Wettability Of Films Research Articles

Improving Buried Interface Contact for Inverted Perovskite Solar Cells via Dual Modification Strategy

AbstractThe non‐wetting issue of the self‐assembled monolayer (SAM) layer can complicate subsequent perovskite deposition and impact device efficiency. This study addresses this challenge using a dual approach involving co‐self‐assembly and a buffer layer to enhance the wettability and interfacial contact of the buried perovskite film. A weakly acidic boronic acid derivative, 4‐N, N‐dimethylbenzeneboronic acid hydrochloride (4NPBA), is used to co‐self‐assemble with the regular SAM molecule on ITO and the subsequent FAI buffer layer further increased perovskite film coverage to 89%. This dual buried interface strategy—SAM‐4NPBA/FAI—results in a flat and dense perovskite interface. The optimized device demonstrates a high fill factor of 88.35%, a power conversion efficiency of 25.29%, and retains over 99% of its initial efficiency after 500 h of maximum power point testing.

POE-Mediated Tunable Quantum Yield of Carbon Dots-Derived From Agapanthus Africanus (L.) Hoffmann Leaves.

The green synthesis of carbon dots (CDs) from natural sources is a challenging goal. Herein CDs are produced from Agapanthus africanus (L.) Hoffmann leaves by carbonization at 200/300 °C for 2/3h. Samples are named CZ-X-Y, where Z, X, and Y represent carbonization, temperature, and time, respectively. CZ-200-3, CZ-300-2, and CZ-300-3 CDs have average sizes of 3.7 ± 0.7, 5.3 ± 1.2, and 5.1 ± 1.6nm, respectively. Their surface, devoid of chlorophyll, contains ─OH, ─C═O, and ─C(═O)OH groups and sylvite. Isolated CZ-300-3 emits at 400nm (excited at 260nm) and exhibits an emission quantum yield (QY) value of 2 ± 1%. Embedding in the d-U(600)/d-(900) di-ureasil matrices resulted in transparent films with emission intensity maxima at 420/450nm (360nm), and QY values of 7 ± 1/16 ± 2% (400nm). The enhancement of the QY value of the bare CDs agrees withan efficient passivation provided by the hybrid host. The hydrophilic CZ-300-3 CDs also exerted a marked surface modifying role, changing the surface roughness and the wettability of the hybrid films.

Morphology and Wettability of Polystyrene film on QCM Sensor Caused by Oxygen Plasma with DC Bias

Surface wettability and morphology are important aspects of developing QCM sensors for chemical sensors and biosensors. The functionality and morphology of the sensitive coating on the sensor surface affect the sensor sensitivity and selectivity. Various materials and methods to improve the functionality and morphology of the sensor surface have been developed, one of which is plasma. Species and parameters of the generated plasma play an important role in the treatment. One parameter is the DC-bias voltage of RF plasma, which plays an important role in plasma generation and bombardment on the surface being modified. This work shows the effect of the DC bias of the 2 MHz RF plasma with oxygen species. Surface functionality and morphology modification of the polystyrene film on the QCM sensor was done by surface modification using oxygen plasma. Partial etching of the polystyrene film occurred when treated with oxygen plasma generated using 2 MHz with negative DC-bias. CII, CO+, and CO were detected during the exposure of oxygen plasma on polystyrene film, indicating a chemical reaction between the plasma species, oxygen plasma, and the polystyrene. Observation by optical microscope and SEM showed the occurrence of partial etching on the polystyrene film. As there is no masking, the partial etching occurred randomly. The average size of the etched film increased with the DC bias voltage, but the percentage of the etched area was not. The oxygen plasma converts the polystyrene film from hydrophobic to hydrophilic, but hydrophobicity increases with the DC bias voltage. HIGHLIGHTS Polystyrene surface treatment using oxygen plasma can be used to alter the surface hydrophobicity. The DC bias plays important role in the surface modification. High DCV bias gives stronger plasma energy which may etched the polystyrene film. Observation using SEM shows part of the polystyrene film was etched as the DC bias voltage increase. The amount of the etched surface can be measured using optical microscope and processed using ImageJ. Increasing the DC bias result in a wider etched film. GRAPHICAL ABSTRACT

