Crystal Planes Research Articles

Impact of pH and ZnO NPs on the fabricated PVA-PVP/ZnO nanofibers: Morphology, absorption behavior, anticancer, and antibacterial activity

In this study, a cost-effective hydrothermal method was successfully used to synthesize ZnO NPs at different pH levels (8, 10, and 12). Nanofibers were produced from polymeric blends PVA-PVP and PVA-PVP/ZnO nanocomposite precursor through electrospinning. XRD analysis revealed the hexagonal wurtzite structure of the synthesized ZnO NPs, with the dominant crystal plane (101). The impact of pH variation was evident in the increased intensity values of the peaks corresponding to (100), (002), and (101) planes as pH levels rose. The average crystallite size decreased from 31.4 to 27.0 nm using Scherrer's calculation, while the microstrain increased from 11.2 to 12.4 ×10−4 as the pH increased from 8 to 12. As wellas the average particle size of the ZnO NPs decreased from 75.05 to 51.35 nm with increasing pH levels, as depicted in FESEM images. The PVA-PVP/ZnO electrospun nanofibers exhibited smooth surfaces and uniform structures, with average diameters of 80.14, 93.33, and 124.13 nm for pH 8, 10, and 12, respectively. The calculation of the optical energy gap using the ASF approach closely matched Tauc's model, ranging from 3.57 to 3.20 eV. Evaluation of the anticancer activity of the nanofibers against MCF-7 cells showed an increase in cytotoxicity from 18 to 64 % with varying concentrations of ZnO NPs ranging from 6.25 to 100 μg/ml. The highest inhibitory effect (about 16 mm) was observed at pH 12 against gram-positive (Staphylococcus aureus).

Monodisperse silver nanocubes composite Ag@C/SrTiO3 photocatalytic decomposition of water for hydrogen reduction

Metal-induced photocatalysis has been a relatively effective strategy for the efficient use of solar energy. In this paper, highly efficient and stable Ag@C/SrTiO3 photocatalysts were prepared by compounding silver nanocubes wrapped with few layers graphite with strontium titanate materials. We obtained silver nanocubes with a uniformly dispersed size of about 35 nm by varying the surface energy of silver and inducing the preferential binding of PVP on the (100) crystal plane with the help of selective adsorption of chloride ions on the different crystal planes of silver. As obtained under the characterisation of UV–visible absorption spectra, the material has a broad visible light absorption (450–900 nm). The Ag@C/SrTiO3 has a hydrogen reduction rate of up to 457.5 μmol g−1·h−1 under simulated sunlight, which is ∼200 % higher than the SrTiO3 and ∼900 % higher than the sliver. Moreover, the catalyst was stable, still producing 93.5 % hydrogen after three cycles of testing, and the photocatalyst structure did not change as known from the XRD data of the material before and after testing. The present work demonstrates the feasibility of rational design of efficient and stable silver-based photocatalysts.

Non‐Epitaxial Electrodeposition of Overall 99% (002) Plane Achieves Extreme and Direct Utilization of 95% Zn Anode and By‐Product as Cathode

Zn anode protection in Zn‐ion batteries (ZIBs) face great challenges of high Zn utilization rate (i.e., depth of discharge, DOD) and high current density due to the large difficulty in obtaining an extreme overall RTC (relative texture coefficient) of Zn (002) plane. Through the potent interaction of Mn(III)aq and H+ with distinct Zn crystal planes under an electric field, large‐size Zn foils with a breakthrough (002) plane RTC of 99% (i.e., close to Zn single crystal) are electrodeposited on texture‐less substrates, which is also applicable from recycled Zn. The ultra‐high (002) plane RTC remarkably enhances cyclic performance of the Zn anode (70% DOD @ 45.5 mA cm‐2), and the DOD is even up to 95% (@ 28.1 mA cm‐2) with an electrolyte additive of polyaniline. Furthermore, MnO2, the by‐product of electrodeposition, is directly used as cathode of both coin cell and pouch battery, surpassing the cyclic performance exhibited by the majority of Zn||MnO2 batteries in previous instances. These results demonstrate the great potential of our strategy for high‐performance, low‐cost and large‐scale ZIBs.

