Preferred Crystal Orientation Research Articles

Solution‐Processed Sb2(S,Se)3 Seed‐Assisted Sb2Se3 Thin Film Growth for High Efficiency Solar Cell

Antimony selenide (Sb2Se3) emerges as a promising sunlight absorber in thin film photovoltaic applications due to its excellent light absorption properties and carrier transport behavior, attributed to the quasi‐one‐dimensional Sb4Se6‐nanoribbon crystal structure. Overcoming the challenge of aligning Sb2Se3‐nanoribbons normal to substrates for efficient photogenerated carrier extraction, a solution‐processed nanocrystalline Sb2(S,Se)3‐seeds are employed on the CdS buffer layer. These seeds facilitate superstrated Sb2Se3 thin film solar cell growth through a close‐space sublimation approach. The Sb2(S,Se)3‐seeds guided the Sb2Se3 absorber growth along a [002]‐preferred crystal orientation, ensuring a smoother interface with the CdS window layer. Remarkably, Sb2(S,Se)3‐seeds improve carrier transport, reduce series resistance, and increase charge recombination resistance, resulting in an enhanced power conversion efficiency of 7.52%. This cost‐effective solution‐processed seeds planting approach holds promise for advancing chalcogenide‐based thin film solar cells in large‐scale manufacturing.

Scalable Customization of Crystallographic Plane Controllable Lithium Metal Anodes for Ultralong-Lasting Lithium Metal Batteries.

A formidable challenge to achieve the practical applications of rechargeable lithium (Li) metal batteries (RLMBs) is to suppress the uncontrollable growth of Li dendrites. One of the most effective solutions is to fabricate Li metal anodes with specific crystal plane, but still lack of a simple and high-efficient approach. Herein, a facile and controllable way for the scalable customization of polished Li metal anodes with highly preferred (110) and (200) crystallographic orientation (donating as polished Li(110) and polished Li(200), respectively) by regulating the times of accumulative roll bonding, is reported. According to the inherent characteristics of polished Li(110)/Li(200), the influence of Li atomic structure on the electrochemical performance of RLMBs is deeply elucidated by combining theoretical calculations with relative experimental proofs. In particular, a polished Li(110) crystal plane is demonstrated to induce Li+ uniform deposition, promoting the formation of flat and dense Li deposits. Impressively, the polished Li(110)||LiFePO4 full cells exhibit unprecedented cycling stability with 10000 cycles at 10 C almost without capacity degradation, indicating the great potential application prospect of such textured Li metal. More valuably, this work provides an important reference for low-cost, continued, and large-scale production of Li metal anodes with highly preferred crystal orientation through roll-to-roll manufacturability.

Silane Doping for Efficient Flexible Perovskite Solar Cells with Improved Defect Passivation and Device Stability.

In this work, doping 3-amino-propyl triethoxysilane (APTES) into a perovskite precursor is proven to be an effective strategy, which can passivate crystal defects, control the crystallization rate, and improve the morphology. APTES can form oligomers through hydrolysis and a condensation reaction, thus blocking the invasion of external water molecules. In addition, the lone pair electrons on the N atom in the amino group of APTES form a coordination bond with perovskite by sharing the empty 6p orbital on Pb2+, which can effectively passivate the defects of the film and realize a highly uniform and dense perovskite film with preferential crystal growth orientation. The film exhibits high (110) crystal plane orientation and long carrier lifetime and mobility, which improves the performance of flexible perovskite solar cells. Using this approach, the champion device presents an optimal power conversion efficiency of 19.84% with much promoted air stability. Moreover, the efficiency of flexible devices does not decrease after maximum power point irradiation for 360 s.

Orientation Manipulation and Defect Passivation for Perovskite Solar Cells by a Natural Compound.

Different facets in perovskite crystals exhibit distinct atomic arrangements, influencing their electronic, physical, and chemical properties. Perovskite films incorporating tin oxide (SnO2) as the electron transport layer face challenges in facet regulation. This study reveals that tea saponin (TS), a natural compound serves as a SnO2 modifier, facilitates optimal growth of perovskite crystals on the (111) facet. The modification promotes preferential crystal orientation through hydrogen bond and Lewis coordination. TS forms a chelate with SnO2, resulting in a smoother film and n-type doping, leading to improved carrier extraction and reduced defects. The TS-modified perovskite solar cells achieve a champion efficiency of 24.2%, leveraging from an obvious enhancement of open-circuit voltage (Voc) of 1.18V and fill factor (FF) of 82.8%. The devices also demonstrate enhanced humidity tolerance and storage stability, ensuring improved stability without encapsulation.

