Film Processing Research Articles

Managing Solvent Complexes to Amplify Ripening Process by Covalent Interaction Driving Force Under External Field for Perovskite Photovoltaic

AbstractUp to now, post‐annealing is most commonly used to post treat the perovskite film to accelerate the ripening process. Nonetheless, the top‐down crystallization mechanism impedes the efficient desolvation of solvent complexes. Thus, residual solvent complexes tend to accumulate at the bottom of the film during the ripening process and deteriorate the device. Here, a new strategy with unique concept is promoted to amplify ripening process of perovskite film, in which a nematic thermotropic liquid crystal (LC) molecular is introduced to facilitate the conversion of solvent complexes by utilizing the liquid crystalline behavior under external field. Upon the concurrent application of thermal and force fields, the covalent interaction between LC and solvent complexes generates a driving force, which promotes upward migration of solvent complexes, thereby facilitating their engagement in the ripening process. In addition, the driving force under external fields assists the flattening of grain boundary grooves. Therefore, film quality is improved efficiently with amplified ripening process and adequately handled buried interface. Based on the positive effects, the devices achieve a champion efficiency of 25.24%, and sustained ≈75% of its initial efficiency level even after undergoing a damp heat test (85 °C/85% RH) for 1400 h.

Glass-based air-cavity with parylene C/spin-on- glass suspended film process for low loss microstrip antenna

Glass-based air-cavity with parylene C/spin-on- glass suspended film process for low loss microstrip antenna

Male jurors, male awards?

Film festivals are an added value to the film industry. The research of these events is growing, although it is limited in terms of jury committees, and less so in terms of gender bias. The initial assumption is that if juries are mainly made up of men, awards will be given mainly to men. In the context of Spain, this process is related to the fact that the most prominent jobs in the film process are still held by men (Arranz et al, 2007). This paper discusses the composition of the juries and the awards given at animation film festivals in Spain in 2022 as an approach to the study of juries from a gender perspective. The first results show that awards are predominantly made up of men (65%), despite the fact that, the juries are made up mostly of women (60.42%). This shows an imbalance: although there is more female presence on the juries, the majority of the awards continue to be given to men.

On sensitometric characteristics of screen/film systems for general radiography using manual film processing

On sensitometric characteristics of screen/film systems for general radiography using manual film processing

Additive-Driven Enhancement of Crystallization: Strategies and Prospects for Boosting Photoluminescence Quantum Yields in Halide Perovskite Films for Light-Emitting Diodes.

Halide perovskite light-emitting diodes (PeLEDs) hold great potential for applications in displays and lighting. To enhance the external quantum efficiency (EQE) of PeLEDs, it is crucial to boost the photoluminescence quantum yield (PLQY) of the perovskite films. The use of additives has emerged as a powerful chemical strategy to control the crystallization process in solution-processed perovskite films. The different types of additives that can be used reflect the various types of chemical interactions with the perovskite materials, influencing their crystallization process in various possible ways. Understanding the relationship between these chemical interactions and their impact on the crystallization process is a key step for designing emitters with improved PLQY and devices with superior EQE. Following the logic chain of additive-perovskite interactions, impacts on crystallization, and subsequent enhancement of PLQY and EQE, this review discusses how additives play a pivotal role in influencing the crystallization process to enhance the PLQY of the perovskite films. Furthermore, this assessment addresses the open challenges and outlines future prospects for the development of PeLEDs.

Enhanced the efficiency of carbon based perovskite solar cells via g-C3N4 as functional additives

The quality of perovskite layer plays an important role in the performance of perovskite solar cells. Various defects can arise during the crystal growth process of Perovskite thin film. However, by using additives. It is possible to effectively enhance crystallize and form high-quality perovskite films with improved morphology. g-C3N4, a carbon–nitrogen ring with delocalized π electrons and certain conductivity, facilitates the transport of charge carriers. When it is utilized as an additive in perovskite solar cells, g-C3N4 not only improves the quality and crystallinity of perovskite films, but also passivates defects. As a result of these improvements, the optimal efficiency for preparing carbon-based perovskite solar cells is 13.74 %. This represents a significant increase in photoelectric conversion efficiency from 10.39 % to 13.74 %, corresponding to a remarkable enhancement of 32.24 %. These findings provide valuable insights into the potential application of two-dimensional materials and carbon nitrogen ring for enhancing the performance of perovskite solar cells.