Non-Epitaxial Electrodeposition of Overall 99 % (002) Plane Achieves Extreme and Direct Utilization of 95 % Zn Anode and By-Product as Cathode.

Zn anode protection in Zn-ion batteries (ZIBs) face great challenges of high Zn utilization rate (i.e., depth of discharge, DOD) and high current density due to the large difficulty in obtaining an extreme overall RTC (relative texture coefficient) of Zn (002) plane. Through the potent interaction of Mn(III)aq and H+ with distinct Zn crystal planes under an electric field, large-size Zn foils with a breakthrough (002) plane RTC of 99 % (i.e., close to Zn single crystal) are electrodeposited on texture-less substrates, which is also applicable from recycled Zn. The ultra-high (002) plane RTC remarkably enhances cyclic performance of the Zn anode (70 % DOD @ 45.5 mA cm-2), and the DOD is even up to 95 % (@ 28.1 mA cm-2) with an electrolyte additive of polyaniline. Furthermore, MnO2, the by-product of electrodeposition, is directly used as cathode of both coin cell and pouch battery, surpassing the cyclic performance exhibited by the majority of Zn||MnO2 batteries in previous instances. These results demonstrate the great potential of our strategy for high-performance, low-cost and large-scale ZIBs.

Influence of catalyst shape on plasma-assisted dry reforming of methane: A comparative study of Ni-CeO2 nano-cubes and nano-octahedra

This study investigated the performance of 10 wt% Ni-CeO2 nano-cubes (NC) and nano-octahedra (NO) shaped catalysts in plasma-assisted dry reforming of methane (DRM) environment to understand the influence of catalyst morphology on catalytic activity and global reaction pathway. The presence of different exposed crystal planes (i.e., (111), (110), and (100)) in the CeO2 shapes led to varied NiOx-CeO2 interactions, with the NO-shaped catalyst exhibiting a higher oxygen vacancy concentration, lattice defects, and moderate basic sites compared to the NC catalyst. This interaction in the plasma DRM environment significantly enhances conversions for both shaped catalysts, with the effect more pronounced in the case of the NO-shaped catalyst. The performance data suggest that running plasma DRM at moderate temperature and higher plasma power is relatively efficient. Increasing temperatures or plasma power diverts the DRM reaction towards more H2 production, reducing CO production for both shaped catalysts. This confirms the crucial role of the catalyst in controlling the global reaction pathway considering plasma power or temperature enhancement. Plasma interactions create additional surface defects during the DRM reaction, and defect concentration is closely linked to catalyst morphology. Carbon deposits on the catalyst surface can be readily removed via CO2 plasma regeneration treatment without affecting catalyst performance. Additionally, prolonged plasma exposure leads to NiO phase separation into concentrated Ni, suggesting a cyclical DRM and regeneration approach rather than a continuous reaction.

Solvothermal preparation of CuO/g-C3N4 and photocatalytic degradation of ciprofloxacin

