Morphology Of Films Research Articles

Impact of Cu doping on morphology, structural and optical characteristics of SnO2 thin films prepared by spray pyrolysis

Impact of Cu doping on morphology, structural and optical characteristics of SnO2 thin films prepared by spray pyrolysis

Scalable Slot-Die Coating of Passivation Layers for Improved Performance of Perovskite Solar Cell Modules.

Upscaling the perovskite solar cell (PSC) while avoiding losses in the power conversion efficiency presents a substantial challenge, especially when transitioning from ≤1cm2 cells to ≥10cm2 modules. In addition to the fabrication of key functional layers, scalable technologies for surface passivation, considered indispensable for achieving high-performance PSCs, are urgently required. However, studies on this topic remain limited. In this study, an industry-ready slot-die coating method for the effective passivation of perovskite films as a practical alternative is developed to the spin-coating procedures commonly used in research. The coating conditions and molecular structure of the passivation agent are systematically optimized to achieve high-quality film morphology and substantially suppress interface recombination. 2-chloro-5-(trifluoromethyl)-phenylammonium bromide exhibited the best results, improving the open-circuit voltage of cells and subcells in a module by 80±4 and 72±10mV, respectively. Correspondingly, the larger-area (active area: 10cm2) modules sustained the highest efficiency of 21.9% under simulated 1-sun irradiation. The encapsulated devices retained 94% of their initial performances after 750h of continuous operation. The proposed surface-passivation slot-die technology is compatible with high-throughput processes and is employable for large-scale PSC fabrication.

Effect of discharge pulse frequency on the microstructure and field-emission performance of CNX films deposited by pulse cathode arc evaporation

CNX thin films were prepared by a pulse cathode arc technique using nitrogen as a dopant at different frequencies. Microstructure, compositions, and morphology of CNX thin films were investigated in the dependence of discharge pulse frequency by Raman spectroscopy, x-ray photoelectric spectroscopy (XPS), atomic force microscopy, scanning electron microscopy, UV–vis spectrophotometry, Hall measurements, and field-emission test. The results of Raman and XPS showed that the Csp2 cluster size of CNX films decreases and then increases and decreases with discharge pulse frequency increasing. The Csp2 cluster size of the films prepared at 9 Hz was the largest. The size of Csp3 content increases for the CNX films at the high discharge pulse frequency. The variation of C–N bonding content with frequency in CNX films is similar to that of Csp2. CNX thin films prepared at a frequency of 9 Hz were improved field-emission properties corresponding to the variation of microstructure parameters (the size and ordering of Csp2 clusters) and compositions (C–N bonds). The excellent field-emission properties, such as a low turn-on electric field of 2.1 V/μm and a high field-emission current density of 517.34 μA/cm2, were obtained.

High‐Performance Organic Solar Cells Enabled by 3D Globally Aromatic Carboranyl Solid Additive

AbstractA key factor in optimizing organic solar cells (OSCs) is the precise control of blend film morphology to enhance exciton dissociation and charge transport. Solid additives play a vital role in this process, with 3D polyhedral or spherical molecules being ideal candidates due to their delocalized π‐orbitals and omnidirectional charge transport. However, the application of classical fullerene derivatives as spherical additives is limited by their synthetic complicacy and poor solubility. Herein, the potential of 3D globally aromatic carboranyl cages as solid additives, specifically 1‐amino‐o‐carborane (CB‐NH2) and 1‐carboxy‐o‐carborane (CB‐COOH), is explored to fine‐tune the film morphology and improve the performance of OSCs. These spherical molecules provide an extensive surface for hydrogen bonding interactions, which serve as the driving force for manipulating the vertical phase separation and active layer crystallinity. Remarkably, CB‐NH2‐processed devices with well‐tuned morphology yield a remarkable power conversion efficiency of 19.48%, highlighting the effectiveness of 3D carboranyl additives on improving OSC performance. This work challenges the reliance on fullerene derivatives as spherical additives and offers new insights into the mechanisms by which 3D globally aromatic additives can achieve high performance in OSCs, emphasizing the significance of molecular engineering in the development of next‐generation solar cell technology.