Study on hardness and corrosion resistance of Co-Mo-P/ZrO2 composite coating electrodeposited on Q345 steel

Co-Mo-P/ZrO2 composite coating was prepared on the surface of Q345 steel by electrodeposition technology, and the effect of different ZrO2 particle concentrations on the surface morphology, chemical composition, thickness, microstructure and mechanical properties of the composite coating was investigated. The results show that different composite coatings prepared by changing the concentration of ZrO2 particles in the bath show aggregated cellular surface morphology, which is composed of Co, Mo, P, Zr, and O elements. With the concentration of ZrO2 particles increasing from 4 g/L to 20 g/L, the average grain size and the amount of ZrO2 particles incorporated both decrease first and then increase. Moreover, along with the increase in concentration of ZrO2 particles, the hardness and scratch resistance of the composite coating both show a trend of increasing first and then decreasing. However, changing the concentration of ZrO2 particles has no obvious effect on the grain structure and growth orientation of the composite coating. When the concentration of ZrO2 particles is 12 g/L, the surface of the composite coating is relatively dense with an average grain size of 40.78 nm and (200) crystal face preferred orientation. More ZrO2 particles are incorporated on the surface and boundary of the grain aggregation, which plays an obvious dispersion strengthening effect. The hardness of the composite coating reaches 580.2 HV, showing good scratch and corrosion resistance.

Effect of 2-Mercapto-1-methylimidazole on the Electrodeposition of Nickel on an Ordered Au(111) Electrode.

A nickel film electroplated onto a metal substrate can be used as a catalyst for water splitting and a magnetic material for spin valves. Although the nucleation and growth of Ni on Au(111) have already been examined with in situ scanning tunneling microscopy (STM), the current study provides new insights of the structure of the first layer of Ni on an ordered Au(111) electrode in 0.1 M KSO4 + 1 mM H2SO4 + 10 mM NiSO4 (pH 3). Prolonged STM scanning of the Ni monolayer on a Au(111) electrode revealed interfacial mixing to produce a surface alloy, initially assuming segregated Ni domains and later transforming them to a homogeneous Ni/Au phase. The formation of the Ni/Au(111) surface alloy affected the structure of the subsequent bulk Ni deposition. The inclusion of 2-mercapto-1-methylimidazole (MMI) in the deposition bath incurred Ni deposition at a less negative potential and a faster rate, resulting in an overall 5.3 times more Ni deposited on the Au electrode in potentiodynamic experiments. MMI molecules were adsorbed on the Ni deposit to prevent Ni dissolution in the Au(111) electrode. MMI could catalyze the presumed rate-determining step from Ni2+ to Ni+ en route to the metallic Ni. The resultant Ni film with MMI had a 3D texture without a preferred crystal orientation on the Au electrode, as opposed to a layer type growth of Ni on Au(111) without MMI.

4‐Phenylthiosemicarbazide Molecular Additive Engineering for Wide‐Bandgap Sn Halide Perovskite Solar Cells with a Record Efficiency Over 12.2%

AbstractThe utilization of wide bandgap (WBG) tin halide perovskites (Sn‐HPs) offers an environmentally friendly alternative for multi‐junction Sn‐HP photovoltaics. Nonetheless, rapid crystallization leads to suboptimal film morphology and substantial creation of defect states, which undermine device efficiency. This study introduces 4‐Phenylthiosemicarbazide (4PTSC) as an additive to achieve a densely packed Sn‐HP film with fewer imperfections. The strong chemical coordination between SnI2 and the functional groups S═C─N (Sn···S═C─N), NH2, and phenyl conjugation enhances solution stability and supports the delay of perovskite crystallization through adduct formation. This process yields pinhole‐free films with preferred grain growth. 4PTSC acts as a strong coordination complex and a reducing agent to passivate uncoordinated Sn2+ and halide ions and reduce the formation of SnI4, thereby reducing defect formation. The π‐conjugated phenyl ring in the 4PTSC facilitates the preferred crystal growth orientation of perovskite grains. Furthermore, the hydrophobic nature of 4PTSC mitigates Sn2+ oxidation by repelling moisture, enhancing stability. The open circuit voltage significantly increased from 0.78 to 0.94 V, resulting in achieving the champion efficiency of 12.22% (certified 11.70%), surpassing all previously reported efficiencies for WBG Sn halide perovskite solar cells. Additionally, the unencapsulated 4PTSC‐1.0 device maintained outstanding stability over 1200 h under ambient atmospheric conditions.

