Efficient and Stable Inverted Perovskite Solar Modules Enabled by Solid-Liquid Two-Step Film Formation

A considerable efficiency gap exists between large-area perovskite solar modules and small-area perovskite solar cells.The control of forming uniform and large-area film and perovskite crystallization is still the main obstacle restricting the efficiency of PSMs.In this work,we adopted a solid-liquid two-step film formation technique,which involved the evaporation of a lead iodide film and blade coating of an organic ammonium halide solution to prepare perovskite films.This method possesses the advantages of integrating vapor deposition and solution methods,which could apply to substrates with different roughness and avoid using toxic solvents to achieve a more uniform,large-area perovskite film.Furthermore,modification of the NiO_(x)/perovskite buried interface and introduction of Urea additives were utilized to reduce interface recombination and regulate perovskite crystallization.As a result,a large-area perovskite film possessing larger grains,fewer pinholes,and reduced defects could be achieved.The inverted PSM with an active area of 61.56 cm^(2)(10×10 cm^(2)substrate)achieved a champion power conversion efficiency of 20.56%and significantly improved stability.This method suggests an innovative approach to resolving the uniformity issue associated with large-area film fabrication.

Up-Scalable Fabrication of SnO_(2)with Multifunctional Interface for High Performance Perovskite Solar Modules

Tin dioxide(SnO_(2))has been demonstrated as one of the promising electron transport layers for high-efficiency perovskite solar cells(PSCs).However,scalable fabrication of SnO_(2) films with uniform coverage,desirable thickness and a low defect density in perovskite solar mod-ules(PSMs)is still challenging.Here,we report preparation of high-quality large-area SnO_(2) films by chemical bath depo-sition(CBD)with the addition of KMnO_(4).The strong oxidiz-ing nature of KMnO_(4) promotes the conversion from Sn(II)to Sn(VI),leading to reduced trap defects and a higher carrier mobility of SnO_(2).In addition,K ions diffuse into the per-ovskite film resulting in larger grain sizes,passivated grain boundaries,and reduced hysteresis of PSCs.Furthermore,Mn ion doping improves both the crystallinity and the phase stability of the perovskite film.Such a multifunctional interface engineering strategy enabled us to achieve a power conversion efficiency(PCE)of 21.70% with less hysteresis for lab-scale PSCs.Using this method,we also fabricated 5×5 and 10×10 cm^(2) PSMs,which showed PCEs of 15.62% and 11.80%(active area PCEs are 17.26%and 13.72%),respectively.For the encapsulated 5×5 cm^(2) PSM,we obtained a T80 operation lifetime(the lifespan during which the solar module PCE drops to 80%of its initial value)exceeding 1000 h in ambient condition.

Scalable spray coated high performance sulfurized electron transporter for efficient and stable perovskite solar modules

The stability issue has been acknowledged as the bottleneck in the practical application of perovskite photovoltaics,while the stabilized interface between the perovskites and charge transport layers dominates their stability performance under different stresses.Here,we developed a high-performance sulfurized zinc-titanium mixed oxide(ZTO-S)electron transport layer(ETL)to fabricate large-area efficient and long-term 85℃/85%RH stable perovskite solar modules.The scalably prepared ZTO-S using the facile spray coating method demonstrates excellent electron mobility close to that of Zn O,in addition to promoting the uniform crystallization of perovskite film across the entire module via the interaction between surface S and Pb^(2+).Furthermore,this novel coordination stabilized the interface and reduced the interfacial non-radiative recombination defects within the devices,yielding an efficient and stable performance for the modules.High efficiency of 21.73%and 17.50%was achieved for blade-coated 36 cm^(2)and 100 cm^(2)perovskite solar modules,respectively.In addition,the encapsulated module(36 cm^(2))shows an attractive humidity and heat stability(85℃/85%RH)performance with a maintained 93.5%of the initial PCE over 1000 h.