Innovative transparent silk-melamine formaldehyde film with enhanced corrosion resistance and high tensile strength for surface decoration

Transparent films with reduced light reflection and excellent wear resistance are crucial for applications that require anti-reflective properties without causing environmental harm. However, the preparation process of conventional anti-reflective films is relatively complicated. This paper proposes a simple method to prepare transparent film based on silk fabrics and melamine formaldehyde (MF) resins. The silk fabric's lattice structure serves as a frame, while the MF resin provides transparency and corrosion resistance as a functional filler. The resulting composite films, produced via hot pressing, exhibit excellent tensile strength (up to 617.4 MPa), anti-abrasion properties, and improved flexibility compared to pure MF films. Importantly, these films achieve a high transmittance (>85%) and a significant haze (ranging from 71.8% to 94.9%), with the silk fiber content primarily influencing scattering and haze levels while minimally affecting light transmittance. Additionally, the films demonstrate good pollution resistance and environmental friendliness, allowing contaminants to be removed after 5 h, and exhibit a TVOC emission of <0.1 mg/m3. These findings indicate that the developed composite films are promising candidates for wood surface decoration and applications that benefit from haze, such as anti-glare products. This work not only provides a straightforward method for creating flexible, anti-reflective transparent films utilizing natural fibers but also contributes to advancing sustainable practices in material design.

Optimization of the deposited Al2O3 thin film process by RS-ALD and edge passivation applications for half-solar cells

Optimization of the deposited Al2O3 thin film process by RS-ALD and edge passivation applications for half-solar cells

Raising the performances of copoly(ether-imide) films by structural design modulation towards energy storage applications

The present study aims to shed light onto the influence of structural design on the overall properties of a series of aliphatic–aromatic CN-based copoly(ether-imide)s, with emphasis on energy storage performance, with the support provided by selected benchmarks. To boost the energy storage capability of the free-standing films made therefrom, three molar ratios of a CN-aromatic hard segment and a Jeffamine-based soft component were used. Thus, through different chemical strategies and their synergism, the films morphology and their physico-chemical properties like wetting, optical, mechanical, thermal, dielectric and, particularly breakdown strength and energy storage were modulated. The results showed high thermal stability, single glass transition temperatures, good mechanical properties, and relative low dielectric constants of the copolymers. The absence of crystallization demonstrated the amorphous nature of the films due to the good interpenetration of soft and hard components, although some phase separations were observed in some copolymers with no clearly defined boundaries. Due to the balanced thermal stability, dielectric behavior, mechanical features, and film processing ability, these copoly(ether-imide)s display potential applications in high-temperature energy storage field, reaching breakdown strength and energy storage density values up to 459 kV/mm and 2.70 J/cm3, respectively.

Ultrafast Time-Domain Spectroscopy Reveals Coherent Vibronic Couplings upon Electronic Excitation in Crystalline Organic Thin Films.

The coherent coupling between electronic excitations and vibrational modes of molecules largely affects the optical and charge transport properties of organic semiconductors and molecular solids. To analyze these couplings by means of ultrafast spectroscopy, highly ordered crystalline films with large domains are particularly suitable because the domains can be addressed individually, hence allowing azimuthal polarization-resolved measurements. Impressive examples of this are highly ordered crystalline thin films of perfluoropentacene (PFP) molecules, which adopt different molecular orientations on different alkali halide substrates. Here, we report polarization-resolved time-domain vibrational spectroscopy with 10 fs time resolution and Raman spectroscopy of crystalline PFP thin films grown on NaF(100) and KCl(100) substrates. Coherent oscillations in the time-resolved spectra reveal vibronic coupling to a high-frequency, 25 fs, in-plane deformation mode that is insensitive to the optical polarization, while the coupling to a lower-frequency, 85 fs, out-of-plane ring bending mode depends significantly on the crystalline and molecular orientation. Comparison with calculated Raman spectra of isolated PFP molecules in vacuo supports this interpretation and indicates a dominant role of solid-state effects in the vibronic properties of these materials. Our results represent a first step toward uncovering the role of anisotropic vibronic couplings for singlet fission processes in crystalline molecular thin films.