Spray pyrolysis grown Cu and Ni co-doped ZnO thin films: a study of their structural, optical, wettability, and photocatalytic performance

This study explores the impact of Cu and Ni doping on the structural, wettability, optical, and photocatalytic properties of ZnO thin films. The co-doped thin films, with varying Ni concentrations, were deposited using a spray pyrolysis method onto pre-heated soda lime glass substrates. X-ray diffraction analysis confirmed the hexagonal wurtzite structure with preferred orientation primarily along the (002) plane, while crystallinity decreased with higher Ni concentrations. Scanning electron microscopy reveals a compact, adherent structure in all films, with Ni incorporation altering the surface morphology. Fourier transform infrared spectroscopy identified characteristic absorption bands for metal-oxygen bonds. Optical analysis indicated that all thin films exhibited over 88% average transmittance in the visible region, accompanied by a red shift in the optical bandgap. Photoluminescence spectra exhibited a broad emission band in the visible region, indicating intrinsic and extrinsic defects induced by doping. Co-doping transforms the wettability character of ZnO thin films from hydrophilic to hydrophobic. Finally, the photodegradation efficiency of the thin films against methylene blue under sunlight significantly increases from 72% to 92% with an increase in Ni concentration.

Green synthesized CeO2 nanoparticles-based chitosan/PVA composite films: Enhanced antimicrobial activities and mechanical properties for edible berry tomato preservation.

The current study is intended to enhance unique bioactive and eco-friendly composite films following a simple solvent-casting approach by incorporating cerium oxide nanoparticles (CeO2 NPs) with a chitosan (CS)/polyvinyl alcohol (PVA) matrix. Antimicrobial activity, preservation impact, mechanisms for the edible berry tomatoes and physicochemical properties of the produced films were tested. FTIR, SEM-EDX, XRD, UV–vis spectroscopy and contact angle were used to characterize the films. Incorporated (3.0 wt%) CeO2 NPs practically developed composite film's thermal stability, structural, mechanical, bioactive, antioxidant, barrier and wettability properties. The tomatoes' look, weight loss and stiffness were better preserved after 25 days of storage at room temperature (25 ± 5 °C) when 3.0 wt% CeO2 NPs films were used instead of the original CS/PVA film. CS and CeO2 NPs have unique physiochemical and antibacterial properties. Food packaging extensively investigates the modified films as antimicrobials and preservatives to increase the shelf life of packaged foods, owing to their ability to inhibit gram-positive bacteria (Bacillus cereus and Staphylococcus aureus), gram-negative bacteria (Klebsiella pneumoniae and Pseudomonas aeruginosa), and filamentous fungi (Bipolaris sorokiniana, Fusarium op., and Alternaria sp.). Our findings indicated that the CeO2/CS/PVA composite films could be used as effective wrapping materials for food preservation.

Optimization of photocurrent and surface wettability of new As10Bi30Se30Te30 thin films through annealing at different temperatures for optoelectronic applications

Group V-VI-based metal-doped double chalcogenides are essential in thermoelectric and suitable optoelectronic devices. The present investigation is based on optimising various optical, structural, and electrical behaviours of quaternary As10Bi30Se30Te30 films through thermal annealing at different temperature scales. The structural study by X-ray diffraction (XRD) exhibited the presence of various Bi2Se3, Bi2SeTe2, and Bi2Te3 phases in the annealed films. The crystallinity gradually enhanced after the annealing process. The microstructural modifications in the material have been confirmed through the Raman spectra. The elemental confirmation was verified from the energy dispersive X-ray (EDX) spectra, whereas the cross-sectional scanning electron microscopy (SEM) view showed the annealing-induced modifications in the films. The granular structure in the films is seen from the surface morphology study. The reduction of the energy gap from 1.36 ± 0.002 eV to 1.26 ± 0.001 eV upon annealing induced the increment in refractive index from 3.08 to 3.15. With annealing, the non-linear refractive index varied from 4.341x10−10 esu to 5.218 x10−10 esu. This indicates the narrowing of the bandgap and enhancement in the non-linear optical response of the material after the annealing process. The 3rd-order nonlinear susceptibility is also increased by annealing, thus making it suitable for nonlinear device applications. Annealing-induced surface change in the material enhances its surface wettability and makes it more hydrophilic. The linear enhancement in photocurrent with the voltage is ohmic and makes it suitable for various optoelectronic applications.