Emplacement of shergottites in the Martian crust inferred from three‐dimensional petrofabric and crystal size distribution analyses

AbstractShergottites are mafic to ultramafic igneous rocks that represent the majority of known Martian meteorites. They are subdivided into gabbroic, poikilitic, basaltic, and olivine–phyric categories based on differences in mineralogy and textures. Their geologic contexts are unknown, so analyses of crystal sizes and preferred orientations have commonly been used to infer where shergottites solidified. Such environments range from subsurface cumulates to shallow intrusives to extrusive lava flows, which all have contrasting implications for interactions with crustal material, cooling histories, and potential in situ exposure at the surface. In this study, we present a novel three‐dimensional (3‐D) approach to better understand the solidification environments of these samples and improve our knowledge of shergottites' geologic contexts. Shape preferred orientations of most phases and crystal size distributions of late‐forming minerals were measured in 3‐D using X‐ray computed tomography (CT) on eight shergottites representing the gabbroic, poikilitic, basaltic, and olivine–phyric categories. Our analyses show that highly anisotropic, rod‐like pyroxene crystals are strongly foliated in the gabbroic samples but have a weaker foliation and a mild lineation in the basaltic sample, indicating a directional flow component in the latter. Star volume distribution analyses revealed that most phases (maskelynite, pyroxene, olivine, and oxides/sulfides) preserve a foliated texture with variable strengths, and that the phases within individual samples are strongly to moderately aligned with respect to one another. In combination with relative cooling rates during the final stages of crystallization determined from interstitial oxide/sulfide crystal size distribution analyses, these results indicate that the olivine–phyric samples were emplaced as shallow intrusives (e.g., dikes/sills) and that the gabbroic, poikilitic, and basaltic samples were emplaced in deeper subsurface environments.

Quantitative determination of quaternary solid waste-based binders and its hydrates by XRD

Solid waste-based binders offer intrinsic low-carbon advantages and non-primary resource consumption, making them one of the most promising low-carbon binders. However, the compositions of multiple components and the complex nature of their raw materials—mainly industrial solid wastes—make the stability and control of their quality very difficult, thereby limiting their practical applications in industry. The core of controlling product stability lies in quantifying the blended mixes. The progress in X-ray diffraction and its analysis methods has provided an opportunity to directly and non-destructively measure the phase compositions of solid waste-based binders. Rietveld refinement has been widely used to quantify the blend of crystals. However, due to the X-ray amorphous diffraction characteristics of aluminosilicates in most solid wastes, distinguishing and quantifying them is challenging. The PONCKS method has provided a strategy for indexing the amorphous phases and facilitating the distinction of different amorphous phases in various raw materials. In this study, by combining the Rietveld and PONCKS methods, a strategy has been presented that applies the XRD method to quantify the mixing proportions and their hydration products, and its validity has been verified. Factors such as crystal preferred orientation, background selection, and the structure for establishing the CASH model have been identified as more significant for accurate analysis and the optimal fitting strategy has been suggested. Lastly, in-situ XRD measurements, a very promising technology for studying the fresh paste hydration processes, have also been conducted. The real-time continuous determination has provided a more insightful understanding of the hydration and setting behaviors of the solid waste-based binder.

Deformation microstructures of blueschists in Alpine Corsica, France, and implications for seismic anisotropy and the low-velocity layer in subducting oceanic crust

Understanding the deformation microstructures and seismic properties of blueschists is important for interpreting the seismic anisotropy at the top of subducting oceanic crust. The deformation microstructures and seismic properties of epidote blueschist, epidote-lawsonite blueschist, and lawsonite blueschist from Alpine Corsica, France, were studied using electron backscatter diffraction mapping and transmission electron microscopy. The crystal-preferred orientations (CPOs) of glaucophane show a strong maximum of the [001] axes aligned sub-parallel to the lineation. The maximum of the (010) poles of epidote is aligned sub-parallel to the lineation. The [001] axes of lawsonite are strongly aligned sub-normal to the foliation. Intracrystalline misorientation, dislocation, and occasional fragmentation of glaucophane indicate that glaucophane CPO was developed mainly by dislocation creep. The intracrystalline deformation features of epidote, such as subgrain boundaries and dislocations, indicate that the CPO of the epidote was formed by dislocation creep. In contrast, our data indicate that lawsonite CPO was developed by a combination of rigid-body rotation and dislocation creep with a minor effect of twinning. The P-wave anisotropy (AVp) and maximum S-wave anisotropy (max.AVs) of epidote blueschists (AVp = 12.3–16.9% and max.AVs = 6.53–11.75%) are higher than those of lawsonite blueschists. The seismic velocities of the blueschists are lower than those of mantle peridotites. The coexistence of epidote and lawsonite in the blueschist results in variations in seismic anisotropy and P-wave velocity in the whole rock, depending on the modal content of epidote and lawsonite. A high content ratio of epidote to lawsonite in blueschist produces strong P- and S-wave anisotropies of blueschist when the glaucophane content is more than ∼50%. The P-wave velocity of blueschist decreases proportionally with increasing epidote content. Our results indicate that the seismic properties of deformed blueschists contribute to the seismic anisotropy and the low-velocity layer in subducting oceanic crusts in subduction zones.

