus accelerated the texturization process and completed within only 10 min. In summary, low-concentration, short-time and less silicon consumption texturization for mono-crystalline silicon could be achieved using our one-step MACE-induced method, exhibiting great potential in commercial photovoltaics utilization and ultra-thin silicon solar cells.

Doping strategies for small molecule organic hole-transport materials: impacts on perovskite solar cell performance and stability.

Hybrid organic/inorganic perovskite solar cells (PSCs) have dramatically changed the landscape of the solar research community over the past decade, but >25 year stability is likely required if they are to make the same impact in commercial photovoltaics and power generation more broadly. While every layer of a PSC has been shown to impact its durability in power output, the hole-transport layer (HTL) is critical for several reasons: (1) it is in direct contact with the perovskite layer, (2) it often contains mobile ions, like Li+ - which in this case are hygroscopic, and (3) it usually has the lowest thermal stability of all layers in the stack. Therefore, HTL engineering is one method with a high return on investment for PSC stability and lifetime. Research has progressed in understanding design rules for small organic molecule hole-transport materials, yet, when implemented into devices, the same dopants, bis(trifluoromethane)sulfonimide lithium salt (LiTFSI) and tris(2-(1H-pyrazol-1-yl)-4-tert-butylpyridine)cobalt(iii) tri[bis(trifluoromethane)sulfonimide] (FK209), are nearly always required for improved charge-transport properties (e.g., increased hole mobility and conductivity). The dopants are notable because they too have been shown to negatively impact PSC stability and lifetime. In response, new research has targeted alternative dopants to bypass these negative effects and provide greater functionality. In this review, we focus on dopant fundamentals, alternative doping strategies for organic small molecule HTL in PSC, and imminent research needs with regard to dopant development for the realization of reliable, long-lasting electricity generation via PSCs.

Solar Concentrator’s Effect on Solar Panel Efficiency

Given the current energy emergencies, the existing emphasis is increasing on the renewables as researchers predict near the end to fossils. In the light of the current renewable energy resources, the solar energy is seen to be one of the most reliable ones for the third world countries. Moreover, the efficiency of current commercial photovoltaics hardly touches 30 %. This paper studies the mechanism of empowering solar concentrators to collect higher solar irradiation to concentrate on the solar panel and study the variations in the amount of power received and the temperature constraints. The study utilises the use of solar concentrators in regions under and over the mentioned standard temperature ranges by the manufacturer on the specification sheet, and thoroughly studies the variations observed in output parameters.

Integrating Desalination and Energy Storage using a Saltwater-based Hybrid Sodium-ion Supercapacitor.

Ever-increasing freshwater scarcity and energy crisis problems require efficient seawater desalination and energy storage technologies; however, each target is generally considered separately. Herein, a hybrid sodium-ion supercapacitor, involving a carbon-coated nano-NaTi2 (PO4 )3 -based battery anode and an activated-carbon-based capacitive cathode, is developed to combine desalination and energy storage in one device. On charge, the supercapacitor removes salt in a flowing saltwater electrolyte through Cl- electrochemical adsorption at the cathode and Na+ intercalation at the anode. Discharge delivers useful electric energy and regenerates the electrodes. This supercapacitor can be used not only for energy storage with promising electrochemical performance (i.e., high power, high efficiency, and long cycle life), but also as a desalination device with desalination capacity of 146.8 mg g-1 , much higher than most reported capacitive and battery desalination devices. Finally, we demonstrate renewables to usable electric energy and desalted water through combining commercial photovoltaics and this hybrid supercapacitor.