Enhanced propagation of free films with fast spread-out phenomena under the influence of megahertz surface acoustic waves

In this study, a novel approach for enhancing the rapid spreading of free liquid film on lithium niobate (LiNbO3) substrate under megahertz (MHz) surface acoustic wave (SAW) excitation is presented by treating it with surfactants. Through the design of a specific interdigital transducer structure, it was discovered that exciting the SAW at a frequency of 32.3 MHz can achieve optimal spreading performance for water droplets on the surface of surfactant-treated LiNbO3 substrate. The maximum average velocity reaches 1.76 mm/s at position P2 = 1250 μm in the water film front, and the stable film spreading speed shows a 204.9% increase compared to the existing research. Simultaneously, through the investigation of the spreading experiment phenomenon of silicone oil and de-ionized water droplets at varying frequencies, we have discovered the dynamic mechanism of “reverse phase” propagation in liquid film for the first time. This entails that the advancing edge of the wetting film demonstrates a spreading motion law that is opposite to the traditional spreading phenomena, with the spreading velocity in the central exceeding that on both sides. Our research demonstrates that this microfluidic device developed by SAWs enhances the spreading efficiency of the free films, enabling rapid expansion of the target liquid to form a high-surface area film layer. This advancement holds promise for overcoming the limitations of low sensitivity and short response time in the field of rapid pathological diagnosis in contemporary medicine.

Multifunctional molecular bridge enabled interface passivation and strain release for stable and efficient all-inorganic perovskite solar cells

The precise management of the buried interface in n-i-p perovskite solar cells (PSCs) to achieve efficient charge extraction and transport is crucial for improving the photovoltaic performance. Here, a 4-chloro-2,5-dimethoxyaniline (CDA) modifier with multifunctional groups is utilized as a molecular bridge at the TiO2/CsPbBr3 buried interface to enhance the qualities of TiO2 and CsPbBr3 films and the arrangement of interface energy level. The chlorine atom in CDA can heal the oxygen vacancies defects on the TiO2 film surface, thereby improving its electron mobility and conductivity. The –O– and -NH2 groups in CDA play a passivation effect on the ions defects of CsPbBr3 film, and especially the two –O– groups can anchor the lattice Pb atoms of CsPbBr3 perovskite, which effectively reduce the trap states of CsPbBr3 film and release the residual lattice strain. The modification of CDA also improves the wettability and energy level of TiO2 film to optimize CsPbBr3 crystal growth and charge transport, respectively. Consequently, the CsPbBr3 PSCs with CDA molecular bridge free of encapsulation achieve a highly increased power conversion efficiency of 10.85%, in contrast with 8.16% value of the control device. After 720 h of storage at 85 °C and in air environment with 85% relative humidity, the efficiency of the CDA-modified device retains 93.1% of the initial value, demonstrating excellent long-term humidity and thermal stability.

Physical Properties of Cellulose Derivative-Based Edible Films Elaborated with Liposomes Encapsulating Grape Seed Tannins.

