Special Issue “Functional materials for energy applications”

Special Issue Editor

Guo-Ming Weng ,

* Correspondence: guoming.weng@yale.edu

Department of Chemical and Biomolecular Engineering, New York University, Brooklyn, NY, 11201, USA

Interests: energy storage technologies and functional materials.  

Special Issue Information

Aim and Scope: The problem of energy shortage is becoming increasingly serious with economic development and population explosion. Developing functional materials is the key to innovate energy science and technologies. Much efforts on this subject have been recently made, leading to substantial progress towards higher performance energy applications. To provide an essential guide to the development of these state-of-the-art functional materials for energy applications, we seek to present a related special issue in the platinum open access journal Materials International. In this issue, we will feature promising functional materials that have been used in various energy conversion and storage devices such as rechargeable batteries, flow batteries, fuel cells, carbon dioxide conversion systems and solar cells. This special issue could provide materials engineers, scientists and academics with the most recent progress in the rapid development of functional materials for energy applications. We kindly invite you to submit a manuscript(s) for this Special Issue. Full papers, communications, and reviews are all welcome.

Subtopics: Batteries; Fuel cells; Hydrogen energy; Carbon dioxide utilization; Solar energy conversion and photovoltaics.

Keywords: Functional Materials; Energy Conversion and Storage; Batteries; Fuel cells; Solar Cells.


Deadline for manuscript submissions: 30 November 2020


Manuscript Submission Information

All submissions to Materials International should be made at review@materials.international. The corresponding author has the responsibility of the manuscript during the submission and peer-reviewing process. Please do not forget to state in the email “Subject” the title of this special issue.

Submission Checklist

  1. read the Aim & Scope to gain an overview and assess if your manuscript is suitable for this journal;
  2. use the Microsoft Word Template to prepare your manuscript;
  3. make sure that issues about publication ethics, copyright, authorship, figure formats, data and references format have been appropriately considered;
  4. please try to cite only articles with DOI (digital object identifier); also add DOI for each reference;
  5. please add at least 10 references from the last 2 years (2018-2019) in order to highlight the novelty of your work;
  6. ensure that all authors have approved the content of the submitted manuscript.

Published papers

This special issue is now open for submission.


Planned papers


1) Thickness dependence of the optical parameters ofCdTethin films prepared by thermal evaporation

Shadia J. Ikhmayies

Correspondence: shadia_ikhmayies@yahoo.com

Abstract: Cadmium telloride (CdTe) thin films are of potential use in many optoelectronic and photovoltaic applications. So the optical parameters are important in determining its suitability for these uses. In this work CdTe thin films of thickness 50–300 nm are produced on glass substrates at ambient temperature by thermal evaporation. The transmittance measurements which are recorded at room temperature in the wavelength range 400-1100 nm are used to estimate the bandgap energy, refractive index, extinction coefficient. The dispersion parameters such as Eo (single-oscillator energy) and Ed (dispersive energy) of the deposited thin films are determined. Tailing in the forbidden gap is observed and found to follow the empirical Urbach rule. The influence of film thickness on all of these parameters is discussed.


2) Methodologies for Achieving One Dimension ZnO Nanostructures Potential for Solar Cells

Kelvii Wei Guo*

Department of Mechanical and Biomedical Engineering, City University of Hong Kong, 83 Tat Chee Avenue, Kowloon Tong, Kowloon, Hong Kong


Correspondence: kelviiguo@yahoo.com

Abstract: One-dimensional (1D) nanostructures are generally used to describe large aspect ratio rods, wires, belts and tubes. The 1D ZnO nanostructures have become the focus of research owing to its unique physical and technological significance in fabricating nanoscale devices. When the radial dimension of the 1D ZnO nanostructures decreases to some lengths (for example, the light wavelength, the mean of the free path of the phonon, Bohr radius, etc.) the effect of the quantum mechanics is definitely crucial. With the large ratio of the surface to volume ratio and the confinement of two dimensions, 1D ZnO nanostructures possess the captivating electronic, magnetic, and optical properties. Furthermore, 1D ZnO nanostructure’s large aspect ratio, an ideal candidate for the energy transport material, can conduct the quantum particles (photons, phonons, electrons) to improve the relevant technique applications. To date, many methods have been developed to synthesize 1D ZnO nanostructures. Therefore, methodologies for achieving 1D ZnO nanostructures are expressed and the relevant potential application for solar cells are also present to highlight the attractive property of 1D ZnO nanostructures.

