Inorganic Films Research Articles

Single‐Component White Emissive Organic–Inorganic Hybrid Copper Halide Composite Films for Remote UV‐pumped White Light‐Emitting Diodes with High Color Rendering Index

AbstractLead‐free organic–inorganic metal halides (OIMHs) are highly desirable owing to their remarkable properties including low toxicity, structural diversity, high stability, and solution processability. Nevertheless, the development of their single‐component white emissive films remains a formidable challenge for remote white light‐emitting diodes (WLEDs) application. In this work, (C16H36N)2Cu2I4/polyvinylidene fluoride (PVDF) white emissive composite film is successfully fabricated through an in situ solvent evaporation crystallization process at room temperature. The elemental analysis and bonding between (C16H36N)2Cu2I4 and PVDF are demonstrated by X‐ray photoelectron spectroscopy (XPS) and Fourier transform infrared (FTIR) measurements. In addition, this composite film exhibits a broadband white emission with two peaks. Notably, the best photoluminescence quantum yields (PLQYs) of the PVDF based composite film reaches an impressive 96.7%. A (C16H36N)2Cu2I4/PVDF based remote UV‐pumped WLEDs with an impressive color rendering index of 95.5 is realized. Finally, the in situ fabrication method is expanded to fabricate (C16H36N)2Cu2I4/polyacrylonitrile (PAN) composite films, and we further realized their single component remote WLEDs.

LiF-induced in-situ engineering of a dense inorganic SEI for superior lithium storage in black phosphorus anode

Black phosphorus (BP) has been highly regarded as a favourable candidate for fast-charging anode applications owing to its high theoretical capacity and advantageous charge–discharge platform. However, BP faces challenges related to compromised electrochemical performance resulting from an unstable solid-electrolyte interface (SEI) and substantial volumetric expansion. This study proposes the engineering of an inorganic-dense SEI on the surface of BP-C through the strategic incorporation of lithium fluoride (LiF). The presence of LiF in the system preferentially promotes LiPF6 adsorption from the electrolyte, facilitating the in-situ formation of a lithium-enriched inorganic SEI film on the BP-C particulate surfaces. This strategic formation effectively mitigates subsequent electrolytic decomposition, accommodates volumetric expansion, and substantially improves the rate capability and cycling stability of the system. Consequently, the BP-LiF-C electrode demonstrates high initial coulombic efficiency of 86.8 % and maintains a steady capacity of 926.1 mAh g−1 over 700 cycles at 2000 mA g−1. Moreover, when paired with a LiFePO4 cathode, the full cell exhibits long cycling stability, retaining 98.6 % of its capacity after 500 cycles at 2000 mA g−1, and performs at high rate. Therefore, utilising LiF to modulate the interfacial architecture of BP-based electrode composites provide notable guidance to enhance energy storage systems.

Performance enhancement of inverted CsPbI2Br perovskite solar cells via butylammonium cation additive modification

Defects in all inorganic perovskite films currently limit the efficiency and long-term stability of perovskite solar cells (PSCs). In this study, we utilized the butylammonium cation as an additive to enhance the performance of PSCs. By incorporating butylammonium iodide, modifications in crystallization were achieved, resulting in high-quality CsPbI2Br perovskite films with larger grain sizes. As a result, the inverted PSCs with 1 mol percent additive exhibited an enhanced power conversion efficiency (PCE) of up to 13.0%, compared to the control PCE of 10.8%. The improvement can be primarily attributed to reduced trap states and suppressed charge recombination within the inverted PSCs. Furthermore, the hydrophobic nature of the additive noticeably improved the long-term stability of CsPbI2Br PSCs.