Scalable all polymer dielectrics with self-assembled nanoscale multiboundary exhibiting superior high temperature capacitive performance

Polymers are key dielectric materials for energy storage capacitors in advanced electronics and electric power systems due to their high breakdown strengths, low loss, great reliability, lightweight, and low cost. However, their electric and dielectric performance deteriorates at elevated temperatures, making them unable to meet the rising demand for harsh-environment electronics such as electric vehicles, renewable energy, and electrified transportation. Here, we present an all-polymer nanostructured dielectric material that achieves a discharged energy density of 7.1 J/cm³ with a charge-discharge efficiency of 90% at 150°C, outperforming the existing dielectric polymers and representing more than a twofold improvement in discharged energy density compared with polyetherimide. The self-assembled nano-scale multiboundaries effectively impede the charge injection and excitation, leading to more than one order of magnitude lower leakage current density than the pristine polymer matrix PEI at high electric fields and elevated temperature. In addition, the film processing is simple, straightforward, and low cost, thus this all-polymer nanostructured dielectric material strategy is suitable for the mass production of dielectric polymer films for high-temperature capacitive energy storage.

Shaping the spatial intensity profiles of ultra-short lasers for enhanced selective thin film processing in the fabrication of silicon membrane filters

Shaping the spatial intensity profiles of ultra-short lasers for enhanced selective thin film processing in the fabrication of silicon membrane filters

Epitaxial Thin Film Growth on Recycled SrTiO3 Substrates Toward Sustainable Processing of Complex Oxides.

Complex oxide thin films cover a range of physical properties and multifunctionalities that are critical for logic, memory, and optical devices. Typically, the high-quality epitaxial growth of these complex oxide thin films requires single crystalline oxide substrates such as SrTiO3 (STO), MgO, LaAlO3, a-Al2O3, and many others. Recent successes in transferring these complex oxides as free-standing films not only offer great opportunities in integrating complex oxides on other devices, but also present enormous opportunities in recycling the deposited substrates after transfer for cost-effective and sustainable processing of complex oxide thin films. In this work, the surface modification effects introduced on the recycled STO are investigated, and their impacts on the microstructure and properties of subsequently grown epitaxial oxide thin films are assessed and compared with those grown on the pristine substrates. Detailed analyses using high-resolution scanning transmission electron microscopy and geometric phase analysis demonstrate distinct strain states on the surfaces of the recycled STO versus the pristine substrates, suggesting a pre-strain state in the recycled STO substrates due to the previous deposition layer. These findings offer opportunities in growing highly mismatched oxide films on the recycled STO substrates with enhanced physical properties. Specifically, yttrium iron garnet (Y3Fe5O12) films grown on recycled STO present different ferromagnetic responses compared to that on the pristine substrates, underscoring the effects of surface modification. The study demonstrates the feasibility of reuse and redeposition using recycled substrates. Via careful handling and preparation, high-quality epitaxial thin films can be grown on recycled substrates with comparable or even better structural and physical properties toward sustainable process of complex oxide devices.