Combined use of edible films (EF) with nanoencapsulation systems could be an effective alternative for improving the films' physical properties and maintaining bioactive compounds' stability. This research work focuses on the combined use of EF of cellulose-derived biopolymers enriched with liposomes that encapsulate grape seed tannins and on the subsequent evaluation of the physical properties and wettability. Tannin-containing liposomal suspensions (TLS) showed 570.8 ± 6.0 nm particle size and 99% encapsulation efficiency. In vitro studies showed that the release of tannins from liposomes was slower than that of free tannins, reaching a maximum release of catechin of 0.13 ± 0.01%, epicatechin of 0.57 ± 0.01%, and gallic acid of 3.90 ± 0.001% over a 144 h period. Adding liposomes to biopolymer matrices resulted in significant decrease (p < 0.05) of density, surface tension, tensile strength, elongation percentage, and elastic modulus in comparison to the control, obtaining films with greater flexibility and lower breaking strength. Incorporating TLS into EF formulations resulted in partially wetting the hydrophobic surface, reducing adhesion and cohesion compared to EF without liposomes. Results indicate that the presence of liposomes improves films' physical and wettability properties, causing them to extend and not contract when applied to hydrophobic food surfaces.

Highly-efficient low-voltage electrodeposition of superhydrophobic diamond-like carbon films from N-methyl pyrrolidone

N-methyl pyrrolidone was proposed as a new carbon source for efficiently preparing the diamond-like carbon (DLC) films by a one-step electrodeposition technique at a low voltage. The responses of surface morphology, microstructure and surface wettability of the DLC films on the variation of the area ratio of anode to cathode were investigated in terms of current density in the process of electrodeposition. Especially, the dynamic behaviors of water droplets impacting on one of the superhydrophobic DLC films were studied in detail as a function of Weber number and inclined angle. Results revealed that either a larger or a smaller area ratio than 1.56 could facilitate the formation of hierarchical structure with more hydrocarbon features, which is in favor of creating superhydrophobicity with low surface adhesion. Further, it was found that a competitive strategy between deformation and movement depending on Weber number and inclined angle, where the movement is balanced by sliding with rolling, dominates the impact dynamics of water droplets. This work provides new insight and explanation for the efficient electrodeposition of DLC films at low voltage and the dynamic evolution of impacting droplets on the inclined superhydrophobic surface.

Patterned PEDOT:PSS‐Flexible Electrode Using Electrospinning Nano‐Fiber Substrate with UV‐Induced Selective Wettability

AbstractWater‐soluble conductive polymer poly(3,4‐ethylenedioxythiophene)/polystyrene sulfonate (PEDOT:PSS) has a broad application prospect in the field of flexible wearable electronics, but the simple and efficient manufacture of patterned PEDOT:PSS flexible electrodes is still challenging. In this paper, a patterned PEDOT:PSS‐flexible electrode with a electrospinning nano‐fiber substrate is proposed. The electrode substrate is produced by electrospinning a hydrophobic polyvinylidene difluoride (PVDF) matrix material loaded with TiO2 UV‐induced hydrophilic‐hydrophobic conversion particles. The PEDOT:PSS flexible electrode is prepared using a simple UV‐induced selective wettability(UV‐SW) process and optimized vacuum filtration method. The method of manufacturing flexible electrodes based on patterned wetting film substrates is simple and feasible, while the electrode features high precision, good conductivity, and excellent deformation ability. The electrode has a line width error of less than 5%, an initial conductivity of 584.44 S m−1, and maintains stable conductivity under 0–180° bending and 0–30° torsion, with variation rates of only 4.9% and 2.3%, respectively. This paper presents a simple method to fabricate patterned PEDOT:PSS flexible electrode with high precision. This study provides an efficient method for the manufacturing of fibric‐based patterned flexible electrodes, this method is promising for fabric‐based wearable electronics.

Low‐Temperature Atomic Layer Deposition of Hole Transport Layers for Enhanced Performance and Scalability in Textured Perovskite/Silicon Tandem Solar Cells