Fluorinated Polyimides incorporated with heterogeneous ZrO2@KNbO3 as multiple carrier transport barriers for Ultra-High energy storage

Advanced electronic devices and electrical power systems require high capacitor energy storage, fast charge–discharge speed and high temperature stability. Inorganic and organic nanocomposite film can achieve this great goal, but the major obstacle is the easy failure of breakdown in harsh environments. Here, we report a seires of inorganic–organic composite films prepared by blending a novel core–shell heterogeneous ZrO2@KNbO3 with fluorinated polyimide (FPI). The ZrO2@KNbO3 forms a distinctive sandwich-like microstructure, which delivers the p-n-p heterojunction interfaces. Multiple energy barriers, arisen at the interfaces, block the charge carrier transport. As a result, the 0.3 ZrO2@KN/FPI nanocomposite film achieves ultrahigh energy densities of 11.62 J cm−3 and 7.9 J cm−3 under electric fields of 665.6 MV m−1 and 550 MV m−1 at 25 °C and 150 °C, respectively, giving rise to a concurrent enhancement in breakdown strength and electrical displacement. Additionally, the 0.3 ZrO2@KN/FPI composite film exhibits superior charge–discharge cycling stability, enduring up to 100,000 cycles. This research provides a cutting-edge perspective to regulate the charge transport path, especially to inhibit charge transport at the interfaces, demonstrating a great potential for high-temperature dielectric capacitor applications.

Ionic Liquid-Assisted Strategy for Morphology Engineering of Inorganic Cesium-Based Perovskite Thin Films Toward High-Performance Solar Cells.

The wide bandgap CsPbI2Br perovskite materials have attracted significant attention due to their high thermal stability and compatibility with narrow bandgap materials in tandem devices. The performance of perovskite solar cells (PSCs) is highly dependent on the quality of the perovskite layer, which is governed by the crystallization process during solution processing. However, the crystallization dynamics of CsPbI2Br thin films remain less explored compared to conventional organic-inorganic perovskites. Achieving high-quality CsPbI2Br films with uniform morphology and large perovskite grains remains challenging with standard solution techniques. This study applies the ionic liquid (IL) [EMIM]+[PF6]- as an additive within the bulk CsPbI2Br absorber layer. Within our experimental regime, [EMIM]+[PF6]- accelerates the crystallization process while promoting the formation of large perovskite grains, a feature not commonly observed in previous studies. Our experimental results suggest that the IL acts as heterogeneous nucleation sites, and varying IL incorporation amount significantly impacts the morphology of CsPbI2Br perovskite films. Consistent UV-vis and photoluminescence (PL) red-shifts are observed in the IL-incorporated CsPbI2Br films, with X-ray diffraction (XRD) data projecting an influence on the perovskite crystal structure. These findings provide new insights into the role of ILs in controlling crystallization and morphology that have been minimally discussed in the literature. The incorporation of an optimized amount of [EMIM]+[PF6]- promotes the formation of highly crystalline perovskite thin films with excellent morphology, reducing defect density, enhancing carrier transport, and yielding large grain sizes. As a result, PSCs fabricated with [EMIM]+[PF6]- achieved a power conversion efficiency (PCE) of 17.11% (stabilized at 15.87%) and an open-circuit voltage (VOC) of 1.39 V, along with improved stability compared to control devices. This work provides a straightforward approach for producing high-quality CsPbI2Br thin films with high reproducibility, contributing valuable advancements to Cs-based PSCs.

Photothermal Infrared Radiometry and Thermoreflectance-Unique Strategy for Thermal Transport Characterization of Nanolayers.

Thermal transport properties for the isotropic and anisotropic characterization of nanolayers have been a significant gap in the research over the last decade. Multiple studies have been close to determining the thermal conductivity, diffusivity, and boundary resistance between the layers. The methods detailed in this work involve non-contact frequency domain pump-probe thermoreflectance (FDTR) and photothermal radiometry (PTR) methods for the ultraprecise determination of in-plane and cross-plane thermal transport properties. The motivation of one of the works is the advantage of the use of amplitude (TR signal) as one of the input parameters along with the phase for the determination of thermal parameters. In this article, we present a unique strategy for measuring the thermal transport parameters of thin films, including cross-plane thermal diffusivity, in-plane thermal conductivity, and thermal boundary resistance as a comprehensively reviewed article. The results obtained for organic and inorganic thin films are presented. Precise ranges for the thermal conductivity can be across confidence intervals for material measurements between 0.5 and 60 W/m-K for multiple nanolayers. The presented strategy is based on frequency-resolved methods, which, in contrast to time-resolved methods, make it possible to measure volumetric-specific heat. It is worth adding that the presented strategy allows for accurate (the signal in both methods depends on cross-plane thermal conductivity and thermal boundary resistance) and precise measurement.