Composite materials CuO/g-C3N4 (CuOCN) were prepared using a solvothermal method to investigate their degradation effect on ciprofloxacin (CIP). The materials were characterized through X-ray diffraction analysis (XRD), Fourier transform infrared spectroscopy (FTIR), transmission electron microscopy (TEM), UV-visible diffuse reflectance spectrophotometry (DRS), and X-ray photoelectron spectroscopy (XPS). The toxicity of degradation products of CIP was assessed through antibacterial experiments, and the degradation mechanism of CIP was investigated using quenching agent capture and high-performance liquid chromatography-mass spectrometry (HPLC-MS). The results of XRD and FTIR indicate that the CuOCN composite has been successfully synthesized. The photocatalytic experiment shows that adding 15% (w/w) of Cu3(BTC)2(H2O)3 in melamine (CuOCN2) has a relatively good degradation effect on CIP and can be reused multiple times. The TEM results indicate that both CuO and g-C3N4 have a layered structure and are attached together. HRTEM analysis reveals that the two components in CuOCN2 are arranged in a layered structure, with CuO displaying two crystal planes. Energy Dispersive Spectrometer (EDS) analysis reveals that the proportion of CuO in the three composite materials is 7.86% (w/w), 15.93% (w/w), and 84.83% (w/w), respectively. DRS detection reveals that the greater the amount of CuO added, the broader the visible light absorption range of the composite material, and the narrower the bandgap width. The photocurrent and photoresistance indicate that CuOCN2 exhibits a good photoelectric effect. XPS analysis shows that the CuOCN2 composite material possesses both the chemical composition and structure of CuO and g-C3N4. During the catalytic degradation process of CIP, four active substances, h+, e−, ·O2 −, and ·OH, were produced, leading to a reduction in the toxicity of the degradation products. Through HPLC-MS analysis, it was found that CIP undergoes reactions such as defluorination, ring opening of piperazine, and quinolone during degradation, resulting in reduced toxicity. This study provides an experimental basis for the degradation of CIP by CuOCN2.

Structural evolutions and tribological properties of laser cladded FeCoNiCrMo high-entropy alloy coating by laser remelting and tempering process: TEM and DFT calculations

A laser cladded FeCoNiCrMo high-entropy alloy (HEA) coating was treated by laser remelting and tempering process in sequence to improve its tribological properties. The morphologies, phases and nanostructures of obtained coatings were analyzed using a scanning electron microscope, X-ray diffraction and transmission electron microscope. The effects of laser remelting and tempering process on the tribological properties were investigated by a ball-on-disc wear tester, and the wear mechanism was revealed with the density functional theory calculation. The results show that the main crystal planes of laser cladded, laser remelted and tempering processed HEA coatings are transformed from (200) and (220) to (111), and the reduced free energy and differential charge density of crystal plane (111) contribute to the improvement of tribological properties on the HEA coatings.

Tailoring metal oxide nanozymes for biomedical applications: trends, limitations, and perceptions.

Nanomaterials with enzyme-like properties are known as 'nanozymes'. Nanozymes are preferred over natural enzymes due to their nanoscale characteristics and ease of tailoring of their physicochemical properties such as size, structure, composition, surface chemistry, crystal planes, oxygen vacancy, and surface valence state. Interestingly, nanozymes can be precisely controlled to improve their catalytic ability, stability, and specificity which is unattainable by natural enzymes. Therefore, tailor-made nanozymes are being favored over natural enzymes for a range of potential applications and better prospects. In this context, metal oxide nanoparticles with nanozyme-mimicking characteristics are exclusively being used in biomedical sectors and opening new avenues for future nanomedicine. Realising the importance of this emerging area, here, we discuss the mechanistic actions of metal oxide nanozymes along with their key characteristics which affect their enzymatic actions. Further, in this critical review, the recent progress towards the development of point-of-care (POC) diagnostic devices, cancer therapy, drug delivery, advanced antimicrobials/antibiofilm, dental caries, neurodegenerative diseases, and wound healing potential of metal oxide nanozymes is deliberated. The advantages of employing metal oxide nanozymes, their potential limitations in terms of nanotoxicity, and possible prospects for biomedical applications are also discussed with future recommendations.

Tailored crystal planes of VO2 cathode power fast Zn2+ storage

Vanadium dioxide (VO2) cathode with specific tunnel structure and favorable specific capacity is critical for developing aqueous zinc-ion batteries (AZIBs) with excellent electrochemical performance. However, sluggish electrochemical kinetics hampered its development in burgeoning energy storage devices. Herein, we tailored VO2 material with different exposed crystal planes and employed as cathodes for AZIBs. The comprehensive analyses indicate the exposed (201) and (001) crystal planes are favorable for fast electrochemical kinetics, high capacitance storage, and the smallest diffusion energy barrier, which guarantee electrodes with high discharge capacity (367 mA h/g at 0.1 A/g), excellent rate capability (281 mA h/g at 4 A/g) and cycling stability over 800 cycles. Besides, Ex-situ characterizations manifest VO2 cathode with specific exposed crystal planes easily transformed to Zn3+x(OH)2V2O7·2H2O in the first discharge process, hence allowing continuous embedding of Zn2+ in this layered structure, and the ex-situ scanning electron microscopy (SEM) analysis confirms the morphology change matched well with the structural transformation. This study may enlighten and promote the role of exposed crystal plane to develop high-performance rechargeable batteries.