AbstractPerovskite tandem solar cells on textured silicon hold potential for surpassing single‐junction limits and industrial compatibility. However, integrating hole‐transporting layers (HTLs) onto textured silicon poses challenges in conformal coating, low‐temperature fabrication, and perovskite solution process compatibility. Here, an atomic layer deposition (ALD) copper‐doping process is introduced to fabricate low‐temperature NiOx HTLs (ALD Cu:NiOx), tailored for textured tandems. Copper‐doping reduces hydroxyl group content and Ni3+ defects, addressing the challenge of enhancing hole conductivity while mitigating recombination loss. This advancement enables to lower the post‐annealing temperature from &gt;300 to 200 °C, achieving compatibility with silicon heterojunction (SHJ) cells and boosting the power‐conversion efficiency (PCE) of 1.65‐eV p–i–n perovskite solar cells to 22.47%. Integrating ALD Cu:NiOx beneath conventional self‐assembled monolayer HTL on textured SHJ leads to notable PCE enhancements, from 28.6% to 30.5% for 1‐cm2 tandems (certified stabilized PCE of 30.04%) and from 23.9% to 26.4% for 8.89‐cm2 tandems. Following 1000 h of maximum‐power‐point (MPP) tracking, tandems maintain 95% of initial efficiency. Notably, losses in open‐circuit voltage and PCE due to area upscaling reduced by over 20%, attributed to ALD Cu:NiOx’s ability to enhance perovskite film wettability and minimize shunting on silicon pyramid texture, underscoring its impacts for textured tandem upscaling.

Microstructural, wettability, and corrosion behaviour of TiO2 thin film sputtered on aluminium

Microstructural, wettability, and corrosion behaviour of TiO2 thin film sputtered on aluminium

О влиянии «гидрофобности» газовой фазы на образование флотокомплексов в процессах флотации

Introduction. A model of a three-phase system in which, as a result of hetero coagulation from a bulk liquid, its thin layer has formed, the surfaces of which separate the gas and condensed phases with different potentials, is a wetting film. The study of wetting films adds to the knowledge of the nature of the structure-induced surface forces acting in them, which serves to develop the theory of hetero coagulation and is of interest for solving various topical problems of the theory and practice of flotation. The purpose of the work is to study the influence of “hydrophobic” properties of the gas phase on the separation of minerals by flotation with a vapor-air mixture in flotation schemes with jet countercurrent flow of feed and rough concentrate. Materials and Methods. Methods and installations have been developed to investigate the temperature dependence of the equilibrium thickness of wetting films and wetting edge angles. Studies of wetting films are supplemented by measurements of induction time at adhesion of minerals to each other and to an air bubble on a specially designed installation. In-situ flotation experiments were performed on a sample of apatite-nepheline ores. Results. The temperature dependence of the equilibrium thickness of the wetting film has been revealed, which does not contradict the experimentally established decrease of the exponentially decreasing (non-oscillating) part of the cleavage pressure with increasing temperature. It is shown that the temperature dependence of the boundary angles formed by the wetting film on the hydrophobic and hydrophilic surface is multidirectional. The connection between the temperature dependence of the boundary angle and the temperature dependence of the spreading coefficient obtained from Young’s law and determined by multiplication of parameters characterizing the magnitude and long-range action of forces caused by the difference between the structure and properties of the liquid in the boundary layers and their values in the volume is shown. “Hydrophobicity” of the bubble is associated with a smaller range effect of structural repulsion forces compared to hydrophobic attraction forces. By measuring the induction time, it is shown that the “hydrophobicity” of air manifests itself in the difference in the stability of wetting (when hydrophobic and hydrophilic particles adhere to the air bubble) and symmetric (when particles of the same hydrophobicity/hydrophilicity adhere to each other) films as the temperature increases. Discussion. In the framework of the phonon mechanism of surface forces, the dynamic structure of the liquid in the boundary layers (the sign and magnitude of the phonon component of the bowing pressure) determines the selectivity of aggregation and completeness of particle extraction, as well as the stability of symmetric and wetting films from temperature. Conclusion. When discussing the stability of disperse systems, the concepts of additional (to dispersive (van der Waals) and ionic-electrostatic interactions) forces associated with the overlap of boundary layers of liquids with structure parameters changed compared to their bulk values are fruitfully used. Such differences are understood as static deviations of the structure and properties of the liquid induced by the surface. However, the main reason for changes in the stability of wetting films at increasing temperature may be the high sensitivity to temperature of the entire set of rotational and vibrational motions of atoms and molecules of the liquid, i. e., its dynamic structure and the associated phonon component of the wedging pressure. Resume. The results of the study can be used to improve the technological performance of ores enriched by flotation. Consideration of the influence of linear tension on the system with the line of threephase contact will be useful for revealing the peculiarities of flotation of micro-dispersions of minerals by the developed technology.