SEM and TEM Image Analysis for Morphology and Phase Transition of CZTS, Sb2Se3 and Perovskite Thin Films under Thermal Stress

SEM and TEM Image Analysis for Morphology and Phase Transition of CZTS, Sb2Se3 and Perovskite Thin Films under Thermal Stress

Rapid Prototyping for Accelerated Establishment of Film Processing‐Performance Relationships in Silicon Phthalocyanine OFETs

AbstractUnderstanding the complex relationships underlying the performance of organic electronic devices, such as organic field‐effect transistors (OFETs), requires researchers to navigate a multi‐dimensional parameter space that includes material design, solution formulation, fabrication parameters, and device geometry. Herein, a recently developed materials acceleration platform is demonstrated, named the RoboMapper, to perform direct on‐chip fabrication of OFETs by ultrasonic meniscus printing using silicon phthalocyanine (SiPc) derivatives as the semiconductor. OFETs using bis(tri‐n‐butylsilyl oxide) SiPc ((3BS)2‐SiPc) exhibited the best device performance characterized by the highest electron field‐effect mobility (µe). Through optical microscopy and grazing‐incidence wide‐angle X‐ray scattering (GIWAXS), the favorable performance of (3BS)2‐SiPc is attributed to the specific film morphology and molecular packing achieved with optimal print conditions. Investigating the impact of deposition parameters reveals the crucial role of solvent evaporation rate and print speed in achieving high‐quality film formation. Overall, optimal fabrication conditions for (3BS)2‐SiPc devices include slow print speeds and fast evaporating solutions achieved by using a mixture of co‐solvents and an elevated substrate temperature. The results of this work reveal distinct relationships between deposition conditions, film properties, and device performance for each SiPc derivative and emphasize the necessity of high throughput experimentation to comprehensively understand process‐performance relationships in organic semiconductors.

Theoretical and experimental insights of two surfactants’ effects on SnIn electrodeposited coatings from ethaline

This work uses computational methodologies to investigate the behavior of Sn2+ and In3+ ions in deep eutectic solvent (DES) based on choline chloride and ethylene glycol (1ChCl:2EG, ethaline), under different conditions, such as different temperatures, ion ratios, and in the presence and absence of hexadecyltrimethylammonium bromide (CTAB) and sodium dodecyl sulfate (SDS) surfactants. Furthermore, SnIn alloys were electrodeposited on Cu surfaces to analyze the effect of the investigated different conditions on the surface morphology and chemical composition of the electrodeposited coatings. Morphology and composition were analyzed using Scanning Electron Microscopy (SEM) and Energy Dispersive X-ray (EDS). For computational approach, twelve Molecular Dynamics (MD) simulations were conducted using the GROMACS software. After MD simulations, Quantum Theory of Atoms in Molecules (QTAIM) properties were obtained. The results presented that In3+ showed a stronger affinity for Cl− than Sn2+ but it presents weaker and less stable interactions with OA (OA = oxygen of ethylene glycol-EG), particularly at higher temperatures. Electron Density and Electron Localization Function analysis indicated that In-Cl interactions are stronger and more polarized than other interactions. The Laplacian of Electron Density suggested an intermolecular nature for all interactions. The surfactant addition altered these interactions slightly, with CTAB reducing the density of Cl− around In3+ and SDS positively interacting with In3+ at 297 K and in a Sn2+:In3+ 1:1. As SDS interacted more with In3+ ions, the electrodeposition times varied between 4965 s and 75,541 s. SEM images revealed temperature- and potential-dependent changes in film morphology, changing from globular to smooth. CTAB and SDS additions led to uniform coating in Sn2+: In3+ solutions. For the 1:1 ratio at −1.4 V, there were no significant changes (between 75 and 77 %) in the percentage of Sn deposited with the use of surfactants at 297 K. At 343 K, the surfactant-free coating exhibited 69 % Sn, CTAB facilitated the Sn deposition, increasing the percentage to 92 %. At the same time, the presence of the SDS resulted in 79 % Sn. Similar behavior was obtained for −1.0 V. For 1:4 at −1.0 V at 297 K, 35 % of Sn was observed without surfactant, 29 % with CTAB, and 33 % with SDS. At 343 K, there was an increase in Sn content for 42 %, 49 % and 60 %, indicating the positive influence of the temperature, respectively. At −1.4 V, however, there was no observed influence on the Sn percentages without surfactant. With CTAB (between 29 and 34 %) at 297 and 343 K. At these temperatures, the addition of SDS promoted a higher content of Sn, increasing to 56 % and 43 %, respectively.

