NanoMITe Annual Symposium & Nanotechnology Malaysia Annual Symposium 2019

This Special Collection on Nanomaterials and Nanotechnology is devoted to the collection of articles from several different research fields and applications of nanotechnology which have been presented at the NanoMITe Annual Symposium and Nanotechnology Malaysia Annual Symposium (NanoSym2019) in Putrajaya during 21^st-22^nd August 2019. This Special Issue includes a selection of contributions among the papers presented at the Conference, with a peculiar emphasis on Energy, Wellness, Medical and Healthcare, Food and Agriculture and Electronics, Devices and Systems. All the published articles were peer-reviewed and selected on the base of technical novelty, scientific quality and impact in current trends of nanotechnology.

Among several submissions, eleven quality papers have been selected covering the topics of nanophotonics, functional nanomaterials and application of nanotechnology in energy, biomedical and environmental fields. The purpose of publishing this special edition is twofold, firstly to promote interest in nanomaterials and nanotechnology, and secondly to convey the states of the art of the technological developments in these areas that would give a tremendous impact on the future technology, product development and on the academic society so as to encourage the increasing the research and development in nanotechnology. Here, we present a brief overview of each published article of the Special Collection and topics covered, as a guideline for the readers encouraging and stimulating the interest in reading the whole articles.

Thanks to their wide direct bandgap tunability, III-nitride (III-N) compound semiconductors resulted fundamental in the development of blue light-emitting diodes that led to the so-called solid-state lighting revolution and blue laser diodes that are used for optical data storage. Beyond such conventional optoelectronic devices, 2D photonic crystal (PhC) cavities also cover an important role among the photonic devices. However, critical aspects related to their design and fabrication still need to be addressed. ¹ In this Special Collection, among the articles in the nanophotonics field, the article titled “Design of 2D GaN photonic crystal based on hole displacement for L3 cavity” by Nur Dalila Mohd Zamani et al. ² discusses about the 2D GaN Photonic Crystal that has the ability in controlling the propagation of light. The authors from university Kebangsaan Malaysia studied a 2D photonic crystal cavity side holes in GaN-AlN-sapphire layer that would improve the quality factor up to 22,500 at 152-nm cavity distance.

To the same nanophotonics field belongs also the paper “On the performance of polymer-inorganic perovskite oxide composite light-emitting diodes: The effect of perovskite SrTiO3 additives”, presented by Ummi Kalsom Noor Din et al. ³ also from University Kebangsaan Malaysia. It describes the performance of polymer-inorganic perovskite oxide composite light-emitting diodes based on polymer material mixed with perovskite SrTiO3 particles. The authors showed that the effect of perovskite SrTiO3 additives could improve the LED performances: the LED could obtain reduced turn-on voltage from 11.25 V to 1.8 V with increasing luminance intensity up to 10 times.

The third paper in nanophotonics, by Muhammad Ashraf Saiful Badri et al. ⁴ regards transparent conductive electrode made of exfoliated graphene-alkaline lignin-PEDOT: PSS (GL-PPS composite). This article, titled “Exfoliated graphene-alkaline lignin-PEDOT:PSS composite as a transparent conductive electrode”, discussed about the superior property of graphene when augmented in the composites. Graphene is found as an alternative material in improving the conductivity of the electrodes that significantly increased its conductivity up to 1030 times. Highly conductive and transparent GL-PPS composite thin film should find an extensive application in a wide range of fields, such as sensors, dye-sensitized solar cells, and organic photodetectors.

Although most of the selected papers are on materials research, here we have selected four scientific reports that specifically address nanomaterials for wide range of applications. The first paper “Formation of anisotropic gold nanoparticles on indium tin oxide substrates as a plasmonic sensing material” presented by Nur Liyana Razali, ⁵ deals about plasmonic sensing material. The study focuses on the anisotropy gold nanoparticles grown on solid substrates using seed-mediated growth. The study concludes that gold nanoparticles on solid surface are potentially useful as a sensing material for fungicide detection.

Recently great attention has been paid in exploring 2D layered materials, because of their unique layered structure, excellent optical/electrical/magnetic properties, and remarkable thermal and chemical stability, allowing them as potential candidates for next-generation high-performance nano-(opto)electronic devices. ⁶ The second paper in the area of nanomaterial deals with 2D materials and it is entitled “Effects of post-annealing on MoS2 thin films synthesized by multi-step chemical vapor deposition” presented by Muhammad Hilmi Johari. ⁷ This article reports the results of collaboration work between UKM Malaysia and NIMS Japan that focused on the fabrication process of MoS2 thin films. It was concluded that trough annealing process optimization, the optical and structure quality of MoS2 thin films can be increased.

