The thermal instability of the perovskite layer hinders the commercialization of perovskite solar cells (PSCs). In this work, the effect of cold isostatic pressing (CIP) on the thermal stability of poly (methyl methacrylate) (PMMA) interlayer-encapsulated methylammonium lead iodide (MAPbI3) perovskite (PMMA-MAPbI3) film was investigated. The MAPbI3 perovskite film was prepared via a vacuum-assisted solution process (VASP) on the SnO2-coated FTO glass substrate. Following this, a PMMA interlayer was spin-coated on the MAPbI3 film. The PMMA-MAPbI3 film was then vacuum-sealed in a thermoplastic bag and pressed in a CIP chamber filled with silicone oil at a pressure of 5 MPa for 10 min. The CIP-treated film was then subjected to thermal stressing at 150 °C for 1–5 h to compare its thermal stability against a pristine film untreated with CIP. The CIP treatment densified the MAPbI3 perovskite grains and enhanced the interfacial bonding between the PMMA interlayer and the perovskite film. These enhancements contributed to the superior thermal stability of the CIP-treated film, as its morphology retained most of the MAPbI3 perovskite grains with minimal conversion to PbI2 nanorods, evidenced by the minimal evolution of the PbI2 XRD peak. The photoluminescence (PL) spectra of the CIP-treated film showed higher retention of the emission peak at 770 nm after 5 h of thermal stressing, signifying less thermal degradation than the untreated pristine film. Thus, CIP is demonstrated as a simple method that can enhance the thermal stability of the PMMA-MAPbI3 film.

This study focuses on developing a composite material using graphene oxide (GO) as a dielectric film. First, GO was mixed with DI water and dried to form a film. Then, a titanium (Ti) film was deposited on the film surface through electron beam evaporation. The composite comprising graphene oxide with the Ti metal film was then dispersed in water, to which cellulose nanofiber (CNF)—noted for its high mechanical strength, stability, and lightweight attributes—was added. The mixture was then re-layered with cellulose nanofibers by agitating it in water, and subsequently dried to form a composite film. The electrical properties of the material were studied using an LCR meter. The results show that pure GO has a dielectric constant of about 1600 at 1 kHz and a dielectric loss of about 25. After adding Ti, the Ti composite film maintained a dielectric constant above 1000 at 1 kHz while significantly reducing the dielectric loss to 1.5. Additionally, the resistivity of pure GO at 1 kHz is approximately 1200 Ω·m, whereas the Ti composite film with Ti and cellulose nanofibers shows a resistivity as high as 50 k Ω·m at 1 kHz. The relationship between dielectric strength and resistivity indicates that the Ti composite film can withstand higher voltages compared to pure GO, demonstrating a significant increase in dielectric strength. Compared to graphene oxide, the Ti composite film combines high dielectric constant, low dielectric loss, and increased dielectric strength.

In this study, we delve into the electromechanical characteristics of the CF monolayer using ab initio theory. The CF monolayer possesses flexible mechanical properties with relatively small elastic coefficients. Additionally, our findings reveal that the CF monolayer can sustain significant strains of up to 24% along the x-axis and 14% along the y-axis under tensile stress. The critical stresses corresponding to these strain values are 21.79 N/m and 17.46 N/m, respectively. Specifically, as the charge varies from 0.00 to -0.07 e/atom, there is an increase in the failure strain along the x-axis, from 24% at equilibrium to 30% at -0.07 e/atom. At equilibrium, the CF monolayer is identified as a direct semiconductor with a band gap of 3.21 eV. Despite charge doping, the monolayer CF retains its direct semiconductor properties. Notably, the energy band gap of the CF monolayer is dependent on charge doping and can be modified by about 10%. Furthermore, the electronic properties of the CF monolayer suggest its potential applications in spin-polarized electronics. Our results provide evidence of the applicability of the CF monolayer in electronic devices.

Due to its abundant availability and classification as biomass, the focus in renewable energy is currently centred on the use of Oil Palm Empty Fruit Bunches (OPEFB) as an alternative material for carbon production that can be used in many applications, one of which is batteries. The type of battery that is trying to use is a primary battery. The purpose of this study is to determine the effect of different concentrations of NaOH activation and immersion time on OPEFB activated carbon by analyzing the result of surface area, morphology, and electrical properties. The study found that 1 M NaOH concentration and an 18-hour immersion time were optimal, producing a surface area of 281.96 m²/g and a voltage of 0.785 V. These findings align with and contribute to existing research on biomass utilization in energy storage, demonstrating the potential of OPEFB-activated carbon in battery applications and highlighting the significance of further research in this area to enhance battery performance and scalability.