Comparative study of zirconium-zinc oxide thin films on ceramic and glass substrates: Structural, optical, and photocatalytic properties

This study investigates the structural, optical, and photocatalytic properties of zirconium-doped zinc oxide (Zr) thin films deposited on ceramic and glass substrates. X-ray diffraction (XRD) analysis revealed that all samples exhibited a polycrystalline wurtzite structure, with grain sizes ranging from 25 to 43 nm for ceramic substrates and 19 to 32 nm for glass substrates. UV–visible absorbance measurements indicated that Zr films absorbed visible light around 410 nm, with the band gap widening to 2.93 eV on ceramic substrates. Scanning electron microscopy (SEM) showed that Zr doping significantly affected the morphology of thin films, resulting in rougher surfaces and larger grains on ceramic substrates. Photocatalytic tests demonstrated that the 5 wt% Zr on DD1Z ceramic achieved a degradation efficiency of 61.44 % for orange II dye after 5 h of UV irradiation. In contrast, Zr on ceramic substrates achieved only 18.56 %, and the bare DD1Z substrate reached just 4.02 %. These findings highlight the superior photocatalytic performance of Zr on ceramic substrates, indicating their potential for advanced water purification technologies. The mechanism of photolysis was investigated using hole/radical scavengers, revealing that Zr-ZnO networks enhance the adsorption of hydroxyl ions on the surface. This acts as a trap site, reducing hole/electron pair recombination and thus increasing activity and photodegradation efficiency.

FAPbI3-nanoparticles with ligands act synergistically in absorbent layers for high-performance and stable FAPbI3 based perovskite solar cells

The performance of perovskite solar cells (PSCs) depends on the quality of the perovskite absorber layer. In this study, oleic acid (OA) and oleylamine (OAm) ligand-capped formamidinium lead iodide (FAPbI3) nanoparticles (NPs) were incorporated into the formamidinium iodide (FAI) solution, which is one of the precursors for the sequential deposition of the FAPbI3 layer. The synergistic effect of the FAPbI3-NPs and the capped ligand substantially improves the crystallinity, uniformity, and morphology of the bulk FAPbI3 perovskite films. The enhancements lead to a reduction in charge recombination and a boost in charge transfer efficiency, enabling the optimized PSCs to achieve a remarkable peak power conversion efficiency (PCE) of 25.68 %. Moreover, these PSCs show good stability, with unencapsulated devices maintaining 93 % of the peak performance under ambient air (RH 50 %) for 1000 hours.

Synthesis, Structures and Air-stable N-type Organic Field-effect Transistor (OFET) Properties of Functionalized-phenanthrene Conjugated Asymmetric N-heteroacenes.

The development of stable high-performance n-type organic semiconductors for applications in organic field-effect transistors (OFETs) under ambient conditions is desirable but challenging. To address this issue, we here synthesized a series of functionalized-phenanthrene conjugated asymmetric N-heteroacenes, where the phenanthrene moiety was modified by N substitution or Br functionalization at different positions to induce various degrees of asymmetry in their structures. The photophysical and electrochemical properties of these molecules were studied, and their packing patterns were analysed. The OFETs based on these materials were fabricated through simple spin-coating method, and the as-resulted thin films were treated with different conditions. The devices exhibit typical n-type performances under ambient conditions with charge carrier mobilities up to 4.27×10-3 cm2 V-1 s-1. The crystallinities and morphologies of these thin films were studied to investigate the correlations between the device performances and thin-film characteristics. Our study suggests that phenanthrene conjugated N-heteroacenes can be developed as promising air-stable solution-processable n-type semiconducting materials, and Br modification at certain positions of phenanthrene is beneficial in adjusting the thin-film properties for the improvement of OFET performances.

Effect of the Surface Morphology of a Metal Film on Ion Yields in a Platinum-Film Surface-Assisted Laser Desorption/Ionization Mass Spectrometry.