Another interesting topic, the multiwalled carbon nanotubes (CNTs), unique one-dimensional carbon structures, is the object of the third selected paper in this field by P.Y. Foong. CNTs are advanced materials which may find different potential technological applications. Their functionalization allowing to address low dispersion and solubilization of CNTs in many solvents or polymers. ⁸ Moreover, CNTs present excellent mechanical properties, high aspect ratios, and large interfacial area allowing them promising reinforcements for the enhancement of mechanical properties of polymer matrix composites for applications to thermoplastics. The article by Phey Yee Foong et al. ⁹ from University Malaysia Perlis is titled “Feasibility study on microwave welding of thermoplastic using multiwalled carbon nanotubes as susceptor”. In this paper, multiwalled carbon nanotubes were proposed as the susceptor for the microwave welding of high-density polyethylene, considering multiwalled carbon nanotube is a good microwave absorber. As result of the article, the presence of a thick unwelded multi-walled carbon nanotubes layer at the joint interface is believed to cause the lowering of joint strength.

CNTs are also the object of the research presented in the last paper in the nanomaterials field authored by N. Ismail, which focuses on the investigation of CNTs for an improved welding process. Adding or mixing CNTs to different matrix materials may change and enhance the functionality in particular, the electrical properties of the formed CNTs nanocomposite. Considering these aspects, CNTs-based nanocomposites may find different potential technological applications. The article titled “Electrical resistivity of Sn–3.0Ag–0.5Cu solder joint with the incorporation of carbon nanotubes” is presented by Norliza Ismail. ¹⁰ The aim of the study was to replace the conventional solder bulk Sn3.0Ag5.0 to enhance the mechanical strength of the solder joint. Considering the results reported in the latter two articles, along with some recent and remarkable publications in the field, ¹¹ it seems that CNTs would be the potential materials in improving the welding and soldering process.

Moving to the energy field, there is an article presented by the researchers from University Teknologi Malaysia entitled “Conversion of jet biofuel range hydrocarbons from palm oil over zeolite hybrid catalyst” by Norsahika Mohd Basir et al. ¹² The authors present a study on the catalytic conversion of palm oil to produce jet biofuel. The results conclude that, the highest conversion of palm oil to hydrocarbon compounds can be achieved by zeolite Y-ZSM-5 hybrid catalyst (99%).

The last three papers are selected within the environmental and biomedical fields. The first paper published in the issue is related to surface plasmon resonance glucose sensor. In the last decades, surface plasmon resonance (SPR)-based sensors were receiving profound attention for their fast response and high accuracy to measure biomolecular interaction in real time and label-free environment. ¹³ The paper entitled “Multi-response optimization of chromium/gold-based nanofilm Kretschmann-based surface plasmon resonance glucose sensor using finite-difference time-domain and Taguchi method” reports the work of Najmiah Radiah Mohamad et al. ¹⁴ from Universiti Kebangsaan Malaysia, in which they showed the important role of the control and noise factors of Taguchi Method analysis in optimizing the process fabrication of Kretschmann-based Surface Plasmon Resonance sensors for improving the sensitivity of glucose sensor.

The second paper, entitled “Annealing temperature dependency of structural, optical and electrical characteristics of manganese-doped nickel oxide nanosheet array films for humidity sensing applications” deals with nickel oxide based humidity sensor. In this study conducted by Parimon et al., ¹⁵ researchers form University Teknologi MARA, University Malaysia Sabah, Institute of Science and Technology India, University Tun Hussein Onn Malaysia and Universiti Pendidikan Sultan Idris, Tanjung reports the successfully fabrication of Manganese-doped nickel oxide nanosheet array films. The films are annealed at different temperatures and subsequently studied the structural, optical and electrical properties of the samples and their humidity sensing performance as well. The authors found that the sensitivity of the humidity sensors reveals an ascending curve with increasing temperature. The highest sensitivity of 270 was obtained with annealing at 500^oC, with fast response and recovery times.

The third paper, “Identification of Leptospira in water by Fe-Pd-doped polyaniline nanocomposite thin film” presented by Huda Abdullah et al. ¹⁶ is the final contribution in the issues that discusses the Fe-Pd doped Polyaniline (PANI) Nanocomposite Thin Film. This paper reports the result of collaboration work between University Kebangsaan Malaysia and Institute of Teknologi Bandung. Here, the researchers present the report on the study of the potentials of polyaniline metal alloys nanocomposite thin films to be used for Leptospira bacteria detection in water.

The publication of these eleven scientific papers in this special collection would be also an opportunity for the scientific community to showcase the beauty of nanoworld and the great potential of nanotechnology in improving the existing technologies. We are aware that this special collection does not cover all the dimensions and aspects of nanotechnology needed to solve future technological challenges, but we hope that the readers can get at least a brief overview of the state of the art in the field, and enjoy to read this special selection written by experts in the field.

Azrul Azlan Hamzah

Institute of Microengineering and Nanoelectronics, Universiti Kebangsaan Malaysia

Guest Editor and Symposium Chair

Jumril Yunas

Institute of Microengineering and Nanoelectronics, Universiti Kebangsaan Malaysia

Guest Editor