In this study, we investigate the formation and stability of non-topological spatial solitons in a cubic-quintic nonlinear medium integrated with photonic Moiré lattices. This particular type of nonlinearity can be observed in carbon disulfide. For applying the competing nonlinearities of cubicand quintic orders, this study mitigates the catastrophic collapse that typically occurs in cubic nonlinear media, thereby stabilizing the soliton beams. Our approach is to identify fundamental soliton solutions by employing the Squared Operator Method (SOM), with further stability validation performed through the Split-Step Fourier method. Moiré lattices formed by the superposition of two periodic sublattices with a twist angle, exhibit unique properties that can significantly modify the light propagation characteristics. The shift from commensurate to incommensurate Moiré configurations influences critically soliton localization and power, highlighting the potential of cubicquintic nonlinear media for advanced soliton control in photonic and communication applications.

A green and nontoxic ring-opening polymerization (ROP) of ε-caprolactone (CL) with appreciably high molecular weight (Mn), low dispersity (PDI), and high conversion was achieved using FeCl3 as a catalyst and Benzyl alcohol as an initiator in solvents at ambient temperature. Effects of Fe compounds, solvents, reaction temperature, catalyst concentration, and monomer concentration were investigated. The kinetic experiments reveal the controlled nature of using FeCl3 as a catalyst.

Silica-coating is one of simple methods to colloidally stabilize particles. The present work proposed a method for fabricating silica-coated ruby particles having a particle size of ca. 1 µm (ruby/SiO2) by a process based on a Stöber method. Two systems were examined, which were the systems using sodium hydroxide (NaOH) and aqueous ammonia (NH4OH) as base catalysts for a sol-gel reaction. In the NaOH system, not only the ruby/SiO2 particles with silica shells with a thickness of ca. 61 nm but also core-free SiO2 particles were produced by adding tetraethyl orthosilicate/ethanol solution and NaOH aqueous solution to ethanol dispersing the ruby particle powder. In the NH4OH system, it was demonstrated that it was possible to increase the shell thickness to 132 nm by repeating addition of TEOS and NH4OH to a mixture of ruby particles, water, and ethanol, which meant that it was found to vary the shell thickness. The ruby particles emitted luminescence even after the silica-coating, which found that the silica-coating did not deteriorate luminescence property of ruby particles.

Gamma-aminobutyric acid (GABA) is a crucial inhibitory neurotransmitter that decreases nervous system activity by inhibiting signal transmission across synapses. Imbalances in GABA levels are linked to neurological diseases. This study developed an electrochemical sensor for detecting GABA using a ZnO/GO composite as the sensing material. Graphene oxide (GO) was synthesized via a modified Hummer’s method, while nanoparticulate zinc oxide (ZnO) was prepared using a solution combustion method. X-ray diffraction and morphological analysis showed crumpled graphene oxide sheets stacked into multilayers and a single phase of wurtzite-structured ZnO with a crystallite size of 69.37 nm; however, the particles tended to cluster together into larger agglomerates, leading to a reduction in specific surface area. The ZnO/GO composite demonstrated synergistic electrocatalytic activity. Cyclic voltammetry in GABA solutions (0.1 to 1000 µM) revealed distinctive oxidation and reduction peaks with sensitivity ranged from 0.0184 to 0.6629 µA mM-1 mm-2. Despite moderate electrocatalytic performance, the ZnO/graphene oxide composite shows potential as a GABA sensing material.

In this study, the effects of processing temperatures of indium nanoparticles (In NPs) on the thermal conductivity (κ) of an organic phase change material (PCM) were investigated. 1-octadecanol (1-OD) also known as stearyl alcohol, with chemical formula C18H38O was selected as the organic PCM. Surface of Indium nanoparticles are functionalized with polyvinylpyrrolidone (PVP) to promote particles dispersion in 1-OD medium. Experimental analysis showed that for the In NPs/1-OD composite phase change material (CPCM) with a ~12 vol.% (~55 wt.%) of In NPs loading, specific melting latent heat (Lm) of the mixture is 103.1 J/g (~41.5% Lm,1-OD). This value is proportional to weight % loading of 1-OD (~45 wt.%) in the mixture. The κ versus processing temperature graph showed a turning point between 100 °C and 110 °C reaching a κ = 2.56 ± 0.07 W/mk at this processing temperature range. This is ~ 6.74-fold higher than κ of the 1-OD organic PCM matrix at 0.38 ± 0.01 W/mK. This is due to formation of high aspect ratio (length/diameter) conductive network pathways of In NPs in 1-OD organic PCM.

Compressor valve spring failure and rapid fracture occurred in a petrochemical enterprise. To find the cause of the failure, and to ensure the safe, stable, and continuous operation of the device, the failure of the spring is analyzed. In this paper, through the macro inspection, chemical composition analysis, metallographic analysis, scanning electron microscopy analysis, energy spectrum analysis, hardness analysis, and other tests, it is concluded that the main reason for the spring fracture is the fatigue fracture caused by unqualified materials. Suggestions are given to avoid similar problems in the future, and it is hoped that this failure analysis will provide valuable experience for similar failure problems in petrochemical enterprises.