A multilevel resistive switching memristor based on flexible organic–inorganic hybrid film with recognition function

Abstract Brain-inspired neuromorphic computing systems fueled the emergence of memristor-based artificial synapses, however, conventional silicon-based devices restricted their usage in the wearable field because of their difficulty in bending. To tackle the above challenge, a vertically structured flexible memristor with aluminum-based hydroquinone organic–inorganic hybrid film and Al2O3 as the functional layer, ITO and Pt as the bottom and top electrodes, and PET as the substrate has been developed utilizing molecular/atomic layer deposition to achieve a tradeoff between the resistive transition properties and the flexibility of memristors. The obtained devices combine stable resistive switching behavior and flexibility, showing high switching ratio of 103, better retention (up to 105 s) and endurance properties (up to 104 cycles), and robustness at radius of curvature of 4.5 mm after 104 bending cycles. Furthermore, the presence of multilevel resistive states in these devices ensures that the memristor can emulate synaptic properties such as paired-pulse facilitation, transition from short-term plasticity to long-term plasticity, long-term potentiation and depression, and spike-time-dependent plasticity. The resistive switching mechanism and the role of the bending state on the electrical performance of the device are explored. The fully connected artificial neural network based on the memristor can achieve a recognition accuracy of 90.2% for handwritten digits after training and learning. Flexible memristor will bring feasible advances to the integration of neuromorphic computing and wearable functionality.

Co3O4-Induced Na2CO3-Rich SEI Film on an FeNCN Electrode with Promoted Loading and High-Rate Na-Storage Performance.

Iron carbodiimide (FeNCN) often suffers from unstable interfacial structure with an unexpected failure of Na-ion storage performance. In this work, Co3O4 particles were deposited on the surface of FeNCN. This Co3O4 nanolayer led to the formation of a Na2CO3-rich inorganic component SEI film to enhance the stability of a promoted-loading FeNCN electrode interface with fast Na+ migration pathway. Benefitting from this strategy, the FeNCN electrode could present a capacity retention rate of 99.95% per cycle after 1500 cycles at 1 A g-1. The design of interfacial structure in a promoted-loading electrode could be a reference for stable and high-rate performance of carbodiimide-based materials.

High-Voltage Stable Perovskite Light-Emitting Diodes Enabled by an Optoelectric-Tunable Sandwiched Nanostructure.

While metal halide light-emitting diodes (PeLEDs) with unique optoelectronic properties are promising emitters for next-generation displays, their performance degrades rapidly due to severe ion migration during continuous operation, especially at high voltages. Here, we realize highly stable PeLEDs by designing inorganic dielectric/perovskite semiconductor emitter/organic dielectric sandwiched nanostructures to mitigate ion migration via regulating the electric field distribution. The bilateral cesium carbonate (Cs2CO3) and tetraoctylammonium bromide (TOAB) thin interlayers can not only largely reduce the voltage imposed on the perovskite layer by serving as series resistors and, thus, mitigate the ion migration but also regulate the charge carrier transfer to improve the radiative recombination efficiency. In addition, the underneath inorganic Cs2CO3 film also provides more heterogeneous nucleation sites for growing high-crystallinity perovskite crystals, while the atop TOAB with bifunctional groups (organic amino and Br- ions) refines the morphology and enhances the optical properties of the perovskite film. As a result, efficient and stable green PeLEDs based on such an optoelectric-tunable nanostructure exhibit extremely slow efficiency decay as the applied voltage increases, and the external quantum efficiencies were maintained over 10% at a high bias up to 20 V.

Flame-Resistant Inorganic Films by Self-Assembly of Clay Nanotubes and their Conversion to Geopolymer for CO2 Capture.