Effect of annealing temperature on bismuth vanadate nano thin films for solar cell applications

Bismuth vanadate (BiVO4) has been used as the photoanode electrodes in ferroelectric solar cells owing to its unique combination of properties: a narrow bandgap among ferroelectrics, economic viability, negative conduction band edge, and remarkable stability. The present work explores the fabrication and characterization of BiVO4 thin films prepared via spin coating, with a specific focus on elucidating the influence of the annealing temperature (400–550 °C) on their structural, optical, and photovoltaic properties. From X-ray diffraction (XRD) analysis, it is observed that higher annealing temperatures have promoted the formation of larger grains, enhanced crystallinity, and induced a preferred crystal orientation characteristic of the monoclinic scheelite structure. Tauc plot analysis shows the dependence of the optical band gap on the annealing temperature for BiVO4 thin films. The band gap values have decreased slightly from 2.50 eV at 400 °C to 2.44 eV at 550 °C. This is indicated by the slightly narrowed bandgap, which influences the structure of the material or defect states at higher annealing temperatures. A narrower bandgap allows for the absorption of lower-energy light, potentially improving the light absorption efficiency of BiVO4 thin films in photoanode applications. The influence of annealing temperature on BiVO₄ thin film solar cell performance was investigated further through the analysis of open-circuit voltage (Voc), short-circuit current (Isc) and power conversion efficiency.

Hydrogen‐Bond‐Based Polymer‐Ammonium Intermediates Induced Buried Interface Engineering for High‐Performance Inverted Perovskite Solar Cells

AbstractPerovskite interfaces where defects enrich are pivotal for both device efficiency and stability. Herein, a high‐molecular‐weight polyvinyl pyrrolidone (PVP) is proposed as a robust multi‐functional interlayer to engineer the buried interface. Besides the well‐known defect passivation, perovskite crystallization is intriguingly modulated via the formation of hydrogen‐bond‐based polymer‐ammonium intermediates (e.g., PVP‐FA+ or PVP‐MA+, where MA and FA are methylamine and formamidine, respectively). The interaction energies derived from density functional theory calculations (−34.5, −26.8, and −9.9 kcal mol−1 for PVP‐FA+, PVP‐MA+, and PVP‐Pb2+) suggest that PVP predominately interacts with ammonium cations to form the intermediates, thus largely excluding other chemical interactions and retarding the perovskite crystallization. As such, the hydrophilic PVP interlayer leads to spontaneous perovskite spreading yet a counterintuitively similar nucleation density with respect to the hydrophobic poly[bis(4‐phenyl)(2,4,6‐trimethylphenyl)amine] (PTAA), a change of preferred crystal orientation, improved crystallinity, and remarkably suppressed non‐radiative recombination. These conducive effects jointly minimize the open‐circuit voltage loss and give rise to superior power conversion efficiency for small‐area and large‐area devices.

Uniaxial-Oriented Perovskite Films with Controllable Orientation.