Matrix-assisted laser desorption ionization (MALDI) and surface-assisted laser desorption ionization (SALDI) mass spectrometry (MS), which can detect biomolecules and polymers, are widely used in biochemistry and material science. Some compounds that are difficult to ionize using MALDI can be ionized using SALDI. However, it is difficult to obtain high ion yields using SALDI/MS. In this study, a fabricated platinum (Pt) film with nanostructures on the sample surface using a sputtering method was evaluated to determine the optimal metal film for ion yield in SALDI. The surface morphology of the Pt film was analyzed using scanning electron microscopy (SEM), atomic force microscopy (AFM), transmission electron microscopy (TEM), X-ray reflectivity (XRR), and ultraviolet-visible-near-infrared (UV-Vis-NIR) reflectance spectroscopy. The SEM, AFM, and TEM images of the Pt film showed the deposited metal film giving high ion yields of polyethylene glycol (PEG) in SALDI/MS with a Pt film (Pt-SALDI) that had a rough surface. The densities and reflectivity of films were analyzed by XRR and UV-Vis-NIR. The higher ion yields of PEG were obtained by Pt-SALDI with the Pt films with lower densities and reflectivity. This indicates that the deposition conditions for the Pt films significantly improved the ion yield in Pt-SALDI/MS. The Pt-SALDI has ionization capabilities different from those of MALDI. Therefore, optimization of Pt film for SALDI/MS and the MS imaging allows more compounds to be detected with higher sensitivity.

Interdependence of Support Wettability ‐ Electrodeposition Rate‐ Sodium Metal Anode and SEI Microstructure

AbstractThis study examines how current collector support chemistry (sodiophilic intermetallic Na2Te vs. sodiophobic baseline Cu) and electrodeposition rate affect microstructure of sodium metal and its solid electrolyte interphase (SEI). Capacity and current (6 mAh cm−2, 0.5–3 mA cm−2) representative of commercially relevant mass loading in anode‐free sodium metal battery (AF‐SMBs) are analyzed. Synchrotron X‐ray nanotomography and grazing‐incidence wide‐angle X‐ray scattering (GIWAXS) are combined with cryogenic ion beam (cryo‐FIB) microscopy. Highlighted are major differences in film morphology, internal porosity, and crystallographic preferred orientation e.g. (110) vs. (100) and (211) with support and deposition rate. Within the SEI, sodium fluoride (NaF) is more prevalent with Te−Cu versus sodium hydride (NaH) and sodium hydroxide (NaOH) with baseline Cu. Due to competitive grain growth the preferred orientation of sodium crystallites depends on film thickness. Mesoscale modeling delineates the role of SEI (ionic conductivity, morphology) on electrodeposit growth and onset of electrochemical instability.

Effect of annealing conditions on resistive switching in hafnium oxide-based MIM devices for low-power RRAM

Abstract This work presents resistive switching (RS) behaviour in HfO2-based low-power resistive random-access memory (RRAM) devices. A metal-insulator-metal (MIM) structure (Au/HfO2/Pt) was fabricated by sandwiching a thin insulating layer of HfO2 between Pt and Au electrodes. HfO2 films deposited by RF sputtering at room temperature were rapid thermally annealed in N2 ambient at 400 °C and 500 °C. Grazing angle x-ray diffraction (GIXRD), Field emission gun-scanning electron microscopy (FEG-SEM), atomic force microscopy (AFM), and x-ray photoelectron spectroscopy (XPS) were employed to analyse the phase, crystal structure, morphology, surface roughness and chemical composition of the HfO2 films. The bipolar RS could be observed in both as-deposited and annealed HfO2 film-based devices from I–V characteristics measured using a source meter. We have investigated the effect of annealing temperature and annealing ambient on the phase formation of HfO2 as well as the RS characteristics and compared with as-deposited film-based device. Annealed HfO2 film-based devices exhibited improved electrical characteristics, including stable and repeatable RS at significantly lower switching voltages (<1 V) which indicates low power consumption in these devices. The relatively lower processing temperature of the HfO2 films and that too in the films deposited by physical vapor deposition (PVD) technique-RF magnetron sputtering makes this study significantly useful for resistive switching based non-volatile memories.