Sodium Diffuses from Glass Substrates through P1 Lines and Passivates Defects in Perovskite Solar Modules

Most thin-film photovoltaic modules are constructed on soda-lime glass(SLG)substrates containing alkali oxides,such as Na_(2)O.Na may diffuse from SLG into a module's active layers through P1 lines,an area between a module's constituent cells where the substrate-side charge transport layer(CTL)is in direct contact with SLG.Na diffusion from SLG is known to cause several important effects inⅡ-Ⅵand chalcogenide solar modules,but it has not been studied in perovskite solar modules(PSMs).In this work,we use complementary microscopy and spectroscopy techniques to show that Na diffusion occurs in the fabrication process of PSMs.Na diffuses vertically inside P1 lines and then laterally from P1 lines into the active area for up to 360 pm.We propose that this process is driven by the high temperatures the devices are exposed to during CTL and perovskite annealing.The diffused Na preferentially binds with Br,forming Br-poor,l-rich perovskite and a species rich in Na and Br(Na-Br)close to P1 lines.Na-Br passivates defect sites,reducing non-radiative recombination in the perovskite and boosting its luminescence by up to 5×.Na-Br is observed to be stable after 12 weeks of device storage,suggesting long-lasting effects of Na diffusion.Our results not only point to a potential avenue to increase PSM performance but also highlight the possibility of unabated Na diffusion throughout a module's lifetime,especially if accelerated by the electric field and elevated temperatures achievable during device operation.

Crystallization regulation for stable blade-coated flexible perovskite solar modules

Effective perovskite crystallization control strategies for flexible substrates with scalable processing techniques have rarely been reported and remain an important challenge.In this study,3-mercaptobenzoic acid(3-MBA)was introduced into the perovskite precursor to modulate the crystallization dynamics,facilitating rapid nucleation while slowing down crystal growth.This approach enabled the formation of uniform,dense large-area perovskite films on flexible substrates.Consequently,a 12 cm²flexible perovskite solar module achieved a power conversion efficiency(PCE)of 16.43%.Additionally,the module exhibited enhanced mechanical stability under various bending radii and improved light stability,marking a substantial advance toward the practical application of flexible perovskite solar modules.

Highly transparent anti-reflection coating enhances the underwater efficiency and stability of perovskite solar modules

Perovskite solar cells have shown great potential in the field of underwater solar cells due to their excellent optoelectronic properties;however,their underwater performance and stability still hinder their practical use.In this research,a 1H,1H,2H,2H-heptadecafluorodecyl acrylate(HFDA)anti-reflection coating(ARC)was introduced as a high-transparent material for encapsulating perovskite solar modules(PSMs).Optical characterization results revealed that HFDA can effectively reduce reflection of light below 800 nm,aiding in the absorption of light within this wavelength range by underwater solar cells.Thus,a remarkable efficiency of 14.65%was achieved even at a water depth of 50 cm.And,the concentration of Pb^(2+)for HFDA-encapsulated film is significantly reduced from 186 to 16.5 ppb after being immersed in water for 347 h.Interestingly,the encapsulated PSMs still remained above 80%of their initial efficiency after continuous underwater illumination for 400 h.Furthermore,being exposed to air,the encapsulated PSMs maintained 94%of their original efficiency after 1000 h light illumination.This highly transparent ARC shows great potentials in enhancing the stability of perovskite devices,applicable not only to underwater cells but also extendable to land-based photovoltaic devices.

Research progress on large-area perovskite thin films and solar modules

Organometal halide perovskites have exhibited a bright future as photovoltaic semiconductor in next generation solar cells due to their unique and promising physicochemical properties.Over the past few years,we have witnessed a tremendous progress of efficiency record evolution of perovskite solar cells(PSCs).Up to now,the highest efficiency record of PSCs has reached 22.1%;however,it was achieved at a very small device area of<0.1 cm^(2).With the device area increasing to mini-module scale,the efficiency record dropped dramatically.The inherent causes are mainly ascribed to inadequate quality control of large-area perovskite thin films and insufficient optimization of solar module design.In current stage of PSCs research and development,to overcome these two obstacles is in urgent need before this new technology could realize scale-up industrialization.Herein,we present an overview of recently developed strategies for preparing large-area perovskite thin films and perovskite solar modules(PSMs).At last,cost analysis and future application directions of PSMs have also been discussed.