Keywords: ZnO; One dimensional, Nanostructures; Chemical vapour transport and condensation (CVTC); Chemical vapour deposition (CVD); Metal chemical vapour deposition (MOCVD); Vapour-liquid-solid (VLS); Hydrothermal; Electrochemical; Solar cell.


3) Graphene Hybrid Electrodes to improve the Silicon Heterojunction Solar Cells technology

Ignacio Torres1, Susana María Fernández1, J. Javier Gandía1, Nieves González1, Rocío Barrio1, Álvaro Cordón2, Elena Taboada2, Israel Arnedo2,3

1 Renewable Energy Department. CIEMAT. Avda. Complutense 40, 28040, Madrid. Spain. 2Das-Nano, Polígono Industrial Talluntxe, Calle M-10, Tajonar, Navarra 31192, Spain.

3Departamento Ingeniería Eléctrica, Electrónica y de Comunicación, Universidad Pública de Navarra, 19, Campus Arrosadía, Pamplona 31006, Spain

Correspondence: Ignacio.torres@ciemat.es; susanamaria.fernandez@ciemat.es

Abstract: Simultaneous requirement of excellent transparency and low sheet resistance is essential for transparent conductive electrodes (TCE) used in solar cells. In this work, we evaluate a hybrid TCE consisting of an 80 nm-thick indium-tin oxide (ITO) layer and a chemical vapor deposited single layer graphene for its application to silicon heterojunction solar cells. The addition of a single graphene monolayer is shown to have a very beneficial effect on the solar cell performance. By adding the graphene monolayer, the sheet resistance of the ITO electrode is reduced without sacrificing its excellent optical properties. As consequence, the series resistance of the solar cell is significantly reduced from 2.30 Ω·cm2 to 1.65 Ω·cm2 and the solar cell’ fill factor is enhanced from 72.2% to 74.1%. The overall effect on the solar cell is an increase in efficiency from 15.8% to 16.1%, opening a new field of application for graphene.

Keywords: Graphene, Photovoltaic cells, Silicon Heterojunction, Terahertz time-domain spectroscopy, Transparent conductive electrodes


4) Optoelectronic features of chalcogenides VCu3Q4 (Q= Se, Te) for potential p-type transparent conducting materials: HSE06 approach

Souraya Goumri-Said

College of Science, Physics department, Alfaisal University, Riyadh 11533, Saudi Arabia

*Corresponding author’s email: sosaid@alfaisal.edu

Abstract: With a purpose to look for valuable material in optoelectronic industries that have many applications in optical properties at low cost, we have explored ternary chalcogenides. VCu3Q4 (Q= Se, Te) crystals have caused enhanced interest due to their potential as transparent materials. We used the state of art of density functional theory based on HSE06 screened hybrid functional as well as the gradient approximation (GGA) approach. Throughout the work, we performed a comparison of the electronic structure and the optical response for VCu3Te4 and VCu3Se4. The impact of the functional will be discussed first. We reported the indirect band gaps using various functionals for VCu3Se4 and VCu3Te4 respectively. A full depiction of the atom/orbitals have been observed across the densities of states (total and partial). Optical properties were computed, described and contrasted in order to assess the potential application of VCu3Q4 (Q= Te, Se) compounds. Consequently, the investigated compounds can be used in optoelectronics and p-type transparent conducting materials.

Keywords: p-type transparent conducting materials; chalcogenides; HSE06; optoelectronic properties.


5) Graphene-based Nanocomposites for Energy Harvesting/Storage Applications

aBibhu P. Swain, bRabina Bhujel,  bSadhna Rai,  aSumitra Nongthombam, aN. Aruna Devi,   aSayantan Sinha, aW. Ishwarchand,aP. Sushama Devi, aS. Nonganbi Chanu

aDepartment of Physics, National Institute of Technology, Langol, Imphal-795005, Manipur, India

bCentre for Materials Science and Nanotechnology, Sikkim Manipal Institute of Technology, Sikkim Manipal University, Rangpo, Sikkim, India