Integrated Omnidirectional Design of Non‐Volatile Solid Additive Enables Binary Organic Solar Cells with Efficiency Exceeding 19.5 %

AbstractSolid additives have drawn great attention due to their numerous appealing benefits in enhancing the power conversion efficiencies (PCEs) of organic solar cells (OSCs). To date, various strategies have been reported for the selection or design of non‐volatile solid additives. However, the lack of a general design/evaluation principles for developing non‐volatile solid additives often results in individual solid additives offering only one or two efficiency‐boosting attributes. In this work, we propose an integrated omnidirectional strategy for designing non‐volatile solid additives. By validating the method on the 4,5,9,10‐pyrene diimide (PyDI) system, a novel non‐volatile solid additive named PyMC5 was designed. PyMC5 is capable of enhancing device performance by establishing synergistic dual charge transfer channels, forming appropriate interactions with active layer materials, reducing non‐radiative voltage loss and optimizing film morphology. Notably, the binary device (PM6 : L8‐BO) treated by PyMC5 achieved a PCE over 19.5 %, ranking among the highest reported to date. In addition, the integration of PyMC5 mitigated the degradation process of the devices under photo‐ and thermal‐stress conditions. This work demonstrates an efficient integrated omnidirectional approach for designing non‐volatile solid additives, offering a promising avenue for further advancements in OSC development.

Integrated Omnidirectional Design of Non-Volatile Solid Additive Enables Binary Organic Solar Cells with Efficiency Exceeding 19.5 .

Solid additives have drawn great attention due to their numerous appealing benefits in enhancing the power conversion efficiencies (PCEs) of organic solar cells (OSCs). To date, various strategies have been reported for the selection or design of non-volatile solid additives. However, the lack of a general design/evaluation principles for developing non-volatile solid additives often results in individual solid additives offering only one or two efficiency-boosting attributes. In this work, we propose an integrated omnidirectional strategy for designing non-volatile solid additives. By validating the method on the 4,5,9,10-pyrene diimide (PyDI) system, a novel non-volatile solid additive named PyMC5 was designed. PyMC5 is capable of enhancing device performance by establishing synergistic dual charge transfer channels, forming appropriate interactions with active layer materials, reducing non-radiative voltage loss and optimizing film morphology. Notably, the binary device (PM6 : L8-BO) treated by PyMC5 achieved a PCE over 19.5 %, ranking among the highest reported to date. In addition, the integration of PyMC5 mitigated the degradation process of the devices under photo- and thermal-stress conditions. This work demonstrates an efficient integrated omnidirectional approach for designing non-volatile solid additives, offering a promising avenue for further advancements in OSC development.

Interdependence of Support Wettability - Electrodeposition Rate- Sodium Metal Anode and SEI Microstructure.

This study examines how current collector support chemistry (sodiophilic intermetallic Na2Te vs. sodiophobic baseline Cu) and electrodeposition rate affect microstructure of sodium metal and its solid electrolyte interphase (SEI). Capacity and current (6 mAh cm-2, 0.5-3 mA cm-2) representative of commercially relevant mass loading in anode-free sodium metal battery (AF-SMBs) are analyzed. Synchrotron X-ray nanotomography and grazing-incidence wide-angle X-ray scattering (GIWAXS) are combined with cryogenic ion beam (cryo-FIB) microscopy. Highlighted are major differences in film morphology, internal porosity, and crystallographic preferred orientation e.g. (110) vs. (100) and (211) with support and deposition rate. Within the SEI, sodium fluoride (NaF) is more prevalent with Te-Cu versus sodium hydride (NaH) and sodium hydroxide (NaOH) with baseline Cu. Due to competitive grain growth the preferred orientation of sodium crystallites depends on film thickness. Mesoscale modeling delineates the role of SEI (ionic conductivity, morphology) on electrodeposit growth and onset of electrochemical instability.

