Abdul Kariem Arof

By Muhammad Ammar Mingsukang, Mohd Hamdi Buraidah and Abdul Kariem Arof

The need to produce renewable energy with low production cost is indispensable in making the dream of avoiding undue reliance on non-renewable energy a reality. The emergence of a third-generation photovoltaic technology that is still in the infant stage gives hope for such a dream. Solar cells sensitized by dyes, quantum dots and perovskites are considered to be third-generation technological devices. This research focuses on the development of suitable and reliable sensitizers to widen electromagnetic (EM) wave absorption and to ensure stability of the photovoltaic system. This article discusses the basic principles and the progress in sensitized photovoltaics.

Part of the book: Nanostructured Solar Cells

By Zurina Osman and Abdul Kariem Arof

Chitin and chitosan are widely found in nature. Chitin can be obtained from fungi and in the lower animals. Chitosan can be derived from chitin. The process of chitosan derivation from chitin is called deacetylation. Chitosan is non-toxic, odourless, biocompatible in animal tissues and enzymatically biodegradable. It has found many applications in the fields of cosmetics, wound healing, dietetics and waste-water treatment. Chitosan holds many promising potentials, but its inability to dissolve in many of the common solvents has restricted its application. Hence, chitosan has been modified, and there are now many derivatives of chitosan. In the current chapter, we discuss chitosan and only the phthaloyl chitosan derivative. Their applications in several electrochemical devices are also discussed.

Part of the book: Biological Activities and Application of Marine Polysaccharides

By Siti Nor Farhana Yusuf, Rosiyah Yahya and Abdul Kariem Arof

Ionic liquids (ILs) are molten salts at ambient temperature and consist of poorly coordinating cations and anions. They have good electrical conductivity with a wide voltage window and high thermal stability, but negligible vapor pressure. ILs can enhance ionic conductivity when added to polymer electrolytes. Conductivity enhancement is due to the additional ions supplied by the IL, the plasticizing nature of the IL and the low viscosity that facilitates ion mobility. The plasticizing nature of ILs softens the polymer chain giving rise to easier polymer segmental motion. Increase in polymer segmental motion implies that IL can increase amorphousness of a polymer electrolyte (PE). This article discusses the involvement of ionic liquid as electrolytes in selected devices, namely dye sensitized photovoltaics, batteries, fuel cells and supercapacitors.

Part of the book: Ionic Liquids

By Abdul Kariem Arof and Teo Li Ping

Chlorophyll, being the most abundant pigment that commonly found in plants, bacteria, bryophytes and algae, plays a vital role in photosynthesis. Chlorophylls are natural pigments and therefore safe, environmental friendly, easily available and cheap. Chlorophyll has been experimented to function as a photosensitizer in dye-sensitized solar cells (DSSCs) as DSSCs mimic the photosynthesis process in green plants. DSSC was first developed by Gratzel in 1991 and since then has gained tremendous attention as its fabrication is cheap and easy. A DSSC basically comprises a semiconductor that has been soaked in sensitizing dye (chlorophyll), a counter electrode, and an electrolyte containing a redox mediator. The dye absorbs light, which is transformed into electricity. Chlorophyll can be extracted from the leaves of pomegranate, bougainvillea, papaya, Pandanus amaryllifolius, spinach, green grasses, seaweeds, algae and bryophytes. Chlorophyll from these sources has been studied as possible photosensitizers for DSSCs. Most researches done in chlorophyll DSSC use the extracted natural pigments. The type of solvent and pH of the dye solution will also affect the stability of chlorophyll and subsequently the performance of the DSSCs. This chapter will present an inexhaustive overview on DSSCs using chlorophyll as dye.

Part of the book: Chlorophyll

By Li Na Sim and Abdul Kariem Arof

Elastomers refer to natural or synthetic amorphous polymers which exhibit elastic properties of rubber. Elastomers are able to deform under stress and return to its original state upon removal of stress. As elastomers exhibit glass transition temperatures (Tg) below room temperature (r.t.), elastomers are soft and rubbery at r.t, and segmental motion exists. Elastomers, which contain polar atoms, such as oxygen (O), fluorine (F) and nitrogen (N), can be suitably employed as matrices in polymer electrolytes (PEs). The electronegative atoms serve as electron donors and are able to coordinate with cations from inorganic salts to form a complex. Among elastomers that have been employed in PEs include modified and copolymerised polyisoprene or natural rubber, polyurethanes, and polysiloxanes. This chapter focuses on the progress of natural rubber and its derivatives in the field of polymer electrolytes, and discussesc their interactions with other components of the PEs and ion conduction. Area percentage of ionic species, as well as ion transport parameters, such as number density, mobility and diffusion coefficient of lithium ions as obtained from deconvolution of infrared (IR) spectra, are also discussed in this book chapter.

Part of the book: Elastomers

By Abdul Kariem Bin Mohd Arof and Mohd Hamdi Bin Ali Buraidah

Two types of third-generation photovoltaic (PV) cells are sensitized by dyes and quantum dots (QDs), the former being dye-sensitized solar cell abbreviated as DSSC. The second is the quantum dot-sensitized solar cell or QDSSC. There are three main components in DSSC and QDSSC. The photoanode is the component where the light is being absorbed either by molecules of the dye or by the quantum dots (QDs). The sensitizers are attached on the semiconductor (normally TiO2) surface. The conduction band (CB) of the semiconducting material should be at a level lower than the lowest unoccupied molecular orbital (LUMO) of the dye molecules or CB of QDs for fast electron transfer. Incorporation of plasmonic materials into the photoanode can increase light absorption efficiency by surface plasmon effect and thus improve the efficiency of the DSSCs and QDSSCs. Plasmonic materials that have been employed include gold (Au), silver (Ag) and aluminum (Al) nanoparticles (NPs). Different NPs exhibit different effects on the cell parameters. Covering the NPs with a thin wide bandgap semiconducting film is necessary to protect the plasmonic NP materials from the corrosive nature of the electrolyte.

Part of the book: Plasmonics