Quick, Quick, Slow: Making Time for Sustainable Photography Practices in Contemporary Higher Education

AbstractAs environmental awareness grows, so do questions about the environmental impact of photography, in particular traditional film development and processing, which includes the use of plastics, gelatine and other environmentally harmful chemicals notwithstanding water usage and waste. Pioneering practice and research into sustainable alternatives to conventional processes has quickly established, supported by organisations such as The Sustainable Darkroom. Students in Higher Education are environmentally aware and prepared to take action to mitigate their impacts where possible. As such, there is a coalescence of perceptions within and beyond the classroom which asks to be addressed in the curriculum. This paper draws upon the research project Under a Green Light: A Darkroom for the Future which investigated how university darkroom practices can pivot toward more environmentally friendly methods. The paper describes the learning environment of the darkroom as a space of slowness, immersion and experimentation and the pedagogic value of this for photography students. The paper argues that incorporating environmental awareness into day‐to‐day teaching through systemic changes to process and practice, rather than through short term curriculum interventions, contributes to transformative learning experiences and promotes positive long‐term change.

Ultrathin membranes comprising polymers of intrinsic microporosity oligomers for high-performance organic solvent nanofiltration

Microporous organic polymers (MOPs) featuring chemically rigid backbones and permanent micropores are desirable for fabricating molecular selective membranes towards organics separation. However, coordinating facile film processing with high micropore persistence remains a challenge. In this paper, a low molecular weight polymers of intrinsic microporosity was rationally designed by precisely controlling the stoichiometric equilibrium of polymerization monomer. The polymers of intrinsic microporosity oligomers combine rigid and contorted structures with the aqueous solution processability, promoting the formation of 25-nm-thick polyacrylamide nanofilms with enhanced microporosity via support-free interfacial polymerization (SFIP). The resulting composite membranes have superior retention of small molecular solutes and high nonpolar and polar solvent permeances. Experiment and simulation results show that their excellent separation performance is due to substantially open and interconnected microporosity formed in the polymer networks based on rigid and contorted diamines as well as reduced film thickness. This study provides a new sight for using MOPs to construct high-microporosity membranes for precise and rapid molecular sieving.

Generation and Clearance of Superoxide Radicals at Buried Interfaces of Perovskites with Different Crystal Structures.

One of the most notorious issues with classic perovskite (MAPbI3) is its rapid degradation caused by generating superoxide radicals (O2 •-) on its surface under light and oxygen environments (light/O2). The differences in O2 •- generation rate and tolerance to O2 •- among perovskite with different structures are pending. For the first time it is validated through solid-electron paramagnetic resonance (EPR) that MAPbI3 and Cs0.175FA0.75MA0.075PbI3 (PVSK) crystals can generate O2 •- in an air atmosphere. The rapid degradation of perovskite buried interfaces caused by O2 •- dominates the nonexposed air aging process of SnO2-based perovskite film, and the degradation rate of MAPbI3 film is faster than that of PVSK film. The fullerene pyridine derivatives (C60OPD), which function as a buffer layer between SnO2 and PVSK to scavenge O2 •- and prevent degradation at the buried interface of the PVSK film, reduce the density of defect states, and accelerate the transmission of photogenerated electrons. The photoelectric conversion efficiency (PCE) of perovskite solar cells (PSCs) optimizes with C60OPD increased from 21.15% to 23.11% while significantly improving the stability in light/O2. This work reveals the hidden degradation of perovskite-buried interfaces caused by O2 •- and explores efficient ways for perovskite to resist O2 •-.

Black Phosphorus for Mid-Infrared Optoelectronics: Photophysics, Scalable Processing, and Device Applications.

High efficiency mid-infrared (λ = 3-8 μm) light emitters and photodetectors are pivotal for advancing next-generation optoelectronics. However, narrow-bandgap semiconductors face fundamental challenges such as pronounced nonradiative carrier recombination and thermally generated noise, which impede device performance. Recently, two-dimensional layered black phosphorus (BP) and its alloys have attracted substantial interest for mid-infrared device applications, demonstrating superior performance relative to conventional III-V and II-VI semiconductors with similar bandgaps. In this review, we discuss the optical properties of BP, contrasting these with those of covalent compounds. Owing to its inherently self-terminated surface structure and reduced nonradiative recombination, BP exhibits high performance in light emission and photodetection at room temperature. Furthermore, this review highlights recent advances in the large-area processing of BP thin films, paving the way for practical device applications and integration. Finally, we explore ongoing challenges and emerging opportunities in the utilization of BP for functional mid-infrared devices.