Suppression of crystallization process in Atomic Layer Deposited hafnium oxide films

Research on the deposition process of atomic layer deposition (ALD) of hafnium oxide thin films is important because it enhances the performance of nonvolatile memory devices and optical coatings and contributes significantly to advancements within the semiconductor industry. In this study, the alternating deposition of tetrakis(dimethylamido) hafnium and cyclopentadienyl tris(dimethylamino) hafnium precursors was studied. Moreover, this method allows for modulation of the refractive index, surface morphology, preferred orientation and phases of the material. Theoretical calculations revealed that the two precursors selectively adsorb on different crystal planes during the ALD process, elucidating the mechanism behind their preferred orientations. This study reports a method for regulating the phase development of thin films. The crystallization of the hafnium oxide thin films was suppressed by controlling the conditions of deposition.

Fabrication of a hyphenated S-scheme and Schottky-junction photocatalyst based on a ternary TiNbCTx@α-Bi2O3/ZnSe heterostructure with enhanced optical and photoelectrochemical properties

Environmental pollution by pharmaceuticals poses a serious threat to humans and animals. Hence there is a need for a low-cost, environmentally friendly, and sustainable treatment technology for environmental remediation. Herein, we report the synthesis of a novel TiNbCTx@α-Bi2O3/ZnSe ternary photocatalytic nanocomposite, characterised using spectroscopic and microscopic techniques. Moreover, the optical and photoelectrochemical properties of the photocatalysts were assessed using spectroscopic tools such as UV–Vis DRS, EIS and PL. The synthesised pristine, cubic ZnSe, monoclinic Bi2O3, α-Bi2O3/ZnSe and the ternary composites’ crystallinity were all confirmed by the co-existence of their crystal planes and bands in XRD, SAED, and Raman spectroscopy, correspondingly. SEM and TEM analysis confirmed the anticipated characteristic morphologies and the interfaces. Improved optical properties deduced from UV–Vis DRS measurements revealed α-Bi2O3 and ZnSe to have band gaps of 2.7 eV and 2.41 eV, respectively. Upon creating an α-Bi2O3/ZnSe heterostructure and TiNbCTx@α-Bi2O3/ZnSe ternary system, a red shift was observed in their band gaps, indicating improved optical properties. The electrochemical properties of the materials were determined using EIS. These were used to deduce the charge transfer kinetics of the heterostructure and ternary system, which showed TiNbCTx@α-Bi2O3/ZnSe to be an outstanding photocatalyst over the synthesised pristine materials and α-Bi2O3/ZnSe heterostructure. The photocurrent response of the TBZ-7 % exhibited enhanced generation and separation of photoexcited charge carriers 4 folds higher than those of pristine materials. The PL spectra of the TBZ-7 % showed low intensity due to the suppression of charge recombination rates. Moreover, the Nyquist and LSV plots of TBZ-7 % presented improved charge transfer ability and a prolonged lifetime of photoinduced charge carriers (280 ms), respectively. With these enhanced properties, TiNbCTx@α-Bi2O3/ZnSe ternary photocatalytic nanocomposite demonstrates the extraordinary potential for environmental remediation in degrading ARVs from water.