Highly Efficient and Stable FAPbI_(3) Perovskite Solar Cells and Modules Based on Exposure of the(011)Facet

Perovskite crystal facets greatly impact the performance and stability of their corresponding photovoltaic devices.Compared to the(001)facet,the(011)facet yields better photoelectric properties,including higher conductivity and enhanced charge carrier mobility.Thus,achieving(011)facet-exposed films is a promising way to improve device performance.However,the growth of(011)facets is energetically unfavorable in FAPbI_(3) perovskites due to the influence of methylammonium chloride additive.Here,1-butyl-4-methylpyridinium chloride([4MBP]Cl)was used to expose(011)facets.The[4MBP]^(+)cation selectively decreases the surface energy of the(011)facet enabling the growth of the(011)plane.The[4MBP]^(+)cation causes the perovskite nuclei to rotate by 45°such that(011)crystal facets stack along the out-of-plane direction.The(011)facet has excellent charge transport properties and can achieve better-matched energy level alignment.In addition,[4MBP]Cl increases the activation energy barrier for ion migration,suppressing decomposition of the perovskite.As a result,a small-size device(0.06 cm2)and a module(29.0 cm2)based on exposure of the(011)facet achieved power conversion efficiencies of 25.24%and 21.12%,respectively.

Modulating J-V hysteresis of planar perovskite solar cells and mini-modules via work function engineering

Commercialization of perovskite solar cells(PSCs) requires the development of high-efficiency devices with none current density-voltage(J-V) hysteresis. Here, electron transport layers(ETLs) with gradual change in work function(WF) are successfully fabricated and employed as an ideal model to investigate the energy barriers, charge transfer and recombination kinetics at ETL/perovskite interface. The energy barrier for electron injection existing at ETL/perovskite is directly assessed by surface photovoltage microscopy, and the results demonstrate the tunable barriers have significant impact on the J-V hysteresis and performance of PSCs. By work function engineering of ETL, PSCs exhibit PCEs over 21% with negligible hysteresis. These results provide a critical understanding of the origin reason for hysteresis effect in planar PSCs, and clear reveal that the J-V hysteresis can be effectively suppressed by carefully tuning the interface features in PSCs. By extending this strategy to a modified formamidinium-cesium-rubidium(FA-Cs-Rb) perovskite system, the PCEs are further boosted to 24.18%. Moreover, 5 cm × 5 cm perovskite mini-modules are also fabricated with an impressive efficiency of 20.07%, demonstrating compatibility and effectiveness of our strategy on upscaled devices.

Dye-sensitized solar cell module realized photovoltaic and photothermal highly efficient conversion via three-dimensional printing technology

Three-dimensional （3D） printing technology is employed to improve the photovoltaic and photothermal conversion efficiency of dye-sensitized solar cell （DSC） module. The 3D-printed concentrator is optically designed and improves the photovoltaic efficiency of the DSC module from 5.48% to 7.03%. Additionally, with the 3D-printed microfluidic device serving as water cooling, the temperature of the DSC can be effectively controlled, which is beneficial for keeping a high photovoltaic conversion efficiency for DSC module. Moreover, the 3D-printed microfluidic device can realize photothermal conversion with an instantaneous photothermal efficiency of 42.1%. The integrated device realizes a total photovoltaic and photothermal conversion efficiency of 49% at the optimal working condition.

Intelligent Solar Chasing Street Light System Design and Fabrication Summaries

This project adopts an advanced microcontroller as the core control unit,which accurately commands the servo drive,realizes the real-time light chasing and charging function of the solar panel,and effectively manages the power supply system of the street light.At the same time,the system is able to continuously monitor the operation status of the servo within the range of 0°to 180°to ensure that it is trouble-free and not offline.The hardware system construction consists of five modules:a power module,solar panel module,servo module,street light module,and Organic Light-Emitting Diode(OLED)display module.Each module works together to support the stable operation of the whole system.The system workflow is to accurately determine the direction of the light source by collecting real-time light intensity data through four precision photoresistors.Subsequently,the microcontroller intelligently controls the helm module based on these data to drive the solar panel to rotate within a range of 180°to accurately track the sun’s orientation.The street light provides two lighting modes,automatic and manual,to meet the needs of different scenarios.During the daytime,the solar panels work actively to monitor and collect solar energy efficiently in real-time,meanwhile,when night falls,the solar panels switch to standby mode and the streetlights light up automatically,illuminating the road ahead for pedestrians.Compared with the traditional solar street lights on the market,the intelligent solar light chasing road system introduced in this project has significant advantages.Its unique light-chasing algorithm enables the solar panel to continuously track the light source from sunrise to sunset,thus significantly improving the charging efficiency.Compared with traditional street lights,the biggest advantage of this project is the proposed light-chasing algorithm,which can always charge from sunrise until sunset,making the charging efficiency increase by 38%to 47%.The charging efficiency is 20%to 38%higher than that of traditional street lamps.Simultaneously,the biggest advantage of this project is that the power storage capacity is higher than 35%of the traditional solar street light.Bringing users a more durable and stable lighting experience.