Perovskite films with large crystal size, preferred orientation, and facile fabrication process, combining advantages of single-crystal and polycrystalline films, have gained considerable attention recently. However, there is little research on the facet properties of perovskite films. Here, (111)- and (001)-oriented perovskite films with bandgaps ranging from 1.53 to 1.77eV, and systematically investigated their orientation-dependent properties are achieved. The (111)-oriented films show electron-dominated traps and the (001)-oriented films show hole-dominated traps, which are related to their atomic arrangement at the surface. Compared with the (001)-oriented films, the (111)-oriented films exhibit lower work function and superior water/oxygen robustness. For the wide-bandgap films, the lattice of the (001)-oriented film provides an unobstructed passage for ion migration. Comparably, the (111)-oriented films exhibit suppressed ion migration and excellent phase stability. The optimized unencapsulated solar cells based on both (001) and (111) orientations show a similar high efficiency of ≈23%. The (111)-oriented solar cell exhibits excellent stability, maintaining 95% of its initial efficiency after 1500h maximum power point (MPP) tracking test, and 97% initial efficiency after 3000h aging in ambient conditions. This work paves the way for the rational design, controllable synthesis, and targeted optimization of uniaxial-oriented perovskite films for various electronic applications.

Amphoteric Chelating Ultrasmall Colloids for FAPbI3 Nanodomains Enable Efficient Near-Infrared Light-Emitting Diodes.

Perovskite light-emitting diodes (PeLEDs) are the next promising display technologies because of their high color purity and wide color gamut, while two classical emitter forms, i.e., polycrystalline domains and quantum dots, are encountering bottlenecks. Weak carrier confinement of large polycrystalline domains leads to inadequate radiative recombination, and surface ligands on quantum dots are the main annihilation sites for injected carriers. Here, pinpointing these issues, we screened out an amphoteric agent, namely, 2-(2-aminobenzoyl)benzoic acid (2-BA), to precisely control the in situ growth of FAPbI3 (FA: formamidine) nanodomains with enhanced space confinement, preferred crystal orientation, and passivated trap states on the transport-layer substrate. The amphoteric 2-BA performs bidentate chelating functions on the formation of ultrasmall perovskite colloids (<1 nm) in the precursor, resulting in a smoother FAPbI3 emitting layer. Based on monodispersed and homogeneous nanodomain films, a near-infrared PeLED device with a champion efficiency of >22% plus enhanced T80 operational stability was achieved. The proposed perovskite nanodomain film tends to be a mainstream emitter toward the performance breakthrough of PeLED devices covering visible wavelengths beyond infrared.

In-Plane Anisotropy in the Layered Topological Insulator Ta2Ni3Te5 Investigated via TEM and Polarized Raman Spectroscopy.

Layered Ta2M3Te5 (M = Pd, Ni) has emerged as a platform to study 2D topological insulators, which have exotic properties such as spin-momentum locking and the presence of Dirac fermions for use in conventional and quantum-based electronics. In particular, Ta2Ni3Te5 has been shown to have superconductivity under pressure and is predicted to have second-order topology. Despite being an interesting material with fascinating physics, the detailed crystalline and phononic properties of this material are still unknown. In this study, we use transmission electron microscopy (TEM) and polarized Raman spectroscopy (PRS) to reveal the anisotropic properties of exfoliated few-layer Ta2Ni3Te5. An electron diffraction and TEM study reveals structural anisotropy in the material, with a preferential crystal orientation along the [010] direction. Through Raman spectroscopy, we discovered 15 vibrational modes, 3 of which are ultralow-frequency modes, which show anisotropic response with sample orientation varying with the polarization of the incident beam. Using angle-resolved PRS, we assigned the vibrational symmetries of 11 modes to Ag and two modes to B3g. We also found that linear dichroism plays a role in understanding the Raman signature of this material, which requires the use of complex elements in the Raman tensors. The anisotropy of the Raman scattering also depends on the excitation energies. Our observations reveal the anisotropic nature of Ta2Ni3Te5, establish a quick and nondestructive Raman fingerprint for determining sample orientation, and represent a significant advance in the fundamental understanding of the two-dimensional topological insulator (2DTI) Ta2Ni3Te5 material.

Pore‐scale freezing of a sandy saline soil visualized with micro‐computed tomography

AbstractSandy saline soils are widely distributed and commonly experience seasonal or long‐term freezing, yet the freezing process in these soils is rarely studied. This research utilized in situ X‐ray computed tomography (CT) to visualize pore‐scale freezing processes in sandy saline soils under various initial water and salt contents. Micron‐resolution observations of pore ice and unfrozen water produced new insights into the preferential orientation and grouping of pore ice crystals, intersections between different pore ice crystal groups causing anisotropic behavior, decreasing pore ice crystal size under faster freezing rates, and the formation of interconnected networks of both pore ice and unfrozen water upon freezing. From a thermodynamic perspective, the salt content in the unfrozen liquid is dependent on the local temperature as described by water–salt phase diagram. Furthermore, the local volume ratio between unfrozen water and pore ice reflects the initial salt content and salt mass transfer occurring due to both diffusion and fluid flow processes. This work improves the understanding of complex freezing phenomena in sandy saline soils through high‐resolution evidence of crystallization patterns, transformation mechanisms, and coupled heat‐mass transfer.