Self-assembling of very long natural clay nanotubes represents a powerful strategy to fabricate thermo-stable inorganic thin films suitable for environmental applications. In this work, self-standing films with variable thicknesses (from 60 to 300µm) are prepared by the entanglement of 20-30µm length Patch halloysite clay nanotubes (PT_Hal), which interconnect into fibrosus structures. The thickness of the films is crucial to confer specific properties like transparency, mechanical resistance, and water uptake. Despite its completely inorganic composition, the thickest nanoclay film possesses elasticity comparable with polymeric materials as evidenced by its Young's modulus (ca. 1710MPa). All PT_Hal-based films are fire resistant and stable under high temperature conditions preventing flame propagation. After their direct flame exposure, produced films do not show neither deterioration effects nor macroscopic alterations. PT_Hal films are employed as precursors for the development of functional materials by alkaline activation and thermal treatment, which generate highly porous geopolymers or ceramics with a compact morphology. Due to its high porosity, geopolymer can be promising for CO2 capture. As compared to the corresponding inorganic film, the CO2 adsorption efficiency is doubled for the halloysite geopolymeric materials highlighting their potential use as a sorbent.

Effect of organic spacer cations on the stability of organic–inorganic hybrid perovskite thin film transistors

Effect of organic spacer cations on the stability of organic–inorganic hybrid perovskite thin film transistors

From molecules to materials: SHG-CD microscopy of structured chiral films

The interplay between molecular and structural chirality as a function of local sample morphology determines the nonlinear optical properties of many organic and hybrid organic–inorganic thin films. Here, we used second harmonic generation circular dichroism (SHG-CD) microscopy of thin molecular films of 1,1′-bi-2-naphthol (R-BINOL) as a research model. Our results show that the SHG signal measured at frequencies close to the electronic transition of BINOL molecules is resonantly enhanced by more than an order of magnitude compared to the non-resonant case. The extracted resonant SHG-CD signal is dominated by the chiral response of the molecule. In contrast, structural chirality determines the non-resonant SHG-CD images. We see clear evidence that the interference of the SHG signals caused by the molecular and structural chirality can lead to a decrease in the overall SHG intensity when both SHG signals are out of phase. These findings highlight the intricate relationship between molecular and structural chirality on the one hand and structural morphology on the other hand and pave the way for novel applications by exploiting the chiroptic properties of thin films.

Flexible Porous Ag2Se Films: From Freestanding Inorganic Films to Inorganic‐Network/Organic‐Skeleton Thermoelectric Generators

AbstractSilver selenide (Ag2Se) flexible films are promising near‐room‐temperature thermoelectric candidates for low‐grade heat harvesting. However, existing Ag2Se films are generally attached on substrates, which impedes further flexibility improvement of the films and constrains the scenarios of applications. Here a cost‐effective and scalable strategy is presented, which combines screen printing and annealing, for synthesizing freestanding Ag2Se inorganic films with different densities of pores. High‐density pores and thin thickness endow the films with high flexibility, while films with low‐density pores obtain higher power factor. Furthermore, by utilizing the porous microstructure, a composite structure consisting of a Ag2Se conductive network and an organic polydimethylsiloxane (PDMS) skeleton is fabricated, which further improves films’ stability under bending and torsion. Finally, a flexible thermoelectric generator comprising five Ag2Se/PDMS legs and encapsulated PDMS outputs a voltage of 20.2 mV and a maximum power of 810 nW (the corresponding power density is 5.4 W m−2) at a temperature difference of 30 K, verifying potential application at near room temperature. This work offers a useful paradigm for fabricating substrate‐free Ag2Se porous films with high flexibility for near‐room‐temperature thermoelectric applications.

Through thickness anisotropy in all inorganic perovskite thin films via two-step synthesis: implications for voltaic devices.

Cesium-lead-bromide (CsPbBr3) has shown promise in thin film photovoltaics due to its desirable energy band gap, charge mobility and chemical and thermal stability. The low solubility of its single crystal in organic solvents has driven development of the two-step spin-coating technique. In this work, precursor solutions of different PbBr2 and CsBr concentrations were spin-coated and investigated via Photoelectron Spectroscopy. The properties of the CsxPbyBrz film in cross-section demonstrate this method leads to varying stoichiometries, work functions and band gaps through the thickness. This anisotropy of the perovskite thickness has ramifications for design of photovoltaic devices.