Correspondence: bibhuprasad.swain@gmail.com

Abstract: In the quest for novel energy storage and conversion solutions, supercapacitors, lithium-ion batteries, fuel cells, and solar cells have risen to eminence as an important and rapidly growing class of devices. These classes of energy storage and conversion devices need novel electrode materials to find broad applications in areas, which include hybrid vehicles, consumer electronics, medical electronics, power back-up, and load leveling. The research focus on the energy field has undergone immense growth in the past decade due to the emerging energy needs of modern society and ecological concerns. Nonetheless, graphene has gained considerable attention in recent years because of its fascinating properties such as atom-thick 2D structure, high electrical conductivity, large specific surface area, and excellent electrochemical stability. The unique characteristics of graphene enable it to be widely applied in energy storage and conversion platform. There are some trade-offs in graphene electrode materials applied in electrochemical energy storage and conversion devices. In the case of supercapacitors, highly porous graphene electrodes offer a large surface area and favor ion diffusion, resulting in a high gravimetric capacitance, but usually have a lower volumetric capacitance due to the relatively low packing density. Graphene finds importance in fuel cells, where to replace the conventional Pt-based materials that have been recycled as active electrode materials for both anodes and cathodes in fuel cells. Rising energy costs coupled with climate change are driving the increase in the use of energy storage and conversion technologies. Therefore, continuous advancements in the field of batteries, supercapacitors, fuel cells and solar cells along with significant reductions in cost, and this helps drive further adoption of such technologies.


6) Char formation mechanism of ammonium polyphosphate-melamine-expandable (APP-MEL-EG) intumescent fire retardant coating system using ceria and dolomite as additives for materials application

Joshua B. Zoleta1,3*, Gevelyn B. Itao1 , Vannie Joy T. Resabal1, Arnold A. Lubguban 1, Carlito B. Tabelin 2, Mayumi Ito 3, Naoki Hiroyoshi3

1 Department of Materials and Resources Engineering and Technology, College of Engineering and Technology, Mindanao State University–Iligan Institute of Technology, Iligan City, PHILIPPINES

2School of Minerals and Energy Resources Engineering, The University of New South Wales, Sydney, NSW 2052, AUSTRALIA

3Laboratory of Mineral Processing and Resources Recycling, Division of Sustainable Engineering, Hokkaido University, Sapporo, JAPAN

*Corresponding author:  joshua.zoleta@g.msuiit.edu.ph

Abstract: Bureau of Fire Protection (BFP) in the Philippines identified that power overloading and electrical glitches are the main sources of fire incidents in the country. Also, the role of BFP on strengthening its anti-fire campaign programs are limited only to provide fire inspections on electrical wirings and outlets, design of fire exits and the provisions of tangible halogen based fire retardants prior to the application and acquisition of building permits. In this case, reinforcements on fire safety components in materials infrastructures are lacking. Thus, to resolve this problem, this study develop and describes the effects of mineral fillers using ceria (CeO2)and dolomite (CaMg(CO3)2) on the char formation mechanism of an improved intumescent Flame retardant (IFR) coating for any functional material substrates application called ammonium polyphosphate-melamine-expandable graphite (APP-MEL-EG) system. The fire resistance of various formulations was evaluated using the standard horizontal Bunsen burner fire test. The best formulation identified to have highest fire resistance among the various formulations. Thermogravitmetric analysis (TGA) revealed various degradation reactions of the coating when subjected to 1000˚C at 10˚C/min heating rate. Observations by scanning electron microscopy with energy dispersive X-ray spectroscopy (SEM-EDX) demonstrated that optimum formulation had more homogeneous compacted char structures, which were predominantly composed of carbon (C), phosphorus (P), and oxygen (O). These three main components of the char were also found to be in various binding combination with other lighter elements like nitrogen (N) and hydrogen (H) as illustrated by the attenuated total reflectance Fourier transform infrared (ATR-FTIR) spectroscopy results. X-ray photoelectron spectroscopy (XPS) further suggest that polyethylene( [(CH2–C2H2–CH2)n-]) free radicals are abundant on the char surface for best formulations and the binding energy of this radical promoted the formation mechanism of aromatic carbon chains that enhanced the char’s thermal stability. This study revealed that the selection of appropriate fillers and combinations of flame-retardant ingredients could significantly change the morphology of the char layer and improve its thermal stability during fire exposure.

Keywords: Intumescent coating; CeO2; Dolomite; char formation; morphology; thermal stability; ammonium polyphosphate; melamine; expandable graphite