In Situ Assembly of Metal‐Organic Coordination Polymer Layers Enables Highly Reversible Zn Anodes with a Long Cycle Life of over 6900 h

AbstractZn anodes in aqueous zinc‐ion batteries chronically suffer from pernicious side reactions and ineluctable dendrite growth, resulting in inadequate reversibility and suboptimal Coulombic efficiency (CE) and impeding commercialization. Herein, a multifunctional metal–organic coordination polymer layer (FAZ) is constructed on the zinc anode surface (FAZ@Zn) utilizing a simple self‐assembly strategy. The zincophilic FAZ interfacial layer with a high Zn2+ transfer number and low nucleation barrier effectively facilitates the de‐solvation process, supports the rapid transport of zinc ions, and contributes to the preferential growth of Zn (002) crystal planes, enabling dendrite‐free Zn deposition. Furthermore, the FAZ layer, as an interfacial pH regulating layer, effectively inhibits the direct contact between Zn and active water molecules, lowering the severity of side reactions. Consequently, the FAZ@Zn anode furnishes an eminent cycle stability over 6900 h, with a low polarization voltage at 1 mA cm−2 and 1 mA h cm−2 and a boosted CE of 99.88% over 4100 cycles. More encouragingly, when coupled with Na2V6O16·3H2O, the FAZ@Zn anode enables the full cell to deliver satisfactory rate performance and a 97% capacity retention over 1600 cycles. This work provides a simple strategy for the effective preparation of highly reversible zinc anodes for high‐performance aqueous zinc‐ion batteries.

Molecular dynamics simulation study of Zr interposer promoting Cu-Cu low-temperature hybrid bonding

With the development of the microelectronics industry, microelectronics packaging technology continues to develop towards higher integration and smaller size. To overcome the problem that the micro-bump size of solder cannot meet the fine pitch bonding, Cu-Cu direct bonding has become one of the most promising methods in advanced packaging technology. However, since the temperature required for Cu-Cu direct bonding is approximately 400 °C, currently Cu-Cu direct bonding is mostly achieved through a hot-pressing process. Such high temperatures will lead to reduced alignment accuracy, damage to device performance, and increased equipment requirements. In order to overcome these problems, this study proposed to use active metal Zr as the interposer material to improve the Cu-Cu atomic diffusion ability and reduce the Cu-Cu direct bonding temperature. The research results indicated that the interposer structure of Zr with (111), (11-2), and (1-10) surfaces contribute to promote Cu-Cu diffusion and bonding at low temperatures. Among them, the Zr (11-2) structure had the strongest promoting effect. Due to the tight arrangement of atoms in the densely packed crystal plane, the diffusion ability of atoms is significantly weakened during the bonding process of the densely packed crystal plane. Therefore, the Zr (001) structure can only promote bonding process under specific crystalline surface of Cu, and the bonding ability was very weak. The application of this research result will have a beneficial effect on the reliability and manufacturability of three-dimensional integrated packaging.

Investigation of sodium–manganese oxides with various crystal phases for the efficient catalytic removal of diesel soot particles

Sodium–manganese oxides with various crystal phases (Na2Mn5O10, Na2Mn3O7, and Na4Mn9O18) were synthesized using a facile sol-gel method, and applied in the catalytic purification of soot particles from diesel engines. In this study, as-prepared samples with a single Na2Mn3O7 phase exhibited higher soot oxidation activity, with the lowest T10, T50, and T90 values of 279 ℃, 320 ℃, and 349 ℃, respectively. Numerous characterization techniques reveal that the Na2Mn3O7 catalysts have superior reducibility, NO oxidation, and storage capacity compared with the other crystal phases. In the meantime, the Na2Mn3O7 catalyst surface possesses a greater abundance of oxygen vacancies because of the emergence of Mn3+, which serve as crucial active sites during the dynamic cycling process of gaseous oxygen adsorption and activation. Moreover, the E-R reaction mechanism for soot combustion over the steps of (100) crystal plane of Na2Mn3O7 catalysts is proposed based on density functional theory (DFT) calculations and multiple characterization results. This study presents a facile and cost-efficient method for designing and preparing superior performance sodium–manganese composite oxides for soot combustion.

Structure-activity relationships, product species distribution and the mechanism of effect of multi-component flue gas on Hg0 adsorption and oxidation over CuO/ACs.