Comprehensive Examination of Solar Panel Design: A Focus on Thermal Dynamics

In the 21st century, the deployment of ground-based Solar Photovoltaic (PV) Modules has seen exponential growth, driven by increasing demands for green, clean, and renewable energy sources. However, their usage is constrained by certain limitations. Notably, the efficiency of solar PV modules on the ground peaks at a maximum of 25%, and there are concerns regarding their long-term reliability, with an expected lifespan of approximately 25 years without failures. This study focuses on analyzing the thermal efficiency of PV Modules. We have investigated the temperature profile of PV Modules under varying environmental conditions, such as air velocity and ambient temperature, utilizing Computational Fluid Dynamics (CFD). This analysis is crucial as the efficiency of PV Modules is significantly impacted by changes in the temperature differential relative to the environment. Furthermore, the study highlights the effect of airflow over solar panels on their temperature. It is found that a decrease in the temperature of the PV Module increases Open Circuit Voltage, underlining the importance of thermal management in optimizing solar panel performance.

The Main Progress of Perovskite Solar Cells in 2020-2021

Perovskite solar cells(PSCs)emerging as a promising photovoltaic technology with high efficiency and low manufacturing cost have attracted the attention from all over the world.Both the efficiency and stability of PSCs have increased steadily in recent years,and the research on reducing lead leakage and developing eco-friendly lead-free perovskites pushes forward the commercialization of PSCs step by step.This review summarizes the main progress of PSCs in 2020 and 2021 from the aspects of efficiency,stability,perovskite-based tandem devices,and lead-free PSCs.Moreover,a brief discussion on the development of PSC modules and its challenges toward practical application is provided.

Additives in metal halide perovskite films and their applications in solar cells

The booming growth of organic-inorganic hybrid lead halide perovskite solar cells have made this promising photovoltaic technology to leap towards commercialization.One of the most important issues for the evolution from research to practical application of this technology is to achieve high-throughput manufacturing of large-scale perovskite solar modules.In particular,realization of scalable fabrication of large-area perovskite films is one of the essential steps.During the past ten years,a great number of approaches have been developed to deposit high quality perovskite films,to which additives are introduced during the fabrication process of perovskite layers in terms of the perovskite grain growth control,defect reduction,stability enhancement,etc.Herein,we first review the recent progress on additives during the fabrication of large area perovskite films for large scale perovskite solar cells and modules.We then focus on a comprehensive and in-depth understanding of the roles of additives for perovskite grain growth control,defects reduction,and stability enhancement.Further advancement of the scalable fabrication of high-quality perovskite films and solar cells using additives to further develop large area,stable perovskite solar cells are discussed.

Strategies from small-area to scalable fabrication for perovskite solar cells

Recently,perovskite solar cells(PSCs) have flourished,and their power conversion efficiency(PCE) has increased from the initial 3.8% to 25.2% in 2019,which is an unprecedented advance.However,usually high-efficiency and stable PSCs are small-area devices prepared by spin coating.This method is not suitable for the preparation of large-area devices in commercialization.Therefore,there is an urgent need to develop new materials and methods for the scalable fabrication of PSCs.In this review,we first describe the common small-area PSCs preparation methods,understand the nucleation and crystal growth kinetics of perovskite,and analyze the reasons that hinder the development of small-area devices to large-area devices.Next,in order to meet the challenges of PSC’s scalable fabrication,we summarize and analyze four strategies:scaling up precursor solutions,scalable deposition methods for large-area films,scaling up charge-transport layers and back electrodes,developing solar modules.Finally,challenges and prospects are proposed to help researchers prepare high-efficiency large-area PSCs.