Inorganic film materials for flexible electronics: A brief overview, properties, and applications

AbstractThe field of flexible electronics has experienced remarkable expansion in response to the escalating demand for lightweight, bendable, and multifunctional electronic devices. As the world increasingly integrates electronics seamlessly into everyday life, the importance of flexible electronics becomes more apparent. While existing reviews have examined materials used in flexible devices, they often overly focus on specific materials or provide broad generalizations about different material types. Thus, this review offers a concise yet comprehensive overview of critical inorganic film materials crucial to the advancement of flexible and wearable devices. Each material is introduced with a succinct overview of its structure and production processes. This review elucidates their unique characteristics and potential applications in flexible electronics by comparing their mechanical, electrical, and thermal properties. This review is a valuable resource for researchers entering this emerging field of flexible electronics, providing a concise yet comprehensive insight and property comparisons. Accompanied by figures illustrating material structures and applications, readers will gain access to summarized discussions. Comparative figures of material properties will enhance comprehension. Additionally, discussions on diverse applications will offer insight into their versatility across various fields of flexible electronics.

Five Volts Lithium Batteries with Advanced Carbonate-Based Electrolytes: A Rational Design via a Trio-Functional Addon Materials.

Lithium metal batteries paired with high-voltage LiNi0.5Mn1.5O4 (LNMO) cathodes are a promising energy storage source for achieving enhanced high energy density. Forming durable and robust solid-electrolyte interphase (SEI) and cathode-electrolyte interface (CEI) and the ability to withstand oxidation at high potentials are essential for long-lasting performance. Herein, advanced electrolytes are designed via trio-functional additives to carbonate-based electrolytes for 5V Li||LNMO and graphite||LNMO cells achieving 88.3% capacity retention after 500 charge-discharge cycles. Theoretical calculations reveal that adding adiponitrile facilitates the presence of more hierarchical DFOB- and PF6 - dual anion structure in the solvation sheath, leading to a faster de-solvation of the Li cation. By combining both fluorine and nitrile additives, an efficient synergistic effect is obtained, generating robust thin inorganic SEI and CEI films, respectively. These films enhance microstructural stability; Li dendrite growth on the Li electrode is being suppressed at the anode side and transition-metals dissolution from the cathode is being mitigated, as evidenced by cryo-transmission electron microscopy and synchrotron studies.

Significantly enhanced energy storage performance in multi-layer polyimide films with nano dielectric layer

Polymer-based composites with multilayer structure were emerging as an effective way to solve the contradiction between high breakdown strength and large permittivity in past decades. However, the incorporating layers in conventional multilayer composite films are usually inorganic thick films, which is not beneficial for the retention of excellent mechanical properties of the polymer matrix. In this work, the multilayer films consisting of micrometer polyimide (PI) and nanoscale TiO2 layer were prepared by spin-coating and atomic layer deposition (ALD), respectively. Carrier migration in PI-TiO2 multilayer films was hindered effectively by the interfacial barrier, as indicated by the results of the Pulsed Electro-Acoustic (PEA) tests. Compared to pure PI, both the permittivity, dielectric loss and breakdown strength were optimized in the PI-TiO2 multilayer films. A satisfactory discharge energy density of 6.77 J cm−3 (efficiency >90 %) was obtained in the multilayer films, which is about 5 times higher than that of pure PI. The strategy of constructing heterogeneous interfaces by incorporated nanoscale TiO2 layers is promising for designing high performance capacitors in practical application.

Molecular Insight into CO2 Improving Oil Mobility in Shale Inorganic Nanopores Containing Water Films.

CO2 injection into shale reservoirs has been recognized as one of the most promising techniques for enhanced oil recovery and carbon capture, utilization, and storage. However, the omnipresent nanopores and the water films formed near the pore walls affect the understanding of mechanisms of CO2 regulating crude oil mobility in shale nanopores. In this work, we employ molecular dynamics simulations to study the occurrence and flow of CO2 and octane (nC8) mixtures in quartz nanopores containing water films, to illustrate the impact mechanisms of CO2 on nC8 mobility. The results indicate that nC8 exists between water films, and CO2 is mainly miscible with nC8 in the pore center, and a small portion of it accumulates at the interface between nC8 and the water film. CO2 significantly decreases the apparent viscosity of nC8 in both the bulk nC8 region and the nC8-water interface region, improving nC8 fluidity. As the percentage of CO2 in the CO2 and nC8 mixtures increases from 0 to 50%, the mean flow velocities of nC8 in the bulk phase region and the nC8-water interface region increase by 92.85 and 60.64%, respectively. Three major microscopic mechanisms of CO2 improving nC8 fluidity in quartz nanopores with water films are summarized: (i) CO2 reduces friction between nC8 and the water film by increasing the angle between nC8 molecules and the plane of the water film; (ii) CO2 widens the distance between nC8 molecules, causing the volume expansion of nC8 and its viscosity reduction; (iii) CO2 significantly increases the most probable and average velocities of nC8 molecules, thus improving their mobility. Our results enhance the comprehension of how CO2 facilitates oil flow in water-bearing shale reservoirs and the exploitation of unconventional oil resources.