A series of Cu-doped activated cokes (CuO/ACs) were synthesized via an impregnation method and applied for the removal of elemental mercury (Hg0). Structure-activity relationships between Hg0 removal and CuO/AC surface characteristics were identified. Hg0 removal over CuO/AC occurs through a combination of physisorption and chemisorption and is mainly dominated by chemisorption. It was found that 1 nm micropores facilitate Hg0 physisorption. Hg0 could weakly adsorb onto an O-terminated crystal layer, whereas strongly adsorb onto Cu-terminated single highly dispersed, clustered and bulk CuO (110) crystal planes via the Mars-Maessen mechanism. Product distributions and mechanisms of Hg0 adsorption and oxidation over the CuO/AC catalyst under multi-component flue gases are also discussed. O2 enhances both physisorption and chemisorption toward Hg0 by 38%. Inhibition of Hg0 removal by SO2 originates from the competitive adsorption and deactivation of CuO cation vacancies, whereas the impact is weakened by O2 through generating 20% of physically adsorbed mercury product species. NO and O2 promote Hg0 chemisorption efficiency by 93% to form Hg(NO3)2. HOCl and/or Cl2 produced by HCl can oxidize 100% of Hg0 to HgCl2, and the catalytic oxidation efficiency is approximately 29%, but O2 slightly lowers the Hg0 catalytic oxidation efficiency by 8%. The affinity ability between various flue gases and Hg0 follows the order O2 < NO < HCl.

P123-assisted synthesis of Co3O4 catalyst for efficiently catalyzing N2O decomposition under simulated real tail-gases

The 8.0P-Co3O4 catalyst was prepared by sol-gel method with the assistance of P123 and investigated for catalyzing N2O decomposition. Research indicated that although the specific surface area of 8.0P-Co3O4 catalyst was only 18 m2·g−1, it exposed more highly active crystal planes, such as (111), (331), (400), and (222), and possessed higher surface oxygen vacancy density (5.64 µmol·m−2) compared with that of 0P-Co3O4 and Co3O4(P) catalysts. Due to these reasons, the corresponding reaction activation energy of 8.0P-Co3O4 for the reaction was significantly reduced, and the catalytic activity of 8.0P-Co3O4 was enhanced compared with that of Co3O4(P). Most importantly, the N2O conversion can maintain about 73 % over the catalyst for at least 24 h when the three impurity gases of 5 vol% O2, 100 ppmv NO, and 2 vol% H2O were coexisted at 400 °C, GHSV = 20,000 h−1.

In-situ investigation of coordinated deformation behavior of Ti-6242S alloy with duplex microstructure

In this work, the coordinated deformation behavior related to slip activation, slip transfer and microcrack growth of Ti-6242S alloy with duplex microstructure was investigated through the in-situ tensile testing. It was found that the deformation process of duplex microstructure can be divided into three stages: slip deformation, the formation of slip band and microcrack nucleation, crack propagation and fracture. And single slip was the dominant slip mode, and multiple slip was the auxiliary slip mode. During the initial tensile stage, the slip lines appearing within colony α were shallower than those within primary α owing to the hindering of α/β interface. The slips penetrated across the entire colony region by straight line. This was because there existed a Burgers orientation relationship between lamellar α and β layer, and the orientation of lamellar α was similar. Meanwhile, the common crystal plane between adjacent grains can still provide good condition for slip transfer when the grain boundary was greater than 15°. Moreover, the slip transfer between adjacent slip systems was more prone to occur when there existed good geometric compatibility and high Schmid factor of exit slip system, which provided coordinated deformation between adjacent grains and avoided stress concentration. However, due to the existence of incompatible deformation, the cracks were generated at the stress concentration areas and then grew along the grain boundary or localized slip band.

