This study addresses the challenge of the scalable, cost-effective synthesis of high-quality turbostratic graphene from low-cost carbon sources, including biomass waste such as sugarcane leaves, bagasse, corncobs, and palm bunches, using the Direct Current Long Pulse Joule Heating (DC-LPJH) technique. By optimizing the carbonization process and blending biomass-derived carbon with carbon black and turbostratic graphene, the gram-scale production of turbostratic graphene was achieved in just a few seconds. The synthesis process involved applying an 18 kJ electrical energy pulse for 1.5 s, resulting in temperatures of approximately 3000 K that facilitated the transformation of the carbon atoms into well-ordered turbostratic graphene. Structural and morphological characterization via Raman spectroscopy revealed low-intensity or absent D bands, with a high I_2D/I_G ratio (~0.8–1.2), indicating monolayer turbostratic graphene formation. X-ray photoelectron spectroscopy (XPS) identified sp²-hybridized carbon and oxygenated functional groups, while NEXAFS spectroscopy confirmed the presence of graphitic features and both sp² and sp³ bonding states. Energy consumption calculations for the DC-LPJH process demonstrated approximately 10 kJ per gram, demonstrating the potential for cost-effective production. This work presents an efficient approach for producing high-quality turbostratic graphene from low-cost carbon sources, with applications in enhancing the properties of composites, polymers, and building materials.

Building 3D electrospun macrostructures and monitoring the biological activities inside them are challenging. In this study, 3D fibrous polycaprolactone (PCL) macrostructures were successfully fabricated using in-house 3D electrospinning. The main factors supporting the 3D self-assembled nanofiber fabrication are the H₃PO₄ additives, flow rate, and initial distance. The effects of solution concentration, solvent, H₃PO₄ concentration, flow rate, initial distance, voltage, and nozzle speed on the 3D macrostructures were examined. The optimal conditions of 4 mL/h flow rate, 4 cm initial nozzle-collector distance, 14 kV voltage, and 1 mm/s nozzle speed provided a rapid buildup of cylinder macrostructures with 6 cm of diameter, reaching a final height of 16.18 ± 2.58 mm and a wall thickness of 3.98 ± 1.01 mm on one perimeter with uniform diameter across different sections (1.40 ± 1.10 μm average). Oxygen plasma treatment with 30-50 W for 5 min significantly improved the hydrophilicity of the PCL macrostructures, proving a suitable scaffold for in vitro cell cultures. Additionally, 3D images obtained by synchrotron radiation X-ray tomographic microscopy (SRXTM) presented cell penetration and cell growth within the scaffolds. This breakthrough in 3D electrospinning surpasses current scaffold fabrication limitations, opening new possibilities in various fields.

BiFeO3 thin films were grown on Nb-doped SrTiO3 substrates using radio frequency magnetron sputtering and subsequently annealed to enhance their structural and ferroelectric properties. With piezoresponse force microscopy, with a width of ∼500 nm, thin films were successfully created by controlling polarization through direct current poling. Here, we found a significant reduction in polarization amplitude around 81% when the sample was irradiated under ultraviolet (UV). These results highlight the interplay between poling and UV-induced effects, which can control the ferroelectric states. This study will pave the way for promising applications in optoelectronic devices and non-volatile memory technologies.

The effect of oxygen on the electrical conductance and local structural properties of BiFeO3 (BFO) thin films on SiO2/Si substrates grown by RF magnetron sputtering was investigated. The conductivities of BFO were studied in a planar electrode with blue light irradiation. The BFO films grown with oxygen (BFO-O2) show a large conductivity increase, which is 12.66 times more than the BFO grown without oxygen (BFO), and the conductivity change is entirely caused by the BFO thin films. To explain the mechanism of increased electrical conductance, the local structure at the Fe K-edge was investigated by using time-resolved x-ray absorption spectroscopy (TRXAS). The applied voltage and blue light exposure affected the Fe–O bond, while the valence states of Fe atoms in BFO thin films remained unchanged. When the BFO films were irradiated, the bonding distance of the Fe–O bond was deviated, resulting in an oxygen vacancy. These findings imply that BFO thin films with more oxygen components exhibit higher electrical conductivity when exposed to blue light. The results of this research should pave the way for optoelectronic applications to modulate the electrical conductivity driven by oxygen and blue light.