COMPARISON OF MATERIAL FOR ENCAPSULATING MINIMODULES

The main characteristics of glass, polymethyl methacrylate (PMMA) and polycarbon ate (PC) were presented. The transmittance of glass, PMMA and PC was measured by the UV-VIS spectroscopy analysis. PMMA and PC have the advantages of higher tra nsparency, higher resistance and lower density. It is indicated that both PMMA a nd PC are suitable for encapsulating solar minimodules.

Recent Progress in Large-Area Perovskite Photovoltaic Modules

Perovskite solar cells(PSCs)have undergone a dramatic increase in laboratory-scale effi ciency to more than 25%,which is comparable to Si-based single-junction solar cell effi ciency.However,the effi ciency of PSCs drops from laboratory-scale to large-scale perovskite solar modules(PSMs)because of the poor quality of perovskite fi lms,and the increased resistance of large-area PSMs obstructs practical PSC applications.An in-depth understanding of the fabricating processes is vital for precisely controlling the quality of large-area perovskite fi lms,and a suitable structural design for PSMs plays an impor-tant role in minimizing energy loss.In this review,we discuss several solution-based deposition techniques for large-area perovskite fi lms and the eff ects of operating conditions on the fi lms.Furthermore,diff erent structural designs for PSMs are presented,including the processing technologies and device architectures.

Bilayer interface engineering through 2D/3D perovskite and surface dipole for inverted perovskite solar modules

The persistency of passivation and scalable uniformity are vital issues that limit the improvement of performance and stability of large-area perovskite solar modules(PSMs).Here,we design a bilayer interface engineering strategy that takes advantage of the stability and passivation ability of low-dimensional perovskite and the dipole layer.Introducing phenethylammonium iodide(PEAI)can form 2D/3D heterojunctions on the perovskite surface and effectively passivate defects of perovskite film.Interestingly,the upper piperazinium iodide(PI)layer can still form surface dipoles on the 2D/3D perovskite surface to optimize energy-level alignment.Moreover,the bilayer interface engineering enables large-area perovskite films with uniform surface morphology,lower trap-state density and stability against environmental stress factors.The final devices achieved a small-area PCE of 25.20% and a large-area(1 cm^(2))PCE of 23.96%.A perovskite mini-module(5×5 cm^(2) with an active area of 14.28 cm^(2))could also be fabricated to achieve a PCE of 23.19%,ranking it among the highest for inverted PSMs.Additionally,the device could retain over 93% of its initial efficiency after MPP tracking at 45℃ for 1280 h.This study successfully demonstrates a bilayer interface engineering with respective functions,offering valuable insights for producing efficient and stable large-area PSCs.

High-speed doctor-blading PM 6:L 8-BO organic solar cells from non-halogenated green solvent with a module efficiency of 16.07%

Highly efficient organic solar cells(OSCs)are normally produced using the halogenated solvents chloroform or chlorobenzene,which present challenges for scalable manufacturing due to their toxicity,narrow processing window and low boiling point.Herein,we develop a novel high-speed doctor-blading technique that significantly reduces the required concentration,facilitating the use of eco-friendly,non-halogenated solvents as alternatives to chloroform or chlorobenzene.By utilizing two widely used high-boiling,non-halogenated green solvents-o-xylene(o-XY)and toluene(Tol)-in the fabrication of PM 6:L 8-BO,we achieve power conversion efficiencies(PCEs)of 18.20%and 17.36%,respectively.Additionally,a module fabricated with o-XY demonstrates a notable PCE of 16.07%.In-situ testing and morphological analysis reveal that the o-XY coating process extends the liquid-to-solid transition stage to 6 s,significantly longer than the 1.7 s observed with Tol processing.This prolonged transition phase is crucial for improving the crystallinity of the thin film,reducing defect-mediated recombination,and enhancing carrier mobility,which collectively contribute to superior PCEs.

Impact of the 11-yr Solar Activity on the QBO in the Climate System

The QBO (quasi-biennial oscillation) in the climate system, with a mean cycle-length slightly above or below 2 years, is studied in a simple forced dynamical system. The fundamental cause of the quasi-biennial periodicity of the QBO is nonlinear resonance of the system to the seasonal forcing that is modulated by the 11-yr solar cycle. For a given nonlinearity, the cycle-length and the amplitude of the QBO depend on the intensity of both the unmodulated seasonal cycle and the 11-yr solar cycle, which may be one of the reasons why the QBO properties in climate vary with time and space.