Indochina Applied Sciences

Comparation of Activated Carbon Electrodes from Natural Materials for Supercapacitor Applications in Energy Storage Systems

2026-06-04T19:37:39+07:00

This study presents the fabrication of activated carbon (AC) electrodes derived from natural materials for high-performance supercapacitor applications. Five types of biomass were used as carbon precursors: bamboo, rain tree wood, tiger grass, redwood, and litchi wood, respectively. The activated carbon was prepared via physical activation at 800 °C for 2 h. under an argon atmosphere. Structural, morphological, and elemental properties were characterized using X-ray diffraction (XRD), scanning electron microscopy (SEM), and energy dispersive X-ray spectroscopy (EDX). Electrochemical performance was evaluated through charge–discharge testing. The results reveal that the synthesized carbon exhibits an amorphous structure with characteristic peaks at (002) and (101) planes. SEM images show irregular porous structures with rough surfaces, contributing to high surface area. EDX analysis confirms high carbon purity (~99 wt%). The electrochemical measurements demonstrate a maximum specific capacitance of 50.50 F g⁻¹ at a constant current of 20 mA.

ZnO Nano/Microwires Ethanol Sensors: Role of TiO2 Additive

2026-07-13T14:06:33+07:00

ZnO nano/microwires (ZnO-NMWs) with varying TiO₂ additions (0 − 30 mol% TiO₂) were synthesized at temperatures ranging from 600 − 800°C for 12 h via a simple thermal oxidation reaction method in a normal atmosphere. The characterizations of the ZnO-NMWs were carried out, and it was found that the greatest quantity and longest ZnO-NMWs were observed at a heating temperature of 600°C. The heating temperature significantly influenced the quantity and dimensions of the ZnO-NMWs. The formation of the fcc-Zn₂TiO₄ phase was distinctly identified using XRD and Raman analyses, and an increased proportion of the Zn₂TiO₄ phase was achieved with elevated heating temperatures. The ZnO-NMWs, synthesized at 600°C with varying TiO₂ additives, were applied as ethanol sensors, and their ethanol sensing properties were investigated. An improvement of sensor response due to TiO₂ addition can be attributed to the reduction in electron concentration within the sensor, resulting from the formation of Zn₂TiO₄ phase. The NWs-TiZnO-30 sensor shows the highest sensing response of 9.30 at 360°C. Consequently, the incorporation of TiO₂ with ZnO-NMWs is a promising method for improving sensor response.

Optimization of Oxygen Flow for Tailoring the Properties of AZO Thin Films Deposited by DC Magnetron Sputtering

2026-04-08T09:56:39+07:00

This study reports on the preparation of aluminum-doped zinc oxide (AZO) thin films by DC magnetron sputtering using a Zn/Al target. The influence of reactive oxygen gas flow rate (10–100 sccm) was investigated while maintaining a constant Ar flow rate of 40 sccm. Films were deposited on both silicon and glass substrates, and further examined in their as-deposited state as well as after annealing at 400 °C in vacuum for 2 h. Morphological, structural, optical, and electrical properties were systematically characterized by FE-SEM, GI-XRD, UV–Vis–NIR spectroscopy, and Hall effect measurements, respectively. The results reveal that increasing O₂ flow rate affects the deposition rate while the films consistently exhibit a hexagonal wurtzite structure with preferred orientations along (002) and (103). The degree of crystallinity strongly depends on the O₂ concentration. The optical transmittance was found to be in the range of 76.10–84.79%, with estimated band gap energies between 3.32 and 3.52 eV. Notably, AZO thin films deposited at an O₂ flow rate of 20 sccm exhibited optimum electrical properties, including a resistivity of 4.0 × 10⁻³ Ω·cm, conductivity of 246 S/cm, carrier mobility of 5.83 cm²·V⁻¹·s⁻¹, and carrier concentration of 2.66 × 10²⁰ cm⁻³. These findings highlight the critical role of O₂ flow control in tailoring the physical properties of AZO thin films, underscoring their potential for various optoelectronic applications.