Controlling Polarization‐Induced Polaron Accumulation in OLEDs via Device Design

AbstractSpontaneous alignment of molecular electric dipole moments, known as spontaneous orientation polarization (SOP), is present in many organic electronic materials. The SOP‐induced field changes the internal voltage distribution within the device, altering polaron injection and accumulation. The important role of SOP in organic light‐emitting devices (OLEDs) has recently been emphasized with clear links between dipole alignment and device efficiency and operational lifetime. Prior work has thus sought to engineer SOP via changes in thin film composition or processing conditions. These efforts have generally been directed at the OLED electron transport layer, which can show strong SOP. This work takes a different approach, focusing instead on how changes in device architecture can be applied to tune the magnitude and dynamics of polaron accumulation in response to SOP. In this work, it is demonstrated that the introduction of SOP into the device emissive layer offers control over the spatial location of accumulation. In parallel, insertion of a spacer layer between the hole transport and emissive layers can be used to tune the polaron accumulation rate and density during device operation. Both of these architectural changes permit an increase in OLED efficiency and a pathway around the deleterious impact of SOP‐induced polaron accumulation.

Targeted synergistic chemical bonding strategy for Efficient and stable CsPbI3-based perovskite solar cells

Regulating the crystallization process of perovskite film and suppressing iodine-related defects hold significant importance in improving the efficiency and stability of CsPbI3-based perovskite solar cells (PSCs), thereby endowing their more potential for commercial applications. Herein, we introduced 2-Aminoethyl methylsulfone hydrochloride (AMS) into the perovskite precursor solution to establish targeted synergistic chemical bonding involving Lewis acid-base interactions and hydrogen bonds with CsPbI3 perovskite. We emphasize the importance of the DMAPbI3 intermediate phase for the crystal quality of CsPbI3 perovskite, and reveal that diminishing the size of Pb-I framework colloids in precursor solution can facilitate the formation of DMAPbI3 and optimize the crystallization process of CsPbI3 perovskite. Simultaneously, we demonstrate the generation of high valence iodine defects due to the photoinduction, and prove that constructing N-H···I hydrogen bond can effectively passivate the iodine-related defects. Consequently, the CsPbI3-based PSCs display an impressive power conversion efficiency of 19.59% along with markedly improved stability. Our finding presents a feasible strategy for managing perovskite crystallization and mitigating the defects-induced perovskite degradation, thus promoting the commercialization of CsPbI3-based PSCs.

Toward mechanical recyclability of high barrier food packaging films through filler incorporation on the EVOH layer

AbstractTo preserve food from moisture and oxygen, polymers, such as ethylene vinyl alcohol (EVOH) are used in multilayer structures to provide oxygen barrier, while low‐density polyethylene (LDPE) is used for a water vapor barrier. While this material combination is functionally ideal, it may not comply with the new packaging recycling guidelines. Some European markets have implemented rules that limit the weight percentage of EVOH in LDPE films. One way to increase recyclability is by reducing the amount of EVOH in the film structure while maintaining the packaging's oxygen barrier properties. To achieve this, it is necessary to improve the barrier properties of EVOH. With this objective in mind, this study evaluated the incorporation of nanoclays (NC), cellulose microcrystals (MCC), silicon dioxide nanoparticles (SiO2), and cellulose nanocrystals (CNC) into an EVOH matrix. The results indicate that NC and MCC facilitate a stable blown film extrusion process and have a better dispersion in the EVOH matrix. Based on this finding, three‐layer films (with an ABA configuration) consisting of LDPE (A) and EVOH (7 μm layer) with 0.5 or 1 wt.% MCC or NC (B) were produced to protect the EVOH from moisture and enable blown film processing. The oxygen transmission rate (OTR) values were lowest for 0.5 wt.% NC and 1 wt.% MCC incorporation. Although the films with micro and nanoparticles had increased haze, this did not affect the visibility of the packaged food.