Enhancing polyvinyl alcohol surface properties through pre-drying treatment and modified electrospun polycaprolactone nanofibers

The application of polyvinyl alcohol (PVA) as a biodegradable polymer is restricted by its low water resistance, particularly for the packaging of moisture-sensitive products. In this paper, we report on a surface-modification approach for PVA films using electrospinning of beeswax-modified polycaprolactone (PCL) following a 10 min pre-drying process. The pre-drying process led to physical binding between the hydrophobic PCL/beeswax nanofibers and the hydrophilic PVA substrate while the addition of beeswax to PCL improved its physical properties, leading to larger surface roughness and lower wettability of the PVA film. In particular, by adding a proper amount of beeswax to PCL, a PVA/PCL/beeswax composite film showed high hydrophobicity with a water contact angle of 144.1°, demonstrating a significant improvement in the surface properties compared to the hydrophilic bare PVA film. Moreover, the oxygen permeability of the PVA film decreased from 5.5 to 2.2 cc.m−2.day−1 after electrospinning the PCL/beeswax, which was related to the rougher surface morphology generated by the electrospun nanofibers. Therefore, our cost-effective approach has the potential to modify the physical properties of hydrophilic polymers and to broaden their industrial applications.

Nanostructuring, fractal characterization and wettability of ion irradiated Au thin films and their thickness effect

This study proposes a method for modifying the wettability of Au thin films of thicknesses 5 nm and 10 nm on Si substrates using 8 keV Ne ion beam irradiation at different fluences, thereby enabling surface wettability adjustment at the nano-scale and its thickness dependence. This advancement would be highly beneficial for applications such as high-resolution printing and nano-biotechnology. The contact angle of the irradiated region for the 5 nm thin film changed from hydrophobic to hydrophilic with increasing ion dosage, whereas for the 10 nm thin film, it changed from hydrophilic to hydrophobic under the same conditions. Fractal analysis was performed on pristine and ion beam modified surfaces to investigate the underlying nano-structuring process, with reported values for average roughness (Ra), Hurst exponent (H), fractal dimension (Df), contact angle (CA), and wettability at different ion dosages. Atomic Force Microscopy and Rutherford Backscattering Spectroscopy were used to examine surface roughness and depth profile. The process of sputtering becomes crucial when the ion range approaches the thickness of thin films, with the sputter yield showing dependence on the thickness of thin films at different ion fluence levels. Monte Carlo simulations SRIM/TRIM and TRIDYN were used for comparison with the experimental results, with TRIDYN taking into account dynamic changes in the target's morphology and composition.

Smart antibiofouling composite coatings based on photothermally-active polyaniline and thermo-responsive poly(N-isopropylacrylamide)

Marine biofouling profoundly affects the economic viability of the marine sector. With a view towards addressing this issue, this work reported the successful development of smart photo-responsive and thermo-responsive antibiofouling coatings by combining photothermally-active polyaniline (PANI) with temperature-sensitive poly(N-isopropylacrylamide) (PNIPAM). Under light irradiation, the PNIPAM/PANI coating could be photothermally heated to temperatures as high as 89.3 ± 1.6 °C, delivering a maximum antibacterial rate of 99.99 %. Impressively, light-induced temperature changes in the PNIPAM/PANI coating caused dynamic changes in film morphology and wettability. Upon lowering the temperature to below the lower critical solution temperature (LCST) of PNIPAM, the water contact angle of the PNIPAM/PANI coating decreased from 81° to 35° and the coating surface roughened appreciably, resulting in a 99.99 % release rate for both E.coli and S. aureus, thus achieving a dynamic self-cleaning effect. Furthermore, the developed PNIPAM/PANI coating demonstrated excellent resistance against protein and algae adhesion. These findings showcase the broad application potential of PNIPAM/PANI antifouling coatings in the marine sector.