Matrix polysaccharides affect preferred orientation of cellulose crystals in primary cell walls

Matrix polysaccharides affect preferred orientation of cellulose crystals in primary cell walls

Simultaneous modification of interface and modulation of crystal growth by deep eutectic solvent for FACs-Based perovskite solar cells

Improving the interface property and crystallographic orientation of perovskite films has been considered as the bottleneck to improve the optoelectronic performance of perovskite solar cells (PSCs). However, the precise manipulation of preferential crystal orientation by interfacial layers and their underlying impact mechanism on the device performance is still not well understood. In this study, deep eutectic solvent (DES), which is prepared by mixing choline chloride (Chcl) and propanedioic acid (PA) in a molar ratio of 1:1, is employed as a buried interface layer to finely adjust the preferred crystal orientation of the FACs-based perovskite. On the one hand, the DES can modify SnO2, which is conducive to improving electron extraction and transport abilities. On the other hand, the DES can interact with perovskite by forming coordination bonds, electrostatic interactions, and hydrogen bonds, which is beneficial for inducing perovskite crystal orientation along the (100) crystal plane, causing reduced trap density and hence retarded non-radiative recombination of PSCs. The preferred crystal orientation enhances the quality of the perovskite film. Consequently, a power conversion efficiency (PCE) of 21.11 % is obtained, which is higher than 18.11 % of the pristine PSC. Moreover, the unencapsulated device maintains 87 % of its initial PCE after aging for more than 1100 h in the air. This work presents a feasible method for controlling perovskite orientation growth by interface DES layer.

Anisotropy of photocatalytic properties of MoO3/TiO2–SiO2 core–shell polycrystalline composites

In this work, the effect of the preferred orientation of MoO3 crystals in polycrystalline MoO3/TiO2–SiO2 composites on their optical properties and photocatalytic activities in the decomposition reaction of organic dyes was investigated. The anisotropy of the photocatalytic properties was shown. The MoO3/TiO2–SiO2 core–shell spherical composites were prepared using TOKEM-320Y anion exchange resin as a template by the combined method, including template and sol–gel methods. The XRD, XPS, EDS, SEM, Raman, IR, DRS, N2 sorption, and PL techniques were used to characterize the elemental and phase compositions, textural and optical properties of the MoO3/TiO2–SiO2 spherical particles. The MoO3/TiO2–SiO2 composites prepared at 600 °C were characterized by the lowest anisotropy coefficient (1.23) of the crystals growth rate in the plane (l00) relative to the crystals growth rate in the plane (lll) and the highest concentration of oxygen vacancies. High temperature treatment of MoO3/TiO2–SiO2 samples up to 700 °C leads to a change in the degree of their texture, which is due to the growth of the anisotropy coefficient up to 1.38 and crystallites in the (l00) plane, which was confirmed by increasing the Lotgering factor. The content of Mo5+ in the surface and subsurface layers of such composites is the highest. The MoO3/TiO2 − SiO2 composites prepared at 600 °C exhibited a much higher photocatalytic activity (the rate constant is 0.0319 min-1). This work demonstrates that the predominant orientation of MoO3 crystals in the (l00) plane negatively affects the oxygen defect (the value decreases to 0.0486) and MoO3/TiO2 − SiO2 polycrystalline composites photocatalytic activity.

2D BA2PbI4 Regulating PbI2 Crystallization to Induce Perovskite Growth for Efficient Solar Cells

AbstractUsing seeds to control the crystallization of perovskite film is an effective strategy for achieving high‐efficiency perovskite solar cells (PSCs). Owing to their excellent environmental stability brought by their long alkyl chain, n‐butylammonium (BA) cations are widely used for fabricating efficient and stable PSCs. However, BA‐based 2D perovskite is seldom been investigated as a seed. Here, BA2PbI4 is employed to regulate the crystallization of PbI2, acting as nucleation centers. As a result, porous PbI2 film with high crystallinity is obtained, which allows the realization of perovskite film with preferential crystal orientations of (001) and large grain size of over 2 µm. The corresponding PSC achieves a high power conversion efficiency (PCE) of 24.30% and exhibits satisfactory stability, retaining 91.70% of the initial PCE after 300 h of thermal aging at 85°C.