Atomistic phase transition mechanism of zero-strain electrode material: Transmission electron microscopy investigation of Li4Ti5O12 spinel lattice upon lithiation

The lithiation mechanism of electrode materials is important for understanding the basic reactions in Li-ion batteries. In particular, zero-strain materials have garnered interest owing to their stable charge–discharge performances. In this study, we investigated the atomistic phase transition mechanism of spinel Li4Ti5O12, a well-known zero-strain material, using high-resolution transmission electron microscopy. A single-crystalline Li4Ti5O12 (100) specimen was prepared and observed in situ at a lattice resolution under electron-beam-assisted lithiation. The lattice fringes originating from the Li plane of the spinel crystal were anisotropically altered during phase transition, suggesting the asymmetrical site shifting of Li atoms during lithiation. This spontaneous symmetry-breaking mechanism for the phase transition is considered essential for the lithiation of spinel lattice.

Blade-Coating (100)-Oriented α-FAPbI3 Perovskite Films via Crystal Surface Energy Regulation for Efficient and Stable Inverted Perovskite Photovoltaics.

Photoactive black-phase formamidinium lead triiodide (α-FAPbI3) perovskite has dominated the prevailing high-performance perovskite solar cells (PSCs), normally for those spin-coated, conventional n-i-p structured devices. Unfortunately, α-FAPbI3 has not been made full use of its advantages in inverted p-i-n structured PSCs fabricated via blade-coating techniques owing to uncontrollable crystallization kinetics and complicated phase evolution of FAPbI3 perovskites during film formation. Herein, a customized crystal surface energy regulation strategy has been innovatively developed by incorporating 0.5 mol % of N-aminoethylpiperazine hydroiodide (NAPI) additive into α-FAPbI3 crystal-derived perovskite ink, which enabled the formation of highly-oriented α-FAPbI3 films. We deciphered the phase transformation mechanisms and crystallization kinetics of blade-coated α-FAPbI3 perovskite films via combining a series of in-situ characterizations and theoretical calculations. Interestingly, the strong chemical interactions between the NAPI and inorganic Pb-I framework help to reduce the surface energy of (100) crystal plane by 42 %, retard the crystallization rate and lower the formation energy of α-FAPbI3. Benefited from multifaceted advantages of promoted charge extraction and suppressed non-radiative recombination, the resultant blade-coated inverted PSCs based on (100)-oriented α-FAPbI3 perovskite films realized promising efficiencies up to 24.16 % (~26.5 % higher than that of the randomly-oriented counterparts), accompanied by improved operational stability. This result represented one of the best performances reported to date for FAPbI3-based inverted PSCs fabricated via scalable deposition methods.

Blade‐Coating (100)‐Oriented α‐FAPbI3 Perovskite Films via Crystal Surface Energy Regulation for Efficient and Stable Inverted Perovskite Photovoltaics

Photoactive formamidinium lead triiodide (α‐FAPbI3) perovskite has dominated the prevailing high‐performance perovskite solar cells (PSCs), normally for those spin‐coated, conventional n‐i‐p structured devices. Unfortunately, α‐FAPbI3 has not been made full use of its advantages in inverted p‐i‐n structured PSCs fabricated via blade‐coating techniques owing to uncontrollable crystallization kinetics and complicated phase evolution of FAPbI3 perovskites. Herein, a customized crystal surface energy regulation strategy has been innovatively developed by incorporating 0.5 mol% of N‐aminoethylpiperazine hydroiodide (NAPI) additive into α‐FAPbI3 crystal‐derived perovskite ink, which enabled the formation of phase‐pure, highly‐oriented α‐FAPbI3 films. We deciphered the phase transformation mechanisms and crystallization kinetics of blade‐coated α‐FAPbI3 perovskite films via combining a series of in‐situ characterizations. Interestingly, the strong chemical interactions between the NAPI and inorganic Pb‐I framework help to reduce the surface energy of (100) crystal plane by 42%, retard the crystallization rate and lower the formation energy of α‐FAPbI3. The resultant blade‐coated inverted PSCs based on (100)‐oriented α‐FAPbI3 perovskite films realized promising efficiencies up to 24.16% (~26.5% higher than that of the randomly‐oriented counterparts), accompanied by improved operational stability. This result represented one of the best performances reported to date for FAPbI3‐based inverted PSCs fabricated via scalable deposition methods.