Hybrid Molecular Layer Deposition of Molybdenum-Aminates as Hydrogen Evolution Reaction Electrocatalysts

The development of high-performance hydrogen evolution reaction (HER) electrocatalysts from noble metal-free materials is critical to achieving cost-effective water splitting and ultimately realizing affordable hydrogen based on renewable energy. Compounds based on earth-abundant transition metals have been the subject of great research interest for this purpose, with metal nitrides gaining recent attention due to their high conductivity and corrosion resistance. Molybdenum nitride-based electrocatalysts have shown particular promise, with many of the best reported activities occurring in composite systems wherein crystalline MoNx domains are embedded in an amorphous N-doped carbon matrix. The present work demonstrates the formation of such uniquely active morphologies in films deposited by organic-inorganic hybrid molecular layer deposition (MLD).Hybrid MLD is a hybridization of other well-established layer-by-layer deposition techniques – namely atomic layer deposition (used to deposit inorganic films) and purely organic MLD. This family of techniques involves the cyclical exposure of a growth surface to alternating vapor-phase chemical precursors which react in a self-limiting fashion to saturate available surface sites, offering atomic- and molecular-level control over the resulting films. This presentation will introduce the successful development of hybrid MLD deposition procedures for new Mo-aminate materials using Mo(CO)6 as a Mo precursor and various amine precursors, including ethylenediamine, p-phenylenediamine, and tris(2-aminoethyl)amine.We will describe how the molecular level of control offered by this technique enables tunable variations in film composition and structure, lending unique insights into how the local bonding environment of Mo active sites affects their catalytic properties towards HER. Increased nitrogen loading in the MLD films was shown to decrease the overpotentials required to drive HER in acidic media (0.5 M H2SO4) and improve film stability. Catalysts with N/Mo ratios above 2 demonstrated the best performance, with overpotentials lower than 400 mV at -10 mA/cm2. By incorporating organic components in the MLD films, it was possible to induce desirable morphological changes in the catalytic material – notably including the development of increased active site density – simply through initial exposure to HER testing conditions. The choice of organic precursor affected the rate and extent of these changes through structural effects like crosslinking and crystallinity, which led to more stable catalysts, slowed the rate of morphological changes, and impacted final film structure.

Interfacial modulation by ammonium salts in hole transport layer free CsPbBr3 solar cells with fill factor over 86 %

CsPbBr3-based perovskite solar cells (PSCs) are potential candidates for the next-generation photovoltaic technology owing to their robust stability. Nevertheless, the inorganic CsPbBr3 PSCs using carbon electrode without hole transport layer usually suffer from severe non-radiative recombination loss at CsPbBr3/Carbon interfaces, thereby generating low fill factors (FFs) and further limiting the improvement of power conversion efficiencies (PCEs). To circumvent this issue, we proposed a universal interfacial engineering strategy to reduce the trap-assisted recombination through depositing butylammonium bromide (BABr) on the surface of CsPbBr3 films, which would enhance the FF and subsequent PCE of inorganic PSCs. The experimental results illustrate that the BABr modification could not only improve the morphology and phase purity of the inorganic perovskite films, but also adjust the energy level alignment between the CsPbBr3 layer and carbon electrode. After the optimization of BABr concentrations, we fabricated the BABr-modified device delivered an impressive PCE of 9.86 % with an extreme high FF over 86 %, which is one of the highest values achieved among the reported inorganic PSCs. Moreover, the PCE of unsealed CsPbBr3 device with BABr exhibited almost no attenuation after 90 days storage under the ambient atmosphere.