Diamond is known as the hardest material with excellent properties including high thermal conductivity at ambient temperature. The ability of diamond to withstand high temperature allows the synthesis of doped diamond by introducing dopants into its structure. The introduced dopants are boron and nitrogen which act as either p-type or n-type, respectively. The doped diamond can act as a photocatalyst for the purpose of water treatment. In this study, different types of dopants introduced into the diamond lattice contributed to different photocatalytic activities. The characterization of Diamond Thin Film (DTF) was done using Scanning Electron Microscopy (SEM) and laser Raman spectrophotometer. Photocatalytic activities of DTF were investigated by degradation of methylene blue and methyl orange as models for the organic pollutants. The concentration of the organic pollutants degraded was analyzed using UV-Vis Spectrophotometer. As a result, n-type doped diamond showed better photocatalytic activities compared to p-type doped diamond with 725 mg/cm2 of methylene blue degraded over the period of 150 minutes. � 2020 Malaysian Institute of Chemistry. All rights reserved.

Dye-sensitized solar cell (DSSC) get recognized due to ability in converting solar energy into electricity by using organic and inorganic materials. Also, society's demand on the sustainable green environment makes DSSC as the best candidates for developing solar devices that flexible, low cost in production and environmental friendly. This research extracts natural sensitizers from avocado peel, blueberry and pomegranate that immersed in the ethanol. It will use in the fabrication of DSSC as a photons absorbent. Apart from that, the dyes are undergoing the characterization analysis using Fourier transform infrared spectroscopy (FTIR) and ultraviolet-visible spectroscopy (UV-Vis) to observe the optical properties. As a result, the graph from FTIR shows the pattern of absorbance of dyes. Whereas, UV-Vis graph provides maximum absorption peak as well as energy band gap information which are for avocado peel is 665 nm with 1.87 eV, blueberry is 540 nm with 2.30 eV and pomegranate has wavelength of 530 nm with 2.34 eV. In addition, the efficiency of natural sensitizers for avocado peel, blueberry and pomegranate are collect which are 48.25×10-12 %, 24.62×10-12 % and 15.75×10-12 % respectively.

EDLC was fabricated using hybrid solid polymer electrolyte from PVA-diapers and an activated carbon powder as electrode by using solution casting method. For comparison, four types of EDLC cells were constructed and tested. It was found that an EDLC with a PVA-diapers (60:40) polymer electrolyte exhibited much higher capacitance and longer cycle-life. The electrocapacitive properties of the supercapacitor (P50HD50, P60HD40, P70HD30 and P80HD20) were done using electrochemical impedance spectroscopy (EIS), cyclic voltammetry (CV), and galvanostatic charge discharge (GCD). Results from these analysis showed that P60HD40 cell had recorded excellent rate capability and highest Csp value of 179 F g-1 (EIS), 50 F g-1 (CV), 328 F g-1 (GCD) respectively. Futher, results from ESR (GCD) analysis showed that P60HD40 composition of PVA/H3PO4 liquid electroyte gave a lower value of 88.05 ? in the supercapacitor cell compared with another cells.

A random laser is an optical device that depends on multiple light scattering and gain to provide the feedback mechanism and light amplification respectively. A random laser is different with a regular laser where the regular laser needs a cavity for the feedback mechanism. Multiple light scattering can be considered detrimental in the regular laser but in the random laser, multiple light scattering can increase the path length of light in the active medium. This article studies the operation principles and characteristics of random lasers including the history and applications of the lasers. The theories of light scattering and light amplification are properly explained, followed by a discussion on characteristics of random lasers in terms of random laser emission, emission linewidth and coherence. Furthermore, the unique characteristics of random lasers can contribute to many applications leading to promising element for the future medical and biosensing development.

Thermoelectric leg made up semiconductor thermoelectric materials fabricated using various techniques. Types of thermoelectric leg is divided into single thermoelectric material or segmented thermoelectric material. The segmented thermoelectric material is the improvement of single thermoelectric material to produce a high performance of thermoelectric device. Previous study shows that electrical contact does give influence to the thermoelectric leg performance. A single thermoelectric leg usually used electrical contact as a connection to n- and p-type thermoelectric leg. The segmented thermoelectric leg also used similar electrical contact to couple the legs. However, there is an interfacial resistance occur in between segmented leg as it formed from different thermoelectric materials. In addition, there is a joining contact in between the segmented materials, which could give effect to the segmented thermoelectric leg. Thus, this study will discuss more on fabrication and the electrical contact in between segmented thermoelectric as the interface layer or joining technique for the segmented leg. A low electrical contact resistance is necessary to produce a high efficiencies thermoelectric device.

The growth of Sn:ZnO nanowires on a silicon substrate using a low thermal evaporation method is reported. A horizontal quartz tube with controlled supply of O2 gas were used to fabricate the samples where Zn and Sn metal powders were previously mixed and heated at 500°C. This allows the reactant vapours to deposit onto the substrate, which placed at a certain distance from the source materials. The samples were characterized using FESEM, EDX and HRTEM measurements. Randomly oriented nanowires were formed with varying dopant concentrations from 3 to 15 at%. It was observed that from FESEM images, when the dopant concentrations were increased, a hexagonal rod with a wire extended at its end was clearly formed and the best images of nanowires were shown at the highest concentration of 15 at% measuring between 26 to 35 nm and roughly 500 nm in diameter and length respectively. The doping process played an important role in order to alter the morphological properties of Sn:ZnO nanowires. Sn:ZnO nanowires have large potential in many applications such as in selected sensor technology including gaseous sensors, liquid sensors and others.

Plastic optical fiber sensing that coated with ZnO is developed and its interaction with ethanol and methanol solution is investigated. ZnO is synthesized sonochemically by using the bath type sonicator. The optical properties such as transmittance, absorbance and refractive index of ZnO is determined by using ultraviolet-visible (UV-Vis) spectrophotometer. Then, the cladding of plastic optical fiber (POF) is etched by using acetone solution, sand paper and deionized water. The unclad region is coated with ZnO and being immersed in the solution of ethanol and methanol in the range from 0 v/v% to 50 v/v%. The performance of ZnO coated POF is achieved by obtaining the output power value that transmitted via power meter. The result of this research is as the alcohol concentration increase, the output power value increase. Refractive index of ZnO is varied due to interaction between modified-cladding area and alcohol. Besides that, more light propagates inside the fiber when the sensor is tested under methanol solution compare to ethanol. Thus, the output power ratio increments as well as the sensor efficiency and shows the effectiveness of POF sensor to detect varied alcohol concentration. � 2020 Trans Tech Publications Ltd, Switzerland.