High-Performance Vis–NIR Photodetectors Based on Two-Dimensional Bi2Te3 Thin Film and Applications

Two-dimensional materials have excellent optoelectronic properties and have great significance in the field of photodetectors. We have prepared a thin film photodetector based on bismuth telluride (Bi2Te3) topological insulator using dual-temperature-zone vapor deposition technology. Due to the high-quality lattice structure of Bi2Te3 and the uniform and dense surface morphology of the Bi2Te3 thin film, the device exhibits excellent photoelectric response and Vis–NIR spectral range. Under 405 nm illumination, the responsivity is 5.6 mA/W, the specific detectivity is 1.22 × 107 Jones, and the response time is 262/328 ms. We designed a photodetector single-point scanning imaging system and successfully achieved high-resolution imaging at a wavelength of 532 nm. This work provides guidance for the application of two-dimensional materials, especially Bi2Te3, in the fields of photodetectors and imaging.

Efficient and Stable p-i-n Perovskite Solar Cells Enabled by In Situ Functional Group Conversion.

Chemical additives play a critical role in the crystallization kinetics and film morphology of perovskite solar cells (pero-SCs), thus affecting the device performance and stability. Especially, carboxylic acids and their congeners with a -COOH group can effectively serve as ligands to fortify the structural integrity and mitigate the risk of lead efflux. However, direct addition of -COOH into the precursor solution could retard the crystallization kinetics of the perovskite during film formation due to the strong coordination. Here, we present a novel approach of in situ functional group conversion using Bis(2,5-dioxopyrrolidin-1-yl) 4,7,10,13-tetraoxahexadecanedioate (Bis-PEG4-NHS ester) as an additive in the antisolvent, which underwent a functional group transformation from -COOR to -COOH during the annealing process through a hydrolysis reaction of Bis-PEG4-NHS ester. The corresponding hydrolysates exhibit enhanced interactions with PbI2 and FAI, contributing to the structural integrity and the defect passivation. Our findings offer valuable insights into the chemical interactions within the crystal growth process, achieving the p-i-n pero-SC device with an efficiency of 25.79% (certified as 25.47%) and notable long-term stability.

Efficient and fully non-halogen solution processed Cs2AgBiBr6 perovskite solar cell

For traditional hole transport material (HTM) 2,2′,7,7′-tetrakis(N,N′-di-pmethoxyphenylamino)9,9′-spirbiuorene(Spiro-OMeTAD) used in Cs2AgBiBr6 perovskite solar cell (PSC), the strong dependence of its performance on the hygroscopic and volatility additives, together with the mismatched energy level with Cs2AgBiBr6 and gold electrodes, are considered to be the two key factors restricting the improvement of performance. Considering this, we reported a series of dopant-free D-π-D type HTMs comprising of FNP as donor unit and Cz-Mp dimer linked benzene as π-bridge, termed o-PCz, m-PCz, and p-PCz by adjusting the linkage position of π-bridge moieties. HTM p-PCz with planar rigid structure, exhibits higher hole mobility and better film morphology compared with o-PCz and m-PCz. Notably, o-PCz, m-PCz, and p-PCz all show good dissolvability in non-halogenated solvent tetrahydrofuran (THF), making it possible to fabricate Cs2AgBiBr6 PSCs with full non-halogenated solution process. As a result, the dopant-free p-PCz based Cs2AgBiBr6 PSC device achieved an efficiency of 2.44 % with enhanced ambient and thermal stability. Hence, the successful development of dopant-free p-PCz would make a great contribution for efficient and stable lead-free Cs2AgBiBr6 PSCs with full non-halogenated solution process.

Improving the morphology of terrace-like transfer film to reduce wear rate of graphite/PTFE composites via filling low content silica

PurposeThe purpose of this paper is to fill low content of silica to improve the wear resistance of graphite/polytetrafluoroethylene (PTFE) composites, and to discuss the effect of low content of silica on the morphology of terrace-like transfer film.Design/methodology/approachThe tribological properties of silica/graphite/PTFE composites were tested by rotating pin-on-disk friction and wear tester, and the morphology of terrace-like transfer film was observed by 3D laser scanning microscope and quantitatively analyzed through the multi-Gaussian function linear combination model.FindingsThe results showed that adding 3 wt.% silica in graphite/PTFE composites can reduce the wear rate by 87%. More importantly, the morphology of terrace-like transfer film changed significantly after filling a small amount of silica, including the increase of the number of layers and the coverage rate of transfer film.Originality/valueThis work is of great significance for further understanding the transfer film and achieving its morphology control to optimize the wear of high performance PTFE composites.