Effect of equilibrium contact angle on water equilibrium film thickness for the carbon dioxide–brine–mineral system based on surface force theory

The thickness of the thin wetting film depends on disjoining pressure forces, and it evolves with pH evolution due to brine acidification at the physical and chemical conditions of geological carbon dioxide storage becoming thinner in response to dewetting. In the literature, molecular dynamic simulation (MDS) studies have been employed to understand the effect of pressure/capillary pressure on the thin wetting film evolution. In this paper, a theoretical approach based on the Frumkin–Derjaguin Equation (FDE), models of electric double layer repulsion, and van der Waals forces have been used for the calculation of the wetting film thickness. The approach excluded hydration forces contribution to disjoining pressure forces due partly to its poorly understood nature, and partly to the high salinity conditions encountered in geological carbon storage. Due to its promising global storage capacity compared to other lithologies, the carbon dioxide–brine–silica systems was chosen to simulate sandstone saline aquifers. The validation of the model benefited much from literature resources on data and a universal model of carbon dioxide–brine interfacial tension. Calculated results confirm pH-induced dewetting and they follow trends controlled by pH and pressure as found in the literature. The novelty of the paper can be seen from the fact that it has demonstrated a theoretical supplement to MDS studies in addition to justifying the fundamental utility and versatility of the FDE. Moreover, the paper links for the first time, a transcendental equation to the thin wetting film theory encountered in the carbon dioxide–solid–brine system found in geological carbon storage.

Isobutyramide Additive to Improve the Performance of CsPbBr3 Perovskite Solar Cells Prepared by Green Solvent

The inorganic cesium lead bromide (CsPbBr3) perovskite solar cell (PSC) is considered as an attractive option for new solar cells due to its outstanding stability. Preparing CsPbBr3 PSCs with H2O can effectively save costs and reduce the harm of toxic solvents to the environment. However, the poor contact property of the PbBr2 layer to the CsBr/H2O solution and the ability of water to dissolve the CsPbBr3 phase has a significant impact on the performance of the CsPbBr3 devices. In this article, isobutyramide is introduced into the PbBr2 film in the first step to improve the wettability of the PbBr2 film to CsBr/H2O solution, followed by spin‐coating of the 150 mg mL−1 CsBr/H2O solution on the PbBr2 film. Using this strategy, the fabricated PSCs with the architecture of FTO/compact‐TiO2/mesoporous‐TiO2/CsPbBr3 film/carbon demonstrate outstanding performance with a maximum efficiency of 9.59%. Furthermore, after 45 days of storage at ambient temperatures, the unencapsulated device retains more than 96% of its original efficiency. Therefore, this work provides a good demonstration for the preparation of high‐efficiency and eco‐friendly CsPbBr3 PSCs.

Enhancing performances of inverted perovskite solar cells by modifying the buried interface with sodium copper chlorophyllin

Defects at the buried interface and poor contact between the hole transport layer (HTL) poly-triarylamines (PTAA) and the perovskite layer are key issues affecting the efficiency and long-term stability of inverted perovskite solar cells (PSCs). In this study, we introduce sodium copper chlorophyllin (SCC, a chlorophyll derivative) as a modification agent at the HTL/perovskite interface to address these issues. Attributed to hydrophilic carboxylate groups of SCC, the wettability of the PTAA film is enhanced, facilitating the formation of the high-quality perovskite film. Meanwhile, SCC can interact with uncoordinated Pb2+ to passivate defects of the perovskite film at the buried interface. As a result, the power conversion efficiency (PCE) of inverted PSCs with the SCC modification reaches to 22.37% (from 20.58%) based on MAPbI3, and to 24.06% (from 21.54%) based on FAPbI3, respectively. Moreover, the devices show excellent stability in air and under light irradiation. This work indicates that the natural chlorophyll derivative is a promising candidate for improving the buried interface of high-performance inverted PSCs.